Abstract:

Based on mass of trials, the paper discussed how to keep out Semanotus bifasciatus (Motschulsky) by making use of Pyemotes zhonghuajia Yu and Zhang. In outdoor trials, we fixed up Platycladus orientalis blocks(1m in length and 10cm in diameter) on the truck of Sabina in a wood instead of trying on live trees. Before releasing Pyemotidae mites, we put Semanotus bifasciatus (Motschulsky) nymphas on Platycladus orientalis blocks as preparation, 30 ones for each block. The trials dates are from the middle of April to the end of May; we set two Pyemotidae mites releasing amounts and one blank as contrasting. The results showed that in Beijing the best time keep out the pest by making use of Pyemotidae mites is the early and middle days in May, when the average temperature of the day is over 20℃.As a result ,the reasonable method is utilizing smaller releasing amouts to control beetles as early as possible when the temperature is avalible.