Greenhouse test of spraying dsRNA to control the western flower thrips, Frankliniella occidentalis, infesting hot peppers

Potential of Virus-Mediated RNAi of Insect Genes in Plants to Control Aphids

Expression of double-stranded RNAs (dsRNAs) in plants is an emerging strategy to efficiently control insects. RNA interference (RNAi)-mediated pest control takes advantage of double-stranded RNA that can suppress the expression of one or more insect genes that encode key proteins. Virus-induced gene silencing (VIGS) is a useful tool for plant expression of dsRNAs to control pests without altering the plant's genome. Trehalase (TRE) and chitin synthase (CHS) are very important in insects. In this study, we first demonstrated that spraying dsRNAs targeting CHS and TRE increased the mortality rate of the peach aphid Myzus persicae treated with the pathogenic fungus Metarhizium anisopliae. When dsRNAs targeting mpTRE and mpCHS were expressed in plants via VIGS, the expression of mpTRE and mpCHS was reduced in aphids, and their fertility and survival rates were decreased. These results indicate that VIGS-mediated RNA interference is a powerful approach to effectively control aphids, and aphids had a higher mortality rate when M. anisopliae was sprayed.

Asymmetric Synthesis and Biological Activity of Contact Pheromone of Western Flower Thrips, Frankliniella occidentalis

Western flower thrips, Frankliniella occidentalis, is a serious worldwide pest of agriculture and horticulture, and its contact pheromone is 7-methyltricosane. Two enantiomers of 7-methyltricosane were synthesized for the first time. The centra of our strategy were chiral auxiliaries to introduce stereocenter, and Wittig coupling to connect two blocks. The overall yields of our synthesis were 29-30% with seven steps. The electroantennogram (EAG) and the contact behavioral responses revealed that (R)-, (S)- and racemic 7-methyltricosane were separately bioactive, and the racemate was the most bioactive in the male arrestant activity and the female EAG test. This result provides valuable insights, showing that the racemate could be used for the support of the control of western flower thrips, which could be more easily prepared relative to more expensive enantiopure pheromone.

Simulating immunosuppressive mechanism of Microplitis bicoloratus bracovirus coordinately fights Spodoptera frugiperda

Parasitoid wasps control pests via a precise attack leading to the death of the pest. However, parasitoid larvae exhibit self-protection strategies against bracovirus-induced reactive oxygen species impairment. This has a detrimental effect on pest control. Here, we report a strategy for simulating Microplitis bicoloratus bracovirus using Mix-T dsRNA targeting 14 genes associated with transcription, translation, cell-cell communication, and humoral signaling pathways in the host, and from wasp extracellular superoxide dismutases. We implemented either one-time feeding to the younger instar larvae or spraying once on the corn leaves, to effectively control the invading pest Spodoptera frugiperda. This highlights the conserved principle of "biological pest control," as elucidated by the triple interaction of parasitoid-bracovirus-host in a cooperation strategy of bracovirus against its pest host.

Overview of Updated Control Tactics for Western Flower Thrips

Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), broadly known as Western flower thrips (WFT), are currently one of the most critical pests worldwide in field and greenhouse crops, and their management is full of yet unsolved challenges derived from their high reproductive potential, cryptic habit, and ability to disperse. The control of this pest relies widely on chemical control, despite the propensity of the species to develop resistance. However, significant advances have been produced through biological and ethological control. Although there has recently been a remarkable amount of new information regarding the management of this pest worldwide, there is no critical analysis of recent developments and advances in the attractive control tactics for WFT, constituting the present compilation's aim. Hence, this narrative review provides an overview of effective control strategies for managing thrips populations. By understanding the pest's biology, implementing monitoring techniques, accurately identifying the species, and employing appropriate control measures, farmers and researchers can mitigate the WFT impact on agricultural production and promote sustainable pest management practices.