How To Get Your Almond Orchard Ready For Next Year
Although your plants are dormant, winter is a time to help your trees get the proper nutrition for next year’s crop. Follow these tips to ensure next season is a success.
- Applications of foliar zinc sprays in fall effectively correct zinc deficiency. The incidental leaf removal reduces both storm wind resistance and the opportunity for shot hole fungus to increase overwintering spores.
- Potassium band applications on both sides of the tree rows will help prevent potassium deficiency and subsequent loss of fruiting spurs. Make applications after 6 inches of rain or equivalent irrigation have wetted the soil profile and ensure that at least 6 inches of rain or irrigation follow the application before trees emerge from dormancy.
- Avoid nitrogen applications until after growth begins next spring.
Insect Pest Management
- Grade sheets may only identify damage as worms or off grade. Collecting nut samples from windrows and cracking out the nuts to identify which pest(s) infested almonds allows for evaluation of the current season’s pest management program and estimation of next season’s pest pressure. You will find descriptions of navel orangeworm (NOW), peach twig borer (PTB), and Oriental fruit moth (OFM) larvae and damage in this link. Select the moth of interest from the list of insects and mites.
- Be sure that equipment and hullers are cleaned of all nuts to minimize overwintering sites for NOW larvae.
- Winter sanitation of mummy nuts is critical for effective NOW management. Ensure that mummy nuts are removed from trees, blown to orchard middles, and destroyed by flail mowing before next season. It is important to bear in mind overwintering NOW survival is better in nuts, both in trees and on the ground during drought conditions. In winters with minimal rainfall, typical sanitation practices should be enhanced accordingly.
- If PTB is the primary off-grade, Bacillus thuringiensis (BT) sprays at petal fall and two weeks after petal fall effectively control this pest and pose minimal risk to honeybees. Avoid treating with any other insecticides when honeybees are present in the orchard.
- Dormant spur samples can help determine the need for dormant treatments. Samples for San Jose scale, European red mite, brown almond mite, and European fruit lecanium can be taken anytime between early November and early January. Sampling guidelines, treatment thresholds, and a link to the dormant spur sample monitoring form can be found here.
- Conduct a weed survey to evaluate the efficacy of the current year’s weed control program and make appropriate changes for next season. More information can be found here.
- Time pre-emergence herbicides for winter weed control mid-to-late fall. Watch the weather and apply shortly before rainfall so that rain will move the herbicide into the soil before seedlings emerge and include a post-emergence material if rains have already stimulated weed growth.
- If almond scab has been a problem, a dormant copper with oil spray will delay sporulation of overwintering scab lesions for a month next spring — possibly past the end of the rainy season, reducing disease next year. Dormant oil will also smother overwintering eggs of European Red and brown almond mites and control moderate populations of San Jose scale.
- Removal and destruction of mummy nuts as part of a sound NOW management program may help minimize hull rot (Monolinia and Rhizopus spp.).
- Scout for rust in young orchards and watch for leaf blight (individual dead leaves remaining on shoots) to inform potential disease management next season.