What is in this article?:
- Arizona Veg IPM: aphid control, downy mildew, and weed science
- Downy mildew on spinach and related plants
- Weed science and the agricultural systems management degree in Yuma
- Chlorotic spots at regular intervals on wheat seedlings
- Alate (winged) green peach aphids have begun to show up on younger lettuce plants (1st side-dress stage) and populations are beginning to colonize in Arizona’s Yuma Valley.
- Downy mildew has been observed on nettleleaf goosefoot and swiss chard in Yuma County, Ariz. and Imperial County, Calif. respectively.
- The University of Arizona in Yuma offers degree programs in agricultural systems management and crop production.
The latest Arizona Vegetable Integrated Pest Management Update from the University of Arizona (UA) Cooperative Extension in Yuma, Ariz., released Feb. 8, 2012.
Aphid control in desert produce
By John Palumbo, UA Research Scientist and Extension Specialist
Aphid pressure in the Yuma Valley has been quite low this season. However, alate (winged) green peach aphids have begun to show up on younger lettuce plants (1st side-dress stage) and populations are beginning to colonize.
Reports from the Dome Valley and Wellton suggest aphid populations are increasing there as well. This is common during February when produce acreage begins to rapidly decline and aphids tend to disperse to available crops.
The key to effective aphid management with foliar insecticide is to initiate sprays at the time apterous (wingless) aphids begin to colonize. This requires diligent scouting and sampling.
The UA action threshold for aphids recommends applications be made when 10 percent of the plants sampled contain aphid colonies (four or more apterous aphids).
Fortunately, pest control advisers (PCAs) have numerous alternatives for foliar aphid control in this Aphid Control Chart 2012.
Movento is highly effective and has the broadest spectrum of activity against aphids commonly found on desert produce crops. In addition, because it is fully systemic, the spray timing or application method is not as critical as with the other alternatives that are translaminar or require contact activity.
Beleaf and Assail are also good foliar alternatives for aphids, and typically perform best with ground applications.
Be sure to check that maximum residue levels are established for export before using these products.
Contact Palumbo: (928) 782-3836 or firstname.lastname@example.org.