QUESTION: I have a lot of grasshoppers in my yard. They are eating everything! How can I control them?
ANSWER: In Cochise County we have several species of grasshoppers, some are very colorful and grow quite large. Grasshoppers emerge in the spring from eggs laid last year. Grasshoppers hatch as miniature adults and molt 5 or 6 times during a period of 40 to 60 days. The young feed in the immediate vicinity and then move on to "greener pastures" as food sources become depleted. Adults begin laying eggs shortly after they mature. Eggs are laid in the ground in pods that contain 15 to 75 eggs. A female can lay a total of 200 to 400 eggs during several weeks. Hatching rate depends on soil temperature and moisture and may continue for 3 months. Some species have more than one generation per year. Grasshoppers feed on grasses and other plants. When populations increase they will feed on nearly any kind of vegetation including bark and leaves of deciduous trees. Adults continue to feed until cold weather kills them. Natural weather cycles cause fluctuations in populations. Mild winters and warm, dry springs increase hopper populations. Cold, wet weather cause slow development and favor grasshopper diseases. Cool summers and early falls delay maturity and decrease the egg laying period.
Control: If desert surrounds your property it can become very difficult to control grasshoppers because of large populations that can become migratory. Disturbing egg pods in the soil by tilling or plowing will expose egg pods, decreasing their viability. Young small hoppers are easier to control than adults. "Picking and squashing" is a time consuming but effective control measure. Several chemical insecticides will control grasshoppers as well as the abrasive nature of diatomaceous earth. Nosema locustae is a naturally occurring disease organism of grasshoppers. Bran and sweeteners are added to Nosema to attract the hoppers. Grasshoppers are cannibalistic and infection spreads as healthy hoppers eat sick ones. Also the females pass this disease on to future generations through laid eggs. Nosema will take longer to destroy grasshopper populations than conventional pesticides. This is a living organism and must be stored in the refrigerator and has a limited shelf life. Contact your local nursery or garden catalog for current recommendations. Always read the label of pesticides and use them accordingly.
Source: Insect Pests of Farm, Garden, and Orchard. 1979. R.H. Davidson and W.F. Lyon. pp. 117-119