Photo 3. Deformed leaves with mosaic (light and dark green), virus-like, symptoms on capsicum caused by the broad mite, Polyphagotarsonemus latus.
Photo 4. Tomato with severe infestation of the broad mite, Polyphagotarsonemus latus, growing in a tunnel enclosure.
Capsicum broad mite
Worldwide. Asia, Africa, North, South and Central America, the Caribbean, Europe, Oceania. It is recorded from Ausralia, Fiji, Guam, New Zealand, Papua New Guinea, Samoa, and Solomon Islands.
Capsicum, chilli, tomato are the main hosts, but also on many other crops, e.g., bean, eggplant, papaya, mango and avocado.
Mites damage the outer cells of the leaf as they feed on the plant sap. The leaves become distorted, bronze coloured, stiff, and rolled under at the margins. Dieback is a common result from mites infesting chilies, capsicum and tomato.
The mites infest the youngest leaves of the bud; they are too small (less than 0.25 mm) to be seen with the eye, and a microscope or powerful hand lens is needed.
The eggs are laid singly on the underside of the leaves or fruit. These hatch giving rise to larvae with six legs, later they have eight as they develop into nymphs. The males are yellowish brown whereas the females are yellowish green. The life cycle takes a week or less.
Whereas the larvae feed close to where the eggs were laid, the adults migrate to the young leaves in the bud to feed. Broad mites spread by walking short distances; they are spread over long distance by wind as well as on the bodies of insects.
The mite causes a common problem on chillies, capsicum (Photos 1,2&3), and tomato (Photo 4). The symptoms - distorted, crinkled, stunted leaves - look as if the plants have a virus infection or, perhaps, suffering the effects of herbicide damage. Later, flowers drop, leaves fall, and fruits are distorted, and there is loss of yield. In extreme cases, plants are killed by the infestation. Damage to tomato is frequent when grown in enclosures (Photo 4). In this case, yield is very poor or non-existent.
Look for the distorted, stiff, discoloured leaves, on stunted plants showing dieback and early death.
In many parts of the world, predatory mites control broad mites, but the situation in Pacific island countries is unknown.
Miticides are available for the control of broad mite, but these chemicals are seldom available in Pacific island countries. Garlic is said to be effective against mites, and other natural products are derris and sulphur. Abamectin is a relatively new product from the soil bacterium, Streptomyces spp. Sprays of white oil (petroleum oil) may also be effective (see Fact sheet no. 56).
AUTHORS Helen Tsatsia & Grahame Jackson
Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.
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