David Doll0 commentsApril 11, 2014Diseases

Jacket Rot on Almond

I have been receiving a few calls about issues with deformed almonds, particularly with the variety of Monterey. When looking at the nuts, it appears that the damage is associated with the jacket. This appears to be jacket rot. Samples submitted were placed in a humidity chamber and produced the gray/brown “fuzz” that is common to Botrytis, one of the causal agents of jacket rot. Based on the weather, this appears to be an issue with the four day rain event that occurred as the jackets were splitting on the later blooming varieties. I dont suspect a major problem, unless we re-enter a period of rainy, cool weather.

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David Doll2 CommentsFebruary 23, 2010Diseases

UPDATE: DMI Fungicides and Botrytis Control

Last week, I suggested the use of DMIs (Quash, Indar, Inspire, Rally, etc.) for brown rot control spray program. A fellow reader shared some experiences with me regarding the use of DMI fungicides during the late bloom period. Although DMIs are good for brown rot, anthracnose, and have some activity against scab, shothole and rust, they do not provide control for the fungus Botrytis, which causes jacket rot and green fruit rot (Photo above). Botrytis is found everywhere and grows rapidly in cool, moist weather. It typically infects young almond jacket and fruit, causing infection and nut abortion. It is greyish in appearance, and affects varieties that cluster – Avalon, for example. It is not found frequently, but when found, is typically in orchards that have only used DMI fungicides. Therefore, if your last fungicide application is a DMI, I would advise to include a broad spectrum as a tank mix (chlorothalonil, Captan, Maneb, Rovral) to help reduce the incidence of Botrytis infection. Any other thoughts on this?

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