Silverleaf whitefly on melons
On melons the harm is less the sap loss than what comes with it. Honeydew can make fruit unmarketable, and the adults carry viruses: UF/IFAS links this whitefly to squash vein yellowing virus, the cause of watermelon vine decline, in which plants often die shortly before or during harvest. UC IPM's melon sampling works in a garden too: within two hours of sunrise, turn 50 leaves and count those with at least one adult. Numbers peak in late summer and fall away by November. Big-eyed bugs, lacewing and lady beetle larvae, and Encarsia and Eretmocerus wasps all attack it, and reflective mulch helps early, before the vines cover it (UF/IFAS).
At a glance
- Damage
- Virus spread, uneven tomato ripening, silvered squash leaves
- Type
- Sap feeding · virus vector
- Settings
- Under glass, Field, Garden
- Threshold
- Treat before 2 adults per leaf (UC IPM, melons)
- Ally
- Geocoris spp.
- Rate
- Wild — nothing to release; spare them by avoiding broad-spectrum sprays
How to confirm it
Smaller and yellower than greenhouse whitefly, with the wings held tent-like and a small gap between them along the back. The pupae under the leaves are yellowish, slope down to the leaf and have no long wax fringe.
Identification, lifecycle, degree days and every control option are on the full Silverleaf whitefly profile. Not sure it is this pest? Answer four questions about the damage.