Natural Insecticide for Blueberry Bush Pests

Pyrethrins

• Pyrethrins are made from an extract of marigolds. They are effective in the control of leafrollers, which are the caterpillars or larvae of various small moths. Leafrollers feed on blueberry blossoms in the spring. It isn't necessary to apply an insecticide unless you see more than 15 leafrollers per bush, because each leafroller eats very little. Pyrethrins should be applied when you first notice an infestation of leafrollers, and again in 10 days.

Neem Oil

• Neem oil is an extract of the neem tree found in several organic pesticides and as a single ingredient. It is used to control aphids, leafhoppers, leafminers and blueberry maggot. Neem oil is nontoxic to both humans and animals, but is short-lived in the environment, so repeat applications may be necessary. Spray neem oil according to label directions for fruit crops, only applying it in the early morning or early evening to avoid leaf burn. On blueberries, there is a risk of spotting on the ripe fruit which will disappear in a few days.

Spinosad

• Spinosad is a natural insecticide that is environmentally friendly and will not harm beneficial insects. Its main compound, spinosyn, is derived from a naturally occurring soil bacterium. It is used to control a number of pests on organic crops. Spinosad is available as a liquid or a wettable powder. Research at the University of Florida showed significant reduction of the number of flower thrips on blueberries with Spinosad application.

Insecticidal Soap

• For more than 200 years, farmers and gardeners have used soaps to kill insects, and it is still not fully understood how they work. In some cases, the soap may work to disrupt the insects' cell membranes. Another theory is that they may dissolve and remove the protective waxy coating on some insects, leaving them to dessicate and die. Commercially formulated insecticidal soaps are less likely to cause damage than dishwashing liquids, but the latter is still effective for the job. Insecticidal soaps are used to control leafrollers and aphids on blueberries. Apply them in the cooler hours of the day to avoid leaf burn.