Whitefly Management in Tomato, Pepper, and Cucurbit Crops

Silverleaf whitefly (Bemisia tabaci) and glasshouse whitefly (Trialeurodes vaporariorum) are key pests of tomato, pepper, cucumber, melon, and many other crops. Beyond direct feeding, Bemisia tabaci transmits Tomato Yellow Leaf Curl Virus (TYLCV) and other begomoviruses, which can cause 100% crop loss.

Life Cycle

Whiteflies develop through egg → 4 nymphal instars → adult. All stages (except egg) feed by sucking phloem sap from the underside of leaves. The immobile 4th instar "pupa" is the most resistant stage to insecticides.

Damage Signs

• •Yellowing and wilting of infested leaves
• •Sooty mould on honeydew deposits
• •Silverleaf disorder in cucurbits (Bemisia-specific)
• •Virus symptoms: yellowing, mosaic, leaf curl, stunting

Chemical Control

Application Tips

• •Target the undersides of leaves where all immobile stages live
• •Use high water volumes and fine droplets for thorough coverage
• •Combine an adulticidal product with an IGR (insect growth regulator) for multi-stage control
• •Yellow sticky traps help monitor adult populations

Resistance Management

Bemisia tabaci biotype B is notorious for insecticide resistance. Rotate IRAC groups strictly. Limit neonicotinoid applications to 2 consecutive sprays maximum.

Physical and Cultural Controls

• •Use UV-reflective mulches to disorient whitefly adults
• •Install insect-proof mesh on greenhouse openings
• •Remove and destroy severely infested plant material