jan-feb-2020

IN YOUR ORCHARD TIME TO CONSIDER Reservoir levels look good, the market is strong. Careful steps in January and February should set growers up for the best possible production for the coming year. Top priorities at this time include orchard sanitation for navel orangeworm management, quality bee rental/care, frost protection, and selection/timing/delivery of bloom fungicides. Dormant Pest Management The key practice for dormant/delayed dormant timing pest management is orchard sanitation; destroying old nuts (“mummies”) that are overwintering sites and spring housing for navel orangeworm (NOW), the key pest of almonds in California. Mummy nuts are also a major source of bacterial spot inoculum and their removal and destruction is an important part of integrated management of this disease. The traditional target has been two mummies per tree, but recent data analysis using extensive, detailed information from Kern County recommends one mummy for every five trees and four or less mummies on the ground under each tree. Sanitation timing is important. Knock mummies from the trees (shaker and/or hand pole) by mid-January. Research in the 1980s reported no loss in yield if mummy removal was done as late as January 31. Then blow, sweep/ window and then grind up mummies with a mower by March 1. Check behind the mower to make sure all mummies were broken up by the mower. If not, slow down the tractor speed until the mummies are destroyed. Just getting the mummies on the ground is not enough. Dormant is a good time for certain insect and/or disease management, if needed. Use orchard pest history and/ or dormant spur or shoot sampling to check for scale, European red/brown almond mite eggs and scab lesions. How-to info and how to interpret the results at ipm.ucanr. edu/agriculture/almond/San-Jose-Scale and click on the link to “Dormant Spur Sampling.” A dormant application of copper to reduce bacterial spot inoculum is also part of an integrated program for this disease that is most damaging to Fritz variety, but can also hit Nonpareil, Butte, Carmel, and Price. Winter sanitation, a dormant copper spray, and one to two copper/mancozeb sprays early in the season ahead of rain and warmer temperatures provide the most effective management program for this relatively new problem in California almond orchards. Pre-bloom is also a great time to put down a preemergent herbicide for extended weed control. Consult with your PCA about preemergent herbicide selection to match the age of the block and target weeds. Good weed control is particularly important in young orchards, where the lack of shade plus added water and fertilizer intended for the trees can grow a “great” crop of weeds. The right preemergent materials can offer long residual weed control. The other option is repeated post- emergent applications that need to go on at the right times with a lot of care in application to avoid damaging young trees. White paint (50/50 paint to water) did not provide trunk protection (2nd leaf trees) from high rates of post- emergent applications in a recent University of California (UC) study. See the whole report from this work at ucanr. edu/blogs/UCDWeedScience/blogfiles/64033_original. png. The healthiest trees in this study were those with solid, new trunk protectors. Controlling weeds in the tree row also helps keep voles (meadow mice) from invading the block and damaging or killing trees. The worst cases of vole damage I’ve seen were in young blocks where growers were unable to get 3 8 A L M O N D F A C T S