Oviposition by frit fly, Oscinella frit, on young ryegrass seedlings.
Abstract
In laboratory experiments, oviposition by females of Oscinella frit at high population densities was negligible on single-leaved seedlings of ryegrass (Lolium spp.), even in the absence of host-plant choice, and a strong aversion to 2-leaved plants was demonstrated. The surrounding soil was a less attractive oviposition site than small seedlings, which were appreciably attacked only if the seed remained exposed, providing oviposition sites within the seed coat when the seedling emerged. It was concluded that young ryegrass seedlings are not selected as oviposition sites for a period of 2-3 weeks after sowing, and the significance of this to control strategies is discussed. At this growth stage, most oviposition differences between ryegrass species and cultivars could be explained by the availability of oviposition sites, or, where the choice was unattractive, by seedling size.