Ask Your PCA: What helps control cherry blossom blight?

Issue Date: March 9, 2022
Cameron Jones PCA, Nutrient Ag Solutions, Stockton

Cherries have a full array of diseases, so they are on a tight fungicide program. Bloom usually starts around March 1, and rain is the main concern. Depending on how much rain, blossom blight can be problematic as the spores are spread by rain.

Blossom blight turns the blossom brown. The pathogen attacks the calyx and flower petals and causes them to wither. As the fruit develops, brown lesions form where the diseased calyx touched the fruit surface. The lesions will spread quickly over the entire fruit and prevent the flower from setting. It can affect fruit set and, ultimately, yield because of the reduced fruit set. It can also result in bud dieback.

Fungicide treatments are used to control the disease. The goal is to keep the flower viable and pollinated. Rain increases pressure with blossom blight. But even in a dry year, morning dew can create problems, too, so growers need to remain vigilant on fungicide applications.

With supply-chain issues, growers may have to become creative with their fungicide usage because not all products will be available this year. Current economics have growers hesitant to spend money up front. But, at the same time, there's going to be definite issues on supply of different active ingredients, so growers should plan ahead.

Cherries have an array of different fungicides available. Currently, cherries have enough fungicides available that growers can rotate their fungicides and reduce the risk of resistance building. While there are many different options, the less expensive ones are already in short supply. That will most likely mean more expensive products will have to be used to control blossom blight this year.

With almonds blooming earlier and a dry bloom, some growers may skip early applications, which could free up some fungicides for the cherry market.

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.

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