Grasshoppers in the Yard and Garden

By PR Extension Office

“Not surprisingly, grasshopper populations are increasing in our area,” according to MSU Powder River Extension Agent Mary Rumph. “Once grasshoppers are adults and have entered the yard and garden, management is extremely challenging. It often becomes a priority of choosing what is most valuable to you.” For example, Rumph said to consider focusing on the most vulnerable trees and plants for management (and those of importance). “Also understand that treating an area once is seldom enough…you might need to re-treat several times to protect your garden, lawn or trees,” said Rumph. “Last year I treated around my lawn and trees three times, approximately a week apart. Fortunately, it was later in the summer, in early August. This summer, I have already treated once for grasshoppers in my yard, and it wasn’t even mid-June. I think it is going to be a long summer!” said Rumph.

Most grasshoppers overwinter in the egg stage in the soil. After egg hatch in mid- to late spring, the nymphs (immatures) immediately begin feeding. There are at least five or six stages of nymphs before the grasshoppers reach adulthood. The adult grasshoppers can live for several months into late summer/early fall.

Many plants and flowers will be hard to protect. Screen the garden and sensitive areas with metal window-type screening, as they easily chew through fabric.

Several insecticides are available and labeled for use on grasshoppers including organic insecticides and biological controls. Some of these include Neem oil which includes products such as AzaGuard and Pyrethrins which are products such as PyGanic. Nosema locustae is also known as NoLo Bait. Nosema locustae is a protozoan/fungus that is selective to grasshoppers and applied with a bran that the grasshoppers have to consume. It is only effective when grasshoppers are in the 1st and 2nd nymph stages (when the grasshoppers are 1/4-1/2” long).

Non-Organic Insecticides include Bifenthrin & zeta-cypermethrin, products such as Ortho Home Defense Insect Killer for Lawn and Landscape and Ortho Bug B Gon Insect Killer for Lawns and Gardens; Cyfluthrin, products such as Bioadvanced Complete Insect Killer and the product Mary prefers to use, Carbaryl, which can be purchased as Eco Bran bait or Sevin.

“My preference last summer was the liquid Sevin that attached to a hose,” said Rumph. “I used it to spray the young trees (juniper and blue spruce) in my yard and along the border of the lawn and garden,” concluded Rumph.