Thrips IPM in floriculture: cutting dips to start clean

Abstract: Biocontrol programs against western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) start early in the crop cycle. Small numbers of thrips that are carried on cuttings used in floriculture production increase to damaging levels within a few weeks despite the application of biocontrol agents. This research determined the frequency and the number of pests coming in on chrysanthemum, mini-rose and spring bedding plant cuttings, and evaluated several reduced-risk materials, such as insecticidal soap (Kopa), oils (Landscape oil, SuffOil-X, Vegol) and biocontrol agents (BotaniGard 22WP, Nemasys) as cutting dips.Low numbers of thrips were present year-round on the majority of the cuttings. Most products and product combinations were not phytotoxic to a range of common crops, including several bedding plants, chrysanthemums and mini-roses. However, the higher concentrations of oil-based products did cause damage. Oil-based dips had the highest efficacy against thrips. When used to treat chrysanthemum cuttings infested with thrips eggs and larvae, thrips numbers were 65% to 95% lower on treated cuttings than on the untreated control. The challenge now is to find rates of oils that are not phytotoxic, but still effective against thrips.