In the summer of 2021, Oregon suffered its worst outbreaks of grasshoppers and Mormon crickets in fifty years. A record 10 million acres of rangeland in 18 counties suffered damaging levels of infestation. At infested sites, grasshoppers reached an average density of 65 animals per square yard (8 or more grasshoppers per yard can cause significant damage to rangeland).
We already had a historic outbreak in 2020, when 60% percent of all ODA survey sites recorded significant grasshopper numbers.
Grasshopper outbreaks often follow or coincide with drought years. Low rainfall and warm spring weather support egg hatches and survival of small grasshopper nymphs. As a result, grasshoppers develop rapidly. These conditions also reduce the impact of predators and diseases that limit grasshopper numbers.
Grasshopper outbreaks mean less forage and vegetation cover essential for livestock and wildlife. Less vegetation leads to environmental damage and erosion. Starving grasshoppers may also invade agricultural areas where they eat crops.
Grasshopper and Mormon Cricket Population Suppression
Senate Bill 5561 passed in response to the forage loss on Oregon rangelands from outbreak grasshopper populations in 2020 and 2021. The bill provides one-time funding of $5,000,000 to help combat the severe grasshopper season expected in 2022.
The bill provides funding for resources to support a grasshopper and Mormon cricket outbreak suppression cost-sharing program.
- $803,207 for pretreatment and post-treatment surveys.
- $4,196,793 for suppression treatments.
- Participation in grasshopper surveys is open to both private and public landowners.
- Public lands treatments will be conducted by USDA APHIS in coordination with ODA.
- Private landowners and land managers may be eligible for reimbursement of treatment expenses.
How to apply
To apply for reimbursement, applicants must first:
And then provide the following:
- A completed application form.
- Itemized invoice marked PAID or receipt for product costs and application costs.
- IRS W-9 form: All applicants must turn in a W-9 regardless of previous reimbursements.
Complete the process:
Approved treatments for all pest grasshoppers and Mormon crickets are with the growth insecticide diflubenzuron. Diflubenzuron is one of a class of insecticides that work by disrupting normal insect development, by inhibiting the synthesis of chitin in the insect exoskeleton.
When used according to label directions, diflubenzuron is low-risk for people, pets, and livestock including honeybees.
The treatment is applied aerially because it is quick and efficient for treating rangeland. Using the “reduced agent/area treatment” strategy, the pesticide is applied at rates below label rates, and only every other pass. This leaves alternating strips of lands that are treated and untreated. This way, pesticide use is minimized.
Grasshoppers are active and mobile insects. Grasshoppers in the untreated areas will move into the treated areas and encounter the pesticide. Populations of beneficial insects, like biological control agents, will find refuge in the untreated areas.
Unlike many other alternatives, diflubenzuron requires only a single application per season. A single treatment can achieve up to 85% control of grasshopper pests.
Diflubenzuron is generally of low toxicity to people, livestock and wildlife, and may be applied to field crops, row crops and orchards.
Diflubenzuron is non-toxic to honeybees.
Diflubenzuron does not persist in the environment long-term. In soil, the half-life of diflubenzuron is from 2 to 7 days.
- Early April - approximately July 4
- Nymph surveys begin when grasshoppers hatch.
- May – August
- Suppression treatment completed based on the area and species.
- Two weeks after treatment
- Follow-up survey completed to evaluate effectiveness.
- July 5 – August 31
- Late-emergence surveys and treatments as needed.
- Adult surveys to create a risk map for the next year.