|Growers spraying fungicides to battle almond diseases.|
Growers usually treat for brown rot at least once during bloom. The brown rot fungus attacks the tree by invading the anthers and pistils of the flower when it is open. The fungus then can kill the spur or shoot.
The most susceptible variety is Butte followed by Carmel. Nonpareil is one of the least susceptible varieties for brown rot.
|Almonds infected by shot hole.|
The disease can lead to lesions on leaves and fruit, which emerge at the leaf bud. Infected leaves can lead to defoliation. By May, the almond hull develops enough to resist a shot hole infection.
|Evidence of scab on a almond leaf.|
Rust also can cause defoliation. High humidity will trigger rust as well as scab problems. Rust and scab emerges in late spring or early summer. The fungus attacks the leaves, but not the fruit. Rust is controlled by one or two applications of sulfur in late spring.
|Monitor for Alternaria leaf spot now.|