Systemic Insecticides for the Control of Western Flower Thrips on Bulb Onions1

The western flower thrips, Frankliniella occidentalis (Pergande), and the onion thrips, Thrips tabaci Lindeman, have been considered insect pests of economic importance on onions in most onion-growing areas for many years. However, at the present time there is disagreement in some areas as to how much damage they cause. Harding (1961) found that research reports concerning the effect of thrips on onion yields are in conflict and apparently indicate a trend suggesting that as onion varieties and cultural methods have been improved, thrips have had less effect on yields of bulb onions.