The dry, mild winter has led to extreme grasshopper numbers in many areas. You may not have noticed them yet because they are small. Soon these insignificant grasshopper nymphs will grow. As they feed, they increase in size, appetite and impact. As with many natural resource issues, we only notice the problem when it has grown beyond our capacity to manage it. Rather than reaping frustration later, sow solutions now.
Be on the lookout for small (<1/4 inch) juvenile hoppers. When they are small, grasshoppers are concentrated near hatching sites. Not only are they more susceptible to treatment in nymph stages but can be more readily targeted. With maturity grasshoppers gain increased jumping mobility and the ability to fly long distances. Assuming the drought trend continues, as hillsides dry up these mature grasshoppers are likely to move to irrigated areas. Repeated treatments are likely going to be necessary.
There are several treatment options:
Baiting: Wheat bran + carbaryl or Nosema locustae (a natural grasshopper pathogen) can be spread around gardens and flower borders. Grasshoppers eat the bait as they are foraging for food. It is easy to apply, but expensive. This selectively kills grasshoppers and other foraging insects.
While effective, baits can be a challenge to acquire. If you have greater than five acres and are experiencing a severe infestation you may be able to get bait from the Idaho State Department of Agriculture. Go to their website under “Grasshopper and Cricket Program” and complete a request form.
Dust (carbaryl): This is easy to apply, but the dust does not readily adhere to foliage and must be reapplied frequently. Grasshoppers are killed as they eat the treated foliage. This is the least effective form to control grasshoppers.
Sprays (malathion, carbaryl, permethrin, bifenthrin, zeta-cypermethrin): This option is less expensive and kills on contact, or when grasshoppers eat foliage. This also is the least selective and can indiscriminately kill beneficial insects, potentially leading to other insect problems later in the year. Treating a border around areas needing to be protected will offer control until grasshoppers mature and become more mobile