AVRDC International Cooperators'
Fact Sheet

Tomato Insect Pests
 

Whitefly
Several species, including Bemisia tabaci 

Found worldwide

Damage Symptoms

Leaves have numerous chlorotic spots or areas. These spots grow together forming different sized yellow areas. In severe cases, only the veins remain green. Some leaves appear completely brown and dried. Wilting and leaf drop may occur. A sticky, black mold may be found on leaves and stems.


Insect Characteristics

Piercing-sucking mouthparts. Adults are about 1mm in size and are white to yellow. Their bodies are covered with a powdery waxy material. At first glance they look like flies. Adults readily fly if disturbed. Immatures are usually pale yellow. Early stages crawl about the leaf, whereas later stages assume a fixed position.		  
Leaf infested with whiteflies
 

Seedlings protected by fine mesh screen
     

Where To Look

The easiest way to find whiteflies is to brush or shake the leaves and look for the whitefly adults which fly off. Inspect the undersides of the leaves for the stationary immatures.


Technical Information

Females lay up to 150 eggs each. Depending on weather conditions, the life cycle can be completed in about 12 days. Multiple overlapping generations occur. These pests are important vectors of diseases which are often more devastating than the injury caused by their feeding. One important disease is the leaf curl virus. Whiteflies are found on many vegetable corps and are common on sweet potato and cassava.


Control

Whiteflies are most damaging when they spread viruses, especially Tomato Yellows Leaf Curl Virus. Protect seedlings from infection by growing them under 60-mesh screening. The traditional 32-mesh screen is not fine enough to prevent whitefly infection.

Crops may be sprayed with insecticides for control. Confidor or Asana are often used.

Last updated: 2001. 
Information from: Field Guide: Insect Pests of Selected Vegetables in Tropical and Subtropical Asia. 1995. B.L. Parker, N.S. Talekar and M. Skinner. Publication 94-427. Pesticide and other control recommendations should be adapted for local conditions. 
 

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