Lesser striped flea beetle, small striped flea beetle, flea beetle, turnip flea beetle
Worldwide. In the tropics, sub-tropics and temperate countries. In Oceania, it has been recorded from Australia, Fiji, New Caledonia and Vanuatu.
Members of the cabbage family, Brassicaceae (Cruciferae), Chinese cabbage in particular.
The adult beetles do the damage. They are 2 mm long, with a pair of wide yellow stripes on their wing cases (Photos 1&2). Adults feed on the leaves, and the larvae feed on the fine roots. Pupation takes place in small cocoons in the soil. The life cycle from egg to adult is about 3-4 weeks.
Spread of the beetle is by flight and wind over short distances, and by the domestic and international trade in fresh vegetables.
This is a very serious pest, especially on Chinese cabbage. The adult beetles feed on leaves by scraping, and by making many small holes (Photo 3&4). The Chinese cabbages become unfit for sale.
Growth of seedlings can be checked by the attack and even killed. Larger plants continue to grow and produce leaves, but when populations are high, the leaves are full of holes, and the plants become unmarketable.
The beetle can spread several virus diseases, e.g., Turnip rosette virus, Turnip yellow mosaic virus and Turnip crinkle virus . However, the virus is usually less of a problem than the direct feeding by the adult beetles.
Look for the pinprick-size scrapings and holes in the leaves. Look for tiny beetles (2 mm long) with two broad yellow stripes on their backs. They can be found within the whorl of new leaves and on the back of older ones.
Nothing is known about the natural enemies of this pest in the South Pacific.
Countries that have not yet recorded the presence of Phyllotreta undulata will need to consider potential pathways for the introduction for this serious pest, and ensure that they do not allow its entry.
Probably all varieties of Chinese cabbage are susceptible to attack by this beetle; however, head cabbages (green and purple varieties) are not attacked in Vanuatu.
Such is the importance of this insect that chemical control may be necessary. Do the following:
AUTHOR 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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