Thrips (or thunderflies), are small, slender insects about 2 mm long, ranging in colour from pale yellow to black, depending on species and stage of life cycle. They thrive in hot, dry conditions and feed on cell sap by piercing leaves or flower buds with their mouthparts. These tissues then become speckled or mottled with a silver-white discoloration with tiny black dots, and may become vulnerable to dehydration. In severe cases foliage may appear to have been scorched, and flower buds may be prevented from opening, or if they do, may become distorted or torn.


Thrips can be controlled biologically by using their natural enemy, the predatory mite Amblyseius cucumeris. As thrips enjoy hot, dry conditions, water greenhouse plants regularly and reduce the temperature with ventilation and shading. Chemical control may be achieved by spraying with pirimiphos-methyl, permethrin, malathion, pyrethrum, HCH or dimethoate as soon as any damage is noticed.