Raspberries & Pesticides

Pesticide Spray Schedule

• Pesticides have to be applied at the right time during the growing season if they are to be at all effective. Dormant horticultural oils, for example, do not kill insects if applied too late in the season, as the window for treatment has already closed. Set up a spray schedule for various types of pesticides and follow it throughout the growing season to keep the raspberry bush healthy. Re-apply pesticides every two weeks for the best coverage.

Dormant Horticultural and Pre-bloom Sprays for Raspberries

• Apply dormant horticultural oils in the spring, before the raspberry has begun budding or flowering. This helps control any remaining eggs of the red-necked cane borer that may still be on the raspberry plant. Spray pyrethrin- and rotenone-containing pesticides on the raspberry bush before it produces blossoms to protect the plant from the raspberry crown borer and fruit work. Follow all directions when using pesticides and chemicals.

Post-bloom Pesticides for Raspberries

• Do not apply pesticides during the bloom period for raspberries, as this can kill off beneficial insects like butterflies and bees that help with pollination. After the blossoms have dropped, resume a regular spray schedule and maintain it through the harvest. Chemicals to use during the post-bloom through harvest time include malathion, esfenvalerate, insecticidal soap, carbaryl and rotenone. These chemicals help control tarnished plant bugs and a variety of beetles.

Chemical Use and Protection

• Pesticides are chemicals that can be as harmful to the environment, the gardener and the raspberry plant as the pests themselves. Wear protective gear when spraying pesticides onto raspberry plants to avoid contact with skin or eyes, as chemical reactions can occur. Follow all directions on the pesticide packaging to avoid over-spraying, which can kill the raspberry bush and leach harmful chemicals into the surrounding environment, water table and atmosphere. Use all chemicals with caution.