Onion thrips, Thrips tabaci, are one of the most economically damaging pests for onion growers in Western NY. In addition to reducing photosynthetic capabilities of plants, they can also vector Iris Yellow Spot Virus (Bunyaviridae: Tospovirus), transport Stemphylium leaf blight disease spores (Pleosporaceae: Stemphylium vesicarium), and provide entry points for bacterial bulb rots. Thus, effective management of thrips is criticaI to onion production. I am currently studying the use of reduced rates of fertilizer as a cultural control tactic for onion thrips, in combination with action-threshold based insecticide usage. In the three years we have done this research, these trials have been replicated in a combined twenty five commercial onion fields in muck regions of western and central New York. In addition to assessing thrips populations throughout the season, I measure yield and bulb rot prevalence following harvest to assess impacts of fertilizer rate and insecticide frequency on yield and storage quality.