WHITEFLIES IN YOUR GARDEN AND HOUSEPLANTS
COMMON NAMES: Whitefly
SCIENTIFIC NAME: Order "Homoptera", Family "Aleyrodidae" (Not really a "fly" or "moth" at all, they are actually related to the aphids.)
DESCRIPTION: ADULTS - Tiny (1/16 inch) moth-like insects with powdery white wings. NYMPHS - Tiny translucent, flat, legless, and oval-shaped. EGGS - Cone-shaped, pale yellow at first, turn to gray in about a week.
LIFE CYCLE: In typical greenhouse (or home) conditions, a whitefly life cycle takes about a month to complete. The adults feed on the undersides of foliage, mate, and lay their eggs there. The eggs incubate and then hatch the nymphal stage "crawlies" that move around feeding for a couple of days before settling down to one feeding site. Pupation occurs about two weeks later, and the new generation of adults hatch in about 10 days to start the cycle all over again.
HOST PLANTS: Almost all fruit and vegetable crops, especially eggplants, peppers, tomatoes, peppermints, and many other herbs.
TIME OF YEAR: From spring thru fall. Moist, hot weather is ideal. The critical time for control is fall. The whitefly cannot overwinter outside in cold weather. Do not accidently take them inside your home on ornamentals or herbs or neglect complete greenhouse cleanup for the winter. All it takes is a few overlooked weeds to provide a cozy home for next years' pest population.
WHAT TO LOOK FOR: Shake your plants, and if you see clouds of flying "plant dandruff" then you can be pretty sure you have whiteflies. LOOK ON THE UNDERSIDE OF THE FOLIAGE, ESPECIALLY ON TENDER, YOUNG GROWTH!
PROBLEMS AND DAMAGE: These tiny insects suck the very life juices out of their target plants causing yellowing foliage and leaf drop. Fungal diseases can move into the damaged areas and severe infestation can cause serious plant damage.
CULTURAL CONTROLS: DOUBLE CHECK ANY NEWLY ACQUIRED PLANTS FOR INFESTATION BEFORE BRINGING THEM INTO YOUR HOME OR GARDEN. NURSERY PURCHASES ACCOUNT FOR THE MAJORITY OF NEW HOME/GARDEN WHITEFLY PROBLEMS! Isolate all new plants for a couple of weeks if possible to give an "invisible" infestation time to show up. A good soap and water wash is a good idea if the plant can handle it. Use a dormant oil before buds open on fruit trees. Make sure all your crops are healthy and not under stress. Deficiencies of magnesium and phosphorus may make plants more vulnerable to this pest. Encourage good air circulation.
COMPANION PLANTING AND REPELLENTS: Rose geranium plants supposedly slow down the activity of this pest and rhubarb plantings are said to repel them. Garlic and onion plantings and sprays may also have some effect.
TRAP PLANTS: Early plantings of host crops away from the main planting area. Destroy these plants and their pests BEFORE putting out your regular crop.
MECHANICAL CONTROLS: Yellow sticky traps, water sprays or soap-n-water baths.
NATURAL CONTROLS: Birds, Lacewings, Ladybird beetles (Ladybugs), Encarcia formosa (a tiny parasitic wasp), and Red or Yellow Aschersonia (fungal diseases).
BIOLOGICAL INSECTICIDES: Insecticidal soaps (Safers, etc.), horticultural oil sprays (test for plant damage first), Pyrethrum, Ryania, and tobacco teas and dusts.