[Effects of four aphid species on development and reproduction of Harmonia axyridis]. / 4种蚜虫对异色瓢虫生长发育和繁殖的影响.

To examine the suitability of Myzus persicae, Lipaphis erysimi, Semiaphis heraclei and Aphis gossypii to propagation of Harmonia axyridis population, we studied the development and reproduction of this ladybird by constructing two-sex life table in the laboratory with those four aphid species as diet. The results showed that the immature duration of H. axyridis decreased in an order of L. erysimi (18.18 d), A. gossypii (17.48 d), S. heraclei (16.23 d), and M. persicae (15.77 d). The survival rates of preadult period were S. heraclei (88.3%), M. persicae (86.7%), L. ery-simi (55.0%), and A. gossypii (55.0%). The fecundity of those species were S. heraclei (1750.5), M. persicae (1441.5), A. gossypii (1006.3), and L. erysimi (965.2). The longevity of adult ladybird were S. heraclei (78.8 d), M. persicae (63.1 d), A. gossypii (54.3 d), and L. erysimi (48.4 d). The intrinsic rate of increase (rm) of H. axyridis population decreased in an order of M. persicae (0.19), S. heraclei (0.18), L. erysimi (0.14), and A. gossypii (0.14). The net reproduction rates (R0) were S. heraclei (895.83), M. persicae (600.62), L. erysimi (273.47), and A. gossypii (268.33). Among those four aphid species, S. heraclei and M. persicae were more suitable for the propagation of H. axyridis population.

[Predatory and control ability of Orius minutus to the diamondback moth (Lepidoptera: Plutellidae).] / 微小花蝽对小菜蛾捕食控制的能力.

In order to make clear the suitability of eggs of Plutella xylostella as foodstuff of Orius minutus and the predatory and control ability of the bug to P. xylostella, the influence of praying on eggs of P. xylostella on development and reproduction of O. minutus was studied indoors with Myzus persicae as reference. The predation functional response was included to evaluate the control ability of O. minutus to P. xylostella. The results showed that O. minutus could finish its generation and reproduce offspring when fed on eggs of P. xylostella. The developmental durations of nymphal bugs (♀: 12.3 d, ♂: 12.2 d), the length of body of adult bugs [♀: (2.13±0.01) mm, ♂: (1.91±0.00) mm], the width of body of adult bugs [♀: (0.87±0.01) mm, ♂: (0.71±0.01) mm], the fecundity per female (12.7±1.1), the pre-oviposition period [(5.1±0.6) d] and the oviposition period [(3.7±0.4) d] all had no significant difference from those of treatment group of M. persicae; the longevity of adult bugs [♀: (10.7±1.4) d, ♂: (9.1±1.3) d] was longer than that of treatment group of M. persicae [♀: (8.5±0.5) d, ♂: (6.4±0.3) d]; the survival rate of nymphal bugs [(65.0±6.8)%] was lower than that of treatment group of M. persicae [(80.0±8.2)%], and the percentage of females was low. The predation functional responses of O. minutus to P. xylostella were all in accord with Holling2 equation. The largest amounts of caught per day (Nmax) of the 1st, 2nd, 3rd, 4th and 5th instar nymphal bugs to eggs of P. xylostella were 7.5, 16.3, 23.3, 29.1 and 38.7, respectively; the Nmax of the female and male adult to eggs of P. xylostella was 39.0 and 26.9, respectively; the Nmax of the 5th instar nymph to lower instar larva of P. xylostella was 41.3; and the Nmax of the female and male adult to lower instar larva of P. xylostella was 40.8 and 23.9, respectively. Single female and male pray eggs of P. xylostella up to (711.3±58.1) and (535.4±30.6), lower instar larvae of P. xylostella up to (371.9±52.0) and (253.9±32.3) during their whole lifetime, respectively. O. minutus could be reared with eggs of P. xylostella, and O. minutus has a good ability to control P. xylostella.

Characterization and gene cloning of a novel serine protease with nematicidal activity from Trichoderma pseudokoningii SMF2.

Trichoderma pseudokoningii SMF2 is a biocontrol fungus with inhibitory ability against phytopathogenic fungi. Here, a crude extract of strain SMF2 in a solid ferment exhibited strong nematicidal activity against Meloidogyne incognita, and a novel serine protease SprT with nematicidal activity was purified from the crude extract. Protease SprT has a molecular mass of 31 kDa, a pH optimum of 8.5, and a temperature optimum of 60-65 degrees C. It had good thermostability, and was stable in an alkaline environment. SprT could degrade bovine serum albumin, lysozyme, and gelatin, and its activity was enhanced by many metal ions. The cuticles of nematodes treated by protease SprT obviously crimpled. Purified protease SprT could kill juveniles of M. incognita and inhibit egg hatch, suggesting that it is involved in the nematicidal process of T. pseudokoningii SMF2. The full-length cDNA gene-encoding protease SprT was cloned by rapid amplification of cDNA ends. Sequence analysis showed that SprT is a monodomain subtilase containing 284 amino acid residues. It had higher identities and a closer relation to the nematicidal serine proteases (59-69%) from nematode parasitic fungi than to the serine proteases (<50%) from Trichoderma. Protease SprT represents the first well-characterized subtilase with nematicidal activity from Trichoderma.