Development and Evaluation of Sex Pheromone Mass Trapping Technology for Ectropis grisescens: A Potential Integrated Pest Management Strategy

Volatile cues of enhanced attractiveness to Parapanteles hyposidrae (Wilkinson) wasps mediated by jasmonic and salicylic acid pathways synergism in tea plant

BACKGROUND

The jasmonic acid (JA) and salicylic acid (SA) pathways are often thought to interact antagonistically in plants when mediating anti-herbivore resistance. However, we previously found that the two pathways in tea plant interact synergistically when treated with 1.5 mmol/L methyl jasmonate (MeJA) and 20 mmol/L SA at 12 h intervals (MeJA+SA treatment). Here, we investigated how and why JA-SA synergism in tea plants affected chemotaxis of Parapanteles hyposidrae (Wilkinson) wasps, the parasite of tea geometers.

RESULTS

Wasp attractiveness of MeJA+SA-treated plants was 1.3-fold higher than MeJA-treated plants, although SA-treated plants could not attract more wasps. Five attractive compounds, including (Z)-3-hexenyl acetate, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), indole and (E,E)-α-farnesene, were emitted more by MeJA+SA-treated than MeJA-treated plants. Based on the difference in volatiles induced by MeJA and MeJA+SA treatments, five attractive components were separately added to artificial MeJA-induced volatiles (MV) or taken out from artificial MeJA+SA-induced volatiles (MSV). The attractiveness of MV to wasps was enhanced when DMNT or indole was added, whereas the attractiveness of MSV decreased when DMNT, indole or linalool was taken out. When DMNT and indole were both added into MV, the attractiveness of volatile blend to wasps became similar to MSV.

CONCLUSION

Increased DMNT and indole emissions are the key cues causing volatiles mediated by JA-SA synergism to be more attractive to P. hyposidrae wasps than those mediated by JA pathway alone. This provides new insights into the phytohormone pathway networks in tea plants and the development of natural enemy attractants. © 2025 Society of Chemical Industry.

Mixture of Synthetic Plant Volatiles Attracts More Stick Tea Thrips Dendrothrips minowai Priesner (Thysanoptera: Thripidae) and the Application as an Attractant in Tea Plantations

The stick tea thrip (Dendrothrips minowai) is one of the most serious sucking pests of tea plants (Camellia sinensis) in China, North Korea, and Japan. Plant volatile lures are widely used for both monitoring and mass trapping. Previously, we demonstrated that sticky traps baited with p-anisaldehyde, eugenol, farnesene, or 3-methyl butanal captured significantly more D. minowai in tea plantations, with p-anisaldehyde notably capturing the most. In this study, we showed that D. minowai adults exhibited significantly higher attraction to mixtures of p-anisaldehyde, eugenol, and farnesene compared to an equivalent dose of p-anisaldehyde alone in H-tube olfactometer assays under laboratory conditions. Moreover, in field experiments conducted in 2022, rubber septa impregnated with a ternary blend of p-anisaldehyde, eugenol, and farnesene (at 3-4.5 mg and a ratio of 3:1:1) captured the highest number of adults on sticky traps, outperforming traps bailed with individual components or a solvent control over two weeks. Significantly, the mass trapping strategy employing these lures achieved control efficacies ranging from 62.8% to 70.7% when compared to traps without attractant, which achieved control efficacies of only 14.2% to 35.4% across three test sites in 2023. These results indicate that the combination of p-anisaldehyde, eugenol, and farnesene exhibits an additive or synergistic effect on D. minowai. In conclusion, our findings establish a theoretical framework and provide practical technological support for integrating attractant-based strategies into comprehensive thrips management strategies.

(Z, Z, Z)-3,6,9-Nonadecadiene, a potential inhibitor of sex pheromone of Grey Tea Geometrid (Lepidoptera: Geometridae): electroantennogram test, wind tunnel, and in silico study

Sex pheromone analogs have high structural similarity to sex pheromone components. They also play a role in studying many agricultural pests. In our study, (Z, Z, Z)-3,6,9-nonadecadiene (Z3Z6Z9-19:Hy) was successfully synthesized, which is an analogue to 1 of 2 sex pheromone components of Ectropis grisescens Warren (Z, Z, Z)-3,6,9-octadecatriene (Z3Z6Z9-18:Hy), and it showed potential inhibition in experiments. In the electroantennogram test, Z3Z6Z9-19:Hy showed a dose-dependent response, and only measured half the response of Z3Z9-6,7-epo-18:Hy. However, the compound significantly reduced positive response of E. grisescens males by up to 70% in the Y-tube olfactometer. Furthermore, in the wind tunnel, it significantly inhibited all types of behavioral responses. The percentage of moths contacting the pheromone odor source was reduced even at the lowest dose tested. In silico study afterward, molecular docking results showed affinity between Z3Z6Z9-19:Hy and sensory neuron membrane protein 1. Our study revealed the potential of Z3Z6Z9-19:Hy as a sex pheromone inhibitor, which would provide new tools for monitoring and mating disruption of E. grisescens.

Mathematical Model of Pest Control Using Different Release Rates of Sterile Insects and Natural Enemies

In the framework of integrated pest management, biological control through the use of living organisms plays important roles in suppressing pest populations. In this paper, the complex interaction between plants and pest insects is examined under the intervention of natural enemies releases coupled with sterile insects technique. A set of nonlinear ordinary differential equations is developed in terms of optimal control model considering characteristics of populations involved. Optimal control measures are sought in such a way they minimize the pest density simultaneously with the control efforts. Three different strategies relating to the release rate of sterile insects and predators as natural enemies, namely, constant, proportional, and saturating proportional release rates, are examined for the attainability of control objective. The necessary optimality conditions of the control problem are derived by using Pontryagin maximum principle, and the forward–backward sweep method is then implemented to numerically calculate the optimal solution. It is shown that, in an environment consisting of rice plants and brown planthoppers as pests, the releases of sterile planthoppers and ladybeetles as natural enemies can deteriorate the pest density and thus increase the plant biomass. The release of sterile insects with proportional rate and the release of natural enemies with constant rate are found to be the most cost-effective strategy in controlling pest insects. This strategy successfully decreases the pest population about 35 percent, and thus increases the plant density by 13 percent during control implementation.

Does organizational participation affect farmers' behavior in adopting the joint mechanism of pest and disease control? A study of Meixian County, Shaanxi Province

BACKGROUND

In China, there are a lack of well-established relationships regarding farmers' behavior and participation in farmer organizations. The main objective of this study was to explore the effects and mechanisms of organizational participation in the joint control of pest and disease among kiwifruit growers (within the members of organizations). To fulfill this objective, the present study utilized survey data from 577 kiwifruit growers collected from Meixian County, Shaanxi Province, China. A combined method utilizing the instrumental variable (IV) ordered probit and bootstrap multiple mediation effect models were employed to determine the effects of participation by farmers' organizations in the joint control of pest and disease among kiwifruit growers.

RESULTS

A positive relationship was found between organizational participation and the joint control of pests and diseases. The empirical analysis of this study found that organizational support, organizational learning and organizational norms have mediating effects in the process of farmers' participation in the joint control of pests and disease. It is essential to go beyond individual behavior and tackle group decision-making at the farm level.

CONCLUSION

This study found a positive effect of organizational participation in joint pest and disease control mechanisms. Moreover, whether the farm is situated in the demonstration zone for kiwifruit cultivation, planting experience, planting area, whether there are people in the family who are village cadres, and the number of older adults in the family significantly positively affect the degree of pest and disease control. © 2020 Society of Chemical Industry.