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ARS Home » Southeast Area » Stoneville, Mississippi » Southern Insect Management Research » Research » Publications at this Location » Publication #369009
Research Project: Integrated Insect Pest and Resistance Management on Corn, Cotton, Sorghum, Soybean, and Sweet Potato

Location: Southern Insect Management Research

Title: Effect of nitrogen fertilization on flea beetle (Phyllotreta cruciferae) and cabbage seedpod weevil (Ceutorhynchus obstrictus) injury and crop yield in dry land canola

Author
item BRIAR, SHABEG - Montana State University
item SHRESTHA, GOVINDA - Oregon State University
item SHARMA, ANAMIKA - Montana State University
item MILLER, JOHN - Montana State University
item Reddy, Gadi V.P.

Submitted to: Phytoparasitica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/27/2019
Publication Date: 11/21/2019
Citation: Briar, S.S., Shrestha, G., Sharma, A., Miller, J.H., Reddy, G.V. 2019. Effect of nitrogen fertilization on flea beetle (Phyllotreta cruciferae) and cabbage seedpod weevil (Ceutorhynchus obstrictus) injury and crop yield in dry land canola. Phytoparasitica. 47:637-645. https://doi.org/10.1007/s12600-019-00762-x.
DOI: https://doi.org/10.1007/s12600-019-00762-x

Interpretive Summary: The flea beetle and the cabbage seed weevil are two economically important pests of canola. In this study, we investigated the effects of N fertilization with or without insecticide seed treatment on flea beetle and cabbage seedpod weevil injury levels, along with canola seed yield and quality in replicated field trials in west central Montana. We found that N fertilization had no influence on flea beetle and cabbage seedpod weevil injury levels, regardless of trial location or sampling date. However, insecticide seed-treatment significantly influenced flea beetle injury ratings at both locations. In contrast, insecticide seed treatment had no impact on pod infestation rates by cabbage seedpod weevil. Insecticide seed-treatment improved canola grain yield and quality parameters compared to the untreated plots.

Technical Abstract: Nitrogen (N) availability is an important factor affecting canola (Brassica napus L.) yield. While N fertilization is commonly used to enhance the yield and quality of canola, it is also known to influence the incidence of key insect pests of the crop. The flea beetle Phyllotreta cruciferae (Goeze) and the cabbage seed weevil, Ceutorhynchus obstrictus (Marsh), are two economically important pests of canola in the northern Great Plains of the United States. In this study, we investigated the effects of N fertilization (0, 56, 112 and 168 kg/ha) with or without insecticide seed treatment on flea beetle and cabbage seedpod weevil injury levels, along with canola seed yield and quality in replicated field trials in west central Montana. We found that N fertilization had no influence on P. cruciferae and C. obstrictus injury levels, regardless of trial location or sampling date. However, insecticide seed-treatment significantly influenced P. cruciferae injury ratings at both locations. At one location (Conrad), insecticide-treated plots had significantly lower injury ratings in the four leaf, pre-flower, and pod formation stages, but insecticide treatment had no effect at the cotyledon stage. At the second location (Sweetgrass), injury ratings were significantly lower in insecticide-treatment plots from the cotyledon through the pre-flowering stages but were not lower at the pod stage. In contrast, insecticide seed treatment had no impact on pod infestation rates by C. obstrictus at either location. Insecticide seed-treatment averaged over all the N rates, improved canola grain yield and quality parameters compared to the untreated plots.