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White Fly Trialeurodes vaporariorum, Bemisia tabaci

White Fly

Whiteflies are not true flies, but belong to the order Hemiptera (true bugs). Together with aphids and scale insects, they belong to the division Sternorrhyncha. The whiteflies form the family Aleyrodidae. The most common species are the greenhouse whitefly, Trialeurodes vaporariorum, and the tobacco whitefly, Bemisia tabaci. Both are widespread, and are broadly comparable in outline. [Read More]

Whiteflies are not true flies, but belong to the order Hemiptera (true bugs). Together with aphids and scale insects, they belong to the division Sternorrhyncha. The whiteflies form the family Aleyrodidae. The most common species are the greenhouse whitefly, Trialeurodes vaporariorum, and the tobacco whitefly, Bemisia tabaci. Both are widespread, and are broadly comparable in outline.

 

Damage symptoms

The larvae of whitefly need a lot of protein for growth, and thus consume a large quantity of plant sap. This contains a high proportion of sugar, and the excess is excreted as honeydew, with larger larvae expelling large quantities. The damage that whiteflies cause to a crop is the result of sucking out the sap from the plant leaves and secreting honeydew. This can have the following consequences:

  • If the population is very large, feeding on plant sap can affect the physiology of the plant, as a result of which growth is retarded. In full sunlight, leaves can wilt and fall. Such leaf damage can in turn influence the development of fruit and lead to a reduction in yield.
  • The honeydew deposited on fruit makes it sticky. Dirt adheres to the fruit, and the growth of sooty moulds (Cladosporium spp.) is encouraged, making it unsuitable for sale. In serious cases the fruit will rot. Sooty moulds also develop on the leaves, reducing photosynthesis and transpiration.
  • Viruses can be transmitted.
  • The consumption of plant sap and secreting of honeydew by whiteflies reduce the aesthetic value of crops. This is particularly important in ornamentals.