Controlling Whiteflies on Pomegranate

Q. This past year our pomegranate bush had a lot of whiteflies. I know they do damage to the bush and so I want to control them organically and naturally. How would you suggest doing that?

Whiteflies on this pomegranate were diagnosed to be Ash whitefly by a USDA entomologist.

A. Whiteflies are a bad insect problem for any plant. I would rank them with the “hard to control” list of insects. In small numbers they can be tolerated but their populations grow so quickly that small numbers lead to large numbers very fast. For this reason, it’s important to get them under control early, as soon as you see them, in late spring and early summer. Don’t wait.

            Damage is associated with their feeding. Their feeding supports a quick growth in their population as summer temperatures get hotter. They love the heat and so they’re not seen around much until June or July. Once you see them and it’s hot, watch out! You are behind the curve and they are way ahead of you!

            In late May begin weekly inspections of the leaf undersides for whitefly adults. The adults look like living dandruff. You probably won’t see the eggs or immature forms because they are so small, but you will see the adult females preparing to lay eggs or protecting their young so that they can build their populations as quickly as possible. Pull these leaves off when you see them infested and dispose of them or vacuum them with a Dust Buster. This practice slows their populations way down.

            Control is two-pronged. First, spray pomegranate bushes on a warm day in December and then again in January with a dormant oil. You can use the commercial brands of dormant oils and horticultural oils or you can use soybean oil, canola oil, rosemary oil or cinnamon oil. 

Horticultural oil aka dormant oil are used for fall, winter, spring and early summer insect control.

Spray all the branches after pruning, top to bottom, and spray a little extra shot at the base of each tree. This spray suffocates insects that might be hiding out during the winter months. It is the most important spray for controlling insects that will be problems in 2020.

            At the beginning of June, hang bright yellow or bright blue thick construction paper in the tree smeared with Vaseline. Whiteflies fly toward bright yellow and bright blue objects and the Vaseline causes them to get stuck. As these traps begin to fill, replace them with new ones. It might look a little funny, but light reflected from aluminum foil repels them.

            If populations are totally out of control, spray with an insecticide to get their populations back under control. As a homeowner, use pesticides when all other attempts fail. Spraying with insecticides, however, have other consequences and should be a last resort.