Timing of Fungal Insecticide Application to Avoid Solar Ultraviolet Irradiation Enhances Field Control of Rice Planthoppers

Abstract

Thechemical control of rice planthoppers (RPH)is prohibited in annual rice–shrimp rotation paddy fields. Here, the fungal insecticides Beauveria bassiana ZJU435 and Metarizhium anisoplae CQ421 were tested for control of RPH populations dominated by Nilaparvata lugens in three field trials. During four-week field trials initiated from the harsh weather of high temperatures and strong sunlight, the rice crop at the stages from tillering to flowering was effectively protected by fungal sprays applied at 14-day intervals. The sprays of either fungal insecticide after 5:00 p.m. (solar UV avoidance) suppressed the RPH population better than those before 10 a.m. The ZJU435 and CQ421 sprays for UV avoidance versus UV exposure resulted in mean control efficacies of 60% and 56% versus 41% and 45% on day 7, 77% and 78% versus 63% and 67% on day 14, 84% and 82% versus 80% and 79% on day 21, and 84% and 81% versus 79% and 75 on day 28, respectively. These results indicate that fungal insecticides can control RPH in the rice–shrimp rotation fields and offer a novel insight into the significance of solar-UV-avoiding fungal application for improved pest control during sunny summers.

Emulsifiable oil‐formulated Beauveria bassiana competes with imidacloprid for seasonal control of cereal aphids in Zhejiang, China

“…A recent spray of the same Bb ES at a rate of 1.32 × 10 13 conidia ha −1 for rice planthopper control led to a deposition rate of 415 (±23) conidia mm −2 on rice plants. 35 The previous and present studies demonstrate a high correlation of conidial deposition rates with the application rates and a linkage of much less variable deposition rates with ES. In addition, the population outbreak of cereal aphids on winter wheat in Zhejiang often occurs in the warming season of late spring to early summer with frequent small rainfalls.…”

“…ZJU435 ES sprayed twice at the rate of 1.32 × 10 13 conidia ha −1 after 5:00 pm to avoid solar ultraviolet irradiation on sunny days of summer resulted in desirable control of rice planthoppers and leaf rollers, providing effective protection for the rice crop at the tillering to flowering stages in the rice-shrimp rotation paddy fields where chemical control of pests is inhibited. 35,36 In this study, we compared control efficacies of ZJU435 ES and the other B. bassiana strain, which was genetically engineered with an endogenous virulence factor, with that of imidacloprid against cereal aphids on winter wheat at the elongating to milk ripening stages in Yuhang, Zhejiang. An emphasis focused on whether the fungal formulation is competitive with imidacloprid for field control of cereal aphids at an affordable cost.…”

Photoreactivation Activities of Rad5, Rad16A and Rad16B Help Beauveria bassiana to Recover from Solar Ultraviolet Damage

“…A period from late afternoon to the early morning of the following day is long enough for the germination of applied conidia to initiate hyphal invasion into the insect body. For this reason, two fungal insecticides sprayed in the late afternoon have proved more efficacious for the control of rice planthoppers and leaf rollers than the counterparts sprayed in the morning for increased exposure to solar UV on the sunny days of summer [ 65 , 66 ].…”

A Novel Deep Learning Model for Accurate Pest Detection and Edge Computing Deployment

“…Therefore, the development of a deep learning model that can accurately and quickly detect rice pests in complex environments is of great practical significance for improving rice production efficiency and ensuring food security [12]. This could not only alleviate farmers' labor intensity and improve the efficiency and accuracy of pest control but also provide technical support for the development of precision agriculture and smart agriculture [13].…”