Whiteflies are tiny, sap-sucking insects that may become abundant in vegetable and ornamental plantings, especially during warm weather. They excrete sticky honeydew and cause yellowing or death of leaves. Outbreaks often occur when the natural biological control is disrupted. Management is difficult once populations are high.
About Whitefly
- These are winged insects that have soft bodies and are closely related to aphids.
- These are tiny, sap-sucking insects that may become abundant in vegetable and ornamental plantings, especially during warm weather.
- It naturally occurs in Belize, Guatemala, and Mexico (Martin, 2008) and has subsequently spread to 22 other countries in Central and South America.
- It mainly infests coconut palms and other broad-leaved hosts in its native range
- It is an invasive insect.
How the insect attacks
- The whitefly starts attacking the lower leaves of the coconut palm.
- It drains the sap from the underside of the leaf, producing a significant amount of honeydew, which settles on the upper surface of the next lower leaf, leading to the growth of black, sooty mould.
- This is the secondary infection from the whitefly infestation.
- It has a serious impact on the production of coconut.
- Not only does it reduce the size of the coconut, but it also decreases the coconut’s water content.
Whiteflies have the following characteristics:
- Nymphs:
- Flat and oval in shape.
- Typically covered with a cottony substance.
- Adults:
- Measure 2–3 mm (0.08–0.12 inch) in length.
- Covered with a white opaque powder.
- Have soft, wedge-shaped bodies that are yellow-white in color.
- Possess white wings.
Whitefly damage
The larvae require a substantial amount of nutrients for their growth, leading them to consume large quantities of plant sap, which is rich in sugar. Excess sugar is excreted as honeydew, with larger larvae expelling significant amounts. This process can result in the following consequences:
- When the whitefly population is very large, their feeding on plant sap can impact the plant’s physiology, leading to retarded growth. In full sunlight, leaves may wilt and drop, which, in turn, can influence fruit development and reduce yield.
- Whiteflies, through their feeding on plant sap and secretion of honeydew, diminish the aesthetic appeal of crops, a concern particularly important for ornamental plants.
- Honeydew deposited on fruit makes it sticky, attracting dirt and promoting the growth of sooty molds (Cladosporium spp.). This makes the fruit unsaleable, and in severe cases, it may lead to fruit rot. Sooty molds can also develop on leaves, reducing photosynthesis and transpiration.
- Whiteflies can transmit viruses from one plant to another. Both T. vaporariorum and B. tabaci are known to be vectors for various plant viruses.
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