How to Manage Pests

UC Pest Management Guidelines



Scientific Names: Melanoplus spp., Trimerotropis spp.

(Reviewed 11/06, updated 11/06)

In this Guideline:


Grasshoppers are readily distinguished from most other insects by hind legs, that have greatly enlarged femurs, are well adapted for jumping. Their bodies are robust and their antennae relatively short. In contrast, another alfalfa pest in the order Orthoptera, crickets, have long antennae. Most grasshoppers are winged and many are good flyers, although a few species are flightless.

Grasshoppers may be a pest in alfalfa production, but vary greatly in importance from area to area and season to season. They sometimes develop in uncultivated areas and move into cultivated fields. They should be controlled before they enter the alfalfa field.


Grasshoppers feed on leaves and stems. When populations are high they can cause severe defoliation.


Economically significant levels vary with the growth of the crop; in general, populations of 15 per square yard or higher are considered severe. Control measures will depend on the growth of the crop and the stage of development of grasshoppers present. Grasshoppers are best controlled before they enter alfalfa fields. Check with your County Agricultural Commissioner regarding the current registration of baits to control grasshoppers in alfalfa fields.


[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Alfalfa
UC ANR Publication 3430

Insects and Mites

L. D. Godfrey, Entomology, UC Davis
E. T. Natwick, UC Cooperative Extension, Imperial County
P. B. Goodell, Entomology, Kearney Agricultural Center, Parlier
R. F. Long, UC Cooperative Extension, Yolo County

Acknowledgment for contributions to Insects and Mites:
C. G. Summers, Entomology, Kearney Agricultural Center
M. Rethwisch, UC Cooperative Extension, Riverside County (Blythe)
D. R. Haviland, UC Cooperative Extension, Kern County

Top of page

Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2015 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance.

Agriculture and Natural Resources, University of California

Accessibility   /PMG/r1301111.html revised: September 2, 2015. Contact webmaster.