Swather Applied Trilogy® Effects on Twospotted Spider Mite Populations and Resultant Alfalfa Yields and Quality

Abstract

Trilogy® was applied via swather at cutting in April to alfalfa infested with twospotted spider mites. Data from samples obtained at 12 days after application noted somewhat reduced spider populations as a result of Trilogy® application, although new growth was thought to be re-infested from previously cut alfalfa which was in contact with new growth. Western flower thrips later became very prominent in plots and resulted in greatly reduced spider mite populations. Trilogy® treatment resulted in increased yields thought due to larger stem diameters as a result of fewer spider mites early in study. Very slight increases were also noted for alfalfa quality parameters as a result of Trilogy® application. Economic analysis indicated that Trilogy® applied via swather in this experiment resulted in a net increase in alfalfa valued at $2.12/acre.