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How to Manage Pests

UC Pest Management Guidelines

| More pests | More crops | About guidelines |

Grasshopper adult.

Small Grains

Grasshoppers

Scientific name: Melanoplus spp.

(Reviewed 2/07, updated 2/07)

In this Guideline:

DESCRIPTION OF THE PEST

Grasshoppers may occasionally attack grain crops, particularly if planted adjacent to foothill rangeland. They normally migrate from the range into cultivated areas as vegetation on the rangeland dries up.

DAMAGE

Grasshoppers destroy leaf tissue and, if present in extremely large numbers, they will consume the entire plant.

MANAGEMENT

Management Decisions
Since most grasshopper problems begin outside the grain field, areas favorable to grasshopper development should be carefully monitored for build-up and control measures taken if necessary.

Common name Amount/Acre R.E.I.+ P.H.I.+
(trade name)   (hours) (days)
The following materials are listed in order of usefulness in an IPM program, taking into account impact on natural enemies and honey bees. When choosing a pesticide, also consider information relating to environmental impact.
 
A. DIMETHOATE 4EC 0.33–0.5 pt 48 60
  MODE OF ACTION: An organophosphate (Group 1B)1 insecticide.
  COMMENTS: For use on wheat and triticale only. Do not make more than 2 applications/year. Do not graze within 14 days. Highly toxic to honey bees if bees are present at treatment time or within a day after.
 
B. MALATHION 8EC 0.5 pt 12 7
  MODE OF ACTION: An organophosphate (Group 1B)1 insecticide.
  COMMENTS: May be used on barley, oats, wheat, rye. If alfalfa is in bloom, apply during the night or early in the morning when bees are not foraging in the field.
 
C. METHYL PARATHION*
  (Penncap-M) 1–3 pt 5 days 15
  MODE OF ACTION: An organophosphate (Group 1B)1 insecticide.
  COMMENTS: May be used on barley, oats, and wheat. Do not graze within 15 days. This product is highly toxic to foraging bees, young hive bees, and brood. Do not apply to any field when bees are present or in the surrounding vicinity.
 
D. CARBOFURAN* 4F 0.25–0.5 pt 48 0
  MODE OF ACTION: A carbamate (Group 1A)1 insecticide.
  COMMENTS: May be used on wheat, oats, barley. Apply before heads emerge from boot. Do not feed treated forage. Do not apply near waterfowl. Highly toxic to bees for 7–14 days after application; do not apply to blooming crops or weeds. Do not make more than 2 applications/season.
 
 
+  Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the R.E.I. exceeds the P.H.I.; the longer of these two intervals is the minimum time that must elapse before harvest may take place.
* Permit required from county agricultural commissioner for purchase or use.
1 Modes of action are important in preventing the development of resistance to pesticides. Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode of action is assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Small Grains
UC ANR Publication 3466
Insects and Mites
C. G. Summers, Entomology, UC Davis/Kearney Agricultural Center, Parlier
L. D. Godfrey, Entomology, UC Davis
Acknowledgment for contributions to the insect and mite section:
D. Gonzalez, Entomology, UC Riverside

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Statewide IPM Program, Agriculture and Natural Resources, University of California
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