Application of ethyl formate for the management of insect pests in commercial greenhouses cultivating watermelon, zucchini, and melon

Ethyl formate (EF) fumigation has been demonstrated as a feasible approach for pest management in small-scale greenhouse systems in previous studies, underscoring the need for further validation and optimization at the commercial scale. This study aims to evaluate optimal conditions of EF fumigation for controlling agricultural insect pests, focusing on both susceptible and imidacloprid-resistant Myzus persicae and spinosad-resistant Thrips palmi, while also preventing invasive pests such as Bemisia tabaci and Aphis gossypii in commercial greenhouse operations. The commercial-scale application of EF fumigation in the greenhouse was optimized by using a 0.3 mm fine nozzle and positioning spray nozzles at locations that facilitated uniform gas distribution. This approach achieved significant efficacy against susceptible and imidacloprid-resistant M. persicae, as well as spinosad-resistant T. palmi. The findings revealed that melon greenhouses provided the most suitable conditions for effective pest management with minimal phytotoxic effects. In contrast, watermelon and zucchini greenhouses exhibited phytotoxicity, attributed to the crop's heightened sensitivity to EF and uneven fumigant distribution. A positive correlation was identified between EF concentration at 1 h and phytotoxicity, as well as between the concentration-time value and mortality of target pests. These findings suggest that EF fumigation could be a promising alternative to conventional pesticides, demonstrating high efficacy and minimal phytotoxicity in melon greenhouse cultivation. However, further research is required to assess the application of EF fumigation across different crop developmental stages and growing seasons, considering seasonal pest dynamics, plant tolerance, and crop sensitivity to both heat stress and EF.