When treating food plants, check how long the safe harvest interval is, between applying the pesticide and eating the plant. Action Contact chemicals kill pests which crawl over treated surfaces or are directly hit when the chemical is applied. Systemic chemicals enter the plant and render the sap poisonous to the pests. They are mainly used against sap-sucking insects, such as greenfly. Liquid drenches are applied to the soil to reach underground pests, such as vine weevils.
Dusts kill existing pests and make surfaces inhospitable to new arrivals.
However they may leave an unsightly deposit on the plant. Pellets must be used with care where pets and children are present. Many contain repellants to deter animals. How to purchase To buy some pesticide, click on the red 'search' button next to any of the retailers below. You will then be taken to the retailer in a pop-up window so you can have a look at the pesticides that they sell.