Q. Where are the grasshoppers now?
A. There always have been grasshoppers in Routt County. Just in the past few years they have increased their numbers to infestation levels. Reports of severe infestations (where grasshopper numbers exceed at least 20 per square yard) this year have been found in the Hilton Gulch area, Long Gulch and south of Milner.
Q. Are they out in full force, or do they still need a few weeks to mature?
A. There are several species of grasshoppers that have hatched, and the majority of them are still in immature stages called instars. Grasshoppers go through five instars before they become adults. Grasshoppers are born fully formed and at each instar, they shed their outer shell and develop a new, larger shell. Each grasshopper species hatches at slightly different times and localized environmental conditions can delay or encourage hatching, it is to early to tell whether the grasshoppers are at their peak. The vast majority of grasshoppers will hatch by late June. The grasshoppers will reach maturity 40 to 60 days after hatching.
Q. When will they be at their peak?
A. They will be at their peak as immature insects from now until late June. The adult populations will peak in mid-summer.
Q. Where were they at this time last year?
A. At this time last year, we had larger areas infested with greater numbers of immature grasshoppers, mostly west and north of Steamboat Springs. Last year's populations were easily over the threshold of 20 per square yard, and many counts were well more than 100 per square yard by June 10. This year, counts by myself, individual landowners and the U.S. Department of Agriculture official, have been much more varied.
Counts taken within a 10-mile radius around Steamboat have ranged from zero to more than 100 per square yard. On average, most sites sampled had eight to 12 grasshoppers per square yard, thus not meeting the threshold for consideration of treatment. However, a few localized areas mentioned above are at severe infestation levels.
Q. Have the grasshoppers spread to new parts of the county? If so, which new parts?
A. Other parts of the county (with the exception of north of Hayden) haven't been extensively surveyed, so I cannot say what those levels might be. North of Hayden has grasshopper counts above 20 per square yard and they have an additional pest called Mormon crickets. Mormon crickets are a cyclical problem in Moffat County, and they are becoming a bigger problem in eastern Routt County. When their numbers increase, they form into "bands" and they begin to move, sometimes up to a half-mile a day, consuming most vegetation in their path. These bands contain thousands of individual Mormon crickets and can be very devastating if they are affecting your property.
Q. What constitutes a grasshopper infestation or grasshoppers at epidemic levels?
A. An infestation is when grasshopper numbers exceed the typical populations in a given area. For Routt County, we are at infestation to be worthy of treatment when grasshopper counts exceed 20 per square yard. Severe grasshopper infestations in rangelands have been defined as 40 adult grasshoppers per square yard.
Q. What do grasshoppers do to people's lawns, gardens or ranches?
A. Each species of grasshopper have slightly different eating habits. Some prefer grass, others forbs, etc. The most common species found last year and this year is called a clear-winged grasshopper and its principal food source is grass. Although each species typically consumes only the preferred foods, when grasshopper populations reach extreme levels they will consume many or all types of vegetation including trees, flowers mesh netting, etc.
Q. How can people stop them?
A. It is best to treat grasshoppers when they're still in the early instar stages. When they are young, they're more concentrated on egg beds, and you can be more judicious in the use of pesticides. For specific recommendations, the Extension Office developed a flier to assist people in choosing the right insecticide or natural bait insectaries that are available by coming to the office or calling 879-0825 and requesting one. The Extension Office can answer questions regarding insecticide use and there risks to the environment, non-target insects, pets and people. Always read and follow label directions when using any insecticide.
Q. What areas have used aerial spraying? When will that start and finish?
A. Many individuals and specific landowner groups have done aerial spraying or are considering it if grasshopper populations exceed 20 per square yard. The Extension office did help organize specific areas in the County to be sprayed. To date, three areas met the population thresholds for spraying and were treated. These areas are the Whitewood Subdivision, Saddle Mountain Estates and Long Gulch. Private landowners not associated with the Extension office may treat other areas, also. Grasshopper treatments are not a mandated program by Routt County, and only those areas where landowners have requested treatment and population thresholds have been meet, will be aerially sprayed. Aerial spraying will last for the next two weeks.
Q. What animal is the primary above-ground herbivore in North American grasslands?
A. Grasshoppers consume more above-ground forage than any other species of animal in the grasslands of North America, including cattle and elk. While they are a nuisance when populations are high, and a real economic threat to crops and grazing land, they are also an important part of the natural ecological system. Grasshoppers stimulate plant growth, contribute to nutrient recycling, and are an important food source of other animals including at-risk species such as grouse.