Strawberry IPM Newsletter No. 3 – May 24, 2013

Wet Strawberry Field, photo by David Handley

Diseases:  Bloom is the critical time to protect strawberries from developing gray mold caused by the Botrytis cinerea. The rain of the past few days has made conditions very conducive to fungal sporulation and flower infection. Two to three sprays of fungicide during bloom are often required to protect against gray mold. Fungicide choices for control of gray mold in strawberries include captan/Topsin M® tank mix, Elevate®, Captevate® (a pre-mix of captan and Elevate®), Switch®, Scala® and Pristine®.

Leather rot (Phytopthora cactorum) can be a problem when there is water standing in the fields during bloom and fruit development, especially if the fields were not mulched last fall and the plants are on bare, wet soil. Leather rot should be managed by growing strawberries in well-drained soil and applying straw mulch between the rows to prevent berries from touching the soil and to reduce soil splashing up onto the berries. Foliar sprays of Aliette®, Agri-Phos® or Phostrol® can be applied during bloom and fruit development to prevent leather rot when there is excessive moisture in the field, especially in fields with a history of this problem.

Anthracnose on Strawberry, photo by North Carolina State University

Anthracnose fruit rot is a potential problem when fruit ripens in fields that are wet from irrigation or rain. This fungus disease is favored by warm, humid conditions and can spread rapidly during rains or when fields are irrigated with overhead sprinklers. In cool seasons, it may appear close to harvest or may not show up at all. Anthracnose fruit rot is identified by black sunken lesions with wet, orange (and sometimes gray) spore masses in them. The fungus can survive and multiply on leaves without visible symptoms, appearing suddenly as a fruit rot when the conditions are right. Fungicides such as Cabrio® and Abound® can provide good control of anthracnose.

Powdery Mildew, photo by David Handley

Powdery mildew:  No severe symptoms of powdery mildew have been observed yet, but we’re starting to see some leaf cupping in fields, suggesting that this disease may become a problem when temperatures start to rise. Upward cupping of the leaves and reddish streaking or lesions on the leaf and flower stems are the most obvious symptoms of powdery mildew. White, powdery growth on the undersides of the leaves appears as the disease develops further.

Strawberry bud weevil or “clipper” is becoming active as flower buds emerge. I have found one field with clipper at levels over threshold this week, but most fields were showing very little, if any damage. Early blooming varieties may have developed beyond the point where clipper can do significant harm to buds, but later blooming fields should still be scouted for injury. Clipper is likely to become more active when conditions become a little drier and warmer.   

Tarnished Plant Bug Nymph on Strawberry Blossom, photo by David Handley

Tarnished plant bugs adults are few and far between this week, which is typical in this kind of weather, but I still have not found any nymphs in blooming fields. It is difficult to find nymphs on wet plants, so we may see activity increase considerably when things dry out. But for now, no fields have been over threshold.  

Cyclamen mites:  We continue to see symptoms of cyclamen mite in strawberry fields this week, including weak growth, crinkled leaves and yellow, pinkish or blackened discoloration. Sprays for these mites must be applied with lots of water to carry the material down into the crowns where the mites reside. Portal®, Thionex® and Kelthane® are registered for control.  

Cyclamen Mite Damage, photo by David Handley

Two-spotted spider mites were not found over threshold in any fields this week. Cool, wet weather tends to significantly slow spider mite development in strawberry fields, but expect populations to rise as conditions become warmer and drier, and keep scouting.   

White grubs:  We have found white grubs in three different fields this week, most likely the larvae of Asiatic garden beetle or European chafer. These grubs have legs and a dark, swollen rear end. They are found in the soil around the roots of weak plants.   Admire Pro®  can be used to control white grubs and should be applied within two hours of irrigation or rainfall to get the chemical into the root zone. This product has a 14 day pre-harvest interval.  

Spring fertilizer for strawberries
Heavy nitrogen fertilizer applications are not recommended in the springtime because excess vegetative growth at this time will result in a dense leaf canopy that will cover flowers and fruit, and encourage gray mold and two spotted spider mites. In the matted row system, most of the nitrogen fertilizer should be applied following harvest to stimulate new leaf and runner growth. For established beds, only 10-20 pounds of actual nitrogen should be applied in the spring. Calcium nitrate [Ca(NO₃)₂, 15% N] is a recommended source of nitrogen at this time because it is readily available, not volatile, and also provides calcium, which can help with fruit development.  Boron is another nutrient which can help early spring growth, and is especially important in the pollination and fertilization process that helps determine fruit size and quality. However, excessive amounts of boron can be toxic to strawberry plants, so only one to two pounds of actual boron (B) is recommended per acre during the spring. This is often applied as a foliar spray in a material such as Solubor® (20% B). While foliar sprays are often an inefficient way to get nutrients to the plants, they are helpful when trying to evenly distribute a small amount of material over a large area.

Honey bee on flower

What about pollination?
After a hard winter for bees and lots of rain during bloom, growers are concerned about good pollination in their strawberries. Cultivated strawberry flowers are self-fertile, meaning that they don’t require cross-pollination with other varieties like some other fruit crops, such as apples or blueberries. Some studies have shown that strawberries will produce a good crop in the absence of bees, with pollination being carried out by wind and small, native insects. Other studies have shown an increased fruit quality and size when bees help with pollination, so it is certainly good to have them working in the strawberry fields, but perhaps not essential for this particular crop.

2013-2014 New England Small Fruit Management Guides are available from the University of Maine Cooperative Extension 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, atten. Pam St. Peter. For more information, contact Pam St. Peter at 933.2100 or pamela.stpeter@maine.edu.

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.

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

STRAWBERRY BLOOM UNDERWAY

Few Insect or Disease Problems, Winter Injury Widespread

Frost Injury to Flowers and Leaves, Photo By David Handley

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.

Clipper Injury, Photo by David Handley

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.

First Instar Tarnished Plant Bug Nymph, photo by David Handley

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, Photo by David Handley

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.

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 credit will be awarded for the meeting.

Pike’s Farm to You is located at 115 Mount View Road (near the corner of Routes 2 & 4 and the Whittier Road) in Farmington, Maine 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.  For more information, please contact David Handley at 207.933.2100 or david.handley@maine.edu.

Any person with a disability who needs accommodations for this program 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.

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

2013 STRAWBERRY PEST MANAGEMENT SEASON BEGINS

Winter Injury Worries

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.

Frost Injury, photo by David Handley

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.

Clipper Beetle on Strawberry Bud, photo by James Dill

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 Bug Adult, photo by David Handley

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 Mite Damage, photo by David Handley

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, photo by David Handley

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).

Strawberry Root Weevil Grub, photo by David Handley

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 Grub, Photo by David Handley

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.

Gray Mold on Strawberries, photo by James Dill

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, photo by David Handley

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.

Bacterial Angular Leaf Spot, Photo by David Handley

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.

Orders are now being taken in the”Grow It Right!” plant sale for highbush blueberry plants — three young plants, two varieties per pack for $35.95 and asparagus — a pack of 10 crowns for $15.00. Plants must be ordered by April 30, 2013 and will be available for pickup at University of Maine Cooperative Extension county offices and at Highmoor Farm in Monmouth on Saturday, May 18. UMaine Extension county office locations are listed online.

UMaine Extension experts will provide advice on growing blueberries and asparagus, as well as take-home instructions from Master Gardener volunteers. Online resources are available to gardeners throughout the growing season and harvest.

“This is more than a plant sale. It is an educational experience with positive results,” says Richard Brzozowski, UMaine Extension educator in the Cumberland County office.

Money raised will assist Master Gardener Volunteer projects and provide scholarships for participants. Since its inception more than 30 years ago, the UMaine Extension Master Gardener Volunteers program has assisted in dozens of community horticultural projects across the state, including Maine Harvest for Hunger, youth gardening and other community-based volunteer efforts.

A soil test is recommended prior to planting to help gardeners get the most out of their garden site. Additional information is available at the plant sale website.

For more information about Grow It Right! contact Brzozowski at 207.781.6099 (toll-free in Maine 800.287.1471), or Marjorie Peronto at 207.667.8212 (toll-free in Maine 800.287.1479), or email richard.brzozowski@maine.edu or marjorie.peronto@maine.edu.

To all Maine fruit, vegetable and grain growers who sell edible produce to consumers or to processors to be made into products for human consumption:  A new law may require you to be licensed to use over-the-counter pest control products.

Please read the following announcement and see details on training below.  Preregistration is required.  Please call 207.287.2661 or email anne.bills@maine.gov to reserve a seat.

In the spring of 2011, the Maine Legislature passed Public Law 2011, Chapter 169: An Act to Require Certification of Private Applicators of General Use Pesticides.  The new law requires the Maine Board of Pesticides Control to begin licensing growers who use only general-use (over-the-counter) pesticides and annually sell more than $1,000.00 of plant or plant products intended for human consumption.

Keep in mind that, by definition, a pesticide is any naturally or synthetically derived substance used to kill, control, or repel undesired insects, weeds, fungi, bacteria, mammals, birds, rodents, or other organisms.

Products which are organic are also pesticides if they are used as described above.  Consequently, these substances may include insecticides or bug sprays; herbicides, including weed killers and top killer products; fungicides or disease controls, rodenticides; deer repellents; defoliants; growth regulators; and disinfectants.

To obtain a license, you must pass the Maine Board of Pesticides Control “core exam.”  The Maine Board of Pesticides Control and University of Maine Cooperative Extension are offering a three-hour training session to help prepare growers for the Private Pesticide Applicator Core Exam at the Maine Agricultural Trades Show on January 9, 2013.  Ideally, exam candidates should review the Pesticide Education (Core) Manual prior to taking the exam.  The Pesticide Education (Core) Manual is available from the University of Maine Cooperative Extension online or call 1.800.287.0279 in Maine, 207.581.3880 outside Maine.

Wednesday, January 9, 2013
Augusta Civic Center, Arnold/Howard Rooms (first floor, north wing)

9:30 AM – 12:30 PM   Private Pesticide Applicator Core Exam Training
Jim Dill, University of Maine Cooperative Extension and Gary Fish, Maine Board of Pesticides Control

1:30 PM – 4:00 PM   Private Pesticide Applicator Core and Commodity Exams Administered
Maine Board of Pesticides Control Staff
Preregistration is required.  Please call 207.287.2661 or email anne.bills@maine.gov to reserve a seat.

If you cannot make it to this session we do plan to hold many more before the requirement becomes fully enforceable on April 1, 2015.  The exam can also be taken at the Maine Board of Pesticides Control office in Augusta (207.287.2731) or at County Cooperative Extension offices.  Contact the Maine Board of Pesticides Control office to have the exam mailed to the Extension office, and then make arrangements with Extension for taking the exam.

The three-year license will cost $15.00  You will need to obtain one hour of continuing education per year in order to maintain your license.

David Handley, Vegetable & Small Fruit Specialist; James Dill, Pest Management Specialist; Kaytlin Woodman, Technician, University of Maine Cooperative Extension

In the fall of 2011 we captured spotted wing drosophila flies for the first time in Maine.  Based on crop damage experienced by southern growers in 2010 and 2011, we knew that this insect posed a serious threat to most of the berry crops we grow here.  As part of the University of Maine Cooperative Extension Pest Management Program, we set up drosophila traps in berry fields around the southern, central and coastal regions of the state.  The traps were simply plastic cups with lids mounted on stakes with 16, 1/8” holes punched under the rim to allow the flies access.  Four ounces of bait (a mixture of cider vinegar, white grape juice and alcohol) was poured into each trap.  We placed traps both within the crops and in the wooded areas near the crops, knowing the insect prefers humid, shaded areas.  We emptied the traps weekly and restocked them with fresh bait.  We were hoping the traps would show us when this new pest would start emerging in Maine, and how rapidly populations would build to damaging levels.

The first spotted wing drosophila were caught in Limington on July 13.  By the following week, we had trapped drosophila flies in Springvale, New Gloucester, Poland Spring, Mechanic Falls, Wales, Litchfield, Fayette, Thorndike and Warren.  By August 13, we had captured flies at all of our monitoring locations, adding Buxton, Bowdoinham, Dresden, Turner, Farmington, and Fayette to the list.  During the same week, traps in wild blueberry fields in Hancock and Washington counties were also catching the flies.  In late August trap counts rose dramatically at most locations.  Raspberry and blueberry fruit infested with the small white larvae were being reported, and we received numerous calls about soft, rotting fruit.  Trap counts continued to rise through mid-September, with catches in some locations exceeding 2,000 flies per week. At this point flies were readily visible around ripe fruit in many fields and larvae were found infesting most of the fruit in any plantings that had not been sprayed.  Populations were highest in the southernmost and coastal regions, but relatively high numbers of flies were caught in nearly all locations at some point in the season.

Growers who were using insecticides to control spotted wing drosophila initially found that weekly sprays appeared to provide adequate control.  However, as fly populations expanded, growers found that twice weekly sprays were needed to keep larvae out of the fruit.  Growers were using Entrust®, Delegate®, Brigade®, Mustang Max®, and/or malathion insecticides, and most found that these products usually offered adequate control if applied on a frequent basis.  Some growers who did not apply pesticides reported total crop loss following the arrival of spotted wing drosophila in their fields.

Spotted Wing Drosophila Trap Captures in Maine, 2012

Spotted Wing Drosophila Trap Captures in Maine 2012 Data (Excel)

Spotted wing drosophila trap catches remained relatively high throughout the remainder of the season, with a slight dip in late September, which may correlate with a dry spell (we are still analyzing weather data).  In fact, some of the highest trap catches occurred late in the season, in early November, well after most of the crops had been harvested or lost to frost.  The lack of food may have made the traps more attractive, accounting for the increased catch, but this still indicates that high numbers of flies appear to survive long after killing frosts have occurred.  By the end of November, populations finally dropped significantly, suggesting that the flies were now entering the over-wintering stage.

This species over-winters as adults, and research suggests that they should emerge early in the spring to seek out food and begin breeding and laying eggs.  It is thought that the over-wintering survival rate will be relatively low here, but enough should survive to cause similar, if not greater, problems in 2013, given that they will be starting in higher numbers and be more widely dispersed than they were in 2012.

Thus, berry growers should anticipate needing to manage drosophila for the 2013 season.  Based on this year’s data and records from other states, we believe it will be unlikely to significantly infest crops until relatively late in the season when populations reach damaging levels (this year early to mid-August).  Therefore, earlier ripening crops such as June-bearing strawberries should not be significantly impacted, but later ripening crops such as late summer and fall fruiting raspberries, later varieties of blueberries and fall strawberries will need to be protected as soon as fruit begin to ripen.  We plan to again monitor drosophila populations in Maine in 2013, and carry out research on improving our trapping strategies to provide an early warning system in the future.

If you have not yet filled out a grower survey of how spotted wing drosophila impacted your crops this year, click here.  Your input will greatly help us develop our research and educational efforts for the future.  There is a very good fact sheet series on spotted wing drosophila from the Pennsylvania State University, and we have some free copies available.  Contact Pam St. Peter at 207.933.2100 or pamela.stpeter@maine.edu.  You can also download a free copy at their website.

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

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/
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.

Spotted Wing Drosophila Update for Maine Fruit Growers – August 24, 2012

Spotted Wing Drosophila Trap, Male SWD Circled, photo by Kaytlin Woodman

Over the last week and a half, spotted wing drosophila numbers in our traps have increased significantly.  We are now finding both male and female flies in the highest numbers of the season.  In addition, we have found drosophila maggots infesting both highbush blueberry and raspberry fruit this week and have been getting reports from growers around the state of infested fruit.  Some farms have closed berry sales for the season as harvest is coming to an end, and the few fruit remaining will not be worth the extra effort of repeated insecticide sprays to rescue them.  For those with late fruit crops still to harvest, protection will now be 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 will now be necessary to keep fruit free from maggots.  Growers in southern states have found that a three to five-day spray schedule was needed to prevent infestation.

Spotted Wing Drosophila Larva in Blueberry, photo by David Handley

Maine Crisis Exemption Label for Gowan Malathion 8 Flowable® to Control Spotted Wing Drosophila on Blueberries:
There are just a few more days left to utilize the  Section 18 Crisis Exemption granted by the EPA for the use of Gowan Malathion 8 Flowable® at a higher rate than the federal label allows, to provide better control of spotted wing drosophila on blueberries.  This label will allow a rate of 2.0 to 2.5 pt/acre per application, with a maximum of two applications per field.  This exemption rate can only be used from August 13 through August 28 this year.  Growers must have a copy of the exemption label in their possession to use this rate, and must fill out a use survey at the end of the season.  Exemption Labels are available through pesticide dealers, and the Board of Pesticides Control (287.7544).

Check product labels for which crops are registered for the product, application limits, rates, post-harvest intervals and safety precautions.  Keeping the fields clean of over-ripe and rotten fruit can also help reduce the incidence of this insect.

We have available a very good series of new fact sheets from Penn State Extension regarding spotted wing drosophila.  If you would like copies please e-mail Pam St. Peter at pamela.stpeter@maine.edu, or call Pam at 207.933.2100.

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

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/
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.

Spotted Wing Drosophila Update for Maine Fruit Growers – August 15, 2012

Male Spotted Wing Drosophila, photo by Griffin Dill. Actual size: 2-3 mm.

During the past week we have seen a significant increase in spotted wing drosophila coming to our traps in southern Maine.  This suggests that the threat of infestation to any soft fruit or berries remaining in the field is now very high.  We are catching these fruit flies in all of the locations where we have placed traps including Limington, Buxton, Springvale, Bowdoinham, Dresden, New Gloucester, Poland Spring, Mechanic Falls, Turner, Farmington, Wales, Litchfield, Fayette, Thorndike and Warren.  In addition, traps in wild blueberry fields in Hancock and Washington counties have caught flies during the past week.  We are confident that the fly is now widespread and active through most, if not all, of the southern, mid-state and coastal regions of the state.  Also, as the quantity of fruit available is reduced through harvesting, pressure on the remaining fruit will intensify.  We recommend protecting any berry crops or other soft fruit with an appropriate insecticide on a frequent and regular schedule.  With fly catches increasing, more frequent spray applications will probably be needed to achieve adequate control.  The table below lists available materials and the estimated days of residual activity, assuming the product is not washed off by heavy rains.

Characteristics of Insecticides for Spotted Wing Drosophila Control

Please check product labels for which crops are registered for the product, application limits, rates, post-harvest intervals and safety precautions.  Keeping the fields clean of over-ripe and rotten fruit can also help reduce the incidence of this insect.

Maine Crisis Exemption Label for Gowan Malathion 8 Flowable® to Control Spotted Wing Drosophila on Blueberries:
Maine has been granted a Section 18 Crisis Exemption by the EPA for the use of Gowan Malathion 8 Flowable® at a higher rate than the federal label allows, to provide better control of spotted wing drosophila on blueberries.  This label will allow a rate of 2.0 to 2.5 pt/acre per application, with a maximum of two applications per field.  The length of this exemption is very short; this rate can only be used from August 13 through August 28 this year.  Growers must have a copy of the exemption label in their possession to use this rate, and must fill out a use survey at the end of the season.  Exemption Labels are available through pesticide dealers, and the Board of Pesticides Control (287.7544).

We have available a very good series of new fact sheets from Penn State Extension regarding spotted wing drosophila.  If you would like copies please e-mail Pam St. Peter at pamela.stpeter@maine.edu, or call Pam at 207.933.2100.

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

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/
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.

Spotted Wing Drosophila Update for Maine Fruit Growers – August 1, 2012

Since our first occurrence of spotted wing drosophila in Limington on July 13, we have now found spotted wing drosophila flies in traps in locations in Springvale, New Gloucester, Poland Spring, Mechanic Falls, Wales, Litchfield, Fayette, Thorndike and Warren.  In the past week additional captures have occurred in Buxton, Bucksport and Franklin, in addition to more captures in the earlier locations.  At this point we assume that the fly is fairly widespread and active through most, if not all, of the southern, mid-state and coastal regions of the state.  We recommend protecting any berry crops or other soft fruit with an appropriate insecticide on a frequent and regular schedule.  At the moment weekly applications appear to be keeping drosophila in check.  However, fly catches in most locations are increasing, so the problem is likely to get worse as the season progresses.  Therefore, more frequent spray schedules will probably be needed to achieve adequate control.

Products that provide good control of Drosophila on berries include spinosad products such as Entrust® and Delegate® (group 5), and pyrethroids such as Brigade®, Mustang Max® and Danitol® (group 3).  Please check product labels for which crops are registered for the product, application limits, rates, post-harvest intervals and safety precautions.  Keeping the fields clean of overripe and rotten fruit can also help reduce the incidence of this insect.

We have recently received a very good series of new fact sheets from Penn State Extension regarding identification, biology, monitoring and management of spotted wing drosophila.  Thanks to a grant from the Northeast IPM Center, we can offer you copies of these fact sheets for free until our supply runs out.  If you would like copies please email Pam St. Peter at pamela.stpeter@maine.edu, or call Pam at 207.933.2100.

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

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/
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.

Spotted Wing Drosophila Management

a.   “X” = the material is not labeled for use on the crop.
b.   2(ee) labels have been issued for use against SWD on this crop.
c.   May be used in organic production.  For PyGanic, the REI is 12 hours even though the PHI is 0 days.
d.   Provides knockdown of nonresistant populations but has little or no residual activity.
From Penn State Extension “Spotted Wing Drosophila, Part 4: Management.”  http://extension.psu.edu/fruit-times/news/2012/spotted-wing-drosophila-fact-sheets-completed-and-on-line.

Spotted Wing Drosophila Update for Maine Fruit Growers – July 23, 2012

Male Spotted Wing Drosophila, photo by Griffin Dill. Actual size: 2-3 mm.

The first spotted wing drosophila of the 2012 season was found in a trap in Limington on Friday, July 13.  Since that time, we have found spotted wing drosophila flies in our traps at locations in Springvale, New Gloucester, Poland Spring, Mechanic Falls, Wales, Litchfield, Fayette, Thorndike and Warren.  While we have not yet caught the flies at all of the locations where we are trapping, it would be best to assume that the fly is now fairly widespread and active through much of the state.  Therefore, if you presently have ripening berry crops or other soft fruit, we are recommending protecting them with an appropriate insecticide on a regular basis at this time.  We are catching relatively low numbers of flies at these locations but the numbers have started to increase.  We know that the traps only tell us when the fly is already in the field, and we also know how rapidly the population can explode, so we are recommending preventive measures be taken as soon as possible.

Products that provide good control of drosophila on berries include spinosad products such as Entrust®, Radiant® and Delegate® (group 5), and pyrethroids such as Brigade®, Mustang Max® and Danitol® (group 3).  Please check product labels for which crops are registered for the product, rates, post-harvest intervals and safety precautions.  Keeping the fields clean of over-ripe and rotten fruit can also help reduce the incidence of this insect.

Male and Female Spotted Wing Drosophila, image by Alan Kenage, Capital Press

For information on identifying spotted wing drosophila and making your own monitoring traps, visit the Michigan State University’s Spotted Wing Drosophila website.  There is also a good fact sheet on management of spotted wing drosophila on the Penn State Extension website.

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

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/
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.

Fruit Growers Alert: Spotted Wing Drosophila has been found in Maine!  July 13, 2012

The first spotted wing drosophila of the 2012 season was found in a trap in Limington on Friday, July 13.  Three male flies were caught in a trap in the woods adjacent to a raspberry planting.  We haven’t caught flies in other locations yet, but growers should be on alert for indications of fruit flies in their plantings and premature fruit decay.

Spotted wing drosophila (Drosophila suzukii) is a new pest which is a concern for raspberries, blueberries and day neutral strawberries, as well as many other soft fruits.  This insect is a small fruit fly, similar to the type that flies around the over-ripe bananas in your kitchen.  However, this species will lay its eggs on fruit before it ripens, resulting in fruit that is contaminated with small white maggots just as it is ready to pick.  As a result, the fruit quickly rots and has no shelf life.  This insect recently came into the U.S. from northern Asia, and caused problems with many berry crops up the east coast last year.  It can complete a generation in under two weeks, with each adult female laying hundreds of eggs.  Therefore, millions of flies can be present soon after the introduction of just a few into a field.  This makes them very difficult to control, and frequently repeated insecticide sprays (3 to 5 times per week) may be needed to prevent infestations once the insect is present in a field.  It is likely that spotted winged drosophila can successfully overwinter here, although it may not build up to damaging levels until summer.  We have set out monitoring traps for spotted winged drosophila in fruit plantings around the state to determine the activity of this pest in Maine.  However, these traps are unlikely to provide early warning, i.e. when we find them in a trap they are probably already established in the field.  We will be alerting growers when we find them in Maine.  Now that spotted wing drosophila has been confirmed in a berry planting in southern Maine, growers should be on the alert and look for fruit flies on their fruit and symptoms of premature fruit decay.  Products that provide good control of drosophila on berries include Delegate®, Brigade®, Danitol®, and malathion.  Please check product labels for rates, post-harvest intervals and safety precautions.  Keeping the fields clean of over-ripe and rotten fruit can also help reduce the incidence of this insect.  For information on identifying spotted wing drosophila and making your own monitoring traps, visit the Michigan State University’s Spotted Wing Drosophila website.  There is also a good fact sheet on management of spotted wing drosophila on the Penn State Extension website.

David T. Handley, Ph.D.
Vegetable & Small Fruit Specialist

University of Maine Cooperative Extension
Highmoor Farm
P.O. Box179
Monmouth, ME  04259-0179
Tel. 207.933.2100
Fax 207.933.4647
david.handley@maine.edu

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/
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.

Contact: George Manlove, 207.581.3756