Agronomic Minute: Staying on Top of Bacterial Blast

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Bacterial blast can be a devastating issue for almond growers. Infections can result in up to a 20 percent loss of yield. Technical Services Manager for UPL North America, Cassie Rieser explained that cold and wet weather is ideal for outbreaks in orchards.  

Bacterial blast

“Under these conditions the pathogen can multiply on the hosts and then it can be disseminated by water and splash, to infect other cuts, leaf scars, and buds may be infected on the almond, cherry, or peaches and other plants as well,” Rieser noted. “Pruning wounds and other injuries can also lead to infections.”

Overall bacterial blast problems can vary from year to year based on weather conditions. Rieser explained that growers have an additional tool to help mitigate the issue this year.

“Recently the Environmental Protection Agency, the EPA, and the California Department of Pesticide Regulation has granted and approved our Section 18 emergency exemption for the use of Kasumin, which is a bactericide for almonds,” said Rieser. “Growers will need to add Kasumin to their permit at their ag commissioner’s office. The ag commissioner will then provide a Cal DPR label for the Kasumin Section 18. And finally, the ag commissioner can then provide use restrictions for Kasumin. Treatment options for bacterial blast include the use of Kasumin, Cuprofix, and Manzate.”

Cal DPR is allowing applications in Butte, Colusa, Fresno, Glenn, Madera, Merced, San Joaquin, Stanislaus, Sutter, Tehama, Yolo, and Yuba counties. The Section 18 exemption is effective through April 15. The registration will allow up to two applications on almonds at a use rate of 64 fluid ounces per acre. Rieser also noted that Kasumin is known to be effective on streptomycin and copper-resistant strains of bacteria. The material can be used during bloom and applications are prohibited after petal fall.

Listen to the full episode below.