Susceptibility of Field Populations of Frankliniella intonsa to Spinetoram, Imidacloprid, and Acetamiprid in Xinjiang Cotton Fields, China

Thrips pests have become an increasing concern in cotton fields in Xinjiang. Frankliniella intonsa is the primary thrips species during the flowering and boll stages, causing boll stiffening or cracking. However, limited studies have been conducted on controlling F. intonsa. In this study, using a leaf-tube residue method, we evaluated the susceptibility of F. intonsa field populations to three insecticides (spinetoram, imidacloprid, and acetamiprid) collected from different geographical sites across major cotton planting areas in Xinjiang. The results showed that F. intonsa populations exhibited very high susceptibility to spinetoram, ranging from 0.003 mg L−1 in the Shihezi population to 0.036 mg L−1 in the Korla population. The susceptibility of F. intonsa to imidacloprid and acetamiprid varied considerably among different field populations, with the relative resistance of 33.00 and 25.71, respectively. Reduced susceptibility to all three insecticides was detected in the Korla and Manasi populations, highlighting the importance of implementing effective resistance management and alternative control strategies. These findings provide valuable information for the appropriate control of F. intonsa in Xinjiang.