Well, it seems to be time for the insect of the week!

There have been reports from numerous locations here in the RRV and some of the drier areas to the east of small grasshoppers both in CRP, ditches, roadsides, fields, etc. Just in case these little hoppers turn out to be one of the Big 5, I thought it might be timely to provide some info on the 5 agriculturally important grasshopper species that are common up here.

All 5 (in order of seasonal appearance - Twostriped, Migratory, Clearwinged, Redlegged, and Differential) are problems because they readily feed on a variety of plant species and will track available resources - i.e. switch from one crop to another when the first either becomes less palatable (e.g. drying wheat) or when the first is harvested. All 5 prefer to lay eggs in no-tilled soil, so infestations generally start at field edges and then progress into the field. Subsequently, the thresholds (see below) are lower within the field (if there are numbers in the middle of the field, there are already higher numbers at the edge). Treating the production area (where the eggs were layed) is only recommended if the numbers there are very high - fields can still be infested by neighboring, but not adjacent, production areas.

Scouting
Scout the field margins first, if there are no grasshoppers there, it is unlikely they are in the middle of the field. The exception is some species will lay eggs in soybeans, alfalfa, and dry bean fields. Also at risk are no-till systems for obvious reasons. The thresholds (see below) are calculated on a sq yd basis but it will be impossible to count the number of hoppers in a sq. yd - so do the following..... Walk along field edges, picture a 1 sq ft area in front of you and as you approach, count the number of grasshoppers that hop out of that area. Do this ~20 times through the region to be sampled and get an average - multiplt the average by 9 and you have the average no. of grasshoppers / sq yd.

Thresholds

Nymphs - 50-75 / sq.yd. at the field margin,
                   15-25 / sq.yd. within the field
Adults - 10-20 / sq.yd. at the margin,
                  >8 / sq.yd. within the field

I realized that I often say I hope this information is useful - actually I hope the problem doesn't develop and you have no use for it at all!!

Table 1 provides a listing of most of the registered insecticides for use in controlling grasshoppers in crop and other land use sites. Always check the label as the final source of application information.