Control of Thrips tabaci Lind. in onion crops in the Lockyer Valley

Abstract

Thrips tabaci Lind. is normally present in bulb and seed onion crops in the Lockyer Valley, the major commercial onion district in Queensland. During 1951-55 an investigation of the pest status of this insect included 11 screening and field trials under irrigated conditions, using 14 insecticides. Thrips populations were reduced satisfactorily by several insecticides, but parallel yield increases were not obtained
consistently. In irrigated plantings, unthrifty onion plants, rather than vigorous ones, carry large thrips populations, and are also more susceptible to thrips damage. Irrigation of onion crops in the Lockyer Valley, as carried out over the past decade, has in effect reduced the status of thrips as a pest, and has forestalled the benefits which might have been derived from the use of modern insecticides under the older dry farming conditions.