Robert Henson1, Denise Olson2, Janet Knodel2, and Bryan Hanson3. (1) North Dakota State Univ, Carrington Research Extension Center, PO Box 219, Carrington, ND 58421-0219, (2) North Dakota State Univ, Dept of Entomology, Hultz Hall, Fargo, ND 58105, (3) Langdon Research Extension Center, 1750 10th Street, Langdon, ND 58249
Crucifer flea beetle, Phyllotreta cruciferae (Goeze), is an economic
pest of seedling canola. Canola is an important crop of North Dakota
agriculture and it is becoming expensive to produce due to high input
costs of pesticides, seed and fertilizer. Efficacy and agronomic
performance of using reduced proportions of insecticide-treated canola
seed was compared using commercially available seed treatments at their
low and high rates. Four different proportions of treated seed were
evaluated: 0%, 33%, 67%, and 100% treated seed. Results from six site
years indicate that flea beetle feeding injury to seedling canola is
inversely related to proportion of treated seed. The 100, 67, 33, and
0% treated seed treatments had an average injury rating of 3.2, 3.6,
4.0, and 5.0. respectively, across site years. Yield was generally
higher for 100% treated seed and decreased proportionally as
percentage of treated seed declined regardless of seed treatment.
This research indicates that proportion of treated seed at high or
low rates of insecticide seed treatment can influence flea beetle
control, and agronomic performance of canola.