The insecticidal activity and mechanism of tebuconazole onNilaparvata lugens(Stål)

Abstract

BACKGROUND Previous studies have shown that fungicides have insecticidal activity that can potentially be used as an insecticide resistance management strategy in the brown planthopper Nilaparvata lugens (Stål). However, the mechanism that induces mortality of N. lugens remains elusive. RESULTS In the present study, the insecticidal activities of 14 fungicides against N. lugens were determined, of which tebuconazole had the highest insecticidal activity compared with the other fungicides. Furthermore, tebuconazole significantly inhibited the expression of the chitin synthase gene NlCHS1; the chitinase genes NlCht1, NlCht5, NlCht7, NlCht9, and NlCht10; and the β‐N‐acetylhexosaminidase genes NlHex3, NlHex4, NlHex5 and NlHex6; it significantly suppressed the expression of ecdysteroid biosynthetic genes as well, including SDR, CYP307A2, CYP307B1, CYP306A2, CYP302A1, CYP315A1 and CYP314A1 of N. lugens. Additionally, tebuconazole affected the diversity, structure, composition, and function of the symbiotic fungi of N. lugens, as well as the relative abundance of saprophytes and pathogens, suggesting that tebuconazole reshapes the diversity and function of symbiotic fungi of N. lugens. CONCLUSION Our findings illustrate the insecticidal mechanism of tebuconazole, possibly by inhibiting normal molting or disrupting microbial homeostasis in N. lugens, and provide an important rationale for developing novel insect management strategies to delay escalating insecticide resistance. © 2023 Society of Chemical Industry.

Research progress of triazole derivatives in the discovery of agricultural chemicals

“…Triazole fungicides mainly belong to sterol demethylation inhibitor (DMI) fungicides, which occupy an important position in the field of fungicides. Currently, there are dozens of commercialized triazole fungicides in the global market [18,19], such as, triadimefon [20] (Figure 1), triadimenol [21], tebuconazole [22], hexaconazole [23], prothioconazole [24], epoxiconazole, flusilazole [25], and difenoconazole [26]. Among them, triadimefon is the first widely used triazole fungicide with high efficiency, low toxicity, low residue, long duration, and strong internal absorption, which is effective against a variety of crop diseases such as wheat powdery mildew [27], wheat stem rust [28], and smut [29].…”