Study On The Non-hazard And Integrated Management Of Soil-borne Diseases In Greenhouse Vegetables In Baiyin Area

The varieties and regular pattern of the soil-borne diseases in greenhouse in Baiyin area was investigated.The non-hazard and environment friendly integrated management of soil-borne diseases were studied from 2003 to 2005.Through the investigation and separate cultivation on PDA,it is clear that there were 15 varieties of soil-borne diseases in greenhouse vegetable production.The main soil-borne Pathogens were Phytophthora drechsleri(melon),Verticillium dahliae(eggplant),Phytophthora capsici(pepper)and Phytophthora sp.(eggplant).The non-hazard and environment friendly controlling measures were thereby studied. Stock grafting was one of the efficient methods that controlled the soil-borne diseases.After grafting with Stocks,the soil-borne diseases of vegetables and watermelons were effectively controlled.Sweet pepper and hot pepper were grafted with No.1 pepper stock and the disease resistant rates to Phytopththora spp.were 77.79%and 86.67%in the end of the season respectively.The yields after grafting were 102.48%and 80.59%greater respectively.The eggplant disease resistant rates to Verticcium spp.were 89.87%and 80.91%after grafted with CRP and Tuolubamu in the end of the season respectively.The yields after grafting were 17.28%and 13.48%greater respectively.The Fusarium disease of watermelon was also controlled completely after grafted with Squash.Soil Solarization(Solar heating)by Polyethylene mulching in greenhouse in Baiyin area was carried out.The average soil temperature reached 42.1℃and 39.7℃at the depth of 5 and 20cm respectively.≥40℃accumulated hours among 24h reached 13.87h and 11.9h at the depth of 5 and 20cm respectively.≥45℃accumulated hours among 24h reached 7.82h at the depth of 5cm.The temperatures were lethal to the pathogens or efficient to reduce the population of the pathogens in the soil.Soil Solarization controlled diseases caused by Phytophthora melonis,Verticillium dahliae,Phytophthora melonis and others as well as weeds remarkably by mulching the soil with transparent polyethylene sheets for at least 30d before planting during the months of July and August.There were evidences showing that soil solarization could control soil-bome diseases for about two or more seasons.The yields of melon after soil solarization was 18.6%—47.7%greater.The organic substances in soil decreased by 0.32%.The content of Potassium in soil increased by 100 mg/kg.The content of Calcium in soil was also increased.Methbromide fumigation experiment was firstly carried out in Baiyin.The results showed that Methbromide controlled soil-borne diseases completely in the first season of melon.It also controlled Verticillium diseases of eggplant significantly in the second season.The controlling effect was 95.86%.But it is high toxicity and can contaminate environment.It is not suitable to the production of organic vegetables.Fungicides controlled soil-borne diseases less effectively compared with other methods. The screening experiments of Fungicides controlling Verticillium diseases showed that 50% Carbendazim plus Sulsur had the highest controlling effect after 3 times root fungicide-irrigation,its controlling effect was 75.72%.64%Mancozeb could give 80.64% result to control melon blight by daubing rootstocks.Fungicides must be combined with other controlling methods in order to reach effective results.The ecological management such as drip irrigation,straw covering to the furrows, hanging up reflection screen on back wall,humidity controlling,and temperature improving were also efficient to soil-borne diseases controlling especially melon blight in greenhouse. The incidence of melon blight caused by Phytophthora was significantly reduced by 85.62% and thereby the yields of melon were increased by 39.63%by means of better ecological management.After experiment and research,the integrated management of soil-borne diseases was thereby put forward in greenhouse vegetables production.It will give technological support to organic production of vegetables in Baiyin area.