Archive for the ‘other diseases’ Category

Valdensinia leaf spot

Tuesday, July 16th, 2013

Now is the time to look for Valdensinia leaf spot in your fields.  The wet weather conditions we have had over the last month will have caused many cycles of spore production and infection if you have this fungus in your field.  I have seen a new field with Valdensinia leaf spot in Ellsworth.  Areas we have often found it are along the edges of roads, in wet areas in the field and areas that are shaded by trees along the field edges.

Do NOT scout your field when the plants or ground is wet.  This may move infected leaves  around your field. 

Symptoms are large brown leaf spots that are rounded with dark margins compared to the inside of the lesion.  On the underside of the lesion, you will see a dark spot with a hand lens, or sometimes the naked eye, which is the spore still attached to the leaf.  Lower leaves, particularly in prune fields, will be falling off by now.  Upper leaves, particularly in crop fields, may have many spots and may still be attached. 

If you think you have Valdensinia leaf spot, please contact Seanna Annis at sannis@maine.edu or the blueberry hotline 800-897-0757 (in Maine only).

lowbush blueberry stems with missing leaves and leaves showing Valdensinia leaf spot symptoms     Picture of leaves with Valdensinia leaf spot lesions

 

Botrytis blossom blight

Wednesday, May 22nd, 2013

If you have had Botrytis blossom blight in your field before, you may have conditions to have this disease occur this week.    The Botrytis blossom blight can be identified by the black hairs that stick out of infected, dead blossoms.  Blossoms can also be killed by the Mummy berry fungus and frost.  Please see previous post from Monday May 20th for pictures of symptoms of these diseases.

I would only suggest applying fungicides for Botrytis blossom blight control, if you are sure that is what has killed off your blossoms in the past or you have already seen this disease in your crop field this year. Please follow the recommendations on the Factsheet # 219 Disease Control Guide for Wild Blueberries for 2013. 

As of 11am on Wed. May 22 there were some monitored fields that had high probability of Botrytis infection of blossoms this past week.  With the weather forecast predicting rain through out the state until Sunday, I expect more possible blossom infection from Botrytis.

Weather station location Chance of Botrytis Blossom Blight infection
West Rockport High
Appleton High
Sedgewick High
Ellsworth low
Silsby Plains low
Deblois moderate
Montegail  moderate
Rocky Pond low
East Machias low
Meddybemps low

If you have any questions please contact Seanna Annis via email at sannis@maine.edu or by phone 107-581-2621.