European Crane Fly: Larval Infestations in Grass Cultivars12

Abstract

The effects of larvae of Tipula paludosa Meigen on 20 irrigated and unirrigated forage grass cultivars and 21 irrigated turfgrass cultivars were evaluated from 1973 to 1975 by determining numbers of larvae in soil cores and examining associations between agronomic characters of the grasses and numbers of larvae. Only minimum infestations of larvae developed in unirrigated forage grasses. Differences in numbers of larvae between irrigated forage grass cultivars were numerically large but not statistically significant, but there were some instances in which an inverse association between hay yields and numbers of larvae was statistically significant. Associations between numbers of larvae and broadleaf weeds in irrigated forage grasses were numerically moderate but had questionable biological significance, and no associations were apparent between stands of weedy grasses or irrigated forage grasses and numbers of larvae. Differences in numbers of larvae between individual turfgrass cultivars were statistically significant but not sharply defined. However, comparisons of turfgrass types showed well-defined differences in numbers of larvae. The number of larvae in ryegrass plots was less by an average factor of 2.4 than numbers in fescue, blue, or bentgrass plots. Differences in larval population levels between irrigated and unirrigated forage and turfgrasses were attributed to differences in soil and atmospheric moisture conditions during the oviposition periods of the European crane fly.