Grasshopper Management Under Drought Conditions
DS-1-97, June 1997
revised May 2004
Department of Entomology
Cultivation of the soil at the proper time can be one of the most effective cultural practices available to farmers for the reduction of grasshopper populations. Tillage reduces grasshoppers by eliminating the green plants on which grasshoppers feed. Fields that are tilled in late summer or early fall will not attract grasshoppers for egg-laying activity. Grasshoppers seldom lay eggs in tilled fields even when a heavy covering of plant residue remains.
Early spring tillage is a better option than fall tillage during seasons of drought for the obvious reasons of reducing wind erosion and trapping snow to maximize moisture for the next growing season. It is advisable to complete early spring tillage to eliminate all green growth before grasshopper egg hatching begins. If no food is available when they hatch, the young grasshoppers will starve because they can only move a short distance (about a yard) to locate food. Early spring tillage will also provide weed control to conserve moisture.
Tillage for the sole purpose of physically destroying grasshopper egg pods or exposing them so that they dry out or are consumed by birds and other predators is of limited value. Again, the primary benefit of a well-timed tillage operation is to either reduce green plant material for attracting adult hoppers or to induce starvation by spring tillage.
If grasshoppers are present when tillage operations begin, it will probably be impossible to achieve adequate control by simply eliminating green plant material in a field. Once grasshoppers have fed and developed to the second growth stage (2nd instar), they usually are mobile enough to move to adjacent crops for a new food supply. In these fields, trap strips could be used to "collect" or concentrate grasshoppers in a relatively small area. Then it is possible to control them quickly and economically using a minimum amount of insecticide.
Trap strips can consist of narrow strips of weeds left during tillage or seeded small grain strips grown to concentrate adult hoppers. The disadvantage of this method is that the grower has to fallow the strip area a second year and utilize another method of control.
Late summer or early fall cover crop seedings and winter wheat may be in jeopardy in areas where grasshoppers have been a problem during the growing season. As an example, flax seeded for a cover crop on fallow ground in areas of high hopper incidence could be lost within a few days of emergence. Winter wheat could also disappear rapidly to hungry adult hoppers. Thimet 20G systemic insecticide applied as a planting time treatment can give effective hopper control in wheat. Since the hoppers will be feeding into fields from the margins, normally only the margins for about 80 to 100 feet into the fields should require treatment.
Green vegetation in fall stubble left for winter wheat cover should be controlled since it will draw hoppers into the field prior to planting winter wheat. Current recommendations for winter wheat include spraying a herbicide at least two weeks ahead of seeding to desiccate volunteer grain used as a food source by the wheat curl mite that transmits wheat streak mosaic. Early control of this fall regrowth has the additional benefit of reducing attractiveness of these fields to grasshoppers.
High hopper populations in stubble left for winter wheat could make spring seeded grain a more practical alternative, especially in drought affected fields. Late seeded winter wheat is a second alternative since hoppers become lethargic and less active as fall approaches.
Additional Resources that can be Accessed through the Internet:
North Dakota State University Extension Service
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Insect Updates for North Dakota - a source of insect information for the region
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NDSU Crop and Pest Report Newsletter - seasonal information for North Dakota agricultural production
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NDSU IPM Field Crop Survey - Grasshopper field surveys affecting cropland around the state.
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E-272 Grasshopper Biology and Management. NDSU Extension Circular (web version).
North Dakota Department of Agriculture
Road Right of Way Grasshopper Control Laws and Considerations
Other Resources:
- Map of the western United States illustrating the current Grasshopper and Mormon Cricket Outbreak and Survey Information: Field surveys and mapping were done by USDA-APHIS-PPQ Western Region.
2004 National Rangeland Grasshopper Forecast Map
2003 National Rangeland Grasshopper Forecast Map
2002 National Adult Grasshopper Survey Map
Grasshoppers: Their Biology, Identification, and Management
(USDA-ARS Northern Plains Agricultural Research Laboratory)
A comprehensive resource for information on grasshopper management that contains the latest research in grasshopper management, identification, ecology and control tactics, including:
- APHIS� Grasshopper Integrated Pest Management User Handbook
This handbook provides practical information on biological and chemical control methods; range management techniques; and environmental impacts. It incorporates decision support tools and an overview of grasshopper ecology, outbreaks and modeling.
- Field Guide to Common Western Grasshoppers
This handy guide provides an overview of grasshopper biology, anatomy, populations and life cycles. It also shows how to survey and collect grasshoppers.
- Grasshopper Species Fact Sheets
This collection of 56 species fact sheets features distribution maps and color photographs for each species, as well as information on their economic importance, identification and biology.
- Grasshopper Identification Tools
Identification guides, keys, and photographs to help identify over 90 species of grasshoppers. While there are more than 400 known species of grasshoppers in the Western United States, only about two dozen are considered pest species and a few are beneficial.
- Decision Support Software for Rangeland Grasshopper Management
Hopper 4.0 and CARMA 3.3 computer software provide advice on the best course of action when dealing with grasshopper outbreaks on rangeland.
- New Grazing Management Research
The latest preventative grasshopper management research on using grazingmanagement to reduce the intensity and duration of grasshopper outbreaks.
- New Grasshopper Chemical Control Methods (RAATs)
The latest techniques for reducing application rates and costs up to 50% by alternating untreated swaths with treated swaths. RAATs maintains effective grasshopper control and reduces environmental impact.
- New Integrated Pest Management Research
Includes: South Dakota RAATs Demonstration Project Report, North Dakota IPM Demonstration Project Report, Preventative Grasshopper Management Brochure
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