Studies On Population Dynamics And Control Of The White Grubs In Turfgrass Of The Golf Courses In Shenzhen City

The population dynamics and control of white grubs in Mingshang and Shenzhen golf courses of the city of Shenzhen was studied. The results showed that the dynamics of moving and population dynamics of white grubs in the fairway and the green of Mingshang and Shenzhen golf courses was affected by the dry and the rainy seasons, topography( or areas ) and maintaining level. The population dynamics of the highland (the rough highland and the high fairway) in the rainy season ( May～October ) were two to two point five fold of witch for the same topography in the dry season( January～April , November～December) and the depressed land (the rough depressed land and the depressed fairway ) in the rainy season, it was in the reverse for the depressed land in the rainy season . The population dynamics in the aborative maintaining areas( the high fairway and the depressed fairway ) for the dry and the rainy season was a little higher than that of the subordinate areas. The population dynamics of Mingshang golf course was larger than that of Shenzhen golf course. The population dynamics in the green I and II was similar to the fairway areas in the rainy season. Amount of grubs in the green I and II made up more than 90% of the total grubs population of the green.The grubs in the fairway during the dry season mainly lived in 4.5～11.0cm soil under ground , 2.6～5.5cm soil for the rainy season. The annual average depth of grubs living in the green soil was lower than that of the fairway. The grubs in the green soil lived annually in 0.7～7.3cm and near the surface during July～September ( 0.7～1cm ).The efficacy of three kinds of Metarhizium anisopliane and one kind of pesticide sulfotep in controlling white grubs was determined. All kinds of M. anisopliane showed better control of grubs than sulfotep did. M. anisopliane-A showed the best control of white grubs. Even after sixty days, its control effect was still more than 90%. Different application rates of M. anisopliane-A had been compared. There was no difference among three application rates. Therefore, the fewest rate of 1g/m~2 should be choosen by golf course for thrift. Different ways of using M. anisopliane-A had also been determined. After sixty days , sifting the sand soil on to the turfgrass and digging the grassland showed 62.28% and 71.97% respectively. However sprinkling and stiletto showed 87.40% and 94.32% control effect respectively, which were suitable for the golf club to use.