Cutworm Issues for Wheat
GRAY: SE Colorado wheat growers are having terrible issues with epic army and pale western cutworm populations. Army cutworms spend the winter as a partially grown caterpillar. It will feed on warmer days throughout the winter. In the spring it feeds more frequently and development proceeds more rapidly. As the cutworms mature they become the moth’s or “millers” that are a household nuisance.
MARTIN: With the large numbers of army cutworms wheat producers in the state are trying to determine the best course of action but because of the sporadic nature of army cutworm outbreaks, management options are limited to the use of insecticides. It will take a bit of detective work to determine the amount of infestation and according to Frank Peairs, Colorado State University, you should treat if the count is more than four to five per square foot.
GRAY: Pale Western cutworm outbreaks are associated with dry conditions in the previous spring. If the preceding May and June had fewer than 10 days with 1?4 inch or more of rainfall, then pale western cutworm populations can be expected to increase. Drought conditions across the west for the last several years have allowed populations to increase and like army cutworms the use of pesticides is recommended.
MARTIN: The other question is what to do if there is a second pest, such as brown wheat mite or Russian wheat aphid, present in the same field? In the case of Russian wheat aphid, pyrethroids at the highest label rate will provide adequate control although not quite at the level of chlorpyrifos like Lorsban 4E and others. Such treatments would be an appropriate choice for a combination of cutworms and aphids.
And that’s Colorado Ag Today. I’m Greg Martin, thanks for listening on the Ag Information Network of the West.