Susceptibilidade do besouro rola-bosta africano a reguladores de crescimento de insetos

Lethal and Sublethal Effects of Contact Insecticides and Horticultural Oils on the Hibiscus Bud Weevil, Anthonomus testaceosquamosus Linell (Coleoptera: Curculionidae)

In 2017, the hibiscus bud weevil (HBW), Anthonomus testaceosquamosus Linell (Coleoptera: Curculionidae), was found outside of its native range of Mexico and Texas, infesting hibiscus plants in Florida. Therefore, we selected 21 different insecticide and horticultural oil products to evaluate their effects on the reproductive rate, feeding, and oviposition behavior of the HBW. In laboratory experiments, significant mortality was observed in adult weevils exposed to diflubenzuron-treated hibiscus leaves and buds, and hibiscus buds treated with diflubenzuron contained the fewest number of eggs and feeding/oviposition holes. Among horticultural oil products, significant mortality was only observed in experiments in which adult weevils were directly sprayed (direct experiments). Pyrethrins and spinetoram plus sulfoxaflor reduced the oviposition rate and caused significant mortality in direct experiments. Diflubenzuron, pyrethrins, spinetoram plus sulfoxaflor, and spirotetramat were further tested via contact toxicity experiments and greenhouse experiments. Contact toxicity experiments demonstrated that the tested insecticides (except diflubenzuron) were highly toxic to HBW adults. In greenhouse experiments, only those hibiscus plants treated with pyrethrins had significantly fewer feeding/oviposition holes and larvae within their flower buds when compared to control (water-treated) plants. These results constitute an important first step in the identification of effective chemical control options for the HBW.

Potential environmental consequences of administration of ectoparasiticides to sheep

Sheep ectoparasiticides, which include the synthetic pyrethroids, the organophosphates, the 'insect'-growth regulators, the formamidines and the spinocyns, enter into the environment primarily through disposal of dip or fleece scours, as well as with contaminated faeces and urine. Due to the large quantities of spent dip, risks associated with environmental contamination are high. Synthetic pyrethroids and organophosphates pose risks to dung, soil and aquatic fauna; concerns over potential ecotoxicity to vertebrates and invertebrates have resulted in the cessation of their use in many countries. There is very little information regarding the ecotoxicity of 'insect'-growth regulators, formamidines or spinocyns, with no studies focussing on sheep. Here, the impact of sheep ectoparasiticides is discussed in terms of their potential to enter into the environment, their toxicity and their impact on ecosystem functioning. Where there are no data for excretion or toxicity of the ectoparasiticides used in sheep production, examples to demonstrate potential impacts are taken from laboratory ecotoxicity tests and the cattle literature, as well on work with foliar insecticides. Future research priorities are suggested to allow assessment of the environmental consequences of sheep ectoparasiticide treatments, which are essential for future sustainable sheep production.