Almonds trees can be host to an assortment of diseases including bacterial, fungal, viral, parasitic or phytoplasmal.
These diseases and how to control them were the topic of Dr. Jim Adaskaveg’s presentation during 2018 North Valley Nut Conference hosted by West Coast Nut in conjunction with the UCCE Butte/Glenn Counties Almond and Walnut Day at Silver Dollar Fairgrounds in Chico.
Adaskaveg, professor and plant pathologist with the Department of Plant Pathology, UC Riverside, who specializes in foliar disease of almonds and other tree crops, shared the springtime diseases of almond that can be problematic in a wet spring season are blossom blight, jacket rot, anthracnose, shot hole and bacterial spot. Late spring-summertime diseases include scab, alternaria, leaf spot, anthracnose, rust and hull rot. Magna-Bon CS 2005 was included in a series of disease control trials showcases several favorable results that stood out including Bacterial Spot in Almonds and Walnut Blight.
Here is a research results overview video of those trials!
According to Dr. Jim Adaskaveg, bacterial spot is a fairly new disease in California, first diagnosed in the spring of 2013 and is caused by the bacteria Xanthomonas arboricola pv. pruni.
The almond variety Fritz appears to be the most susceptible to bacterial spot at this time.
Bacterial spot occurs on the tree’s leaves, twigs, and with the most obvious symptoms on the fruit. Typically, almond hull lesions start as small, watery blemishes that produce light to dark amber gumming. The amber color of the gumming is important as it helps distinguish bacterial spot from the clear gum of leaffooted bug feeding injury. The infection can reach the kernel and cause off grades or unmarketable fruit.
The pathogen overwinters in fruit mummies on the tree.
“So the winter shakes to get rid of those mummies for other pests and diseases is also helping to protect against bacterial spot,” he added.
The most effective management program for bacterial spot is a delayed dormant application to reduce inoculum and at least one or two in-season applications around rainfall events and rising temperatures to prevent new infections.
Adaskaveg recommends the use of copper at full bloom and petal fall, twice in the spring and in the summer, as well as application of mancozeb at petal fall and in the spring.
“That program should work well for management of bacterial spot,” he said.
Of the results on the trials, CS 2005 64 FLOZ mixed with MANZATE 75DF 6 LB, had a 95% success rate combating Bacterial Spot!
The full spray program:
Full bloom 2/18: 64 floz of CS 2005+ 6 lb Manzate 75DF
Petal fall 3/5: 27 floz of CS 2005 + 4 lb Manzate 75DF
2 Weeks APF 3/20: 27 floz of CS 2005+ 4 lb Manzate 75DF
4 Weeks APF 4/3: 27 floz of CS 2005+ 4 lb Manzate 75DF
With Magna-Bon CS 2005, you’ll only use ¾ of a Pound of Metallic Copper Per Acre for the Whole Growing Season! This coincides with our tagline;
Less Copper, More Power!
To Read the full article from West Coast Nut – https://www.wcngg.com/2018/08/02/almond-disease-and-control/