Lethal and parasitism effects of selected novel pesticides on adult Trichogramma chilonis (Hymenoptera: Trichogrammatidae)

Abstract

Integration of chemical and biological controls is an important tactic of integrated pest management. Trichogramma chilonis (Ishii) is an important natural enemy of lepidopteran pests. However, the minute parasitoids are adversely affected by most pesticides. Effects of acute mortality and parasitism of selected novel pesticides on adults of T. chilonis exposed to the dried residues of field doses for 24 h on glass surface were evaluated. Acetamiprid, spinetoram and fipronil induced mortality of > 95%, followed by abamectin (ranged 71.3–83.5%) in four residual-age treatments. Spiromesifen, haloxyfop-p-methyl, mixture of pyraclostrobin + metiram and mixture of trifloxystrobin + tebuconazole revealed mortality of ≤ 36.4% in all treatments (when female parasitoids were exposed to 1 day, 5 days, 10 days and 15 days after treatments). Bispyribac sodium induced mortality of ranged 51.1–54.9% in 1- and 5-day treatments, and approximately ≤ 10% in others (10-day and 15-day treatment). Eggs of Sitotroga cerealella in acetamiprid, spinetoram, fipronil and abamectin treatments showed ≤ 36% parasitism relative to controls in all treatments. Spirotetramat, bispyribac sodium, nicosulfuron, trifloxystrobin + tebuconazole and pyraclostrobin + metiram resulted in parasitism rates of 49.2–71.2% and 81.5–93.8% in 1-day and 15-day treatment, respectively. Helicoverpa armigera nucleopolyhedrovirus, chlorantraniprole, spiromesifen haloxyfop-p-methyl, chlorothalonil + procymidone and myclobutanil showed ≥ 80.6% parasitism in all treatments. Thus, acetamiprid, spinetoram, fipronil and abamectin were the most harmful among the pesticides used for both emergence and parasitism, while remaining pesticides demonstrated relatively compatibility with the emergence as well as parasitism by the minute parasitoids, and can be integrated with the minute parasitoid in agroecosystem.