Plutellidae, a family with only a l

Plutellidae, a family with only a limited number of species often enriched as a subfamily of the Yponomeutidae.

Plutella xylostella (= maculipennis) (L) is the well known Diamond Back Moth (Fig. 166), a truly cosmopolitan insect occurring in troopical, subtropis cal as well as temperate regions. In indonesia its is restricted to the hills and mountains. It feeds on many varieties of cabbage, and several other cruciferistic : leaves of young plants are also eaten, especially if larvae of another pest, the caterpillar Crocidolomia, are absent. The main vein is untouched but the reminder of the leaf has a frayed apperance.

Initially newly hatched caterpillars mine within the leaves for a few days. The full-grown caterpillar can be distinguished from other cabbage pest because of the absence of longitudinal stripes on the body. The head is yellowish, bears dark spots, and the light-green body show sparsely distributed black hair-bearing tubercles. The larva grows up to 9 mm and reacts violenty when touched. The pupa lies in a white, open mesh, and spool-shaped cocoon. The moths (Fig.166) rest at daytime and at dusk make brief massed flight and the resettle. They live for 2-4 weeks, egg production is 180-300 per jantan. The eggs are laid separately on the lower leaf surface. At a height of 250 m total development takes 12-15 days; at 1100 m (where most cabbage is grown) 20-25 days.

The diamond back mothis a striking example of a potentially serious pest normally held in check by parasites,especially ichneumonids of the genus Diadegma (=Angitia). Introduction in 1931 of the most important European parasite, D. Fenestralis (Holmgr.) nto Indonesia failed. Another sp,D. Eucerophaga Horstm. (= cerophaga Grav.) was introduced from England to New Zealand in 1938 and was established in the subtropical Southern Island. It gradually spread over ton the North-Island of New Zealand which is more tropical, and was transferred from there toIndonesia in 1950. This introduction wasan immediate succes (Vos, 1953) . In circumtances where insecticides could not be used, for instance where moth had developeresistance against DDT, the pest could be controlled by the parasite.

Sudarwohadi & Eveleens (1977) did a survey about the present situation : in West Java, the parasite was established and an average of 60-80% parasitism was found which was often sufficient to control the pest. The effectiveness differs in various regions. In North Sumatra the introduction had failed, and the parasite was no more present, possibly killed by chemical control. In South Sulawesi, the parasite was lacking. In Malaysia a larval parasite of Plutella was found, the braconid wasp Apantales plutellae Kurdj. (Lim & Ko, 1975). The rate of parasitism is fairly high, averaging 36%, at times reaching up to 100%. Mass production and field liberation of this parasite haaas been reported in Taiwan.

P. sera Meyr. occurs from India to Australia and New Zealand, and has been found in Java at 700 and on 1500 m. In India the sp is reported on turnip plants where they were mistaken for the Diamond Back Moth. It is also possible that the spp have been misidentified in Indonesia.

YPONOMEUTIDAE vary much in size and biology; some genera of spp of minor importance live in flower buds, infruits, or tunnel in bark