All potatoes in the Columbia Basin should be sampled for mites. All potatoes that are at least one month from harvest should be surveyed for the presence of mites and mite eggs starting July 15. Sampling for mites requires a close visual inspections of leaves from differing levels of the plants. Use of at least a 16x hand lens is important for detecting mites in low numbers. There are no registered miticides available that will provide full control or serve as rescue treatments once mite populations reach outbreak levels.
Thorough coverage is essential for good control.
The two most significant insect pests of potatoes in the world, Colorado potato beetle and green peach aphid have eventually developed resistance to virtually every insecticide used for their control. While the Pacific Northwest has largely escaped this problem, the development of insecticide resistance in these pests is still an issue that the potato industry needs to be prepared for. Once resistance is established in a population to an insecticide, the utility of this product is largely lost. Avoidance of resistance or resistance management is the best means to preserve the effectiveness of potato insecticides. In 2001, PNW potato growers will have access to four planting products, Admire, Gaucho, Genesis and Platinum and two foliar products, Provado and Actara, that belong to the same class of chemistry, the neonicotinoids.