Often undetected by the naked eye, spider mites take advantage of crop stress and weakness for their own gain. These piercing, sucking pests look to severely damage your corn or soybean leaves while satisfying their own appetites.
If you start to notice more stress in your plants, especially corn, check for spider mites with a magnifying glass. If left unchecked, they can kill leaves and reduce photosynthetic capabilities of plants.
60% Yield Robber
Typically, spider mites hang out in the central Plains, where weather conditions are nice and dry. Irrigated fields tend to have less mite damage, but you should still scout and treat when you reach threshold.
“The key thing is to be aware of host areas,” says Brian Battles, UPL territory sales manager.
Factors that can elevate risk of spider mite, according to Battles and the University of Nebraska Extension, include:
- Longer periods of dry, hot weather favor mite infestations.
- Drought that causes stress in crops increases susceptibility.
- Wheat, cover crops and other host fields nearby provide overwintering habitat.
Check leaves for yellow to whiteish spots. If present, check the underside of leaves for webbing, eggs or the presence of mites. Female mites typically only reach 0.016", so bring a magnifying glass to help look for them.
Spider mites cause the most damage in corn when they infect the ear leaf and above. They can cause up to 60% yield loss in soybeans, according to research from the University of Nebraska Extension. Also watch for reduced quality in silage corn from mite feeding.
Treat and Track
If possible, wait to treat crops until they are in the reproductive phases of growth, at a full rate of miticide. However, this year provided extra challenges as prolonged drought conditions pushed some farmers to treat early and again later in the season.
“I’m not a big fan of split applications, most consultants aren’t,” Battles says. “We prefer single, full-rate applications of 54 oz. [rate specific for Comite II brand] rather than split application. You can get four weeks of control of mites in all stages from that.“
If you have early infestation, Battles suggests keeping track of populations in your fields. The longer you can keep damage below the ear leaf, the longer you can hold off on application to hopefully hit better timing.
To learn how to identify the two types of spider mites, visit AgWeb.com/spider-mites
