Effects of temperature and host on the immature development of the parasitoid neochrysocharis okazakii (hymenoptera: Eulophidae)

The development of Neochrysocharis okazakii, an eulophid parasitoid attacking pest Liriomyza leafminers, was studied under laboratory conditions at seven constant temperatures (15°, 17.5°, 20°, 22.5°, 25°, 27.5°and 30°C) on the hosts L. chinensis and L. trifolii. Neochrysocharis okazakii completed development on both host species at all temperatures examined. The total development time from egg to adult emergence was similar on the two host species at 25-30°C Male parasitoids developed faster than females did. The developmental time was inversely proportional to temperature, and decreased from 41 to 9 days for temperatures from 15°to 30°C, with pupae requiring shorter time for development than the earlier stages. The lower developmental temperature thresholds and degree-days were estimated from linear regression equations. For egg to adult emergence, male N. okazakii required 166.7 degree-days (DD) above a lower developmental threshold of 11.5°C on L. chinensis and 166.7 DD above 11.6°C on L. trifolii; females required 172.4 DD above 11.3°C on L. chinensis and 178.6 DD above 11.3°C on L. trifolii. Although the two host species were equally suitable as host for N. okazakii, our findings suggested that L. trifolii is an ideal host for N okazakii mass-rearing.