Thrips tabaci Lindeman (Thysanoptera, Thripidae) in leek: within‐plant distribution

Abstract

Both larvae and adults of the onion thrips (Thvips tubucz Lindeman) showed a preference for particular parts of leek (Allium porrum L.) plants. In the vertical plane most thrips were located in the transition zone where the leaves in the shaft were still white but gradually changed through yellow to pale green. At high population densities mixed groups of adults and larvae could be found along the entire leaf. In the horizontal plane larvae and adults showed a normal distribution pattern preferring certain leaves. Chemical treatments did not influence the within-plant distribution pattern of larvae and adult rhrips in the horizontal plane when compared to distribution patterns in untreated plants. Reinfestation of treated pIants by immigrating adults took place swiftly and developed into the characteristic pattern within a few days.

Onion Thrips (Thysanoptera: Thripidae): A Global Pest of Increasing Concern in Onion

“…Sites and Chambers (1990) found that temperature induces diapause in T. tabaci populations and eggs can be laid as soon as temperature increases during the spring. T. tabaci lay eggs where they feed and move continually to younger tissue (Theunissen and Legutowska 1991). T. tabaci lay more eggs and develop faster on onion leaves than on onion bulbs (Gawaad and El-Shazli 1970); however, they lay their eggs indiscriminately on leaves, cotyledons, petals, sepals, and glumes (Lewis 1973).…”

Evaluation of Sampling Methodology for Determining the Population Dynamics of Onion Thrips (Thysanoptera: Thripidae) in Ontario Onion Fields

“…They are generalists, feeding and overwintering on a diverse selection of plants and weeds (McKinlay 1992, Cho et al 1995 and are considered a serious economic pest of onions, leeks, garlic, and shallots worldwide (Boyce and Miller 1954, Theunissen and Legutowska 1991, Brewster 1994. Although onion thrips are a major concern to growers around the world, in Ontario, their control has often been secondary to managing the onion maggot, Delia antiqua (Meigen) (Tolman et al 1986).…”

Pest and disease management by intercropping: Suppression of thrips and rust in leek

“…Based on the low numbers found, natural enemies do not appear to play a role in controlling populations of thrips. The thrips larvae live and cause damage predominantly in the tightly-packed shaft of the leek plant (Theunissen and Legutowska, 1991b). If a predator was to have a significant influence on the thrips population at such sites, it should have been found in large numbers among the thousands of plants examined.…”