Insects

   Important insect pests in cucumber include aphids, melon flies, leafminers, whiteflies, and thrips. Other pests include spider mites, caterpillars, and slugs. It is important to prevent or minimize pest problems before serious outbreaks occur, to detect pest problems early, and to select appropriate controls. The judicious use of pesticides is important in the management of resistance to pesticides, conservation of beneficials, minimized environmental hazards, improved safety of workers in the field, and overall reduced farm input costs. 

  

        

Outbreaks of the silverleaf whitefly (previously referred to as sweetpotato      whitefly) and the greenhouse whitefly are currently a major problem for cucumber production in Hawaii. Apply insecticides only when necessary and, when possible, rotate pesticide families to delay development of insect resistance. Insects with exploding population growth rates such as thrips, whiteflies, mites, leafminers, and aphids are especially prone to develop pesticide resistance when exposed to frequent applications of the same insecticide.

    Aphids

    Aphids damage cucumber plants by feeding on plant sap, and by spreading important viral diseases such as papaya ringspot, zucchini yellow mosaic, and cucumber mosaic. Feeding damage by aphids can reduce plant vigor and may cause leaf deformation. Heavy aphid feeding may encourage sooty mold growth. Viral diseases spread by aphids can devastate cucumber crops. Aphids have winged forms which can fly into crops and spread viral diseases from weeds or infected plantings in this way. Aphids in Hawaii are generally females which reproduce without mating. In general, aphids can reproduce in one week and therefore several generations are produced in one growing cycle.

    For control, apply timely insecticide applications as needed based on close monitoring of aphids and their natural enemies. Aphid natural enemies include ladybird beetles, maggots of syrphid flies, lacewings, parasitic wasps and fungal diseases. Old crops should be promptly destroyed to reduce aphid movement and the diseases they carry to healthy crops.