Efficacy of Oil and Photosensitizer against Frankliniella occidentalis in Greenhouse Sweet Pepper

Abstract

Many common insect pests have developed resistance against the pesticides currently available, to the point where pest and disease management has become extremely difficult and expensive, increasing pressure on agriculture and food production. There is an urgent need to explore and utilize alternatives. Due to their unique mode of action, photosensitizers may be able to control insect pests effectively, especially in combination with oil-based products, without the risk of resistance build-up. In this study, the efficacy of a mineral oil-based horticultural spray oil, PureSpray™ Green (PSG), and a sodium magnesium chlorophyllin photosensitizer formulation, SUN-D-06 PS, were evaluated and compared to a registered cyantraniliprole insecticide (as positive control) and a negative control against western flower thrips (WFT), Frankliniella occidentalis. In detached leaf ingestion assays, PSG at high concentration was more effective than low concentration, causing >70% WFT mortality, whilst SUN-D-06 PS + PSG caused higher mortality than cyantraniliprole after five days of feeding. The same combination was as effective as cyantraniliprole in the contact assay. In greenhouse pepper, the photosensitizer decreased the WFT more than mineral oil applied alone, whilst a combination treatment of SUN-D-06 PS + PSG was most effective, decreasing the WFT population to fewer than four WFT per plant. SUN-D-06 PS + PSG shows promise as a sustainable, economical way of controlling WFT, with the potential to be incorporated into existing integrated pest (and disease) management (IPM) programs with ease.

Overview of Updated Control Tactics for Western Flower Thrips

“…Other chemical-based tactics have been recently evaluated, within the last three years, against WFT. Such evaluation comprises the mineral oil-based horticultural spray oil, Pure-Spray™ Green (PSG), and a sodium magnesium chlorophyllin photosensitizer formulation, SUN-D-06 PS [55], essential oils from bioactive plants such as Zataria multiflora Boiss [56], and ethanolic extracts from Cercis siliquastrum L., Calendula officinalis L., Peganum harmala L., and Melia azedarach L. [57]. In addition, other commercial insecticides (e.g., proteus (thiacloprid + deltamethrin) and pyridalyl [58], spirotetramat [59], chlorpyrifos, beta-cypermethrin, abamectin, and thiamethoxam [60]) and naturally occurring compounds (e.g., anisole [61], azadirachtin [62], matrine [58], and methyl benzoate [63]) have also been evaluated against WFT to see the direct and fumigant effects.…”