Strawberry IPM Newsletter No. 2 – May 17, 2013
For full page print version, please see link at the bottom. Click on photos to enlarge.
Sprayer Calibration Clinic on May 21, 2013 at 2:00 p.m.
Twilight Meeting on May 21, 2013 at 5:00 p.m.
Pikes Farm to You in Farmington, Maine
Situation: A little rain last weekend provided some relief from this very dry spring for most fields. Frost hit many fields over two to three nights early in the week, and some injury has been noted wherever irrigation wasn’t able to protect the blossoms. Plants in southern Maine are now showing open primary (king) blossoms on early varieties, while in later varieties buds are still emerging from the crown. Fields that were under row covers are in full bloom, or just beyond, suggesting that we could see some ripe fruit in just a couple of weeks, weather permitting. I am still finding winter injury, especially in older fields, where straw and or snow cover was inadequate during the coldest part of the winter. On the bright side, insect activity remains fairly low in all fields scouted this week, but it is important to keep scouting during the bud emergence through bloom stages, because this is when the plants are most susceptible to clipper and tarnished plant bug. Bloom is also the most critical stage for preventing infestation by Botrytis spores, which cause gray mold.
Sprayer Calibration Clinic and Twilight Meeting
The University of Maine Cooperative Extension and the Maine Vegetable and Small Fruit Growers Association will hold a sprayer calibration clinic for airblast sprayers at David Pike’s Farm to You in Farmington on Tuesday, May 21 at 2:00 p.m. George Hamilton with the University of New Hampshire Cooperative Extension will demonstrate new tools for making sure your sprayer is delivering the correct rate of pesticides to your crops. Having a sprayer properly calibrated will improve the effectiveness of your sprays, and can save you money by reducing the amount of pesticide used and reducing crop losses due to pests. Participants will receive two pesticide applicator recertification credits. The calibration clinic will be followed at 5:00 p.m. by a tour of David Pike’s strawberry and vegetable fields. David has been a leader in innovative strawberry production techniques, including raised beds, plastic mulch, fertigation, fall cropping, and season extension. There will be some new low tunnel technology on display, as well as replant experiments and new varieties on trial. One pesticide applicator recertification will be awarded for the meeting. The location is 115 Mount View Road. (corner of Routes 2 & 4 and the Whittier Road) in Farmington, ME 04938. There will be signs posted. The farm phone number is 207.778.2187. Cost for the clinic is free and no registration is required. Hold the date!
Drip Irrigation Workshop
Wednesday, May 22, 2013, 3:00 p.m. to 6:00 p.m. at the Sherman Farm, 2679 East Conway Road, Center Conway, NH 03813. The farm phone number is 603.939.2412.
The purpose of this meeting is to review what drip irrigation options and strategies vegetable and fruit growers should be considering for the coming growing season. Trevor Hardy, of Brookdale Fruit Farm and George Hamilton, UNH Cooperative Extension will present a hands-on demonstration on setting up a drip irrigation system and describe the various components of a system, including set ups for high tunnels. Toro Irrigation Representative Bill Wolfram will also be present. The meeting will begin at 3:00 p.m. and will run until around 6:00 p.m.
For more information contact:
Olivia Saunders, UNH Extension Field Specialist
603.447.3834, e-mail: olivia.saunders@unh.edu, OR
George Hamilton, UNH Extension Field Specialist,
603.641.6060, email: george.hamilton@unh.edu.
2013-2014 New England Small Fruit Management Guides are now available at Highmoor Farm. This new, updated edition of the guide contains the latest information on management options for small fruit pests as well as cultural information. Cost of the guide is $10.00 plus $2.53 postage for a total of $12.53. To order a guide, please send your check made payable to UMaine Cooperative Extension mailed to: Highmoor Farm, P.O. Box 179, Monmouth, Maine 04259, attention Pam St. Peter. For more information, contact Pam St. Peter at 933.2100 or pamela.stpeter@maine.edu.
Strawberry bud weevil or “clipper” should now be coming active as flower buds emerge. We have not found clipper at levels over threshold in any fields scouted to date, but it is important to keep a sharp lookout for clipped buds now, especially along wooded borders of the field. If the average number of clipped buds exceeds 1.2 per two feet of row, or if live clippers are being found, control measures are recommended.
Tarnished plant bug adults are being reported in apple orchards in southern Maine, but we have not yet found any nymphs in the strawberry fields we have scouted. Strawberries are preferred hosts at this time of year, so we should expect to start seeing both adults and nymphs soon. To scout for the nymphs shake 30 flower clusters (six clusters in five different locations) over a plate. If four or more of the clusters out of the 30 sampled have any nymphs, control measures should be taken. Be on the alert and scout your fields as soon as blossoms start to open.
Cyclamen mites: We have found symptoms of cyclamen mites in several plantings this spring. Symptoms include weak growth, crinkled leaves and yellow, pinkish or blackened discoloration. Cyclamen mites are too small to be seen without magnification and reside in the crown of the strawberry plant feeding on the developing leaves and flower buds. Miticides must be applied in lots of water to be sure that the material is carried down into the crowns where the mites reside.
Two-spotted spider mites have been found exceeding the management threshold at one southern location this week, in a field that was under row covers. This is often where we first find mite problems. Expect mite problems to increase as the temperature increases, especially under dry conditions.
White grubs: We have had several reports of white grub infestations in fields this spring. Weak plant growth may be the result of grubs feeding on roots. These grubs are the larvae of beetles, including European chafer and Asiatic garden beetle. The grubs have legs and a swollen anterior (rear end). The grubs can be found by pulling up weak plants and sifting through the soil that surrounded the roots. Controlling white grubs when they are established in a field is difficult. Admire Pro® is labeled for control of white grubs and should be applied within two hours of irrigation or rainfall to get the chemical into the root zone. There is still time to apply nematodes to control the grubs. (Optimal timing is about mid-May.) Two species of nematodes appear to offer the best control. Heterorhabditis bacteriophora (Hb) is the best candidate when the soil temperature is above 60 degrees (‘J-3 Max Hb’ from The Green Spot Ltd., ‘GrubStake Hb’ from the Integrated Biocontrol Network, ‘Larvanem’ from Koppert Biological Systems.
Diseases: Just a reminder that bloom is the critical time to protect strawberries from developing gray mold caused by the fungus Botrytis cinerea. Two to three sprays of fungicide during bloom are typically required to provide good protection against this disease. Any moisture, including irrigation, fog, or even pesticide sprays can stimulate Botrytis spores to germinate. Fruit infections take place almost exclusively through the flowers, so gray mold control efforts must be focused on the bloom period.
Sincerely,
David T. Handley
Vegetable & Small Fruit Specialist
Highmoor Farm Pest Management
P.O. Box 179 491 College Ave
Monmouth, ME 04259 Orono, ME 04473
207.933.2100 1.800.287.0279
Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture Cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment. A Member of the University of Maine System.
Any person with a disability who needs accommodations for these programs should contact Pam St. Peter at 207.933.2100 or TDD 1.800.287.8957 to discuss their needs at least 7 days in advance.
Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.
Image Description: Strawberries
Image Description: Strawberry Frost Injury
Image Description: Clipper Injury
Image Description: First Instar Tarnished Plant Bug Nymph
Image Description: Two-spotted Spider Mites
Strawberry IPM Newsletter No. 1 – May 9, 2013
For full page print version, please see link at the bottom. Click on photos to enlarge.
Sprayer Calibration Clinic on May 21, 2013 at 2:00 p.m.
Twilight Meeting on May 21, 2013 at 5:00 p.m.
Pikes Farm to You in Farmington, Maine
Situation: What seemed to start as a relatively normal spring has now become a very dry spring indeed, with most areas in New England significantly behind on rainfall. While this has helped growers to get on to fields early to plant, established plantings of strawberries could be suffering from drought stress. Dry conditions can also reduce nutrient uptake, resulting in deficiencies, most notably calcium. In southern locations, flower buds are now emerging from crowns in plantings that were mulched over the winter. Plantings that were not mulched are a little further advanced, and plantings that were under row covers are coming into bloom. Frost protection becomes a priority now, and irrigation should be set up to provide frost protection for buds and flowers on any night when temperatures drop below freezing. Bear in mind that fields that are irrigated for frost repeatedly during bloom face an increased risk of bacterial angular leaf spot.
Winter injury is common in fields this spring, especially in plantings that either were not mulched or mulched late in the winter due to trouble getting onto the fields in the fall. Frost heaving is also apparent in fields with heavier soils, which injures plant roots and inhibits water and nutrient uptake. Injured plants appear weakened, with small, dull colored leaves, and crowns that may be pushed out of the soil. Cutting into the crowns will reveal dark brown discoloration in the internal tissue. Helping plantings recover from winter injury involves compensating for the damaged vascular system. Make sure the plants get plenty of water, especially in this dry period, and it may help to apply extra nutrients to encourage root growth and recovery, including nitrogen, calcium, and phosphorus. While we do not recommend heavy nitrogen fertilizer applications in the spring, up to 20 pounds of actual N (e.g. 125 lb. calcium nitrate) may improve early spring growth.
Sprayer Calibration Clinic & Twilight Meeting
The University of Maine Cooperative Extension and the Maine Vegetable and Small Fruit Growers Association will hold a sprayer calibration clinic for airblast sprayers at David Pike’s Farm to You in Farmington on Tuesday, May 21 at 2:00 p.m. George Hamilton with the University of New Hampshire Cooperative Extension will demonstrate new tools for making sure your sprayer is delivering the correct rate of pesticides to your crops. Having a sprayer properly calibrated will improve the effectiveness of your sprays, and can save you money by reducing the amount of pesticide used and reducing crop losses due to pests. Participants will receive two pesticide applicator re-certification credits.
The calibration clinic will be followed at 5:00 p.m. by a tour of David Pike’s strawberry and vegetable fields. David has been a leader in innovative strawberry production techniques, including raised beds, plastic mulch, fertigation, fall cropping, and season extension. There will be some new low tunnel technology on display, as well as replant experiments and new varieties on trial. One pesticide applicator re-certification credits will be awarded for the meeting. Hold the date! We’ll give driving directions next week.
2013-2014 New England Small Fruit Management Guides are now available at Highmoor Farm. This new, updated edition of the guide contains the latest information on management options for small fruit pests as well as cultural information. Cost of the guide is $10.00 plus $2.53 postage for a total of $12.53. Copies of the 2012-2013 New England Vegetable Management Guide with color pictures of the important pests and diseases are also available at Highmoor Farm. Cost of the guide is $25.00 plus $3.43 postage for a total of $28.43.
To order the guides, please send your check made payable to UMaine Cooperative Extension mailed to: Highmoor Farm, P.O. Box 179, Monmouth, Maine 04259, attention Pam St. Peter. For more information, contact Pam St. Peter at 933.2100 or pamela.stpeter@maine.edu.
Members of the Maine Vegetable & Small Fruit Growers Association (MVSFGA) or the New England Vegetable & Berry Growers Association receive free copies of the guides. For MVSFGA membership information, contact Bill Jordan at 799.1040.
Scouting
We will start scouting strawberry fields for major insect pests in earnest next week, including volunteer farms, in North Berwick, Wells, Cape Elizabeth, Poland Spring, New Gloucester, Dresden, Monmouth, Wayne, and Farmington, and will be reporting our findings through this newsletter on a weekly basis until harvest time. You can also get quick access to this information through the Highmoor Farm blog or the Pest Management web page. If you would prefer to receive this message via e-mail, please give us a call at 933.2100 or send an e-mail message to: pamela.stpeter@maine.edu.
The best way to manage strawberry pests is to scout your own fields regularly and often. You should start scouting regularly as soon as flower buds emerge from the crown. You should be able to identify the major pests and their damage, and be able to determine if control measures are necessary. To properly scout your fields you may want a copy of the Strawberry Production Guide for the Northeast, Midwest and Eastern Canada. This contains detailed information on strawberry pest identification and monitoring, and also provides information on all other aspects of strawberry production. It may be purchased for $45.00 per copy from the University of Maine Cooperative Extension online Publications Catalog. You should also have a copy of the 2013-2014 New England Small Fruit Pest Management Guide, which contains the latest information on management options for the major strawberry pests as well as scouting information.
Strawberry bud weevil or “clipper” will soon be active as flower buds begin to emerge. The clipper is a small weevil, which girdles strawberry flower buds, causing them to dry up and fall off the flower stalk. Scout for damage by counting the number of clipped buds in two feet of row length at five different locations in a field. If the average number of clipped buds per two-foot sample exceeds 1.2, or if live clippers are found, control measures are recommended. Damage is usually first noticed at the edges of the field. Border sprays may be effective in keeping this insect from becoming a problem in larger fields. Fields with a history of clipper problems will typically exceed threshold nearly every year. Insecticide options for clipper include Lorsban®, Brigade®, Sevin® and PyGanic®.
Tarnished plant bugs adults have been found in southern Maine, indicating that they will soon be laying eggs. Strawberries are one of their preferred hosts at this time of year. Once the eggs start to hatch, we’ll find the nymphs feeding in the flowers. The nymphs are small, active, yellow-green insects. It is important to scout for them regularly, as they can appear very quickly in warm weather. Tarnished plant bugs feed on the open strawberry flowers, causing the berries to have seedy ends. To scout for the nymphs shake 30 flower clusters (six clusters in five different locations) over a plate. If four or more of the clusters out of the 30 sampled have any nymphs, control measures should be taken. Be on the alert and scout your fields now! Insecticide options for tarnished plant bug include malathion, Brigade®, Danitol®, Thionex® and PyGanic®.
Cyclamen mites: Plants showing weak growth and yellow, pinkish or blackened, crinkled leaves may be infested with cyclamen mite. Cyclamen mites are very small, smaller than spider mites, and reside in the crown of the strawberry plant feeding on the developing leaves and flower buds. They are very hard to see, even with magnification. Infested plants have shrunken distorted leaves and flower stalks, and produce few, if any, marketable fruit. Miticides such as Thionex® or Kelthane® and Temprano® can be effective, but must be applied in lots of water to be sure that the material is carried down into the crowns where these mites reside.
Two-spotted spider mites have not yet been a problem this spring, but growers with plants under row covers should be alert. This is often where we first find mite problems. Spider mites will reproduce rapidly when warmer weather arrives, so it is important to scout for them regularly. Spider mites feed on the undersides of strawberry leaves, rasping the plant tissue and sucking the sap. Infested leaves will develop yellow flecking and a bronzed appearance. The plants become weakened and stunted. Fields that have had excessive nitrogen fertilizer and/or row covers tend to be most susceptible to mite injury. To scout for mites, collect 60 leaves from various locations in the field and examine the undersides for the presence of mites. Mites are very small – you may need a hand lens to see them. Chemical control options for two-spotted spider mites include Acramite®, Savey®, Zeal®, Vendex®, Oberon®, Brigade®, Danitol®, Thionex® and JMS Stylet oil ® (oils will cause plant injury if used in combination with captan or within 14 days of an application of sulfur).
Root weevil management
Fields that were infested with root weevils last summer should be inspected for grubs this spring. Infested plants appear week and stunted, usually in somewhat circular patches in a field. Digging under the plants will reveal small (1/4”-1/2”) crescent-shaped legless grubs. Typically, the grubs begin to pupate when the plants are in bloom. A soil drench of Platinum® (thiamethoxam) insecticide during the spring and/or fall when the grubs are active in the soil can provide control. However, Platinum® has a 50 day pre-harvest interval, so it is too late for applications in most fruiting fields this year. Platinum® may also be used as a pre-plant or planting treatment for root weevils. It is not too late to put on an application of nematodes to control the grubs (optimal timing is about mid-May). Two species of nematodes appear to offer the best control of root weevil grubs. Heterorhabditis bacteriophora (Hb) appears to be the best candidate for control of root weevils when the soil temperature is above 60 degrees (‘J-3 Max Hb’ from The Green Spot Ltd., ‘GrubStake Hb’ from the Integrated Biocontrol Network, ‘Larvanem’ from Koppert Biological Systems).
Nematodes are living organisms and they can be killed if they are misapplied. Order nematodes ahead of time and be ready to apply them through a sprayer or irrigation soon after they arrive. Refrigerate them if you can not apply right away. Do not apply nematodes using a sprayer with a piston pump. Use clean equipment, removing all screens finer than 50-mesh. Apply nematodes in early morning or evening in a high volume of water to already moist soil, pre-irrigating if needed. Apply another ¼ inch of irrigation after application to wash them onto and into the soil. Researchers and suppliers recommended 250 (if banded in the row) to 500 million per acre, at a cost of $100-$200 per acre depending on volume and source. Nematodes tend to work best in heavily infested fields. Strawberry plants can recover their vigor remarkably well if crown feeding has not occurred and diseases haven’t taken over the roots.
Once the adults become active in July, bifenthrin (Brigade®) will provide some control if used at the highest labeled rates. The best timing for this spray is at night during the peak feeding activity of adults, before they start laying eggs, or about the time harvest ends.
White grubs: Weak growth noted in fields this spring may also be the result of white grubs feeding on the roots of newer plantings. These grubs are the larvae of beetles, including European chafer and Asiatic garden beetle. They differ from the larvae of black vine weevil and strawberry root weevil in that they have legs and a swollen anterior (rear end), and they tend to be larger. Their feeding weakens the plants by reducing the number of roots. The grubs can be found by pulling up weak plants and sifting through the soil that surrounded the roots. Controlling white grubs once they have become established in a field can be difficult. These tend to be more of a problem in new fields that have been planted following a grass rotation crop, because the adults prefer to lay their eggs in sod. Admire Pro® and Platinum® insecticides are labeled for control of white grubs and should be applied within two hours of irrigation or rainfall to be sure the chemical gets into the root zone. Admire Pro® requires a 14 day to harvest interval, while Platinum® requires a 50 day pre-harvest interval.
Diseases: Bloom is a critical time to protect strawberry fruit against gray mold caused by the fungus Botrytis cinerea, especially when conditions have been damp. Two to three sprays of fungicide during bloom are typically required to provide good protection against this disease. If you tank mix insecticides and fungicides, avoid spraying when bees are active. Botrytis cinerea overwinters on old leaves and plant debris. Fruit infections take place almost exclusively through the flowers, so gray mold control efforts must be focused on the bloom period. If the bloom period is dry and/or good fungicide coverage is maintained, incidence of gray mold at harvest should be low.
There are several excellent fungicide choices for control of gray mold in strawberries. Elevate® (fenhexamid) has good to excellent activity against Botrytis. Captevate® is a pre-mix of captan and fenhexamid and has a broader spectrum of activity than Elevate® alone. Switch® (cyprodinil and fludioxonil), Scala® (pyramethanil) and Pristine® (pyraclostrobin and boscalid) are also excellent products for gray mold control. Topsin M® + captan is also a good fungicide combination, but remember that captan is strictly a protectant and can be washed off by rain or irrigation water. Thiram is similarly effective but also susceptible to wash-off.
The fungicides Cabrio® (pyraclostrobin) and Abound® (azoxystrobin) are NOT suitable for gray mold control, but are effective against anthracnose and other fruit rot and leaf spot diseases. All fungicides mentioned above have a 0-day pre-harvest interval, except Topsin M® (1 day) and thiram (3 days). Remember to alternate fungicides with different modes of action for resistance management purposes.
Red stele root rot
Although fall and early spring conditions were not especially conducive to red stele development, damp conditions this spring should make us alert for this root rot if any fields appear to be weak, stunted or dying. To diagnose red stele, pull up a few plants that look weak and scrape the roots of these plants to see if the center of the root, known as the stele, is rusty red in color, instead of the normal white. The red color would indicate an infection. Red stele is caused by Phytophthora fragariae, a soil pathogen that infects roots when soils are wet with temperatures around 50°F. The pathogen grows into the roots causing the plants to become weak, stunted and to eventually die. Symptoms are most evident in the spring, and can be mistaken for winter injury. Ridomil Gold®, Alliette® or Phostrol® are fungicides that can be applied in the late fall or early spring for control of red stele. Many varieties have some level of resistance to the disease, but the most effective management strategy is to plant only into well-drained soils, and/or plant onto raised beds.
Powdery mildew: This fungus disease may first show up as purple or red blotches on the leaf petioles and flower stems in strawberry fields. Most of us are more familiar with the later symptoms of upward curling of the leaves and white, powdery growth on the undersides of the leaves. Check your fields for pinkish purple leaf and flower stem lesions as new leaves emerge. Pristine®, Cabrio®, Topsin-M®, captan, Procure®, Torino® and JMS Stylet oil® are presently registered to control powdery mildew.
Angular leaf spot is a bacterial disease that is characterized by translucent leaf spots that may turn yellow and eventually black. The symptoms tend to start on the lower leaves but may move upwards as bacterial spores are splashed up by rain or irrigation water. Infection of the calyxes may result in a blackening of the berry stems and caps, reducing their marketability. Bacterial angular leaf spot is favored by extended cool, wet weather and nights with temperatures close to freezing. Frequent irrigation for frost protection can greatly encourage the development and spread of the disease, as will extended cool, damp weather. Susceptibility to this disease appears to vary significantly between varieties. The copper containing material Kocide®, can reduce the spread of this disease. Start spray applications before bloom to prevent multiplication of the bacteria on the leaves before they jump to the berry caps. Application of copper sprays after bloom can result in fruit injury and is not recommended. Hydrogen dioxide (OxiDate®) may also have some activity against angular leaf spot when used on strawberries as part of a gray mold management program.
Sincerely,
David T. Handley
Vegetable & Small Fruit Specialist
Highmoor Farm Pest Management
P.O. Box 179 491 College Ave
Monmouth, ME 04259 Orono, ME 04473
207.933.2100 1.800.287.0279
Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture Cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment. A Member of the University of Maine System.
Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.
Image Description: Strawberries
Image Description: Frost Injury
Image Description: Clipper Beetle on Strawberry Bud
Image Description: Tarnished Plant Bug Adult
Image Description: Cyclamen Mite Damage
Image Description: Two-spotted Spider Mites
Image Description: Strawberry Root Weevil Grub
Image Description: White Grub
Image Description: Gray Mold on Strawberries
Image Description: Powdery Mildew
Image Description: Angular Leaf Spot
The Central Maine Morning Sentinel published a feature story about the University of Maine College of Natural Sciences, Forestry, and Agriculture’s Highmoor Farm Agricultural Experimental Station in Monmouth and its research on pest management. David Handley, University of Maine Cooperative Extension vegetable and small fruit specialist based at Highmoor, and Highmoor superintendent Greg Koller discussed the university’s integrated pest management policies, including how to control the spotted wing drosophila, a breed of fruit fly originally from Asia that now threatens soft-skinned fruits and vegetables, including blueberries and raspberries. The website Fresh Plaza also carried the story.
Contact: George Manlove, 207.581.3756
For full page print version, please see link at the bottom. Click on photos to enlarge.
This will be the final issue of the Sweet Corn IPM Newsletter for the 2012 season. I would like to thank all of the growers who participated in the program this year, and our team of IPM scouts including John Banville, Tammy Cushman, Chase Gaewski, Griffin Dill and Sean McAuley, with help from John Hutton and Kara Rowley. Special thanks go to Katie Woodman who coordinated the team.
SITUATION
Hurricane Isaac appears to have only caused a mild bump in pest numbers over the past week, and it is likely that cooler temperatures will slow pest activity in the coming days. Any silking corn remaining requires protection from corn earworm statewide, but fall armyworm and European corn borer are only at problem levels in a few sites.
European corn borer: Moth counts continued to be very low last week in most locations. Although fields in Oxford and Wayne exceeded the 5-moth threshold for silking corn, which suggests the start of a second generation. Both sites are on spray schedules for corn earworm, so no additional sprays were needed. Feeding damage was found in a pre-silking field in Biddeford, and exceeded the 15% threshold when combined with fall armyworm damage.
Corn earworm: Moth counts were generally higher last week, returning many fields to tighter spray intervals on fresh silking corn. A 4-day spray interval for silking corn was recommended for Cape Elizabeth, Dayton, Levant, New Gloucester, Nobleboro, North Berwick, Wales,Wayne and Warren. A 5-day spray interval was recommended for Biddeford, Dresden, Lewiston, and one Wells location. A 6-day spray interval was recommended for Jefferson, Oxford, Poland Spring and Wells.
Fall armyworm: Most fields are under spray schedules for corn earworm, so little feeding damage is being noted. Only one Biddeford field was over the threshold when combined with ECB feeding damage. Moth captures remained low, with only one field in Levant exceeding the spray threshold of 3 moths in silking corn. Single moths were caught in Lewiston, Monmouth and New Gloucester.
It’s time for cover crops!
Plowing down corn stalks destroys the over wintering sites of European corn borer, but late plowing can leave soil prone to erosion during the winter and spring. Planting winter rye is a good option for many fields. It can be planted well into September to produce enough of a cover to prevent erosion. Rye will survive the winter and put on more growth in the spring. It should be killed by plowing, mowing or herbicide before it goes to seed. Having rye on the field may delay planting in the spring, as you must wait for conditions to be warm and dry enough to plow it in. Animal manures can also be applied to soils in early fall and incorporated to improve soil structure and provide nutrients. Cover crops should be seeded after manure applications to absorb and hold nutrients, which will be released after the crop is plowed down the following spring.
Sincerely,
David T. Handley
Vegetable & Small Fruit Specialist
Highmoor Farm Pest Management Office
P.O. Box179 491 College Ave
Monmouth,ME 04259 Orono,ME 04473
207.933.2100 1.800.287.0279
| Location | CEW Moths |
ECB Moths |
FAW Moths |
%Feeding Damage |
Recommendations / Comments |
| Biddeford | 5 | 0 | 0 | 24% | 5-day spray interval for all silking corn |
| Cape Elizabeth I | 9 | 0 | 0 | All Silk | 4-day spray interval for all silking corn |
| Cape Elizabeth II | 18 | 0 | 0 | All Silk | 4-day spray interval for all silking corn |
| Dayton I | 8 | 0 | 0 | All Silk | 4-day spray interval for all silking corn |
| Dresden | 4 | 0 | 0 | All Silk | 5-day spray interval for all silking corn |
| Jefferson | 2 | 0 | 0 | All Silk | 6-day spray interval for all silking corn |
| Levant | 15 | 0 | 3 | All Silk | 4-day spray interval for all silking corn |
| Lewiston | 6 | 0 | 1 | All Silk | 5-day spray interval for all silking corn |
| Monmouth | 0 | 0 | 1 | All Silk | No spray recommended |
| New Gloucester | 38 | 0 | 1 | All Silk | 4-day spray interval for all silking corn |
| Nobleboro | 33 | 0 | 0 | All Silk | 4-day spray interval for all silking corn |
| North Berwick | 17 | 0 | 0 | All Silk | 4-day spray interval for all silking corn |
| Oxford | 3 | 13 | 0 | All Silk | 6-day spray interval for all silking corn |
| Poland Spring | 2 | 1 | 0 | All Silk | 6-day spray interval for all silking corn |
| Wales | 23 | 1 | 0 | All Silk | 4-day spray interval for all silking corn |
| Wayne | 11 | 10 | 0 | All Silk | 4-day spray interval for all silking corn |
| Warren | 9 | 0 | 0 | All Silk | 4-day spray interval for all silking corn |
| Wells I | 3 | 0 | 0 | All Silk | 6-day spray interval for all silking corn |
| Wells II | 5 | 0 | 0 | All Silk | 5-day spray interval for all silking corn |
CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB: European corn borer
FAW: Fall armyworm
Corn Earworm Spray Thresholds for Pheromone Traps
| Moths caught per week | Moths caught per night | Spray interval |
| 0.0 to 1.4 | 0.0 to 0.2 | No spray |
| 1.5 to 3.5 | 0.3 to 0.5 | Spray every 6 days |
| 3.6 to 7.0 | 0.6 to 1.0 | Spray every 5 days |
| 7.1 to 91 | 1.1 to 13.0 | Spray every 4 days |
| More than 91 | More than 13 | Spray every 3 days |
Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.
European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.
IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/
Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.
Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.
Image Description: Sweet Corn
Image Description: European Corn Borer Larva on Ear
Image Description: Corn Earworm
Image Description: Adult Fall Armyworm
For full page print version, please see link at the bottom. Click on photos to enlarge.
SITUATION
This is a somewhat abbreviated issue, due to the Labor Day holiday and a much reduced scouting team this week. In addition, it does not include the potential impact of the remains of hurricane Isaac, which are passing over Maine today. Although insect counts have been very low for this time of year, the passing of a tropical storm can bring with it a significant population of corn pests, especially corn earworm and fall armyworm, so we should anticipate higher pressure by the end of the week for any fresh silking corn remaining in the field.
European corn borer: Moth counts are very low this week with only one site in Cape Elizabeth exceeding the 5-moth threshold for silking corn, but the site is also on a spray schedule for corn earworm, so no additional sprays are needed. Feeding damage was also low. Only a North Berwick field exceeded the 15% threshold when combined with fall armyworm damage.
Corn earworm: Moth counts were at low to moderate levels this week, although we anticipate increased activity due to the tropical storm remnants passing through Maine today. A 4-day spray interval for fresh silking corn was recommended for one Dayton location and Nobleboro. A 5-day spray interval was recommended for Cape Elizabeth, Dayton, New Gloucester, North Berwick,Wayne and Warren. A 6-day spray interval was recommended for Biddeford, Charleston, Jefferson, Monmouth, Wales and Wells.
Fall armyworm: Most fields are now in silk and under spray schedules for corn earworm, so very little feeding damage is being noted. Only one North Berwick field was over the threshold when combined with ECB feeding damage. Moth captures remain low for this time of year, with no sites exceeding the spray threshold of 3 moths in silking corn. Single moths were caught in Biddeford, Cape Elizabeth, Monmouth, New Gloucester, and Warren.
The Food Safety Modernization Act (FSMA) and Its Possible Effects on Maine’s Specialty Crop Growers
AgMatters LLC cordially invites you to attend a workshop about this important new legislation. Joy Johanson from the Produce Safety staff with the FDA will give an overview of FSMA and the Produce Safety Rule. Representatives from the Maine Board of Pesticides Control will address Worker Protection Training and a new law requiring Pesticide Licensing of all growers. Lauchlin and Linda Titus from AgMatters LLC will share their impressions on the future of Maine’s Specialty Crop Markets and suggestions on how growers can capitalize on changes in the industry. Please register for one of the following times and locations:
Tuesday, September 11, 2012
10:00 AM to 2:00 PM
Bangor Motor Inn, 701 Hogan Rd., Bangor (Exit 187 off Interstate 95)
Tel. 207.947.0355
Or
Wednesday, September 12, 2012
10:00 AM to 2:00 PM
Ramada Inn, 490 Pleasant St., Lewiston (Exit 80 off Interstate 95)
Tel. 207.784.2331
Please RSVP as soon as possible by phone 873.2108 or by email to ltitus21@myfairpoint.net.
Sincerely,
David T. Handley
Vegetable & Small Fruit Specialist
Highmoor Farm Pest Management Office
P.O. Box179 491 College Ave
Monmouth,ME 04259 Orono,ME 04473
207.933.2100 1.800.287.0279
| Location | CEW Moths | ECB Moths | FAW Moths | %Feeding Damage | Recommendations / Comments |
| Biddeford | 2 | 0 | 1 | 8% | 6-day spray interval for all silking corn |
| Cape Elizabeth I | 5 | 5 | 0 | All silking | 5-day spray interval for all silking corn |
| Cape Elizabeth II | 5 | 1 | 1 | 4% | 5-day spray interval for all silking corn |
| Charleston | 3 | 2 | 0 | All silking | 6-day spray interval for all silking corn |
| Dayton I | 15 | 0 | 0 | All silking | 4-day spray interval for all silking corn |
| Dayton II | 6 | 0 | 0 | All silking | 5-day spray interval for all silking corn |
| Jefferson | 3 | 0 | 0 | All silking | 6-day spray interval for all silking corn |
| Monmouth | 2 | 1 | 1 | All silking | 6-day spray interval for all silking corn |
| New Gloucester | 5 | 0 | 1 | All silking | 5-day spray interval for all silking corn |
| Nobleboro | 14 | 1 | 0 | All silking | 4-day spray interval for all silking corn |
| No. Berwick | 7 | 0 | 0 | All silking | 5-day spray interval for all silking corn |
| Sabattus | 0 | 0 | 0 | All silking | No spray recommended |
| Wales | 2 | 0 | 0 | All silking | 6-day spray interval for all silking corn |
| Warren | 5 | 2 | 1 | All silking | 5-day spray interval for all silking corn |
| Wayne | 4 | 0 | 0 | All silking | 5-day spray interval for all silking corn |
| Wells I | 2 | 0 | 0 | All silking | 6-day spray interval for all silking corn |
| Wells II | 3 | 0 | 0 | All silking | 6-day spray interval for all silking corn |
CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB: European corn borer
FAW: Fall armyworm
Corn Earworm Spray Thresholds for Pheromone Traps
| Moths caught per week | Moths caught per night | Spray interval |
| 0.0 to 1.4 | 0.0 to 0.2 | No spray |
| 1.5 to 3.5 | 0.3 to 0.5 | Spray every 6 days |
| 3.6 to 7.0 | 0.6 to 1.0 | Spray every 5 days |
| 7.1 to 91 | 1.1 to 13.0 | Spray every 4 days |
| More than 91 | More than 13 | Spray every 3 days |
Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.
European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.
IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/
Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.
Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.
Image Description: Sweet Corn
Image Description: Corn Earworm Moth
Image Description: Male Fall Armyworm Moth
For full page print version, please see link at the bottom. Click on photos to enlarge.
SITUATION
Recent relatively cool nights indicate a shift in the weather pattern and have resulted in a dramatic drop in corn earworm captures this week. However, populations are still high enough to keep all silking fields on a regular spray schedule. As we approach Labor Day and the season starts to wind down, we have very little pressure from either fall armyworm or European corn borer. Hot weather predicted for the remainder of the week will push remaining corn maturity along rapidly. Remnants of hurricane Isaac may visit Maine next week and could bring with it a new flush of earworm and armyworm.
European corn borer: Moth counts are very low this week with no sites exceeding the 5-moth threshold for silking corn. Feeding damage was also low, with only the North Berwick site exceeding the 15% threshold when it was combined with fall armyworm damage.
Corn earworm: Moth counts were significantly lower in all locations this week, but pressure still remains moderate to high for many locations. A 3-day spray interval for fresh silking corn was recommended only for North Berwick. A 4-day spray interval was recommended for Biddeford, one Cape Elizabeth location, Dayton, Dresden, East Corinth, Levant, Lewiston, Monmouth, Wales, Wayne and one Wells location. A 5-day spray interval was recommended for one Cape Elizabeth location, New Gloucester, Nobleboro, Oxford, and one Wells location. A 6-day spray interval was recommended for Charleston, Jefferson, Palmyra, Poland Spring, and Warren.
Fall armyworm: We continue to find light feeding damage in some fields, but only North Berwick was over the threshold when combined with ECB feeding damage. Moth captures continue to be very low for this time of year, with no sites exceeding the spray threshold of 3 moths in silking corn. Two fall armyworm moths were caught at Cape Elizabeth, and one Lewiston location, and single moths were caught in Biddeford, Cape Elizabeth, Dresden, East Corinth, New Gloucester, and Warren. Fall armyworm feeding damage was found in Biddeford, Cape Elizabeth and New Gloucester, but was below the 15% threshold. Most remaining fields are silking and under a spray schedule for corn earworm, so field scouting is not necessary.
Spotted Wing Drosophila Update:
Over the last week spotted wing drosophila numbers have risen significantly. Flies are now at their highest levels of the season. We have also found drosophila maggots infesting blueberry, raspberry, blackberry, elderberry, grape and peach fruit this week. For those with late fruit crops still to harvest, protection is necessary to prevent infestation by spotted wing drosophila. Up to this point weekly applications of an allowed insecticide have been adequate, but reports from the field suggest that more frequent applications may be necessary to keep fruit free from maggots. Growers in southern states have found that a 3 to 5-day spray schedule was needed to prevent infestation.
Sincerely,
David T. Handley
Vegetable & Small Fruit Specialist
Highmoor Farm Pest Management Office
P.O. Box179 491 College Ave
Monmouth,ME 04259 Orono,ME 04473
207.933.2100 1.800.287.0279
| Location | CEW Moths |
ECB Moths |
FAW Moths |
%Feeding Damage | Recommendations / Comments |
| Biddeford | 8 | 1 | 1 | 6% | 4-day spray interval for all silking corn |
| Cape Elizabeth I | 9 | 0 | 2 | All silking | 4-day spray interval for all silking corn |
| Cape Elizabeth II | 7 | 0 | 1 | 5% | 5-day spray interval for all silking corn |
| Charleston | 2 | 1 | 0 | 1% | 6-day spray interval for all silking corn |
| Dayton I | 33 | 0 | 0 | All silking | 4-day spray interval for all silking corn |
| Dayton II | 15 | 0 | 0 | All silking | 4-day spray interval for all silking corn |
| Dresden | 32 | 0 | 1 | All silking | 4-day spray interval for all silking corn |
| East Corinth | 16 | 0 | 1 | 0% | 4-day spray interval for all silking corn |
| Jefferson | 3 | 0 | 0 | All silking | 6-day spray interval for all silking corn |
| Levant | 11 | 0 | 0 | 2% | 4-day spray interval for all silking corn |
| Lewiston I | 47 | 0 | 2 | All silking | 4-day spray interval for all silking corn |
| Lewiston II | 11 | 1 | 0 | 0% | 4-day spray interval for all silking corn |
| Monmouth | 40 | 0 | 0 | All silking | 4-day spray interval for all silking corn |
| New Gloucester | 5 | 0 | 1 | 2% | 5-day spray interval for all silking corn |
| Nobleboro | 5 | 0 | 0 | All silking | 5-day spray interval for all silking corn |
| No. Berwick | 129 | 0 | 0 | 18% | 3-day spray interval for all silking corn |
| Oxford | 5 | 0 | 0 | All silking | 5-day spray interval for all silking corn |
| Palmyra | 2 | 0 | 0 | All silking | 6-day spray interval for all silking corn |
| Poland Spring | 2 | 0 | 0 | All silking | 6-day spray interval for all silking corn |
| Wales | 20 | 0 | 0 | All silking | 4-day spray interval for all silking corn |
| Warren | 2 | 0 | 1 | All silking | 6-day spray interval for all silking corn |
| Wayne | 18 | 0 | 0 | All silking | 4-day spray interval for all silking corn |
| Wells I | 9 | 0 | 0 | All silking | 4-day spray interval for all silking corn |
| Wells II | 6 | 1 | 0 | All silking | 5-day spray interval for all silking corn |
CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB: European corn borer
FAW: Fall armyworm
Corn Earworm Spray Thresholds for Pheromone Traps
| Moths caught per week | Moths caught per night | Spray interval |
| 0.0 to 1.4 | 0.0 to 0.2 | No spray |
| 1.5 to 3.5 | 0.3 to 0.5 | Spray every 6 days |
| 3.6 to 7.0 | 0.6 to 1.0 | Spray every 5 days |
| 7.1 to 91 | 1.1 to 13.0 | Spray every 4 days |
| More than 91 | More than 13 | Spray every 3 days |
Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.
European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.
IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/
Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.
Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.
Image Description: Sweet Corn
Image Description: Corn Earworm Larvae
Image Description: Fall Armyworm on Corn Silk
Image Description: Spotted Wing Drosophila Larva in Blueberry
Image Description: Spotted Wing Drosophila Larvae in Raspberry
For full page print version, please see link at the bottom. Click on photos to enlarge.
SITUATION
With continued southerly weather and thunderstorms passing through the state, insect pressure has remained high, mostly due to corn earworm. At this point, every location is on at least a 4-day spray interval, with some locations on 3-day intervals. For many growers, the youngest corn has reached the silking stage as the corn season begins to come to a close. Warm weather will continue to help corn mature rapidly and insect pressure will likely remain relatively high.
European corn borer: Insect counts have decreased, with only two locations over the 5-moth threshold: Biddeford and Charleston. Feeding damage from ECB in whorl to tassel stage corn has been present in all fields scouted, but exceeded the 15% threshold in only two locations (Biddeford and Sabattus) when fall armyworm damage was added to the total.
Corn earworm: Moth counts remain high in all locations, putting very high pressure on all silking corn. A 3-day spray interval for fresh silking corn was recommended for Biddeford, one Cape Elizabeth location, Dayton, one Lewiston location, and Sabattus. A 4-day spray interval was recommended in one Cape Elizabeth location, Charleston, East Corinth, Farmington, Jefferson, Levant, Livermore Falls, Monmouth, New Gloucester, Nobleboro, Oxford, Palmyra, Poland Spring, Wales, Warren, and Wells. No locations had a moth count low enough for a 5- or 6-day spray interval.
Fall armyworm: We continue to find feeding damage in southern fields, but only Biddeford and Sabattus were over the threshold when combined with ECB feeding damage. Moth captures remain low for this time of year, with only one Cape Elizabeth location exceeding the spray threshold of 3 moths in silking corn; but the field is already under a spray schedule for corn earworm so no additional sprays should be needed. Two fall armyworm moths were caught at Monmouth and Sabattus, and a single moth was caught in Biddeford, Cape Elizabeth, and one Dayton location this week, below threshold for silking corn. Fall armyworm feeding damage was also found in Cape Elizabeth, New Gloucester, and North Berwick, but was below the 15% threshold.
Other Pests of Note
Aphids: Some fields are starting to show infestations of aphids on the tassels, silks and husks. While their feeding is not usually a significant problem, the presence of aphids and the sooty mold that develops on the husks as a result of their waste (called honeydew) is often objectionable to customers. Sprays, other than the Bt’s or spinosad products, that are used to control the major corn pests also offer control of aphids as well, including Asana®, Capture®, Warrior® and Lannate®.
Sincerely,
David T. Handley
Vegetable & Small Fruit Specialist
Highmoor Farm Pest Management Office
P.O. Box 179 491 College Ave
Monmouth, ME 04259 Orono, ME 04473
207.933.2100 1.800.287.0279
| Location | CEW Moths |
ECB Moths |
FAW Moths |
% Feeding Damage |
Recommendations / Comments |
| Biddeford | 95 | 10 | 1 | 15% | 3-day spray interval for all silking corn |
| Cape Elizabeth I | 162 | 3 | 1 | All Silk | 3-day spray interval for all silking corn |
| Cape Elizabeth II | 85 | 4 | 11 | 6% | 4-day spray interval for all silking corn |
| Charleston | 11 | 5 | 0 | 4% | 4-day spray interval for all silking corn |
| Dayton I | 118 | 1 | 0 | All Silk | 3-day spray interval for all silking corn |
| Dayton II | 113 | 0 | 1 | All Silk | 3-day spray interval for all silking corn |
| East Corinth | 21 | 0 | 0 | 2% | 4-day spray interval for all silking corn |
| Farmington | 14 | 0 | 0 | All Silk | 4-day spray interval for all silking corn |
| Jefferson | 44 | 0 | 0 | All Silk | 4-day spray interval for all silking corn |
| Levant | 54 | 3 | 0 | 6% | 4-day spray interval for all silking corn |
| Lewiston | 152 | 0 | 0 | All Silk | 3-day spray interval for all silking corn |
| Livermore Falls | 29 | 0 | 0 | 3% | 4-day spray interval for all silking corn |
| Monmouth | 71 | 0 | 2 | All Silk | 4-day spray interval for all silking corn |
| New Gloucester | 30 | 0 | 0 | 9% | 4-day spray interval for all silking corn |
| Nobleboro | 20 | 2 | 0 | 1% | 4-day spray interval for all silking corn |
| Oxford | 50 | 0 | 0 | All Silk | 4-day spray interval for all silking corn |
| Palmyra | 8 | 0 | 0 | 4% | 4-day spray interval for all silking corn |
| Poland Spring | 29 | 1 | 0 | All Silk | 4-day spray interval for all silking corn |
| Sabattus | 145 | 2 | 2 | 16% | 3-day spray interval for all silking corn |
| Wales | 16 | 0 | 0 | 3% | 4-day spray interval for all silking corn |
| Warren | 83 | 2 | 0 | All Silk | 4-day spray interval for all silking corn |
| Wells I | 50 | 0 | 0 | All Silk | 4-day spray interval for all silking corn |
| Wells II | 89 | 3 | 0 | All Silk | 4-day spray interval for all silking corn |
CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB: European corn borer
FAW: Fall armyworm
| Moths caught per week | Moths caught per night | Spray interval |
| 0.0 to 1.4 | 0.0 to 0.2 | No spray |
| 1.5 to 3.5 | 0.3 to 0.5 | Spray every 6 days |
| 3.6 to 7.0 | 0.6 to 1.0 | Spray every 5 days |
| 7.1 to 91 | 1.1 to 13.0 | Spray every 4 days |
| More than 91 | More than 13 | Spray every 3 days |
Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.
European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.
IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/
Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.
Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.
Image Description: Sweet Corn
Image Description: European Corn Borer Larvae on Ear
Image Description: Corn Earworm Feeding on Corn
Image Description: Fall Armyworm Injury on Corn Leaves
Image Description: Aphids on Corn
For full page print version, please see link at the bottom. Click on photos to enlarge.
SITUATION
Warm weather has pushed corn maturity along rapidly and supplies are picking up. A steady flow of weather from the south, including some heavy showers in some areas, is keeping corn earworm pressure very high in most fields this week. Several locations are now on a recommended 3-day spray interval, which we don’t typically see until early fall when tropical storms start moving through Maine.
European corn borer: A jump in moth counts in southern Maine suggests an emergence of a second generation of corn borer in that area. High counts continue to be found in more northern locations as well. These moths pose a risk to any silking corn that is not presently being sprayed for corn earworm. Wells, Biddeford, Sabattus, Charleston, Levant, Palmyra, and East Corinth were over the threshold of 5 moths in silking corn. Feeding injury from larvae in whorl to tassel stage corn was low in most locations, with only Biddeford exceeding the 15% feeding injury threshold. North Berwick exceeded the threshold when fall armyworm damage was added to the total.
Corn earworm: Moth counts continue to increase in most locations, putting very high pressure on all silking corn. A 3-day spray interval for fresh silking corn was recommended for Biddeford, North Berwick, and Wells this week. A 4-day spray interval was recommended in Cape Elizabeth, Dayton, Dresden, Levant, Lewiston, Monmouth, Palmyra, Poland Spring, Sabattus, and Warren. A 5-day spray interval was recommended for New Gloucester, East Corinth and Livermore Falls. A 6-day spray interval was recommended for fields in Charleston and Wales.
Fall armyworm: Moth captures remain low for this time of year, although we have started finding larval feeding damage in some southern fields. Only one Cape Elizabeth location exceeded the spray threshold of 3 moths in silking corn, but the field is already under a spray schedule for corn earworm so no additional sprays should be needed. Two fall armyworm moths were caught at Biddeford and our Dayton locations, and a single moth was caught in Dresden this week, below threshold for silking corn. Fall armyworm feeding damage was found in Biddeford, Dayton, and North Berwick, but was below the 15% threshold.
Other Pests of Note:
Picnic beetles can become a problem during the late summer on silking corn. These beetles are about ¼ inch long, black with orange spots. They can often be found on stalks and ears that are infested with European corn borer or fall armyworm, feeding on sap at an entry or exit hole. They will also feed on the silks and may work their way into the silk channel. While the damage is usually insignificant, customers dislike finding the insects in their bags. Sprays to control corn earworm should provide control of these beetles if they are found in your field.
Sincerely,
David T. Handley
Vegetable & Small Fruit Specialist
Highmoor Farm Pest Management Office
P.O. Box179 491 College Ave
Monmouth,ME 04259 Orono,ME 04473
207.933.2100 1.800.287.0279
| Location | CEW Moths | ECB Moths | FAW Moths | %Feeding Damage | Recommendations / Comments |
| Biddeford | 97 | 25 | 2 | 39% | 3-day spray interval for all silking corn |
| Cape Elizabeth I | 36 | 2 | 0 | 0% | 4-day spray interval for all silking corn |
| Cape Elizabeth II | 70 | 0 | 3 | 0% | 4-day spray interval for all silking corn |
| Charleston | 3 | 12 | 0 | 4% | 6-day spray interval for all silking corn |
| Dayton I | 16 | 2 | 0 | 6% | 4-day spray interval for all silking corn |
| Dayton II | 34 | 1 | 2 | 10% | 4-day spray interval for all silking corn |
| Dresden | 14 | 0 | 1 | 5% | 4-day spray interval for all silking corn |
| East Corinth | 6 | 0 | 0 | 3% | 5-day spray interval for all silking corn |
| Farmington | 0 | 1 | 0 | 3% | No spray recommended |
| Levant | 31 | 11 | 0 | 13% | 4-day spray interval for all silking corn |
| Lewiston | 11 | 4 | 0 | 2% | 4-day spray interval for all silking corn |
| Livermore Falls | 7 | 0 | 0 | 6% | 5-day spray interval for all silking corn |
| Monmouth | 8 | 0 | 0 | 6% | 4-day spray interval for all silking corn |
| New Gloucester | 6 | 0 | 0 | 0% | 5-day spray interval for all silking corn |
| North Berwick | 172 | 4 | 0 | 17% | 3-day spray interval for all silking corn |
| Palmyra | 11 | 6 | 0 | 5% | 4-day spray interval for all silking corn |
| Poland Spring | 45 | 1 | 0 | All Silk | 4-day spray interval for all silking corn |
| Sabattus | 8 | 10 | 0 | 4% | 4-day spray interval for all silking corn |
| Wales | 2 | 0 | 0 | 0% | 6-day spray interval for all silking corn |
| Warren | 38 | 1 | 0 | 10% | 4-day spray interval for all silking corn |
| Wells I | 107 | 1 | 0 | All Silk | 3-day spray interval for all silking corn |
| Wells II | 92 | 5 | 0 | All Silk | 3-day spray interval for all silking corn |
CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB: European corn borer
FAW: Fall armyworm
Corn Earworm Spray Thresholds for Pheromone Traps
| Moths caught per week | Moths caught per night | Spray interval |
| 0.0 to 1.4 | 0.0 to 0.2 | No spray |
| 1.5 to 3.5 | 0.3 to 0.5 | Spray every 6 days |
| 3.6 to 7.0 | 0.6 to 1.0 | Spray every 5 days |
| 7.1 to 91 | 1.1 to 13.0 | Spray every 4 days |
| More than 91 | More than 13 | Spray every 3 days |
Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.
European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.
IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/
Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.
Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.
Image Description: Sweet Corn
Image Description: European Corn Borer Entry Hole
Image Description: Corn Earworm Larvae
Image Description: Fall Armyworm on Corn Leaf
For full page print version, please see link at the bottom. Click on photos to enlarge.
SITUATION
Corn harvest is in full swing across most of the state after the warm weekend weather. Insect pressure has increased, especially from corn earworm with many locations being placed on 4-day spray intervals. ECB pressure has remained low with the exception of a few northern locations, and fall armyworm appears to be slightly on the rise, but hasn’t exceeded thresholds anywhere. With the prospect of southerly thunderstorms throughout most of the next week, insect pressure is not expected to decrease.
European corn borer: Moth counts were still high in a few northern locations this week, requiring protection of silking corn, though only one location wasn’t already protecting against corn earworm. Counts remained low in most southern fields. Biddeford, Charleston, Levant, Palmyra, Wells and East Corinth were over the threshold of 5 moths in silking corn. Feeding injury from larvae in whorl to tassel stage corn remained low in all locations this week, not exceeding the 15% feeding injury threshold in any locations.
Corn earworm: Continued pressure from corn earworm has resulted in spray recommendations at all but 3 locations. A 4-day spray interval was recommended in Biddeford, Cape Elizabeth, Dayton, Dresden, Levant, one Lewiston location, New Gloucester, Nobleboro, North Berwick, Oxford, and Wells. A 5-day spray interval was recommended for Jefferson, Lewiston, Monmouth, Palmyra, Poland Spring, Sabattus, and Warren. A 6-day spray interval was recommended for fields in Charleston and Livermore Falls. Fields in Farmington and Wales caught single moths, which does not warrant a spray.
Fall armyworm: Moth captures of fall armyworm are increasing. When scouting, a spray is recommended if feeding injury exceeds 15% of plants in a pre-silking field. However, larvae may also move into the ears through the silk channel, behaving similarly to corn earworm. Pheromone trap catches of 3 or more moths per week indicate a spray is needed to protect silking corn, unless it is already under a spray schedule for corn earworm. Two fall armyworm moths were caught at each Cape Elizabeth location, both Dayton locations, and a single moth was caught at each Wells location this week. This is below threshold for silking corn. No feeding damage was found.
Other Pests of Note:
Corn smut is often observed in fields this time of year. This fungus disease is easily recognized by the large galls which form in the ears, tassels, and on leaves. The young galls are silvery-white in color. When the galls mature they rupture into masses of powdery, black spores. This fungus tends to infect plants with a prior injury, perhaps from cultivation or insect feeding. Smut usually affects a few plants in a field and is not considered an economically significant problem. There is no effective fungicide for corn smut.
Sincerely,David T. Handley
Vegetable & Small Fruit Specialist
Highmoor Farm Pest Management Office
P.O. Box179 491 College Ave
Monmouth,ME 04259 Orono,ME 04473
207.933.2100 1.800.287.0279
| Location | CEW Moths |
ECB Moths |
FAW Moths |
% ECB Damage |
Recommendations / Comments |
| Biddeford | 36 | 11 | 0 | 2% | 4-day spray interval for all silking corn |
| Cape Elizabeth I | 50 | 0 | 2 | 0% | 4-day spray interval for all silking corn |
| Cape Elizabeth II | 20 | 1 | 2 | 0% | 4-day spray interval for all silking corn |
| Charleston | 3 | 11 | 0 | 3% | 6-day spray interval for all silking corn |
| Dayton I | 14 | 0 | 2 | 1% | 4-day spray interval for all silking corn |
| Dayton II | 8 | 0 | 2 | 0% | 4-day spray interval for all silking corn |
| Dresden | 9 | 0 | 0 | 2% | 4-day spray interval for all silking corn |
| East Corinth | 0 | 6 | 0 | 0% | One spray recommended for ECB on silking corn |
| Farmington | 1 | 1 | 0 | 2% | No spray recommended |
| Jefferson | 7 | 1 | 0 | 4% | 5-day spray interval for all silking corn |
| Levant | 11 | 13 | 0 | 10% | 4-day spray interval for all silking corn |
| Lewiston | 4 | 0 | 0 | 0% | 5-day spray interval for all silking corn |
| Lewiston II | 9 | 0 | 0 | 8% | 4-day spray interval for all silking corn |
| Livermore Falls | 2 | 2 | 0 | 1% | 6-day spray interval for all silking corn |
| Monmouth | 6 | 1 | 0 | 7% | 5-day spray interval for all silking corn |
| New Gloucester | 26 | 0 | 0 | 1% | 4-day spray interval for all silking corn |
| Nobleboro | 14 | 3 | 0 | 5% | 4-day spray interval for all silking corn |
| North Berwick | 15 | 3 | 0 | 6% | 4-day spray interval for all silking corn |
| Oxford | 10 | 0 | 0 | 4% | 4-day spray interval for all silking corn |
| Palmyra | 4 | 5 | 0 | 6% | 5-day spray interval for all silking corn |
| Poland Spring | 5 | 0 | 0 | 6% | 5-day spray interval for all silking corn |
| Sabattus | 7 | 0 | 0 | 9% | 5-day spray interval for all silking corn |
| Wales | 1 | 0 | 0 | 4% | No spray recommended |
| Warren | 7 | 0 | 0 | 8% | 5-day spray interval for all silking corn |
| Wells I | 40 | 0 | 1 | 7% | 4-day spray interval for all silking corn |
| Wells II | 48 | 5 | 1 | 1% | 4-day spray interval for all silking corn |
CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB: European corn borer
FAW: Fall armyworm
Corn Earworm Spray Thresholds for Pheromone Traps
| Moths caught per week | Moths caught per night | Spray interval |
| 0.0 to 1.4 | 0.0 to 0.2 | No spray |
| 1.5 to 3.5 | 0.3 to 0.5 | Spray every 6 days |
| 3.6 to 7.0 | 0.6 to 1.0 | Spray every 5 days |
| 7.1 to 91 | 1.1 to 13.0 | Spray every 4 days |
| More than 91 | More than 13 | Spray every 3 days |
Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.
European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.
IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/
Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.
Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.
Image Description: Sweet Corn
Image Description: European Corn Borer Larvae on Pre-tassel Stage Corn
Image Description: Corn Earworm
Image Description: Fall Armyworm Eggs on Corn
Image Description: Smut on Corn
For full page print version, please see link at the bottom. Click on photos to enlarge.
SITUATION
Harvest is still spotty as growers work through the erratic early corn and hope for better uniformity and quality with the main season crop. Many fields received just enough rain to get a break from irrigation this week. A little bit of weather coming up from the southeast coast appears to have bumped up local corn earworm populations, so silking corn is likely to need protection, especially in the southern and coastal areas of the state.
European corn borer: Moth counts were higher in some northern locations this week, requiring protection of silking corn, but remained low in most southern fields. Charleston, Levant, Palmyra and East Corinth were over the threshold of 5 moths in silking corn. Feeding injury from larvae in whorl to tassel stage corn remained low in most locations this week, only exceeding the 15% feeding injury threshold in Cape Elizabeth and Poland Spring.
Corn earworm: A significant increase in moth activity over the past two nights has increased the number of fields needing to protect any fresh silking corn. A 4-day spray interval was recommended in one Cape Elizabeth location and North Berwick. A 5-day spray interval was recommended for Biddeford, a second Cape Elizabeth location, Monmouth and New Gloucester. A 6-day spray interval was recommended for fields in Lewiston,Warren and Wells. Fields in Dayton, Jefferson, Palmyra, Poland Spring and Sabattus caught single moths, which does not warrant a spray.
Fall armyworm: Two fall armyworm moths were caught in one Cape Elizabeth location this week. This is below threshold for silking corn. No feeding damage was found.
Spotted wing drosophila update: The numbers and range of the “Suzuki Fruit Fly” continue to increase around the state. We have found this small fruit fly in traps in Limington, Buxton, Sanford, New Gloucester, Mechanic Falls, Poland Spring, Wales, Litchfield, Fayette, Thorndike, Warren and Bucksport. This week also saw the first capture of this fly in a wild blueberry field in Franklin. Berry growers need to be on the alert for fruit flies and symptoms of premature fruit decay. Have your pickers keep fields free of overripe fruit. At this point, insecticide sprays every 5-7 days appears to provide adequate control. More frequent sprays may become necessary as populations increase. There is a good fact sheet about the management of spotted wing drosophila on the Penn State Extension website.
Corn rust causes reddish-brown pustules to form on the leaves, stalks and husks, reducing the visual quality of the ears. We see more of this problem in wet, humid seasons. Some varieties are resistant. Severe infections can reduce ear size, especially if they occur prior to tassel. A fungicide spray for rust is only recommended if the infection occurs prior to tasseling. Later infections are unlikely to cause enough damage to the crop to justify control measures. Materials available to control corn rust include Bravo®, Quilt® and maneb/mancozeb.
Sincerely,
David T. Handley
Vegetable & Small Fruit Specialist
Highmoor Farm Pest Management Office
P.O. Box179 491 College Ave
Monmouth,ME 04259 Orono,ME 04473
207.933.2100 1.800.287.0279
| Location | CEW Moths | ECB Moths | FAW Moths | % ECB Damage | Recommendations / Comments |
| Biddeford | 7 | 3 | 0 | 4% | 5-day spray interval for all silking corn |
| Cape Elizabeth I | 11 | 0 | 2 | 0% | 4-day spray interval for all silking corn |
| Cape Elizabeth II | 6 | 0 | 0 | 21% | 5-day spray interval for all silking corn |
| Charleston | 0 | 9 | 0 | 1% | One spray recommended for ECB on silking corn |
| Dayton I | 1 | 1 | 0 | 3% | No spray recommended |
| Dayton II | 1 | 0 | 0 | 1% | No spray recommended |
| Dresden | 0 | 1 | 0 | 5% | No spray recommended |
| East Corinth | 0 | 20 | 0 | 0% | One spray recommended for ECB on silking corn |
| Farmington | 0 | 0 | 0 | 2% | No spray recommended |
| Jefferson | 1 | 0 | 0 | 7% | No spray recommended |
| Levant | 0 | 8 | 0 | 6% | One spray recommended for ECB on silking corn |
| Lewiston | 2 | 1 | 0 | 0% | 6-day spray interval for all silking corn |
| Lewiston II | 2 | 3 | 0 | 9% | 6-day spray interval for all silking corn |
| Monmouth | 6 | 2 | 0 | 7% | 5-day spray interval for all silking corn |
| New Gloucester | 5 | 0 | 0 | 2% | 5-day spray interval for all silking corn |
| North Berwick | 8 | 0 | 0 | 1% | 4-day spray interval for all silking corn |
| Oxford | 0 | 0 | 0 | 8% | No spray recommended |
| Palmyra | 1 | 6 | 0 | 5% | One spray recommended for ECB feeding |
| Poland Spring | 1 | 3 | 0 | 30% | One spray recommended for ECB feeding |
| Sabattus | 1 | 1 | 0 | 8% | No spray recommended |
| Wales | 0 | 0 | 0 | 13% | No spray recommended |
| Warren | 3 | 0 | 0 | 7% | 6-day spray interval for all silking corn |
| Wells I | 3 | 0 | 0 | 0% | 6-day spray interval for all silking corn |
| Wells II | 3 | 0 | 0 | 1% | 6-day spray interval for all silking corn |
CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB: European corn borer
FAW: Fall armyworm
Corn Earworm Spray Thresholds for Pheromone Traps
| Moths caught per week | Moths caught per night | Spray interval |
| 0.0 to 1.4 | 0.0 to 0.2 | No spray |
| 1.5 to 3.5 | 0.3 to 0.5 | Spray every 6 days |
| 3.6 to 7.0 | 0.6 to 1.0 | Spray every 5 days |
| 7.1 to 91 | 1.1 to 13.0 | Spray every 4 days |
| More than 91 | More than 13 | Spray every 3 days |
Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.
European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.
IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/
Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.
Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.
Image Description: Sweet Corn
Image Description: European Corn Borer Moth
Image Description: Corn Earworm Moth
Image Description: Male Spotted Wing Drosophila
Image Description: Male and Female Spotted Wing Drosophila
Image Description: Rust on Corn
