Factors that encourage BGM infestations include host drought stress, elevated temperatures, low rainfall, low humidity, absence of TSM, lack of natural enemies, insecticide use, and adequate moisture for alternate hosts during the previous growing season. Most BGM problems occur in the drier corn-growing areas of the state and always are associated with grasses. For example, many problems in corn start when adjacent wheat starts to dry down. In comparison, TSM occurs in more humid growing areas such as along river bottoms. This mite is found in many Crops, but it is common for corn infestations to occur in fields with nearby alfalfa.
Banks grass mite and two-spotted spider mite.
Biological Control Preservation of biological control agents is critical to proper management of spider mite problems in corn. Thirty-five natural enemy species from 15 families of predatory Insects, mites and spiders have been associated with mites on corn. Mites are also subject to fungal disease. Commercial biological control is not cost effective, so conservation of naturally-occurring biological agents is essential. Many fields go untreated each year because the mites are held in check by various predatory mites, lady beetles, minute pirate bugs, lacewing larvae and thrips.