Pest description, crop damage and life history
Predators and parasites of grasshoppers are numerous and at times play an important role in maintaining grasshopper populations at low densities. Unfortunately, under favorable weather conditions, population increases may overwhelm the natural controls, and grasshoppers may reach high densities.
A biological control that has been tested extensively and is commercially available is the protozoan Nosema locustae (Nolo Bait). Nolo Bait has an REI of 4 hr and is slow acting. It may not reduce grasshopper populations to subeconomic numbers the year of application. It is more effective applied to uncultivated areas such as field borders and pastures where grasshoppers breed. The timing of application is also important.
Disturbance or maturation of crops may cause grasshoppers to disperse. Take care not to cut vegetation or till soil of fields harboring grasshoppers if susceptible crops are being grown nearby. Large blocks of crops with less crop edge tend to be damaged less than smaller blocks.
Management-chemical control: HOME USE
Follow information on the label about the timing and cutoff date for spraying the particular vegetable you are treating. Spray damaged plants and any grass or weeds surrounding the vegetable garden when young hoppers or winged adults are seen.
- azadirachtin (neem oil)-Some formulations are OMRI-listed for organic use.
- kaolin-Applied as a spray to foliage and stems it acts as a repellent to some insect pests. Some formulations are OMRI-listed for organic use.
- plant essential oils (rosemary, etc.)-Some formulations are OMRI-listed for organic use.
- pyrethrins (often combined with other ingredients)-Some formulations are OMRI-listed for organic use.
Management-chemical control: COMMERCIAL USE
- acephate (numerous products) at 0.25 to 0.5 lb ai/a. PHI 14 days. REI 24 hr. Do not feed treated vines. Do not exceed 2 lb ai/a per year.
- beta-cyfluthrin (Baythroid XL, Tombstone Helios) at 0.019 to 0.025 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 14 days. Do not exceed 0.05 lb ai/a per season. Do not feed treated vines or hay to livestock. Toxic to bees, fish and aquatic invertebrates.
- carbaryl (Sevin bait) at 1.5 lb ai/a as bait. PHI 3 days for harvest of succulents, 21 days for harvest of dried, 14 days for forage, and 21 days for hay. REI 12 hr. Do not exceed 6 lb ai/a per crop. Toxic in aquatic habitats.
- chlorantraniliprole/lambda-cyhalothrin (Voliam Xpress) at 0.059 to 0.088 lb ai/a. PHI 21 days. REI 24 hr. Retreatment interval 5 days. Do not exceed 0.12 lb ai of lambda-cyhalothrin or 0.2 lb ai of chlorantraniliprole per acre per growing season. Do not graze livestock or harvest vines for forage or hay.
- cyfluthrin (Renounce) at 0.038 to 0.05 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 14 days. Do not exceed 0.1 lb ai/a per season. Do not feed treated vines or hay to livestock. Toxic to bees, fish and aquatic invertebrates.
- dimethoate (numerous products) at 0.25 to 0.5 lb ai/a. PHI 0 days. REI 48 hr. Do not feed treated vines.
- esfenvalerate (Asana) at 0.03 to 0.05 lb ai/a. Apply reduced rates (0.02 to 0.03 lb ai/a) to first and second instar larvae. PHI 21 days. REI 12 hr. Do not exceed 0.2 lb ai/a per year. Do not feed or graze treated vines.
- gamma-cyhalothrin (Proaxis) at 0.01 to 0.015 lb/a. PHI 21 days. REI 24 hr. Do not apply within 25 ft of an aquatic habitat, 150 ft if applied by air. Do not graze. Do not exceed 0.06 lb ai/a per year.
- lambda-cyhalothrin (Warrior II) at 0.02 to 0.03 lb ai/a. PHI 21 days. REI 24 hr. Do not graze or feed to livestock. Do not exceed 0.12 lb ai/a per year. Do not apply within 25 ft of an aquatic habitat by ground application, or 150 ft if applied by air.
- malathion (numerous products) at 1 lb ai/a. PHI 1 day. REI 12 hr. Do not graze or feed foliage to livestock. Washington and Oregon only. Grasshoppers are not specifically cited on the label.
- Nosema locustae (Nolo Bait)-Use as manufacturer directs. OMRI-listed for organic use.