Efficacy of cyantraniliprole fly bait against housefly (Musca domestica L.) under laboratory conditions

Evaluation of Cyantraniliprole, Spinetoram, and Chromobacterium subtsugae Extract in Bait for Killing and Reducing Oviposition of Rhagoletis indifferens (Diptera: Tephritidae)

Insecticides mixed in sugar-protein baits or insecticides alone have been used to control tephritid fruit flies for many years. Here, effects of cyantraniliprole, spinetoram, and the biopesticide Chromobacterium subtsugae extract in sucrose-yeast extract bait or alone on kill and oviposition of western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), were evaluated in the laboratory. Flies were exposed to dry insecticide bait or insecticide alone in the presence or absence of a nontoxic food strip. Spinetoram alone caused greater mortality than cyantraniliprole alone, while cyantraniliprole in bait caused mortality as high as spinetoram bait and greater mortality than cyantraniliprole alone. Chromobacterium subtsugae extract alone but not in bait caused significant mortality compared with controls, but was much less effective than cyantraniliprole and spinetoram. Spinetoram alone reduced oviposition more than cyantraniliprole alone. However, cyantraniliprole bait reduced oviposition as much or more than spinetoram alone or spinetoram bait. Cyantraniliprole and spinetoram baits caused greater mortality when a nontoxic food strip was absent than present, but there was no corresponding reduction in oviposition. Chromobacterium subtsugae extract did not significantly reduce oviposition compared with controls. Potential benefits of using cyantraniliprole baits as an additional or alternative method to using more toxic spinosyn insecticides for controlling R. indifferens warrant study.

Efficacy of acetamiprid and fipronil fly baits against the housefly (Musca domestica L.) under laboratory conditions

Background:

The housefly Musca domestica L. (Diptera: Muscidae) is permanent pests in livestock facilities. High fly density in livestock and poultry farms can increase the risks of economic loss and public health. Treatment with toxic baits is one of the methods for housefly control. However, development of resistance to insecticides makes it difficult to manage of flies. Anti-resistance strategies include the use of multiple pesticides with different modes of action.

Aim:

This study was conducted to estimate the efficacy of neonicotinoid acetamiprid and phenylpyrazole fipronil, applied alone or in the mixture, against adults of M. domestica and to evaluate the efficacy of fly bait formulations containing acetamiprid and fipronil under laboratory conditions.

Materials and Methods:

The adult flies, M. domestica of laboratory strain, were used in laboratory bioassays. The efficacy of acetamiprid and fipronil as technical substances, when applied alone and in the mixture, against adult flies was tested by no-choice feeding bioassays. The insecticidal efficacy of bait formulations (wet powder) with acetamiprid or fipronil or their mixture was tested against flies by choice feeding bioassays. The probit analysis was used to calculate lethal concentrations of insecticides, and the χ² test was used to analyze the interaction between fipronil and acetamiprid in the mixture.

Results:

Fipronil was more toxic to adults of M. domestica than acetamiprid in laboratory tests. Lethal concentrations for 50% mortality (95% confidence interval) of flies were 0.0159% (0.0124-0.0205) of acetamiprid and 0.000119% (0.000039-0.0002640) of fipronil. The mixture containing fipronil at concentration 0.005% and acetamiprid at concentration 0.05% had the additive effect on fly mortality.

Conclusion:

The results of laboratory feeding bioassays indicate that the mixture of fipronil and acetamiprid might have a potential to use in toxic bait formulations against houseflies.

Silence of inositol 1,4,5-trisphosphate receptor expression decreases cyantraniliprole susceptibility in Bemisia tabaci

Cyantraniliprole is the second active ingredient of anthranilic diamide insecticide, and the first to control a cross-spectrum of chewing and sucking pests such as sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). The inositol 1,4,5-trisphosphate receptor (IP3R) and ryanodine receptor (RyR) are two families of Ca²⁺ release channels to raise the cytoplasmic free calcium concentration when it is activated by various extracellular stimuli. Previous study proved the over-expression of ryanodine receptor (RyR) was associated with the resistance to diamide insecticides, while the roles of IP3R in diamide resistance remain unknown. In this study, a full-length cDNA sequence of IP3R was cloned from B. tabaci through RT-PCR and rapid amplification of cDNA ends (RACE). The gene (named BtIP3R) is 9922bps long, with an open reading frame (ORF) of 8202bps, encoding a predicted IP3R of 2733 amino acids. The BtIP3R shares 47-78% identity with other insect IP3Rs. Quantitative real-time PCR (qRT-PCR) analysis showed that the BtIP3R was highly expressed in larva, pseudopupa, and female adult, while lowly expressed in egg and male adult. RNA interference (RNAi) by dietary introduction of double-stranded RNA (dsRNA) of BtIP3R significantly reduced the mRNA levels of the target gene in the adult, and dramatically decreased the susceptibility of adult B. tabaci to cyantraniliprole. The results shed light on further understanding of cyantraniliprole resistance mechanisms in B. tabaci as well as in other insects.