Study Of Picea Leaf Rust And Chemical Control In Pingwu

Picea is important forest resource in our country and it is also one of the main species for artificial afforestation in sichuan area. Recently, picea leaf rust was prevalented and gradually spread in the northwestern si chuan basin region, making picea leaf yellow and fall off in advance, some trees needles almost completely detached, and even cause picea branch or individual strain death. According to a survey hosted by the forestry bureau of pingwu, Mianyang in 2013, the area in Yang Donghe where was damaged by picea leaf rust reached about 200 hm2 and the morbidity arrived at 75.3%, which had a nagetive impact on forest health, ecological safety and landscape. Therefore, this research according to the bureau of Pingwu county of sichuan province in 2013-2014. hole picea forest region of the leaf rust was studied, aims to find out the cause of the picea leaf rust occurrence and its regularity, provide the basis for effective control the spread of the disease and. The main research content including identification of the pathogen, host investigation and disease pathogenesis regularity, the relationship between disease epidemic and stand factors and chemical control, etc. The results of the study are as follows:In order to define the species, the pathogens from Yang Donghe regions were isolated and identified by morphology and molecular biology, and the pathogen was identified as Chrysomyxa qilianensis Wang,Wu et Li.In the investigation areas of infection situation in surrounding herbaceous shrubs, alternate host was identified as Rhododendron faberi by microscopy and molecular identification, and artificial inoculation experiment still need to be further proceed.The occurrence regularity of picea leaf rust in Yang Donghe reigon was studied. At the beginning of July, disease is gradually developing, then it mainly damaged the under yearling leaf. There are a peak period in late July to early August, and the disease stops in September. The phenomenon of leaf falling have a peak period in the second year April to May. According to forest survey, low altitude areas was more later than high altitude areas in onset time.By analyzing the relativity of linear regression, disease index and factors, it was found that the key factors for the disease epidemics. The key factors are the average diameter, the average height and canopy density. The average diameter is morecoarser, the average is more higher, the growth conditions is better, the more lighter incidence of disease of picea leaf rust, but not vice versa. In addition, the forest canopy density 0.6 above is lighter than the low canopy density stand. The under yearling leaf is heavier than the second leaf, and the upper leaf is heavier than the lower leaf. The disease index of diseases relatively small in sunny slope, gentle slope and forest inside, but the disease index of diseases relatively large in the shade, steep slope and forest edge.By analyzing the relativity of pathogen and the chlorophyll content and moisture content, the results showed that variations of the chlorophyll content and moisture content is closely associated with pathogen infection.After pathogen infected picea leaf rust, picea has a defensive function in a certain extent. It will affect plant itself physiological structure and function, and it ultimately causes variation of color concentration and moisture.Picea leaf rust were performed chemical control through 20% triadimefon in 500 times add to washing powder,20% triadimefon in 500 times, carbendazim wettable powder and An Lin I smoke agent. By statistical analysis of prevention effect, different reagents and the number of times have significant difference. In chemical control, the best control effect was 20% triadimefon in 500 times add to washing powder and three times in a row.