Hadfield

Grasshoppers have come into the valley and are proving once again to be a nuisance. Even though our wet spring has delayed the grasshoppers, they have already began causing damage to crops, gardens and lawns.

Grasses and forbs in rangelands sustain grasshoppers for much of the spring and early summer and when the grasses and forbs begin to dry out, the grasshopper populations continue to increase. Grasshoppers begin to move towards lush green plants to eat, which brings many grasshoppers down into Cache Valley. Irrigated crops, pastures, gardens and lawns are attractive sites to hungry grasshoppers. As grasshoppers migrate down into the valley, here are some tips to protect your plants from grasshopper destruction.

First, to combat grasshopper infestations, it is important to treat as broad of an area as possible as soon as grasshoppers are present. To have success in a neighborhood, a community-wide approach is the best method. Having your neighbors on the same page will help to treat a larger area and will help prevent grasshoppers from moving into your yard or crops. Second, to make sure your treatment is effective, target grasshoppers while they are young or in the nymph stage. Grasshopper do not develop wings until they are adults, making nymphs less mobile than the adult form. Once grasshoppers become adults, they can travel long distances and usually do not remain in one area long enough for insecticides to have an effect.

Grasshoppers can be controlled by mechanical and chemical methods. Mowing a wide swath around the borders of your property can help limit the migration of grasshopper nymphs into your crops. It is especially important to mow any borders that are adjacent to open fields, roadsides, drainage ditches and other unmanaged lands. Chemical methods mainly include using insecticides to help reduce grasshopper numbers. Using both mechanical and chemical methods in areas mentioned above is the most effective way to control grasshoppers.

There are three type of insecticides used to kill grasshoppers: Baits, dusts and sprays. Baits consist of wheat bran mixed with an insecticide (Carbaryl) or a natural grasshopper pathogen (NOLO Bait). Grasshoppers will eat the bait as they are foraging for food. It selectively targets grasshoppers and other foraging insects. It must be reapplied frequently mainly following wetting events (rainfall or irrigation).

Dusts are also easy to apply, but they are more expensive. One of the main problems with using a dust is that it does not adhere to plants and has to be reapplied frequently. The only type of dust approved for home application is carbaryl (Sevin).

Sprays are the least expensive treatment out of the three chemical methods, but they require that you have the equipment to apply the sprays. Sprays stick to plant material better and kill grasshoppers on contact. Some of the sprays that control grasshoppers include malathion, permethrin, bifenthrin and carabryl. Whenever using any insecticide, make sure to read the label. Some insecticides require an applicator license and others are not safe on edible plants. Always read the label before application to make sure that you are applying the insecticide correctly and in a safe manner.

Grasshoppers are in the nymph stage throughout the county; it will not be long before they reach their adult form. Treatments will have their greatest effect on grasshoppers at this stage of their life cycle. Now is the time to treat grasshoppers so you can protect your crops, gardens and yards. Once grasshoppers grow into their adult form they become nearly impossible to control.

Jacob Hadfield is the USU Extension specialist for agriculture covering Cache County, appointed in July, 2019. His office is located in the County Administration Building, 179 N. Main Street, Suite 111, in Logan. He can be reached directly at 435-752-6263 ext. 1574 or jacob.hadfield@usu.edu.