Butte County Status Report

April 2000

After a very successful first year, the Almond Pest Management Alliance is up and running again in Butte County. We are looking forward to another productive year working with Bertagna Orchards, demonstrating reduced risk practices in the same orchard and the same block as last season. The treatments have been kept the same as last season and hopefully a better understanding of almond pests and the use of reduced risk practices can be documented.

This orchard is 50% Nonpareil, 16% Butte, 16% Sonora, and 16% Aldrich and is just under 50 acres. The grower standard treatment is 27 acres, the Pest Management Alliance reduced risk treatment is 12 acres, 5 acres received an organophosphate dormant spray with no hull split spray planned and 5 acres received an organophosphate dormant spray and an organophosphate hull split spray is planned.

Dormant spur samples were taken in December 1999 and inspected for Peach Twig Borer hibernacula, San Jose Scale, San Jose Scale parasites, and mite eggs. All of these pest levels were very low. Almond mummies were counted in January and due to the high number, a recount was done in March.

Traps to monitor PTB, male SJS, SJS parasites, and NOW eggs went up in mid-March. Weekly monitoring for diseases such as shot-hole and scab is underway. SJS and its parasites (Prospaltella and Aphytis) were found on 3/27, and PTB moths were found in the traps on 4/4. NOW eggs have not been noticed on the egg traps as of 4/4.

Since monitoring is a vital tool in demonstrating reduced risk practices we will continue our monitoring on a weekly basis through November. We will also keep an eye out for anthracnose, a problem not currently found in this relatively young and vigorous orchard.

We look forward in seeing you at our regional field day meeting that will be held on Wednesday May 24, 2000, in the Chico area, at 9 a.m. – 11 a.m. at Bertagna Orchard.