Crop pollen effects on the ovipositional rate of western flower thrips, Frankliniella occidentalis on tropical soda apple, Solanum viarum

Over the past 40 years, Frankliniella occidentalis, western flower thrips (WFT), has become one of the most prevalent pests of agricultural and horticultural crops. The success of this insect as a pest is due to the thigmotactic behavior, high fecundity and and the ability to travel long distances on wind currents. WFT are associated with the transmission of tomato spotted wilt virus (TSWV), which can be transmitted to many commonly grown, economically important crop plants such as tomato and pepper, via the feeding habits of the WFT. As the range of this insect has increased, so too has the range of TSWV. This virus has devastating effects on the crops it affects. TSWV has been found experimentally in invasive tropical soda apple (TSA), Solanum viarum plants, which means that this plant may serve as a reservoir of the virus. The feeding and reproductive role that TSA may play in the life cycle of the WFT is unknown, however, and this information is important for agricultural and horticultural crop producers. 

This investigation observed the oviposition of WFT on TSA, using tomato and pepper plants for control species, as the WFT is known to feed and reproduce on these two species of plants. Pollen treatments (TSA pollen, tomato pollen, pepper pollen and no pollen) were applied to each leaf disc to investigate the effects that different pollens may have on the attractiveness of TSA plants for oviposition by WFT. Pepper has been noted as being an acceptable reproductive and feeding host plant, tomato has been reported to be an acceptable feeding host plant, and the acceptability of TSA for feeding and oviposition is unknown. If WFT will utilize TSA as a reproductive plant host, which is required for the acquisition and transmission of TSWV, this investigation will indicate the importance of the plant in the transmission of the virus. 

Results indicate that while plant pollens increase the attractiveness of TSA for oviposition, pepper is the preferred reproductive host, with or without pollen added. Oviposition on TSA was limited to leaf disc edges rather than having central placement of eggs as in pepper leaf discs. TSA leaf disc tissue exhibited lower ovipositional rates overall, but little significant difference is borne out with statistical analysis.