Mating Disruption of Chilo suppressalis From Sex Pheromone of Another Pyralid Rice Pest Cnaphalocrocis medinalis (Lepidoptera: Pyralidae).

The rice stem borer, Chilo suppressalis (Walker), and the rice leaf folder, Cnaphalocrocis medinalis Guenée, are two of the most destructive lepidopteran pests in rice. Since these two pyralid insects overlap in their occurrence in rice paddy fields, farmers prefer to set their pheromone-baited traps together in the rice fields for their monitoring. However, our field observation demonstrated that no male adult of C. suppressalis was captured in traps baited with commercial sex pheromone of C. suppressalis (CCS) combined with commercial sex pheromone of C. medinalis (CCM). To confirm that the C. medinalis sex pheromone component(s) interfere with the attraction of males of the rice stem borers to their conspecific females, single components of C. medinalis sex pheromone combined with CCS in traps were tested in the laboratory and rice paddy field. The results revealed that the two alcohol components in CCM, i.e., (Z)-11-octadecen-1-ol (Z11-18: OH) and (Z)-13-octadecen-1-ol (Z13-18: OH) may cause a significant reduction in capturing C. suppressalis males caused by CCS. We recommend against using these sex pheromones together in the field and suggest that Z11-18: OH and Z13-18: OH could be potential inhibitors or antagonists of C. suppressalis sex pheromone to control the rice stem borer.

Influence of transgenic rice expressing a fused Cry1Ab/1Ac protein on frogs in paddy fields.

As genetic engineering in plants is increasingly used to control agricultural pests, it is important to determine whether such transgenic plants adversely affect non-target organisms within and around cultivated fields. The cry1Ab/1Ac fusion gene from Bacillus thuringiensis (Bt) has insecticidal activity and has been introduced into rice line Minghui 63 (MH63). We evaluated the effect of transgenic cry1Ab/1Ac rice (Huahui 1, HH1) on paddy frogs by comparing HH1 and MH63 rice paddies with and without pesticide treatment. The density of tadpoles in rice fields was surveyed at regular intervals, and Cry1Ab/1Ac protein levels were determined in tissues of tadpoles and froglets collected from the paddy fields. In addition, Rana nigromaculata froglets were raised in purse nets placed within these experimental plots. The survival, body weight, feeding habits, and histological characteristics of the digestive tract of these froglets were analyzed. We found that the tadpole density was significantly decreased immediately after pesticide application, and the weight of R. nigromaculata froglets of pesticide groups was significantly reduced compared with no pesticide treatment, but we found no differences between Bt and non-Bt rice groups. Moreover, no Cry1Ab/1Ac protein was detected in tissue samples collected from 192 tadpoles and froglets representing all four experimental groups. In addition, R. nigromaculata froglets raised in purse seines fed primarily on stem borer and non-target insects, and showed no obvious abnormality in the microstructure of their digestive tracts. Based on these results, we conclude that cultivation of transgenic cry1Ab/1Ac rice does not adversely affect paddy frogs.

[Study on tissue cultivation of adventitious roots of Pseudostellaria heterophylla].

OBJECTIVE: To systematically optimize the cultivation conditions of adventitious roots of Pseudostellaria heterophylla. METHOD: Tissue cultivation technology and ultraviolet spectrophotometry were adopted to observe the effect of inoculum volume, sucrose concentration, inorganic salt concentration, number of cultivation days, gradual scale-up cultivation and bubble different angles of bioreactor on the growth of adventitious roots of P. heterophylla, and determine the content of constituents such as saponin, polysaccharide and amino acid. RESULT: The propagation multiple of adventitious roots reached the maximum when the inoculum was 6 g in a 1 L culture shake flask. With the increase in sucrose concentration, the dry weight propagation multiples of adventitious roots followed an up and down trend. The inorganic salt concentration in a cultivation dish had a greater effect on the growth of adventitious roots, particularly 3/4 MS was the most favorable for the growth of adventitious roots. The growth curve of P. heterophylla was "S", with the biomass reaching the maximum at the 28th day. CONCLUSION: The inoculum volume, sucrose concentration, inorganic salt concentration, gradual scale-up cultivation and angles of bubble bioreactor had a significant effect on the growth of adventitious roots of P. heterophylla. The contents of saponin and amino acid in adventitious roots were higher than that in cultivated P. heterophylla, whereas the polysaccharide content were lower than that in cultivated P. heterophylla.