Last week, a call related to damaged creeping red fescue growing near Bear Canyon triggered a conversation of things to keep in mind when heading out to scout grass fields in the Fall:
Several species of insects utilize grasses grown for seed. Compared to annual crops, perennial grasses grown for seed are typically left in production for 2-3 years (and even longer) so the soil profile is disturbed less frequently when it comes to tillage and seeding. The soil profile stability offers a unique habitat to soil-dwelling organisms. Cutworms, webworms, wireworms, and many species of beetles are just a handful of insect groups that can be found in grass seed production systems and spend large portions of their lifecycle below ground. Even though pest species can be present, natural enemies and pollinator species also inhabit grass fields grown for seed.
More in-depth scouting information can be reviewed in the Alberta Forage Manual. This resource includes two sections describing (i) pest and (ii) beneficial species of arthropods typically present in western Canadian grass seed production systems. Download a searchable PDF copy.
Learn when and where to look in the field by reviewing these cutworm scouting tips published by the Prairie Pest Monitoring Network. The PPMN has multiple cutworm-related posts archived from the past growing seasons and you can review that list here.
If you find insect larvae, determine if it has legs, where the legs are positioned and how many legs are visible. This step helps determine if it's a cutworm, fly larva, or beetle larva. Use Figure 1 below and note how many pairs of legs and where those legs are positioned.
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| Figure 1. Picture key to identifying insect larvae copied from ENTFACT-017: Recognizing Insect Larval Types by Lee Townsend, Extension Entomologist, University of Kentucky College of Agriculture, Cooperative Extension Service. https://entomology.ca.uky.edu/ef017 |
Estimate length of the larva. In the fall, all larvae can be very small and exceedingly difficult to find. In fact, easily encountering larvae in the fall may mean a high density of overwintering individuals are present so live specimens should be examined by an expert. Mark areas of the field where larvae are present in fall. Additionally, prioritize the field for spring field scouting weekly through April, May and June!
When it comes to cutworms, review this excellent Cutworm Field Guide. This resource is a searchable PDF guide to all things cutworms including descriptions and photos of different cutworm larvae, host-crop associations, and scouting tips.