Preliminary Study Of Occurrence Regularity And Forecasting Of Main Apple Pests In Baoding Area

The species composition, quantity and damage degree of apple pests are changed with the change of climate and cultivation. In order to know the occurrence regularity of main apple pests in different type of orchards, the author systematically investigated the population dynamics of Grapholitha molesta Busck, Carposina sasakii Matsmura, Lithocolletis ringoniella Matsumura, Adoxophyes orana Fischer von Rosleratamm, Aphis citricola Vander Goot and Tetranychus viennensis Zacher in Baoding orchard and Wangdu orchard in 2010 and 2011 respectively, and search maneuverable the pest predicted method. The results were as the following.1. The population dynamics of four Lepidoptera pests were investigated by sex-pheromone traps. The results indicated that G. molesta accomplished four generations per year and could complete its annual life history not only in apple–peach–pear mixed planted orchard but also in single apple orchard using measure of bagging fruit. The G. molesta adults of overwinter generation occurred in mid-April. C. sasakii had two generations per year. The unearthing period of overwinter larvae of C. sasakii was associated with rainfall in June and the adults emerged in late June or July. L. ringoniella accomplished 5 generations per year. The L. ringoniella adults of overwinter generation began occurring in late March. A. orana had 3 generations per year and overwintered as second instar larvae under loose scales of bark. The overwinter larvae began to damage leaves in April. The overwinter generation adults appeared in early June.2. A. citricola and T. viennensis all had one peak of damage in a year, and reached its damage peak in the mid-June, then maintained at a low level. The change of A. citricola population in the mid-June was associated with predator enemies from wheat field.3. The effective accumulated temperature method and phenological method were used for forecasting key time of some apple pests. The effective accumulated temperature method could accurately predict the occurrence period of some Lepidoptera pests, especially the overwintering generation, however, its application was limited by many factors such as overwintering sites, living microenvironment, basic research of developmental accumulation temperature and insect diapauses, etc. The effective accumulated temperature method is only used by agricultural extension workers and researchers in China at present, but it is difficult to master for the majority of growers. The phenological method was suitable for the prediction of key occurrence periods of some apple pests which were also primarily affected by temperature. The farmers could easily accept and use phenological method.