UC IPM: UC Management Guidelines for Grasshoppers on Cotton

UC Pest Management Guidelines

Grasshoppers can be occasional early season pests. In late summer and fall, grasshopper eggs are laid in grassy foothills, on ditchbanks, along roadsides and fence rows, in pasture areas, and in alfalfa fields. The eggs hatch in spring and the young nymphs feed on nearby plants. When wild grasses and other plants become dry, the grasshoppers migrate to irrigated croplands.

Grasshoppers feed on foliage, most often on the edges of fields near pasture areas or roadsides. They seldom cause economically significant injury.

Topical treatments are most effective; treating field borders may be adequate. Insecticidal baits are not effective in cotton itself but may be when applied to rangelands or other breeding grounds before grasshoppers migrate to crops.

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 efficacy, selectivity, persistence, and impact on honey bees. When choosing a pesticide, also consider information relating to environmental impact.

MALATHION 8E

1.5–3 pt

SELECTIVITY: Low

PERSISTENCE: Pest–Short; Natural Enemies–Short

MODE OF ACTION GROUP NUMBER¹: 1B

COMMENTS: Limited residual effectiveness.

NALED

(Dibrom) 8EC

0.5–0.75 pt

see comments

SELECTIVITY: Low

PERSISTENCE: Pest–Short; Natural Enemies–Short

MODE OF ACTION GROUP NUMBER¹: 1B

COMMENTS: Apply before bolls open. Do not graze livestock in treated fields. Destructive of natural biological control. Tank mixing may affect selectivity and persistence of this material. Do not apply more than 5 pt/acre/season.

**	Mix with sufficient water to provide complete coverage.
+	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 REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
*	Permit required from county agricultural commissioner for purchase or use.
¹	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 to help prevent the development of resistance. 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 Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.

UC IPM Pest Management Guidelines: Cotton
UC ANR Publication 3444
Insects and Mites
L. D. Godfrey, Entomology, UC Davis
P. B. Goodell, UC IPM Program, Kearney Agricultural Center, Parlier
E. T. Natwick, UC Cooperative Extension, Imperial Co.
D. R. Haviland, UC IPM Program, Kern Co.
Acknowledgment for contributions to the insects and mites section:
E. E. Grafton-Cardwell, Kearney Agricultural Center, Parlier
N. C. Toscano, Entomology, UC Davis

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How to Manage Pests

UC Pest Management Guidelines

Cotton

Grasshoppers

DESCRIPTION OF THE PESTS

DAMAGE

MANAGEMENT

PUBLICATION