A method for raising brown planthopper (BPH), Nila-parvata lugens (Stl)

To get mass ppoulation of the BPH, agood method for rasing BPH isneeded. In this paper, a convenientmethod was recommended.BPH population used in the ex-periment was provided by Jiangsu A-cad of Agri Sci. Six raising BPHmethods, i. e, with rice buds (RB),rice seedling (RS), seedling soillesscultured (SSC), mature rice (MR),and rice stem cultured in nutrient

The Comparison of the Control Effect on the Varroa Mite with Different Ways of Raising Management

[Objective] The aim was to o research the control effect to Varroa destructor and Tropilaeplaps clareae whit new raising management methods, and reduce the pollution caused by drug treatment of bee. [ Metkod] We took the method that was replace the hive and comb on test col- onies with the comb Formalin soaking liquid used three days after the dry and sterilization in advance with the hive. The test groups were 10 colonies randomly selected from the disinfected comb in the breeding. This was the first kind of method. The control groups were 10 colonies randomly se- lected by the conventional breeding management methods. From January 20th, statistic analysis on parasitic situation of bees once every month be- tween the two methods, and take corresponding measures to prevent and control the varroa mite according to the varroa mite parasitic number in time, then the control effect of mite between the two methods were compared with. [ Result] The results showed that the first method was better than the second one in V. destructor, the control time of T. clareae delayed about one month [ Conclusion] Good breeding method could restrain I V. destructor and T. clareae parasitism, speeded up the colony development, and reduced the pollution of chemical drugs on bee products, regar- dod as a kind good method of controlling bee mites to make use of the feeding and management technology.

Effects of soilless substrates on seedling quality and the growth of transplanted super japonica rice

This study was conducted to investigate the effects of soilless substrates of hydroponically grown long-mat seedlings （HLMS） on seedling quality and field growth characteristics of transplanted super japonica rice. A widely grown conventional super japonica rice cultivar （Wuyunjing 23） was selected as the test material. The effect of HLMS on seedling quality, mechanical transplantation quality, field growth characteristics, yield, and benefit-cost ratio were compared with seedlings grown in organic substrates and traditional nutritive soil, whJch was selected as the control. Root number, root twJstJng power and root activity of seedlings cultivated by HLMS were decreased compared to that of the organic substrates andcontrol. However, seedling root length as well as aboveground growth were increased compared to the organic substrates and control seed- lings. In the HLMS, the content of gibberellin acid （GA3） decreased while abscisic acid （ABA） content increased compared to that of the organic substrates and control seedlings. During the early stages after transplanting, the re-greening of HLMS was delayed compared to that of the organic substrates and control seedlings. Nevertheless, there were no significant differences in tiller dynamics and crop yield among the HLMS, organic substrates and control treatments. The effects of HLMS on seedling production were similar to those of the organic substrates and traditional nutritive soil in the present study, suggesting that HLMS have the potential to replace traditional nutritive soil in seedling production without decreasing crop yield. Finally, it is important to reduce organic substrates and topsoil dependence during rice seedling production and worthwhile to consider HLMS popularization and its application on a larger scale.

A RAISED PANEL METHOD BASED ON NURBS FOR FREE-SURFACE POTENTIAL FLOWS WITH FORWARD SPEED

A raised panel method based on NURBS (Non-Uniform Rational B-Splines) forfree-surface flows with forward speed is presented. In this generalized panel method, NURBS areemployed to represent the body geometry, disturbed free surface, and to express the unknown sourcestrength distribution, on the body surface and above the free surface. Compared with commonhigher-order panel methods, it has no need of adopting local coordinates. NURBS make the geometryrepresentation of the body shape and the wave pattern more precise. Raised panels above the freesurface produce less numerical dispersion error, need less CPU consumption and are helpful andcombined with collocation-point shifting up-stream, can satisfy the radiation condition numerically.By using continuous and discrete Fourier analysis, numerical errors of this method are discussedand a general expression for the errors of numerical damping and dispersion, including the effectsof the vertical distance of singularities to the free surface, the order of singularity distributionrepresented by B-splines in panels, and collocation-point shifting is derived.