College of Agriculture

Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/4

As the foundation of the land grant mission at Montana State University, the College of Agriculture and the Montana Agricultural Experiment Station provide instruction in traditional and innovative degree programs and conduct research on old and new challenges for Montana’s agricultural community. This integration creates opportunities for students and faculty to excel through hands-on learning, to serve through campus and community engagement, to explore unique solutions to distinct and interesting questions and to connect Montanans with the global community through research discoveries and outreach.

Browse

Author: search.filters.author.Reddy, Gadi V. P.Subject: search.filters.subject.Nominal thresholds

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Developing nominal threshold levels for Phyllotreta cruciferae (Coleoptera: Chrysomelidae) damage on canola in Montana, USA
    (2014-12) Tangtrakulwanich, Khanobporn; Reddy, Gadi V. P.; Wu, Shaohui; Miller, John H.; Ophus, Victoria L.; Prewett, Julie
    The flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) (Coleoptera: Chrysomelidae) are serious pests infesting canola (Brassica napus L.; Brassicales: Brassicaceae) in the Northern Great Plains of the United States. In Montana, P. cruciferae is the only flea beetle species that attacks canola during the crop growing stage. Management of P. cruciferae is usually focused on treating adults feeding on canola seedlings, which is the stage most vulnerable to flea beetle damage. In the Golden Triangle area in Montana, canola growers traditionally use seed treatments or calendar based spraying to control P. cruciferae. Here, we compared calendar-based spraying with seed treatment and threshold-based treatment. The experiment treatments included threshold levels (15–20, 25, 45% of leaf area damaged), calendar based sprays (15, 30 and 45 day intervals after plant emergence), seed treatments (imidacloprid), and untreated controls. The trials were done at two locations (Conrad and Western Triangle Agricultural Research Center). We found that calendar-based spraying at a 15-day interval did not differ significantly in yields from threshold-based treatment at 15–20% leaf damage. Also, the seed treatment did not give significantly higher yields compared to calendar-based sprays. A negative correlation was detected between leaf damage and yield in each treatment. Overall, calendar-based and threshold-based treatments were most effective in improving yields. However, treatment made at the threshold of 15–20% leaf area damage is recommended in order to reduce the number of chemical applications and also to reduce the possibility of selecting for resistance in flea beetles.
Copyright (c) 2002-2022, LYRASIS. All rights reserved.