Control of tea aphids via attracting the parasitic wasp, Aphelinus sp. with synthetic semiochemicals

Abstract

The tea aphid (Toxoptera aurantii Boyer de Fonscolombe) is an important tea plant pest insect worldwide. The parasitoid wasp, Aphelinus sp., is one of the most important natural enemies of the tea aphid in China. Unfortunately, Aphelinus sp. alone cannot effectively control the outbreaks of the aphid under natural conditions. In this study, 27 volatile compounds from tea aphid-injured tea shoots, tea flowers, aphid sex pheromones, or body rinses were selected and tested in Y-tube olfactometer assays to find potential attractants of the parasitoid wasp, Aphelinus sp. Based on the Y-tube assay results, the following three attractant mixtures were formulated and further tested in the field. Attractant-1 (HIPV-based) included trans-2-hexenal (10−6 g/ml), β-ionone (10−6 g/ml), allyl isothiocyanate (10−4 g/ml), trans-2-pentenal (10−2 g/ml), and jasmone (10−2 g/ml) at equal loading volume of their solutions. Attractant-2 (with aphid sex-pheromone and body rinse compounds) included nepetalactone (10−6 g/ml), 2,5-hexanedione (10−4 g/ml), benzaldehyde (10−2 g/ml), eicosane (10−2 g/ml), and heptadecane (10−2 g/ml) at equal loading volume of their solutions. Attractant-3 (partial combination of Attractant-1 and Attractant-2) included nepetalactone (10−4 g/ml), benzaldehyde (10−2 g/ml), jasmone (10−2 g/ml), trans-2-hexenal (10−6 g/ml), eicosane (10−2 g/ml), and heptadecane (10−2 g/ml) at equal loading volume of their solutions. Field trials showed that Attractant-3 was much more attractive to the parasitic wasps than Attractant-1 and Attractant-2. From late August to late September the controlled release of Attractant-3 effectively attracted Aphelinus sp. to parasitize and colonize the aphid populations in the treated tea plantations, resulting in a progressive decrease of the tea aphid abundances/populations in the fall. The continued enhanced parasitism of overwintered aphids by Aphelinus sp. further reduced this population during the next spring tea harvest season. This approach may present an environmentally sound, non-insecticidal control tactic against tea aphids using synthetic semiochemicals.

Tea green leafhopper‐induced synomone attracts the egg parasitoids, mymarids to suppress the leafhopper

“…For instance, the use of controlled‐release synthetic attractants for attracting the parasitic wasp Aphelinus sp. was reported to control tea aphid efficaciously in tea plantations 45 . Also, the correlation between the number of leafhoppers and that of mymarid wasps in different intercropping tea plantations was significantly positive 27…”

“…was reported to control tea aphid efficaciously in tea plantations. 45 Also, the correlation between the number of leafhoppers and that of mymarid wasps in different intercropping tea plantations was significantly positive. 27…”

Intercropped Flemingia macrophylla successfully traps tea aphid (Toxoptera aurantia) and alters associated networks to enhance tea quality

“…22,23 The tea aphid, Toxoptera aurantia, is a destructive and widespread pest in tea plantations. [24][25][26] It is estimated to cause more than 30% economic reduction in tea plantations in Zhejiang province, China. 25 Traditional treatments for tea aphids predominantly rely on chemical pesticides, exacerbating 3R issues (resistance, residue, and resurgence).…”

“…[24][25][26] It is estimated to cause more than 30% economic reduction in tea plantations in Zhejiang province, China. 25 Traditional treatments for tea aphids predominantly rely on chemical pesticides, exacerbating 3R issues (resistance, residue, and resurgence). 27 Tea aphids are embedded in a complex network involving ants and predators within tea plantations.…”

“…28,29 On the other hand, tea aphids establish antagonistic relationships with natural enemies, including ladybeetles, 30 and parasitoid wasps (Aphelinus spp.). 25 In addition, there are competitive interactions between attending ants and natural enemies that ants drive away predators to protect aphids. [31][32][33] Until now, studies have focused on the individual components of tea aphids, ants, or natural enemies rather than examining the intricate interactions within the community.…”