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DESCRIPTION Delicate, powdery white 1 to 3 mm insects, found on the underside of leaves of fluttering around plants. Stickiness or sooty mold on lower plant leaves usually indicates a significant whitefly population.
DAMAGE
Whitefly feed on many different houseplants, fruits, vegetable and ornamental plants. Nymphs and adults both suck sap, reducing plant vigour and causing pale, yellow or wilted leaves. Whitefly can transmit viruses from plant to plant. LIFE CYCLE Some whitefly species can overwinter outdoors as nymphs or pupae, all species overwinter indoors or in greenhouses. Females lay 200-400 yellow eggs in a circle on the undersides of leaves. Nymphs hatch in 3 to 10 days, crawl for several hours, then lose their legs and settle to feed until they pupate. Adults emerge within a week and repeat the cycle. There are numerous generations per year, with the life cycle taking 25 days at 20 deg. C and only 18 days at 27 deg. CONTROLS - Inspect undersides of plant leaves frequently. Yellow sticky traps are also helpful.
- If practical crush whitefly with fingers or vacuum in early morning when insects are less active.
- Apply pesticides, making sure to get good contact on the undersides of the leaves.
- Introduce Encarsia formosa parasitic wasps.
- Replace plants prone to whitefly with resistant species.
- Keep a pest journal for next year, recording host plants, controls used and when you first noticed pest in relation to other plants in bloom.
PESTICIDES
- Alternative-3 applications of Pyrethrin, Safer’s Soap, Trounce or Rotenone at label rates three days apart, making sure to get good contact on underside of leaves.
Product Highlight
Safer's Trounce
Contains Potassium Salts of Fat. Acid, Pyrethrin.
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