Influence of particle size and dispersibility of penthiopyrad on the fungicidal activity against plant disease was investigated. Suspension concentrates (SC) containing 20% penthiopyrad particles prepared into different particle sizes; 8.7, 4.5, 1.5, 0.30 and 0.24 μm of mean diameter were tested in a greenhouse. The activity of penthiopyrad against cucumber powdery mildew and tomato gray mold at a dose of 100, 20, 4 ppm was evaluated. Regarding rainfastness in case of cucumber powdery mildew, SC containing coarsest penthiopyrad and also agglutinated finest diameter were more effective than others. On the other hand, in case of residual effect against tomato gray mold, SC containing dispersed fine diameter were more effective than others. The results indicate that penthiopyrad SC containing fine diameter and controlling its dispersibility is effective to improve the rainfastness of cucumber powdery mildew and residual effect of tomato gray mold.

Computational fluid dynamics has been increasingly adopted as a promising tool to understand the essential dynamics of particulate flow. The present review gives a brief description of numerical methods to describe the boundary condition of moving solid surface at lattice Boltzmann method (LBM), including bounce-back (BB) method (and improved BB method), immersed boundary (IB) method, and smoothed profile (SP) method. It is essential to choose an appropriate numerical method according to the target system. Among these methods, the author and coworkers have used the SP method to efficiently simulate flows including a number of particles. Here, typical results obtained by the SP-LBM simulations are presented.