In recent years, the diamondback moth, Plutella xylostella (Lepidoptera: Yponomeutidae), has become the most destructive insect of cruciferous plants throughout the world, and the annual cost for managing it is estimated to be U.S. $I billion (168). Members of the plant family Cruciferae occur temperate and tropical climates and represent a diverse, widespread, and important plant group that includes cabbage, broccoli, cauliflower, collards, rapeseed, mustard, and Chinese cabbage, the most important vegetable crop grown in China (90), the most populous country in the world. Although the diamondback moth is believed to have originated in the Mediterranean area (64), the source of some of our most important crucifers (185), diamondback moths now occur wherever cmcifers are grown, and this insect is believed to be the most universally distributed of all Lepidoptera (107). Absence of effective natural enemies, especially parasitoids, is believed to be a major cause of the diamondback moth's pest status in most parts of the world (92). Lack of parasitoids in a particular area may have occurred because the diamondback moth is better able than its natural-enemy complex to become established in newly planted cmcifers. Reports on the ability of diamondback moths to migrate long distances are numerous (

Laboratory and greenhouse studies were conducted to investigate the suitability of 2 hymenopterous parasites, Diadegrna eucerophaga Horstmann and Apanteles plutellae Kurdjumov for introduction to control diamondback moth (DBM), Plutella xylostella (L.), a destructive pest of crucifers in tropical to subtropical Southeast Asia. Parasitism by D. eucerophaga was high at temperature range of 15 ~ to 25 *C and that of A. plutellae, at 20 *C to 35 *C. Both parasites were active in searching for host and oviposited only during photophase. No parasitism was observed during darkness. Whereas A. phttellae could parasitize all instars of DBM larvae, D. eucerophaga parasitized only the first 3 instars and failed to parasitize the 4 'n. Parasitism by D. eucerophaga was greater when DBM larvae were feeding on common cabbageparasitism was greater when DBM larvae were feeding on Chinese cabbage than on common cabbage, cauliflower or broccoli. Storage of pupae at 0 ~ and 4 *C to 6 *C for up to 2 weeks reduced emergence of D. eucerophaga adults more than that of A. plutellae. A non-selective insecticide, deltamethrin, was toxic to adults of both parasites but selective ones such as Bacillus thurfllgiensis, teflubenzuron, and pirimicarb were not. Pupae were more tolerant than adults to insecticides. The insecticide-resistant Luchu strain and susceptible laboratory strain of DBM suffered an equal level of parasitism by both parasites. KEY-WORDS :Diadegma eucerophaga, Apanteles phttellae, temperature, insecticide selectivity, host-plant effect.Diamondback moth (DBM), Plutella xylostella (L.) (Yponomeutidae : Lepidoptera), is the most destructive pest of crucifers in the tropics and subtropics. The insect larva feeds on the foliage which adversely affects the yield and quality of the produce. To combat this pest, farmers use large quantities of insecticides, especially in tropical to sub-tropical Southeast Asia where crucifers are economically important. Due to the availability of hosts practically throughout the year, rapid turnover of generations under an ideal tropical environment, and intensive use of insecticides, the DBM has now developed resistance to most chemical insecticides being sold in the market (Cheng, 1986(Cheng, , 1988Sun et al., 1986 ;Miyata et al., 1986) in Southeast Asia. Indiscriminate use of insecticides has eliminated the parasites and predators which, to some extent, contributed to reducing the pest population in the past. As a result, the pest problem has been exacerbated and efforts are now being made to search for alternative control measures.

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Bruchids (genus Callosobruchus) are among the most destructive insect pests of mungbeans and other members of the genus, Vigna. Genetic resistance to bruchids was previously identified in a wild mungbean relative, TC1966. To analyze the underlying genetics, accelerate breeding, and provide a basis for map-based cloning of this gene, we have mapped the TC1966 bruchid resistance gene using restriction fragment length polymorphism (RFLP) markers. Fifty-eight F2 progeny from a cross between TC1966 and a susceptible mungbean cultivar were analyzed with 153 RFLP markers. Resistance mapped to a single locus on linkage group VIII, approximately 3.6 centimorgans from the nearest RFLP marker. Because the genome of mungbean is relatively small (estimated to be between 470 and 560 million base pairs), this RFLP marker may be suitable as a starting point for chromosome walking. Based on RFLP analysis, an individual was also identified in the F2 population that retained the bruchid resistance gene within a tightly linked double crossover. This individual will be valuable in developing resistant mungbean lines free of linkage drag.