Preliminary Study Of Occurrence Dynamic And Forecasting Of Major Pests And Predators In Baoding Apple Orchards

In recent years，the damages of major pests and over-using chemical pesticides in appleorchards are main reasons to restrict high-quality apple product. On the one hand it is dueto low management level of orchard; on the other hand it is due to a lack of knowledgeregarding of main apple pest communities and correlative factors. The occurrenceregularities of some apple pests still are unclear. Furthermore, the lack ofsimple forecasting methods also influence the pest control effect of apple pests. In orderto deeply understand the occurrence regularities of apple pests and natural enemies, thesystematic field investigations were carried out some apple pests and predators in2012and2013. We also explore the forecasting critical periods of major pests using accumulatedtemperature and phenology. The main results as follow:1. The occurrence regularities of major apple pestsThe occurrence dynamics of Grapholitha molesta (Busck), Lithocolletis ringoniellaMats, Adoxophyes orana Beijingensis Zhou et Fu and Carposinanip ponesis Walsinghamin apple orchard were systematically monitored by pheromone traps in Baoding area. Wefound that G. molesta in monoculture apple orchard, apple and pear mixed orchard hadsimilar occurrence regularities with four generations annually and obvious eclosion peaksof G. molest moth. However, it was different in the apple orchards mixcultivated withpeach with serious overlapping generations. Although the fruit bagging measures couldcompletely control the pest on fruit, but there were high number trapping male moths ineach generation. the larvae of G. molesta could complete the generation developmentthrough eating shoots and maintained a certain population number.After implementing measure of cleaning the fallen leaves from2011, the populationdensities of L. ringoniella obviously declined. The numbers captured male moths in eachtrap per week dropped from816in2011to102in2013. The field survey results showedthat the overwintering stages of A. orana were second instars larvae and third instars larvaein a thin silken cocoon under the bark, near the kerfs, spin a leaf or other suppressible areas.The second instars larvae were more than the third instars larvae，so there were twoeclosion peaks in overwintering generation. Compared with the damage of this pest, thenumbers of captured were always relatively less. It may be relative to the quality of pheromone lure of A. orana. The number of C. ponesis were very few in bagged appleorchards, only15to26male moths could be captured during the whole survey. the resultindicated that bagging technology can be well controlled the population of this pest.A. citricola had two peak periods each year which occurred in late spring and earlysummer and autumn, respectively. The damage in the first peak was the more serious thanthat in the second peak.The results of investigation indicated that the species and quantityof the dominant spider mites changed with the change of the year in the Qilipu appleorchard. Tetranychus viennensis Zacher was the dominant species in2010～2011, butPanonychus ulmi (Koch) became the dominant species from2012. The correlation analysisshowed that the number of activities mites had a significant positive correlation with miteleaf rate.2. The occurence regularities of major predatorsThe three kinds of predators had a migration peak from wheat field to apple orchard inwheat maturity. In early spring, The minute pirate bugs were the dominant species in appleorchard. However, ladybird beetles and lacewings were the dominant species in June andcould controlled quickly population of A. citricola. Most predators moved away from theapple orchard when the number of aphids declined.3. The forecasting of major apple pestsThrough dynamic monitor of apple pests for several years, combined with thephenological period of apple trees and other plant and temperature data, the phenology and≥8℃t emperature accumulationcorresponding key time of pest control were summarized.The IPM projects of main apple pests for apple orchards also were summarized.