Dry Edible Beans: Grasshoppers

Excerpt from Agronomy Guide for Field Crops (Chapter 7)

Order OMAFRA Publication 811: Agronomy Guide for Field Crops

Table of Contents

1. Damage
2. Life History
3. Scouting Technique
4. Action Threshold
5. Management Strategies
6. Updates on Dry Edible Beans: Grasshoppers
7. Related Links

Damage

Both adults and nymphs feed on the leaves and pods, including the seeds. High infestations can defoliate fields and cause yield loss. Feeding damage usually begins around the borders of fields, adjacent to grassy fencerows and pasture. Risk factors include neighbouring grassy fields and drought conditions.

Life History

Grasshoppers overwinter as eggs in the soil, usually in uncultivated fields and pastures. Nymphs hatch from the eggs in early June and begin feeding on emerging plants. Nymphal stages last for approximately 2 months with adults appearing later in the season to feed, mate and oviposit their eggs in the soil for next yearís population. Grasshoppers prefer to lay eggs in sandy soils with grassy, undisturbed areas. Drought conditions for 1-2 years favour egg and nymph survival.

Scouting Technique

Begin scouting in late June when grasshoppers are still young. Scout adjacent fencerows and grassy borders.

Action Threshold

Substantial yield loss does not occur until up to 35% defoliation occurs before bloom and 15% after bloom. If border plants show evidence of grasshoppers, a border spray may be necessary.

| Top of Page |

Management Strategies

Early-season control should be concentrated on the boundaries of the field in those areas with high nymphal populations. Refer to OMAFRA Publication 812, Field Crop Protection Guide, for insecticide recommendations. Several natural enemies, including ground beetles and crickets, feed on the egg stage, while birds and spiders feed on the nymph and adult stage, helping to reduce the populations. The fungus Entomophthora grylli can reduce the populations when weather conditions are warm and humid. Removal of grassy weeds in fields and borders by tillage helps reduce nymphal numbers that require these plants to survive. Tillage buries eggs deeper in the soil, hindering nymphal emergence. Chemical control is more effective on nymphal stages than adults. (Order OMAFRA Publication 812)

Updates on Dry Edible Beans: Grasshoppers

No updates available at this time.

| Top of Page |

Related Links

• Insects
• Dry Edible Beans
• Field Crop Protection Guide - Publication 812

| Top of Page |