The study tested the effect of the chitin metabolic effectors, teflubenzuron, diflubenzuron, and calcofluor, and a combination of a chitinase and soybean trypsin inhibitor (STI) on the population growth of eight species of stored product mites under laboratory conditions. The compounds were incorporated into the diets of the mites in concentrations ranging from 0.01 to 50 mg g(-1). The final populations of mites were observed after 21 days of growth in controlled conditions. Diflubenzuron and calcofluor suppressed the growth of all the tested species more effectively than the other compounds. The doses required to suppress the mite populations to 50% (rc(50)) in comparison to the control ranged from 0.29 to 12.68 mg g(-1) for diflubenzuron and from 1.75 to 37.7 mg g(-1) for calcofluor, depending on the mite species. When tested at the highest concentration (10 mg g(-1)), teflubenzuron also suppressed all of the tested mite species in comparison to the control. The addition of chitinase/STI into the diet influenced population growth in several ways. When the highest concentration of chitinase in a cocktail of chitinase and STI (12.5 mg g(-1) of diet) was compared to the control, populations of Acarus siro, Aleuroglyphus ovatus and Aëroglyphus robustus decreased significantly, whereas populations of Tyroborus lini and Sancassania rodionovi increased significantly. The sensitivity of species to the tested compounds differed among species. The most tolerant species was S. rodionovi, the most sensitive was A. ovatus. The results confirmed that calcofluor and diflubenzuron have a toxic effect on stored product mites.
- MeSH
- Acaridae účinky léků růst a vývoj fyziologie MeSH
- akaricidy farmakologie MeSH
- benzamidy farmakologie MeSH
- benzensulfonáty farmakologie MeSH
- chitin metabolismus MeSH
- chitinasy farmakologie MeSH
- diflubenzuron farmakologie MeSH
- druhová specificita MeSH
- hustota populace MeSH
- inhibitory trypsinu farmakologie MeSH
- kontrola škůdců metody MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The peritrophic membrane in Acarus siro L. (Acari: Acaridae) is produced by distinct cells located in the ventriculus. In this study, the chitin inside the peritrophic membrane was detected using wheat germ-lectin conjugated with colloidal gold (10 nm). The chitin fibrils of the peritrophic membrane were a target for chitin effectors, including 1) chitinase, which hydrolyzes chitin fibers inside the peritrophic membrane; 2) calcofluor, which binds to chitin and destroys the peritrophic membrane mesh structure; and 3) diflubenzuron, which inhibits chitin synthesis. In addition, soybean trypsin protease inhibitor (STI) and cocktails of chitinase/calcofluor, diflubenzuron/calcofluor and chitinase/STI were tested. These compounds were supplemented in diets and an increase of population initiated from 50 individuals was observed after 21 d of cultivation. Final A. siro densities on experimental and control diets were compared. The chitin in the peritrophic membrane was determined to be a suitable target for novel acaricidal compounds for suppressing the population growth of A. siro. The most effective compounds were calcofluor and diflubenzuron, whereas the suppressive effects of chitinase and STI were low. The failure of chitinase could be due to its degradation by endogenous proteases. The combination of chitinase and STI suppressed A. siro population growth more effectively than when they were tested in oral admission separately. The combinations of calcofluor/chitinase or calcofluor/difluorbenzuron showed no additive effects on final A. siro density. The presence of chitin in peritrophic membrane provides a target for novel acaricidal compounds, which disrupt peritrophic membrane structure. The suitability of chitin effectors and their practical application in the management of stored product mites is discussed.
