Editor’s note: Get Growing, written by the La Plata County Extension Office’s Master Gardener Program, appears during the growing season. It features timely tips and suggestions for your garden and landscape.By Darrin Parmenter
Ever since childhood, I have never felt comfortable around grasshoppers, especially the ones that fly. They are big, they can hang onto your clothes or skin quite tightly and they even spit (commonly called “tobacco spit,” the dark brown liquid is partially digested plant material along with some other compounds).
Grasshopper presence can be somewhat sporadic, as populations greatly vary depending on environmental conditions early in the season. For example, if it’s cold and wet when eggs are hatching, the weather can be very destructive to newly hatched hoppers. On the flipside, a dry winter and spring can also be detrimental to their survival as new (and required) tender plant growth is not available.
Apparently, in 2016, none of those conditions existed, as significant damage has been reported throughout the county. Field crops such as grass hay, wheat and even alfalfa can be primary food sources. Garden plants, especially lettuce, beans, corn and onions, are a staple in their salad bar. Even landscape flowers and plants – annuals and perennials alike – do not escape their appetites. Within 16 hours, a grasshopper will eat its own weight in green food. Seven grasshoppers per square yard over 10 acres will eat the same amount as one cow.
For many gardeners, control of the insect can be somewhat challenging, as they can migrate significant distances. But if your property or garden tend to get attacked on a yearly, or every other year basis, I would recommend using a microbial insecticide called Nosema locustae (commonly referred to as Nolo Bait). It is a protozoan (so a biological control) that can cause infection when consumed. The Nosema locustae will build up in the gut of the grasshopper and will reduce their feeding. These weaker insects will then become pray to other, healthier grasshoppers and can become cannibalized.
Ideally, the bait should be applied around and within the garden beds early in the season since young grasshoppers are more susceptible to being infected. It is also slow acting, with death of young, soft-bodied grasshoppers taking up to three weeks. An additional treatment during the summer is also advised, as the protozoan spores can be passed through the egg-laying process of a pregnant female with the next year’s young being infected soon after birth.
Darrin Parmenter is the director and horticulture agent of the La Plata County Extension Office. Reach him at firstname.lastname@example.org or 382-6464.