- Author: Andrea Peck
- Editor: Noni Todd
Red and White, Making Me Blue
By Andrea Peck
The month of April is looming and a whopping whitefly infestation has arrived. There is no red carpet for either, but the whiteflies did land on the red leaves of my poinsettia plant. While making dinner one night, I paused by the poinsettia on my kitchen table. It had a greyish haze surrounding it which on closer examination was more slight- case- of- dandruff than fog bank. I drew closer and blew on one red leaf and tiny entities flew off like hummingbird lint.
In my house, what they say about whiteflies is true: they breed, they infest. Quickly.
Now, my other two houseplants have a brewing affliction. I feel itchy just thinking about it.
So what to do?
According to the Master Gardener Pest Notes, whiteflies are a confusing breed of annoyance. Though called a fly, they are actually not. They are more similar to an aphid. A flying aphid. The ambiguous nomenclature, bewildering habits and ability to fly make the whitefly difficult to control. Before deploying to all parts of your plant, it huddles on the underside of your plant leaves. The whole business is as confusing as trying to figure out compound interest. By the time you know they are there, you've been invaded and instead of making money, you are losing the battle against tiny white flying things. It's like being attacked by the flying monkeys in the Wizard of Oz, except this is happening in your own home and a pair of ruby red slippers will certainly not help you.
Whiteflies are sap-sucking insects that excrete sticky honeydew. Leaves become yellow until death becomes a reality. The honeydew may appear sticky or develop into black sooty mold. Ants are often attracted to the honeydew and may act symbiotically by deterring natural predators. Whiteflies proliferate when the weather warms up and natural controls are lacking. If you see a “Pig Pen” type plume coming from your plant, the best thing to do is inspect the undersides of the leaves. This is where whiteflies are most obvious.
Because management is so difficult, your best bet is prevention. This may mean giving your infected plants a bowl cut, putting the infested clippings in a sealed plastic bag and relinquishing the whole kit and caboodle to the trash bin.
Vigilant spraying of the leaves (or using a syringe with water on the underside) can control populations. For the iconoclasts out there bring a hand-held (battery powered) vacuum to your outside plants and Hoover your plant. Vacuum during cool weather or early morning when the whitefly is less active. Place the vacuum bag in a plastic bag and freeze it. Discard the whole useless mess the following day.
Pesticides have little effect on these little sap sippers. In fact, pesticide use can contribute to infestations by killing off natural enemies of the whitefly. In particular, avoid pesticides that include: carbaryl, pyrethroids, diazinon or foliar sprays of imidacloprid.
Reflective mulch is surprisingly effective. Plastic mulch may be spray painted. Aluminum foil surrounding the plant is a simple solution.
Traps are somewhat effective in lowering numbers, but won't make a dent in a large infestation.
Now, with my poinsettia, I may just try the vacuum since that is one of my favorite tools…even if it just blocks out the noise of flies flying and dogs barking.
P.S. For those of you who followed the post on the poinsettia: April is the month which you need to slowly give your poinsettia less water. This is also the time to move it into a 60°F location. Good luck in this weather…