By John Wood, Certis USA Regional Manager
Q. What factors should I consider for this spring’s disease management plan?
- Be diligent in your scouting and be on top of your fungicide programs.
- Gather input from county extension and universities to keep you informed about disease pressures as they occur throughout the region.
- Consider your orchard’s history of disease in your planning.
- The timing of your fungicide sprays is critical for optimal disease control.
- Be prepared to move quickly if the weather turns rainy. As almonds enter their bloom season, infection of some diseases (like brown rot) will be favored by rainy weather.
- Pistachios begin their bloom in April and a fungicide program for Botrytis and Botryosphaeria should start then.
Most important, put anti-resistance strategies in place for all your tree nuts. It is always important to practice fungicide stewardship. After your dormant Kocide + oil sprays, consider starting your fungicide program with Double Nickel 55 biofungicide and its five multi-site modes of action. Then continue in rotation with or in tank mixes with fungicides of different modes of action.
Q. When should I start my disease program for tree nuts?
A. This year I’m suggesting you consider using Double Nickel 55 biofungicide and Cueva, a low-load copper octanoate fungicide/bactericide, as the cornerstones of your fungicide program. Here’s why. Both Double Nickel and Cueva are contact and systemic materials, which maximizes your flexibility. You can use both in combination with a systemic fungicide or use them alone as a contact material. Both have a short 4-hour reentry and can be used on organic or conventionally grown nuts.
For bacterial canker, you can apply Cueva as a dormant spray when buds begin to swell, repeating at the bud burst stage and weekly thereafter as needed, up to six sprays. For brown rot blossom blight, start and repeat with Cueva or Double Nickel at the bud swell, popcorn, full bloom and petal fall stages. For walnut blight, make your first applications when leaflets start to unfold, prior to, but no later than 1% pistillate bloom.
Please note that Double Nickel 55 and Cueva are also compatible with the Bts you use for PTB and worm control. The Bt I recommend is Deliver. It is based on Bt subspecies kurstaki and is formulated with a higher concentration of Cry1Ac proteins than the average Bt.