GRASSHOPPER CONTROL

    Temperature and rainfall are primary factors for determining grasshopper survival, but the presence of diseases and natural enemies and the number of eggs laid by the previous year's population also affect final grasshopper numbers.

    These grasshoppers came from eggs that were deposited in the soil and started to develop last fall.  During the coldest part of the winter, they "go to sleep" and resume developing in the spring.  Peak egg-hatch usually occurs from late May to mid-June and different species will hatch at different times during the spring and early summer.

    Newly hatched grasshopper nymphs are very small, measuring less than 1/4 inch long and may go unnoticed by the homeowner.  After hatching, a grasshopper nymph will have to molt (shed its outer skin) six times in order to reach adulthood which will occur by early July.

    Most people I talk to want to know what they can do about their grasshopper problem.  Unfortunately we, as homeowners often have very limited control over our surroundings (with the exception of our own yard) therefore our options for management are also limited.  Homeowners really have three options available to them:  1) use of non-preferred plants in the landscape;  2) use of geotextile fabrics for physical protection of plants; and  3) use of residual insecticides.

    Pest grasshoppers commonly encountered by homeowners feed on a variety of plants, but seem to favor certain plants over others.  Consider using some of the non-preferred plants in the landscape to keep some color and foliage in the landscape, even during a grasshopper onslaught.

    Preferred plants - Althea, Amaryllis, Bachelor's Buttons, Bush honeysuckle, Butterfly bush, Canna lily, Cherry Laurel, Day Lily Eleagnus, Hibiscus, Holly, Iris, Liriope, Mondograss, Peach, Photinia, Privet, Rose, Salvia, and Wisteria.

    Non-Preferred: American beautyberry, Artemesia, Bridal Wreath Spirea, Coralberry, Crape Myrtle, Dwarf Yaupon, Dwarf burning bush, Dwarf Mexican petunia, Eldarica (Afgan) pine, Euonymus, Forsythia, Juniper, Lantana, Moss Rose, Nandina, Passion Vine, Perennial dianthus, Persian Lilac, Rock Rose, Salvia greggii, Verbena (perennial) and Vitex.  Geotextile fabrics can be used as a physical barrier to help protect prized plants.  They are made of a lightweight, spun fabric (Remay and others) that allow limited air circulation and permit sunlight to penetrate, but serve a a mechanical barrier.  These fabrics can be found at garden centers or through garden supply catalogues.  If grasshoppers become really numerous, they may start to feed on the fabric.  In that situation, it might be necessary to apply a residual insecticide to the fabric before placing it on the plant.  Select the insecticide based upon which products are labeled for the plant being protected.

    Several products are available for grasshopper control in the yard and garden.  They may have to be reapplied every 5-7 days to obtain adequate protection from large numbers of grasshopper adults.  Products containing bifenthrin (Ortho Home DefenseÒ) cyfluthrin (BayerÒ Advanced Lawn and Garden Products or lambda-cyhalothrin (ScimitarÒ) will probably provide longest residual control and quickest knockdown.  Others containing permethrin (Spectracide Bug Stopâ) esfenvalerate (Ortho Bug-B Goneâ) or carbaryl will work, but have slightly shorter  residual activity.  It is crucial that the label be followed because some insecticide products can injure sensitive plants.

    Homeowners should realize that grasshopper adults are very mobile, and when they occur in large numbers, will likely overwhelm a landscape late in the year.  They will likely abandon any "perference" an feed on nearly anything (including painted house siding).  As adults they will be more difficult to kill with insecticides.  This will lead to a high frustration level, so control programs should be initiated before they reach that stage.