Population Parameters and Parasitism of Chrysocharis oscinidis (Ashmead) (Hymenoptera: Eulophidae), a Parasitoid of Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) in Laboratory

• Main Authors: Salim Al-Nabhani, 那瑟任
• Other Authors: Po-Yung Lai
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/26305306387581332537

碩士 === 國立屏東科技大學 === 熱帶農業暨國際合作研究所 === 93 === Chrysocharis oscinidis (Ashmead) is an arrhenotokous, solitary endoparasitoid of Liriomyza trifolii (Burgess). At 25ºC, the wasp took 13.96 ± 0.62 days to develop from egg to adult. The durations of the egg, larval, prepupal and pupal stages were; 1.30 ± 0.47, 5.98 ± 0.58, 1.12 ± 0.74 and 3.71 ± 1.72 days, respectively. The analysis of life table of C. oscinidis indicated that net reproductive rate (Ro), mean generation time (T), finite rates of increase (λ), and intrinsic rate of increase (r) were 14.22, 10.49 days, 1.29, 0.20, respectively. Neither the longevity of male and female nor the male and female progeny produced were significantly different at (P<0.05). The population of C. oscinidis could be doubled in 3.01 days. The longevity, fecundity and sex ratio of the female were not affected the different densities (1, 3, 5, and 7 pairs) of C. oscinidis adults in a cage of 0.008 m3. When 50 late 2nd and 3rd instar larvae of L. trifolii were provided daily, the overall fecundity of the parasitoid was 48.75 ± 28.04, 94.75 ± 21.19, 75.75 ± 36.81, and 77.25 ± 13.02 adults at 1, 3, 5, and 7 pairs of C. oscinidis per cage, respectively. The longevity of female and male wasps was 19.75 ± 0.96 and 28.75 ± 8.34 days, respectively. The population of female progeny was 0.62, 0.77, 0.85 and 0.72 at 1, 3, 5 and 7 pairs of C. oscinidis per cage, respectively. The type II functional responses curve was identified, when different densities of L. trifolii larvae provided to individual C. oscinidis females for parasitization. The parasitism would probably be low as the majority of time of a female spent was to search for host, especially when the host was at its low density. After that, the number of L. trifolii parasitized increased as the density of the host increased. The mean number of L. trifolii parasitized by a C. oscinidis female at different L. trifolii densities (5, 10, 20, 30, 40, 50 and 80 larvae) were 1.7 ± 0.85, 2.2 ± 1.02 ±, 2.1± 1.01, 3.51 ± 1.73, 4.2 ± 1.35, 5.1 ± 1.97 and 6.6 ± 2.26, respectively. If the initial number of L. trifolii exceeds 6.6 larvae per cage of 0.008 m3, with only one C. oscinidis female searching for hosts, the number of L. trifolii killed will be proportionally smaller than the number of L. trifolii successfully reaching adulthood, resulting in the increase of the L. trifolii population in the next generation. According to the biological characteristics and parasitization performance elucidated in this study, C. oscinidis can be a potentially effective biological control agent of L. trifolii.