Investigations On The Occurrence And Control Of Botrytis Cinerea In Protected Field Of Hu Nan Province

The strawberry grey mould is a fungus disease that hard to deal with in production process and.commonly occurred in each strawberry cultivation area. In recent years, the disease showed a trend of increase year by year with the change of climate conditions. Especially in the Yangtze River basin with more rain, the incidence of the disease become more severe in low temperature and humidity in harvest season. The strawberry grey mould always cause flower and fruit rot, the diseased fruit rate came up to30%, or even60%in susceptible cultivars, which lead great influence on the strawberry yield and quality etc. In order to understand the occurrence and control situation of strawberry gray mold in protected areas, we carried out surveys on various cities throughout Hunan province. They are Chengzhou and Hengyang in southern of Hunan, Changsha, Zhuzhou and Xi angtan in eastern of Hunan, Shaoyang in central of Hunan, Yueyang in northern of Hu nan, and Huaihua in western of Hunan, etc.. The results were given as follows:1) Strawberry gray mold existed widely among the surveyed regions with the sev erity varied. The Daxing village of Shaoyang city had the highest diseased fruit rate a nd disease index, for46.67percent and6.34respectively. The diseased fruit rate of Sh igu village of Hengyang city came the second, though not serious. Among other regio ns, there exited a certain positive correlation between diseased fruit rate and disease in dex, which decreased gradually from Tangchang village of Chenzhou, Xupu village o f Huaihua, Hekou village of Xiangtan, Panhu village of Yueyang, Yingbi village of H engyang, Nanyangqiao village of Zhuzhou to Donganxiang village and Pengjiaxiang village of Changsha in order, without obvious regional differences.2) The disease became more serious with the years of continuous cropping. The d iseased fruit rate and disease index of seven years cropping greenhouse were almost1.94and2.4times to the new one. Rotated cropping can lessen the disease occurrence i n greenhouse, the diseased fruit rate of which were between9to14percent and not se vere.3) The disease incidence varied among different varieties of strawberry. Akihime had the lowest diseased fruit rate and disease index in all the varieties, followed by Fl ange, Hongyan variety and Fengxiang variety had an equivalent rate and index, while Sweet Charlie had the highest rate and index up to32.5percent and5.9, with the most serious gray mold.4) Planting season had impact on the occurrence of gray mold. Planting in early September would result in higher diseased fruit rate and disease index for30percent a nd4.2. The optimum planting period which would reduce disease incidence was from late September to early October. Setting after mid-october would effect economic cha racters including fruit yield and plant anti-cold ability.5) The greenhouse type also affect the severity of the disease. The totally enclos ed pillar shed had the highest diseased fruit rate and disease index for38percent and5.87, followed by simple span shed, then arched single-span shed and non-column se mi-closed shed, and slightest in intelligent solar greenhouse.6) At present, procymidone was used the most frequently in prevention strawberr y gray mold in Hunan, then was Carbendazim, other pesticide were the following seq uence:thiophanate-methyl, Cyprodinil, Fludioxonil, Iprodione, Polyoxins, Dynmetha nil. It is the first survey on the occurrence of strawberry gray mold in protective areas of Hunan province, which laid the foundation for further systemic study and preventio n and control of strawberry gray mold in protective areas.7). The extracts has inhibitory effect on strawberry grey mould. Allium sativum extract has a best inhibition ratio of56.04%. Then is Zingiber aromaticum extract. The inhibition effect of other extract from more to less in proper order are:allium cepa extract, lotus root extract, celery extract. But the inhibition effect of all the extractions are relatively weak compared to control agent. The analysis of variance showed that significant differences existed among different treatments, allium sativum extract has the most significant effect.8). The extracts have no effects on the normal metabolism of leaf. Allium sativum extract has a best control efficiency on excised leaf of66.52%, about1.12times to control agent carbendazim. The control efficiency of Zingiber aromaticum extract, allium cepa extract, lotus root extract, celery extract are54.55%,48.48%,42.11%,37.48%. respectively. The analysis of variance showed that significant differences existed among different extract processing.