24[7] Broad mite [EIFS

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This leaflet is produced by the Ministry of Agriculture & Livestock, Solomon Islands, with support
from IPPSI: Improved Plant Protection in Solomon Islands, a project financed by ACIAR, the
Australian Centre for International Agricultural Research, Canberra. Authors: Helen Tsatsia, MAL &
Grahame Jackson, TerraCircle Inc.

Extension Fact Sheet 49:

Broad Mite

Common name: Broad mite, Chilli mite, Sweet potato. Note, mites are not insects;
they are related to spiders and have eight legs.

Scientific name: Polyphagotarsonemus latus

Hosts: Chilli, bell pepper. This is a common mite worldwide, infesting many crops. It
is possible that additional crops, e.g., bean, egg plant, papaya, and tomato are attacked
in Solomon Islands, but have yet to be recorded.

Damage

The mite causes a common problem on chilies and bell pepper in Solomon Islands.
The symptoms - distorted, crinkled, young leaves and stunting - look as if they have a
virus infection or, perhaps, suffering the effects of herbicide damage (photo, above).
Later, there may be flower drop, distorted fruits, loss of yield and death of the plants.

Biology and Life Cycle

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. There is a larval (6
legs) and pupal stage before the adults (8 legs) are formed. Whereas the larvae feed
close to where the eggs were laid, the adults migrate to the young leaves to feed. The

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males are yellowish brown whereas the females are yellowish green. The life cycle
takes a week or less.

The outer cells of the leaf are damaged by the mouthparts of the mites so that they can
suck up the sap. The result is that the leaves, apart from becoming distorted, are
bronzed, stiff, and rolled under at the margins. Dieback is also a common result from
the mites infesting chilies and bell peppers.

Broad mites spread by walking short distances; they are spread over long distance by
wind as well as on the bodies of insects.

Detection and Inspection

Look for the distorted, stiff, discoloured leaves, on stunted plants showing dieback
and early death.

Management

In many parts of the world, predatory mites control broad mites, but the situation in
Solomon Island is unknown.

Cultural control:

• Avoid planting new crops next to those already infested with mites, otherwise the

mites will spread to the new crop at an early age, and plants may become severely
damaged;

• Avoid planting new crops downwind from those infested with mites, as the mites

will spread to the new crop on the wind;

• When infestations are severe, pull out the plants, burn them, and plant new a new

crop.

Chemical control:

Miticides are available for the control of broad mite, but mostly these chemicals are
not available in Solomon Islands. The best is abametin, a compound derived from the
soil bacterium, Streptomyces spp. Other chemicals that are affective are difocol, sulfur
and dimethoate (Rogor).