1. Past history of Monilinia Blight on the farm.
2. Flower buds become susceptible to infection at the F2 stage (bud scales separating).
3. Once fields reach 40-50% F2 and beyond, a fungicide is required within 72 hrs of the start of an infection period. This application will provide 7-10 days protection.
Observations at Tim Strong’s farm as of May 24th, 2011:
Apothecia cups are breaking down and no longer sporulating.
Recommendations:
The primary mummy berry infection season is now over at Tim’s farm on Brooklyn St. and no further sprays for this disease should be required.
It has been a difficult mummy berry infection season with 12 wet periods with suitable conditions for infection. How do you know if you have been successful in protecting your plants from infection? If primary spore infection does occur, disease symptoms become evident 10 to 20 days afterward. These symptoms appear as water soaked or dark brown areas along the midrib and veins of leaves which themselves soon wilt. Infected blossom clusters become dark purple-brown in color, and shrivel. A characteristic whitish-grey growth of spores (conidia) is produced on the midrib of infected leaves and is very diagnostic for the secondary infection phase of the disease. If you see these ‘blight’ symptoms, primary infection has occurred and you have not been successful in protecting your buds through the past weeks. Good luck!
Typical leaf blight and wilt symptoms
Once again, I remind grower’s that these recommendations apply to Tim’s farm in King’s Co. only and it is a guide only for other farms.
Refer to “Management of Mummy Berry in Highbush Blueberry” factsheet for pictures of F2 stage and temperature and wetness requirements for an infection period.
Refer to AgraPoint’s “Highbush Blueberry Insect and Disease Management Schedule” for a list of registered products for mummy berry (Monilinia) control in highbush blueberry.
