Generally only one generation of grasshoppers is produced each year; however cool, dry weather during the spring months and the successive emergencies of different grasshopper species can result in a seemingly endless procession of these insects throughout the summer and fall months. Grasshopper eggs are generally laid during the fall and late summer in rural, non-crop landscapes, such as along ditches, fencerows, and shelter-belts, and in weedy areas. They may also be laid in crop areas after harvest, within weedy fields, and in forage areas and pastureland. Eggs usually hatch the following spring, in June and July. The development of grasshopper nymphs to the adult stage requires 40 to 60 days or more.
Adult forms of the differential grasshopper usually appear in mid-July. The adult grasshopper is the most voracious feeder, and is able to disperse over large areas due to its strong wings. The adult grasshopper is the most likely stage to invade and damage ornamental landscapes.
Because residents of urban communities generally have little control over the surrounding countryside, management options for grasshoppers in urban landscapes are limited. Homeowners can protect valuable plants, to some extent, through the use of residual insecticides. Geotextile fabrics can be used as barriers to protect valuable vegetables and specimen ornamental plants. Also, landscape plants that are less attractive to grasshoppers can be used.
Recent tests have shown that insecticides containing bifenthrin (found in some Ortho® Home Defense? products) and lambda-cyhalothrin (Scimitar®) provide the fastest knockdown and longest residual control. Products containing permethrin (several manufacturers), cyfluthrin (Bayer® Advanced Lawn and Garden products), and esfenvalerate (Ortho® Bug-B-Gone) should also provide good control. Insecticides containing chlorpyrifos, diazinon and carbaryl will provide control of shorter duration.