farming safe special crops biobit crops dipel thuricide sprays granules caterpillars beetles birds ecofriendly die benefits stop eating toxins damage natural bacteria natural pesticide bacteria found natural solution helpful insects crops bt bt brinjal insects stomach kill insects humans animals humans animals bt insects stomach causing kill harmful insects harm people pets fruits bt cotton pests eat bt bacillus thuringiensis bt fight pests naturally cotton maize vegetables powder common brands fights cropdamaging pests