Date of this Version
Published in Agronomy Journal 96 (2004), pp. 224–228
The clover leaf weevil (Hypera punctata F.) is a sporadic but potentially serious pest of alfalfa (Medicago sativa L.). Feeding of newly emerged adult fourth instar clover leaf weevil was simulated in a field study at the University of Nebraska Haskell Agricultural Research Lab near Concord, Nebraska, in May 2001 and 2002. Twelve 1- by 1-m plots were arranged in a randomized complete block design with three treatments and four replications. Treatments consisted of two levels of simulated clover leaf weevil defoliation of alfalfa and an undefoliated check. Leaflets were removed over 10 d. Dry matter yield and other plant responses were measured during the first two growth cycles. Yield differences among all three treatments were significant for the first growth cycle. The relationship be-tween percentage defoliation and percentage yield reduction was linear both years. Defoliation did not significantly affect percentages of acid detergent fiber, neutral detergent fiber, and protein. Alfalfa development also was not significantly affected in the second growth cycle. Dry matter yield reduction as a result of leaf removal at the early bud stage was the most important effect of first growth cycle defoliation.