One of the most common invaders of gardens is the grasshopper. Unfortunately, they are also one of the most difficult pests to control. Grasshopper populations vary naturally from season to season, and this is certain to be a problem year for gardener grasshopper conflicts in some areas. Grasshopper problems tend to increase as the summer progresses and continue into the fall.
One problem with grasshoppers is that they love the same kinds of food that we do. They are particularly fond of lettuce, carrots, raspberries and onions, but unless they become prolific, they generally do not cause too much damage to squash, peas and tomato leaves. They must be true connoisseurs of what's good because they love both green and ripe tomato fruits.Many ornamental plants are also attacked. Conifers are usually avoided, but if food is scarce, the hoppers will eat virtually anything. Most trees and shrubs are not favored by grasshoppers, however they provide convenient hiding places, and as the hoppers nibble on these over the course of a season, they can cause considerable damage. Large established trees and shrubs are not severely damaged by this injury, but on small, new woody plants this can be fatal.
Grasshoppers breed and develop in dry, undisturbed sites, including pastures, empty lots or roadsides. As plants in these areas dry out, the grasshoppers begin looking for fresh green food. To fully manage grasshopper populations, controls must be directed at these breeding sites. As the grasshoppers hatch in these areas, they are easily controlled with almost any insecticide if spraying or baiting takes place prior to the time the hoppers develop wings. Often, many homes will be infested from a single vacant lot and so controls should be aimed at these breeding sites. As the wingless nymphs are detected, treat them to prevent further problems.
In addition to sprays, baits are available to help control the problem. Baits should be scattered early in the morning before the grasshoppers have started to feed. They usually contain Sevin mixed with bran or other food stuff. Another control is a biological disease organism containing a protozoan, Nosema locustae. This product provides long-term reductions in grasshopper populations, but does not provide immediate control. It is best used in conjunction with insecticides to achieve both rapid knock down and long-term reduction of the hoppers.
One trick to reduce grasshopper damage is to keep a strip of weeds and other vegetation between the yard and the adjoining fields well watered. Spray this area with Dursban, a longer residual pesticide, to keep the insects out of your yard. They will collect and feed in the sprayed area and hopefully will be killed there instead of invading your garden.
Once grasshoppers are in yards, the control options decrease and depend primarily upon sprays. They are not easily controlled, and generally, repeated applications are required in order to keep them under control. Even after controlling all of the grasshoppers in your yard, if the hoppers have not been controlled at the initial breeding site, they will reinvade from those areas. Sprays labeled for grasshoppers include Diazinon, Sevin or Malathion. Organic gardeners can use pyrethrum or insecticidal soap.
Poultry, including turkeys, guinea hens and chickens, will also help control grasshoppers. If you are using poultry for grasshopper control, avoid spraying grasshoppers that the animals may later eat. Be certain to read and follow all label directions. Many sprays are not labeled for food and have specific restrictions as to how soon after spraying the produce can be harvested. Cultivating unused soils will also help control the problem. Cultivate or irrigate unused areas in the fall to reduce egg laying.
If there is a bright side to the grasshopper problem it is that just like the fable, they do not overwinter. Therefore they don't come inside our homes looking for shelter and don't get into our stored food. Direct your efforts as an all-out attack when they are small and wingless and it will solve many problems in your garden.
- LEARN THE BASICS of composting at the "Starting a Compost Pile Workshop on Saturday, June 18, from 9-10:30 a.m. at the USU/Utah Botanical Gardens at 1817 N. Main, Farmington. Don Gruenewald will share his gardening knowledge with the public. For more information, call 451-3204.