Friday Bug: Whiteflies

Greenhouse Whiteflies having a grand old time on a Pelargonium leaf

On offer for this week’s Friday Bug is a sort of antithesis to last week’s Ebony Bug: the nefarious Whitefly. I think these pictures show the Greehouse Whitefly Trialeurodes vaporariorum (Westwood, 1856) and it is not a good sign when you find them on a plant. Whiteflies (family Alyerodidae) are tiny even as adults (~a millimeter and a half long), and the young are flat, scale-like blobs, and so are easy to miss until your houseplant turns into a sticky mess. Even fungus gnats are large compared to whiteflies, but if you see tiny powdery white motes fluttering around your plant, be prepared for an outbreak.

Tiny + powdery white wings = Whitefly

The Connecticut Agricultural Experiment Station has a nice webpage where they review control options for a variety of pests of Pelargonium (aka geranium) including several biocontrol agents that are effective against Greenhouse Whitefly. These probably work much better in a large greenhouse, than in a home. I find that insecticidal soap is all I need for home and my small backyard greenhouse. You do have to keep after them, though, and don’t wait until the population is too large.