Study On The Fungal Diseases Of Amomum Villosum Lour Et. Of Major Economical Plants In Huajiang Gorge Area Guizhou Province And Control Fungicides Selection

Fungal diseases of major economical plants are serious in Huajiang gorge area , Guizhou province. According to the symptom of the each fungal disease ,the morphology and culture characters of pathogen, the diseases were identified to be Zanthoxylum bungeanum felt fungus , leaf rust, bituminous coal fungus, grey spot, anthracnose, foxiness and leaf mold; Amomum villosum Lour leaf blight, anthracnose, leaf spot and root rot; Pennisetum hydridum stem rot , foxiness, leaf spot, spot and sheath blight; Tectona powdery mildew, foxiness.Studies on the biological characteristic of the three pathogens of the Amomum villosum Lour leaf and control fungicides selection showed:1. The optimum temperature could promote the mycelial growth and spores germination. The pathogens could not grow, produce spore and germinate in the extremely high temperature or low temperature. The deadly temperature on the mycelial growth of Pestalotiopsis sp.and Colletotrichum gloeosporioides was 52℃ for 10minute, that the spores was 55 ℃ for 10 minute.The lethal temperature of the mycelial growth of Phyllosticta glycines was 55℃ for 10min, and the spores could not germinate at 60℃ for lOminute.2. The mycelia of Pestalotiopsis sp., Colletotrichum gloeosporioides phyllosticta glycines could grow best at pH within 5~7. Acid conditions could be beneficial to spores germination. The spores of Pestalotiopsis sp. and phyllosticta glycines germinated best when pH value was 6, but the best pH value for Colletotrichum gloeosporioides was 4.3. The mycelia of Pestalotiopsis sp., Colletotrichum gloeosporioides and Phyllosticta glycine could grow on the different C and N source .The optimum C source are maltobiose and glucose to Pestalotiopsis sp. mycelial growth .while NH4NO3 was the optimum N source.The saccharose was beneficial to spores germination of Pestalotiopsis sp.. Collectotrichum gloeosporioides could get best mecylial growth on the medium containing sucrose maltose and Ca(NO3)2, while optimum C source of the spores germination was fructose. The mycelia of phyllosticta glycines grew fast on the medium containing amylum and Ca(NO3)2. The highest spores germination rate of. phyllosticta glycines was on lactose and maltose.4. O2 was beneficial to mycelial growth and spores germination of the pathogens. Treatments of darkness, light, alternative light and darkness and ultraviolet light did not show significant effect on the mycelial growth and spores germination ,but light could promote spores production of Pestalotiopsis sp. and Colletotrichum gloeosporioides. Ultraviolet light was beneficial to phyllosticta glycines spores form. Different C/N ratios had no influence on mycelial growth. Mycelia grew worse when the medium had no NaNO3 and sucrose. RH under 95%, spores could not germinate. RH100% was the best for the spore germination which could be reached the highest rate.5. Ten fungicides were tested in vitro for efficacy against the mycelia.Test on mycelia growth showed that 70%Thiophanate-methyl,18 % Albendazole,60%Carbendazim and 75%Mancozeb were the most effective fungicides. Inhibitive rates were up to 80% at the lowest concentration.