Exploring non-chemical management options for Allium pest insects.

In recent years, allium growers within Vermont have experienced increasing pressure from several resident insect pests, particularly onion thrips (Thrips tabaci) and leek moth (Acrolepiopsis assectella). The emergence of onion thrips as a major pest within the region coincides with the increased usage of black plastic mulch for onion production in Vermont. Black mulch provides growers with a low tech multi-functional practice that reduces weed and disease pressure, elevates soil temperatures, and in combination with drip irrigation can reduce water usage. However, the resultant warmer and drier microclimates at the base of alliums (especially onions) from black mulch application also provide ideal conditions for fast growing thrips populations. Similarly, leek moth infestations are becoming an increasing concern for allium growers within the state, particularly organic growers interested in low-tech solutions. To best address these two pest simultaneously our team explored the interactions and potential interference of pest management tactics for controlling both thrips and leek moth in organic farming systems. Specifically, we examined the interplay of three key tactics: mulching (both plastic and straw), irrigation methods (overhead versus drip), and the utilization of insect exclusion netting.