Population dynamics of eriophyid mites and evaluation of different management practices on timothy grass

Authors: DIVELY, G. - UNIVERSITY OF MARYLAND; HARTMAN, M. - UNIVERSITY OF MARYLAND; Ochoa, Ronald - Ron

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/3/2022
Publication Date: 2/3/2022
Citation: Dively, G.P., Hartman, M.E., Ochoa, R. 2022. Population dynamics of eriophyid mites and evaluation of different management practices on timothy grass. Journal of Economic Entomology. 115(1-2):1-9. https://doi.org/10.1093/jee/toac004.
DOI: https://doi.org/10.1093/jee/toac004

Interpretive Summary: Rust, gall and bud mites feed on all kind of plants and have been estimated that there are close to a million species on the planet. Many plant abnormalities and virus diseases are associated to these mites. They cause millions of dollars in losses in production on grasses, ornamentals, forest and fruit trees. This paper described the role of three rust mites affecting timothy grass in the eastern of United State. This information is useful for people working with grass/hay farmers, livestock farms, quarantine and pest control agents and agriculture ecosystems.

Technical Abstract: Several species of eriophyid mites are important economic pests of timothy grass in the Mid-Atlantic United States. Feeding causes stunting, curling and brown discoloration of leaves, and yield losses ranging 30 to 50%. Carbaryl is the only approved chemical control for these mites. We investigated the population dynamics of field infestations, host plant resistance, and several cultural control measures to develop a more sustainable management strategy. Seasonal phenology and overall abundance differed among timothy fields and between years, with mean peak densities ranging up to 731 eggs and 1163 mites per 2.5 cm of leaf blade. Population differences were related to the age of the field, the prevailing temperatures and snow cover during the fall and winter months. All varieties of timothy tested were susceptible, whereas several other forage grasses were significantly resistant to eriophyid mites and could be used as possible alternatives for replacing timothy. Fall harvesting reduced the buildup of mites during the winter but populations eventually rebounded and still reached economic densities by April. Burn-down herbicide, prescribed burning, and urea-based fertilizer treatments prior to green-up in the early spring had variable effects and may help to prevent economic losses; however, several concerns about the benefit/costs and practicality of these practices are discussed.