Is it possible to control grasshoppers so that they don't eat my garden?
Grasshoppers are very mobile insects, but they have some habits and parts of their life cycle that make them easier to control. Plan to control the grasshoppers when they are young and don't have wings. When female grasshoppers lay eggs, they tend to lay them in the same area. This "nesting site" is a place where young grasshoppers will congregate when they first hatch. If you live in a rural area, have a grassy open area by your home or if there are any areas of taller grass around your home; you should start scouting those areas now to see if young grasshoppers are present. If you find a nesting site, that is an area to treat. For grassy areas or ornamentals, you can use any insecticide labeled for that type of area. There are also some insect growth regulators that will not kill the insect, but will prevent it from molting and the insect will die in molting stage. There are different products for pasture use and for homeowners. Another treatment is Semaspore or Nolobait is a fungus that infects grasshoppers and kills them. It then spreads to other grasshoppers that come in contact with the dead grasshopper.
To protect vegetable or ornamental gardens, the best choice is to stop the grasshoppers before they get to the garden. Keeping weeds and grass short along a fence line will keep them from congregating. You can also treat these areas with an insecticide as well as your lawn or the border around your garden. This way you can hopefully kill the insects as they forage before they get to your prized plantings. For ornamentals only, you can use a systemic called Acephate. For vegetables you can use Pyrethrin, Azadirachtin (both labeled organic) or Carbaryl, Esfenvalerate, cyfluthrin, or lambda-cyhalothrin. Do not use Semaspore on vegetables. Be sure to follow the label when using any chemical. Other ways to control grasshoppers is with floating row covers or poultry. Guineas won't eat your vegetables.
For more information contact the OSU Extension Center, 14001 Acme Road, corner of MacArthur and Acme Road in Shawnee or 273-7683.