Activity and pest status of surface-active Collembola in Tasmanian field crops and pastures

Twenty-six surface-active species of Collembola were identified in Tasmanian field crops, only two of which were not recorded from pasture. Some species were noticeably more abundant in either field crops or pastures. The lucerne flea, Sminthurus viridis (L.), was the most damaging species and some field damage by the sminthurids Bourletiella hortensis (Fitch) and B. viridescens Stach to seedling cucurbits was recorded. No other surface-active species was found causing direct damage in the field. Laboratory studies showed that B. hortensis, B. viridescens, Katianna australis Womersley, Katianna sp. 1, the isotomid, Isotomurus palustris (Mueller), and the entomobryid, Entomobrya unostrigata Stach, can all feed on live plants albeit at low levels, and exhibit a high consumption level on decaying plants. Differences in the susceptibility of plant species to attack were also observed. These results, together with field observations, suggested that live plant material is not necessarily their most preferred food source.