The Occurrence Characteristics Of Grubs In Some Areas Of Anhui And Jiangsu Provinces

A survey on the occurrence of grubs in three areas of Anhui and Jiangsu provinces was carried out2011and2012. The aim of our research was to explore the species composition and dominant pest species under new cultivation system; the temporal and spatial community dynamic in farmland and woodland near farmland; and providesdata for the effective prevention and control of grubs. The detailed results were as follows:1. We conducted6investigations in Taixing city, Guanyun county and Lianyungang city, Jiangsu province, and Xiao county, Anhui province, in September and October2011, March, August, October and December,2012, and found grubs were the dominant soil pests in these areas. The grub community was composed of16species in3families. The dominant family is Rutelidae with eight species. However, the Melolonthidae causes more serious harm to crops. There are14species in3families of grubs in Xiao County, and the dominant species is Holotrichia parallela Motschulsky. We found5species in2families in Guanyun county, the dominant species is Holotrichia parallela Motschulsky. Taixing City has6species in3families, the dominant species is Metabolus flavescens Brenske. At the same time, we found the occurrence of grubs of these three regions were all beyond the5/m2soybean field serious outbreak control index.Some common environmental factors are used to divide the survey results into groups to analysis the possible impact of grub population structure. The study found that the soil didn’t cause grub dominant species difference, but it does havean impact on the occurrence of the number of species and population. The different time of investigation resulted in significant changes in species composition, but had no significant effect on the population. Different surface vegetation resulted in significant differences of grub population, but showed no significant effect on the grub community composition.2. The individuals and species richness of grups in2011to2012showed "n " type changes, with peaks in August and October, and valleys of no grubs in March and December. Farmland grub species changed over time, the dominant species were differences within the same year or in different years, of which in August2011and October 2011was Holotrichia parallela Motschulsky, while in August2012was Serica orientalis Motschulsky, and in october2012was Maladera ovatula(Fairmaire). Soil type is an important factor that may affect the occurrence of grubs. One-way ANOVA analysis showed that the number of different soil types grubs had significant differences. NMDS and ANOSIM analysis showed that there were also significant differences between grubs community structure of different soil types.In the seed dressing prevention comparative tests, we found the grubs’number had significant differences between the control and un-control farmland. A survey of the different periods in the same place showed that the control plots existe a significant change of the amount of grubs, and the un-control plots showed no significant difference.3. A field survey conducted in woodland of Xiao Country showed that the grub community was composed of9species in3families, and the dominant species were Holotrichia parallela Motschulsky, Maladera ovatula (Fairmaire) and Serica orientalis Motschulsky, the species composition and dominant species are same with farmland. There are many similarities between grubs occurrence of woodland and farmland. The woods’ grubs population and the number of species’ occurrence are basically same with farmland, they have the similar"n" type changes, but still had grubs in March2012and December2012. By using the findings of poplar in March2012as abscissa, and the survey results of soybean field in August2012as the vertical axis, we found that there was a strong linear contact between them, this indicated the close contact of them, but the conclusions still need further experimental verification.