The Research On Apple Pests' Species, Regional Distribution And The Occurrence Trend Of Major Pests

In China, apple pests are major obstacles for apple production. In order to strengthen scientific control of plant diseases and insect pests, the research of a national survey on apple pests and distribution was conducted.Through a two-year national survey, we have identified 51 different kinds of apple diseases. Among them, apple canker, leaf spot and ring rot are the three most important diseases in vast area of China and cause much damage for apple trees and for yields. Compared with the previous record, the survey found two new diseases. They are Rhizoctonia solani causing leaf blight and Glomerella causing leaf spots. The former was found in Puyang, Henan in 2010 that spread in branches and leaves, and lead the branches and leaves to death. The latter was found in Shangqiu of Henan, Dangshan of Anhui, Fengxian of Jiangsu and Qingdao of Shandong and other places in recent two years. The survey found 78 different kinds of pests. Among them Bactrocera dorsalis and Schizoneurella indica are two new species recently found in Zhengzhou and Yunnan province respectively. 21 species of pests such as Tetranychus viennensis, Carposina niponensis, Aphis citricola, Eriosoma lanigerum, Adoxophyes orana, Tetranychus urticae and so on are the main insect pests. The most common pests are mites and aphids, The insect pests in lepidoptera, except the codling moth, belong to secondary pests. But in some regions and under specified weather conditions, some secondary pests could cause serious damage, which also needs to be paid much attention.According to the survey data, distribution maps were draw out for the major pests. The map showed that apple canker is serous in most apple producing provinces. Ring rot caused by Botryospuaeria berengeriana are serious in Shandong, Henan, Hebei, Liaoning and Tianjin and the disease is developing from east to west provinces of China, which should be paid close attention. The Venturia inaequalis has been found in Xinjiang, Shandong, Shanxi, Gansu, Liaoning, Heilongjiang, Tianjin and Henan and only cause problems in Xinjiang and Heilongjiang. In other regions it is very light. In general apple pests occur comparatively lighter than diseases. In some years, Tetranychus urticae could cause problems in Henan, Shandong, Liaoning, Hebei, Gansu and Xinjiang. Tetranychus viennensis usually is worse than Tetranychus urticae, especially in central Hebei, southern Shanxi and Northern Henan and Eastern Liaoning. In southwest platau apple producing areas it is also heavier. Carposina niponensis is serious in Handan of Hebei, Changzhi of Shanxi, Luoyang of Henan, some regions of Heilongjiang and Jilin. It has not been found in Xinjiang and southwest regions. Aphis citricola distributed relatively concentrated in southeast Gansu, central Shaanxi and northern Henan, southern Shanxi, as well as around Bohai. The codling moth distributed in Xinjiang, Gansu, Ningxia has the trend of spreading from the west to the east, and the apple growing region in our country is from the east to the west, which will be met and which should be paid enough attention.Using GM(1,1) model and a moving average model, predictions were made for five kinds of diseases, Valsa mali, Botryospuaeria berengeriana, Diplocarpon mali, Alternaria alternaria and Venturia inaequalis, as well as two kinds pests, Tetranychus viennensis and Eriosoma lanigerum, based on the investigation data of the last ten years. It is found that Valsa mali will remain high–occurrence trend in most regions. Botryospuaeria berengeriana and Alternaria alternaria also showed trends of high occurrence, but maintaining steady basically. It predicts that Diplocarpon mali in Shanxi and Venturia inaequalis in Henan would rise up quickly. The prediction reveals that Tetranychus viennensi and Eriosoma lanigerum will be more serious generally and woolly aphid in Shanxi will be much severer significantly. It is forecasted that Laspeyresia pomonella would also slightly spread, but the speed is rather slow.Based on the monitoring data provided by apple research stations of China, a decision support system was established. The basic principle is the application of quantitative theory such as selecting variety resistance, phenophase, the degree of disease, the climate of a few days earlier and later, chemical usage, the degree of disease in previous years as qualitative variables. And different assignment is given to each factor and the control decisions can be given after model operations. It can provide plant disease and insect pest prevention and control decision for the majority fruit growers. Currently the systen works at www.apple-ipm.cn to guide the fruit grower to strengthen scientific control to plant diseases and insect pests.