By Scott Mauney | Palo Pinto County Agrilife Extension Agent
PALO PINTO COUNTY – Grasshoppers are occasional pests of ornamental landscapes, gardens and agricultural crops. But some years are worse than others.
A cool dry spring, like the one we just had, seems to provide the best opportunity for successive emergences of different grasshopper species. This results in a seemingly endless procession of the pests.
Because grasshoppers require relatively large breeding grounds in which to build large populations, most severe outbreaks occur near farmland and other less disturbed areas, such as in rural communities, farmsteads and urban fringe areas.
Although grasshopper damage is difficult to completely prevent during outbreak years, homeowners can minimize their impact through the use of barriers, insecticides and landscape plants that are less prone to damage.
Because residents of urban communities generally have little control over the surrounding countryside – the breeding grounds for grasshoppers – 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 (see the lists of preferred and non-preferred plants).
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, cyfluthrin and esfenvalerate should also provide good control. Products containing chlorpyrifos, diazinon and carbaryl will provide control for shorter periods.
Geotextile fabrics have found increased use among vegetable gardeners as floating row covers to protect plants. These fabrics are light enough to permit needed sunlight and air circulation to occur within plants that are covered, yet strong enough to provide a barrier to many insects.
During heavy grasshopper infestations, even these barriers may be damaged by hungry grasshoppers. It may be necessary to apply insecticides to the fabrics before they are used to cover the plants.
Some plants that require insect pollination may require hand pollination when covered by row covers. These fabrics may be obtained through some garden centers and via mail order catalogs.
The following list of plants, which are preferred and not preferred by grasshoppers, was created by extension horticulture agents, master gardeners and others. The plants listed were observed under heavy feeding pressure from grasshoppers. As with all lists, results may differ as a result of various conditions and different breeds of grasshoppers.
Preferred by grasshoppers:
Liriope & Mondo Grass
Not preferred by grasshoppers:
Bridal Wreath Spirea
Dwarf Mexican Petunia
Perennial thrift and dianthus
Cultural Tips: Control summer weeds in fallow fields. Short grass fields are less attractive to egg-laying adults and also there is nothing for the nymphs to eat when the eggs hatch. Eliminate tall grasses and weeds from around any plants you wish to protect (crops, trees and gardens). This makes the area less attractive to grasshoppers and makes it easier for birds to prey on grasshoppers.
For more information check these websites: AgriLifeExtension.tamu.edu, citybugs.tamu.edu/factsheets; or call your County Extension Office at (940) 659-1228.