Dissertation
Dissertation > Agricultural Sciences > Plant Protection > Pest and Disease Control > Horticultural Crops Pest and Disease Control > Vegetable pests > Solanaceous pests and diseases > Pepper pests and diseases

Study on Phytophthora Blight of Pepper in Guizhou Province

Author YangXueHui
Tutor XiaoChongGang
School Southwest Agricultural University
Course Plant Pathology
Keywords Phytophthora capsici Identification of the pathogen Resistance Prevention and cure
CLC S436.418
Type Master's thesis
Year 2004
Downloads 212
Quotes 4
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Phytophthora capsici infection caused by Phytophthora capsici (Phytophthora capsici Leon.) Is the world's one of the most devastating soil-borne diseases can also infect Solanaceae and Cucurbitaceae a variety of crops, in addition to infecting pepper. With the rapid development of commercial production of pepper cultivation measures strengthening and promotion of different pepper varieties, the disease has been all over the country generally occur, resulting in serious economic losses, pepper producing areas in Guizhou, the trend of increasing year by year. In order to more effectively combat Phytophthora capsici, the field of Phytophthora capsici damage symptoms, pathogens Isolation culture and identification of pepper cultivars disease resistance and disease prevention and control system. The main findings are as follows: 1. The Phytophthora capsici field symptoms of Phytophthora capsici damage pepper plants at different growth stages. Seedling stage caused the seedlings standing dead cataplexy. The adult stage led to the plant root rot, roots ulcers then cause wilting plants, roots rot and wither death. Branches ulcer development produces black necrotic spots, partial or around the branches, causing disease above the dead. Round, gray-brown, water-soaked leaves victims necrotic spots. The fruit highly susceptible to decay victims, under suitable climatic conditions, the diseased fruits covered with a layer of white mold layer, that is, bacteria sporangia, which is the most typical features of Phytophthora capsici. 2. Capsici separation and identification of selective medium the SCA directly Pathogens from the edge of the colonies were picked, purified and save hyphal tip slant medium. Effectively isolates 67, the tieback pepper the onset of symptoms and field performance of exactly the same. Five strains were selected from different sources morphological, physiological, biochemical and biological characteristics. The results show that these five strains large and fast growth in the the CA media and the CMA medium CA medium sporangium fastest, 2 to 3 days to produce one after another. CA tablet colonies white, dense or sparse fluffy mycelium of 1 to 2.5 m in diameter. Sporangium varied shapes, round, nearly round, long-oval, the sporangium average size of 43.5 ~ 52.7 × 33.3 ~ 38.8μm, aspect ratio of 1.0 to 2.3, the mastoid obvious, generally single-mastoid, occasionally double mastoid. Plant culture does not produce oospores. Bacteria growth temperature range of 12 ° C to 35 ° C, the concentration to 1:8 × 10 6 of malachite green is not sensitive to some strains available starch as carbon source. According to these characteristics of these five strains identified as Phytophthora capsici Leonian. 3. Anti-blight of pepper cultivars using IRRIGATING method originated in Guizhou 21 pepper cultivars inoculated by identification. The results showed that Phytophthora capsici were highly resistant varieties the Bijie line pepper, the Thunder Mountain Chaotianjiao Zunyi Chaotianjiao, the performance anti-varieties Guizhou pepper 2, Sui pepper, the Sui pepper, a Wudang chili pepper Lawrence , Hunan spicy, EARLY II, and six the performance anti varieties have, five susceptible varieties accounted for 14.3% of the total number of identified, 33.3%, 28.6% and 23.8%, respectively. Southwest Agricultural University, a master's degree in abstract Dandan Dandan Dandan Dandan Dandan Dandan Dandan Dandan Dandan Dandan Dandan Dandan Dandan Dandan Dandan Dandan Dandan Lane Lane Dandan Dandan Xiang research the 3rd Xiangyan 5, Hunan Institute 13, the Zunyi toward pepper, chili Suiyang, Huaxi pepper and pepper Guizhou l No. 7 in field resistance to disease natural identification, commonly grown local Hunan Institute series pepper varieties were highly susceptible to several local varieties of disease resistance is better, especially Zunyi Chaotianjiao and Suiyang chili pepper varieties. Control techniques using the colony growth rate of 10% Po Lai WP, 72% g Lu WP, 47% Jiarui agricultural WP, 75% good speed net WP, 72% cream Consumers can wettable powder, 80% of new students WP, 58% metalaxyl mancozeb WP 7 Pharmacy Toxicity Measurement results show that 58% metalaxyl mancozeb WP, 72% g dew WP, 80% of new students WP antibacterial better inhibitory concentration (E CS) were 8.8 Retention m, 8.6 plus g / ml and 8.8 g / m! 10% Po Lai WP has no inhibitory effect on Phytophthora capsici. Toxicity Measurement screened inhibitory effect of 72% g Lu WP, 58% metalaxyl mancozeb WP, 80% of new students WP two pharmaceutical field plot efficacy Test results show that 72% g gel WP 500 times and 58% metalaxyl mancozeb WP 500 times better control effects, the control efficiency of 82.9% and 80.2% respectively. At the same time, 58% metalaxyl mancozeb WP 500 times to test chemicals, comparative tests on different application time and frequency of administration and control technology, the results show that the early onset of Phytophthora capsici spraying 3 to 4 times better, and spraying pepper to diseased plants, the control efficiency is not higher than in the early stages, spraying Keywords: pepper Phytophthora identification of disease prevention and control

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