| Potato is an important food crop in China and plays an important role in the world food security system.Yulin City is an important potato producing area in China,and its planting area is in the forefront of prefecture-level cities all the year round.In recent years,due to the influence of various factors,potato diseases are developing and spreading year by year,which poses a huge threat to the sound and rapid development of potato industry in Yulin.In this study,combined with the occurrence of potato diseases in Yulin City in previous years(2014-2018),a confirmatory survey of potato diseases in 2019 was carried out,and combined with the survey results,the field chemical control experiments of late blight,scab and black nevus were carried out,and the integrated control technology demonstration of late blight was carried out.The main results are as follows:1.The data of disease occurrence in previous years provided by Yulin Agricultural Technology Service Center and the results of targeted disease investigation showed that there were three main types of diseases causing potato yield reduction in Yulin City at present,namely,Phytophthora blight,soil-borne diseases and virus diseases.The occurrence area from high to low was late blight > early blight > scab > black scurf > virus disease.2.In this study,7 combinations of 4 fungicides were used to control potato late blight in order to explore the control effect of different treatments on potato late blight.The results showed that the treatment of 50% Acrobat + 70% Thiophanate-methyl could effectively control potato late blight,and improve the commercial potato rate and yield,with the highest control effect of 50.39% and the highest yield increase of 38.35%.3.In order to provide reference for the control of potato late blight in Yulin,the demonstration test of integrated provention and control technology was carried out by using a variety of control methods.The results showed that a series of measures,such as selection of disease-resistant variety Longshu 7,crop rotation,seed treatment before sowing,prevention at seedling stage and aseptic storage after harvest,could effectively control late blight and increase potato yield.4.In view of the high incidence of potato scab in Yulin,five fungicides combinations(70% thiophanate-methyl WP seed dressing at sowing time + fungicide root irrigation at growing stage)and two bacterial biofertilizers combinations(seed dressing at sowing time or root irrigation at growing stage)were used to investigate the control effect of different treatments on potato scab.The results showed that control effects of Bacillus biofertilizers and 70% thiophanate-methyl WP seed dressing + 47% Kasugamycin·Copper Oxychloride root irrigation were 67.84% and 56.09%,respectively,and the yield increase rates were 62.39% and 45.77%,respectively.Which performed well in controlling potato scab and increasing potato yield,and had certain application potential.5.In view of the high incidence of potato scurf disease in Yulin and the trend of increasing year by year,this study used five kinds of fungicides combination treatment(seed dressing in sowing time or + root irrigation in growth period),and one kind of fungicidal biofertilizers seed dressing treatment to explore the control effect of different treatments on black mole disease.The results showed that control effects of 41.7%Penflufen seed dressing+ furrow dressing with Penflufen;11%fludioxonil seed dressing + furrow dressing with25%Azoxystrobin;70%thiophanate-methyl seed dressing + furrow dressing with25%Azoxystrobin,and seed dressing with Pythium oligandrum microbial fertilizer were79.04%,82.13%,56.84% and 68.99% respectively,and the yield increase rates were 37.79%,42.97%,27.46% and 25.38% respectively.Which showed great control effects on black scurf.Therefore,it can be recommended to be popularized in field production. |
