Pest description, crop damage and life history
Common Pests of Vegetable Crops
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 as allowed per label when young hoppers or winged adults are seen.
- azadirachtin (neem oil)-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. Only registered for use in WA.
- 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 XL) 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.
- 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.