Crop & Pest Report

Accessibility


| Share

European Corn Borer Trap Update (07/19/18)

The Iowa (or Z-race) of European corn borer (ECB) was captured in 8 of the 10 trap sites.

European Corn Borer Trap Update

The Iowa (or Z-race) of European corn borer (ECB) was captured in 8 of the 10 trap sites. This is an increased incidence from 3 trap sites the previous week. Trap catches also are slowly increasing, with the highest trap catch, 16 moths per trap per week, near the Antelope site in Richland County. Maps of the trapping results for ECB are posted weekly on the IPM website. Pheromone traps serve as an indicator of when moths are active – first and peak emergence - and are not used as action thresholds to trigger insecticide applications.

Knodel.6

Regardless, it is time to start scouting conventional field corn for egg masses and larvae. In whorl stage corn, pull the whorls from 10 plants at 5 locations across the field. For tassel stage or older corn, examine the underside of the middle 6 leaves (3 leaves above and 3 leaves below the ear leaf) on 20 plants from 5 locations in the field. Inspect plants for the presence of egg masses, whorl feeding, and active larvae.

In Table 1, the value of the corn crop is calculated as: [expected yield (bushel per acre) x projected price ($ per bushel)]. For expected corn yields, data were obtained from the 2018 ND Crop Budgets prepared by Andy Swenson, NDSU Farm Management Specialist, for the different areas of ND. For projected price, a futures market price of $3.54 per bushel from July 9th was used (Source:  Frayne Olson, NDSU Crop Economist/Marketing Specialist).

Knodel.7

In Table 2 (next page), the economic threshold for ECB is shown as larvae per plant, and factors in crop values and control costs. Again, crop value is the expected yield (bu/acre) X projected price ($/bu). Control cost is the insecticide price ($/acre) + application costs ($/acre). For example, if you grow corn in the South Valley, use $509.76 from Table 1 as your estimated crop value and if you select your control cost as $10 per acre, the economic threshold would be about 0.50 larvae per plant. If you grow corn in Southwest ND, use $325.68 from Table 1 as your estimated crop value and then if you select your control cost of $10 per acre, the economic threshold would be between 0.83-0.71 larvae per plant.

For insecticides registered for control of ECB in field corn, see the 2018 North Dakota Field Crop Insect Management Guide E1143. Pesticide applicators must READ, UNDERSTAND, and FOLLOW ALL LABEL DIRECTIONS.

Knodel.8

Janet J. Knodel

Extension Entomologist

This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

USDA logo

Creative Commons License
Feel free to use and share this content, but please do so under the conditions of our Creative Commons license and our Rules for Use. Thanks.