【作者】 丁颜敏；

【导师】 黄俊斌；

【作者基本信息】 华中农业大学 ， 植物病理学， 2010， 硕士

【摘要】 油菜菌核病是由核盘菌(Sclerotinia sclerotiorum)引起的油菜上最重要的病害之一,常年损失达10-30%。近些年,由于免耕制度的推行,油菜菌核病的发生呈上升趋势。但是因为抗病品种的缺乏和化学农药引起的食品安全问题,人们越来越重视通过农业措施和生物农药的途径来控制该病害。本文研究了免耕模式中,湖北省两种耕作制度(棉花—油菜连作田和水稻—油菜连作田中)对油菜菌核病发生规律的影响,并通过室内、田间试验评估了盾壳霉制剂的防治效果。为轻简化耕作模式下,使用水旱轮作和生物防治油菜菌核病的技术提供思路。通过室内模拟两种类型田,研究了不同土壤深度菌核的存活动态。结果表明：温室条件下,1-9cm深度的土壤中,菌核连续18个月的存活率均为100%；室内淹水条件下,秋季试验中(平均温度为30.1℃)的菌核存活时间为20d,冬季试验中(平均温度为4.8℃),菌核存活时间为45d。通过2008-2010年对武穴市、黄冈市两种类型田(棉花—油菜连作田和水稻—油菜连作田中)中油菜菌核病的发生动态调查,结果表明：棉花—油菜连作田的子囊盘数量明显高于水稻—油菜连作田。水旱轮作可以有效控制病害,除了2009年黄冈市棉花—油菜连作田病害的发生比水稻—油菜连作田偏轻,其他年份所有田块均发现前者比后者发生重。三年的调查结果表明：棉花—油菜连作田子囊盘初现于3月上旬,高峰期为3月下旬或4月初。油菜菌核病在两种类型田的发生动态基本一致,病叶初现于3月中旬,病茎初现于3月末或4月初。对两种类型田油菜菌核病的发病率与花期5个气象因子(日最低气温、日最高气温、日平均气温、日降雨量和降雨日数)进行相关性分析,结果表明发病率与这些气象因子均无显著相关性(P＜0.05)。室内盆栽防治试验结果表明：107孢子/ml盾壳霉对病叶率的防效为60%、对茎秆的病指防效为68.8%。田间土壤施用盾壳霉对菌核萌发抑制试验表明：1×106个孢子/ml的盾壳霉对核盘菌菌核萌发子囊盘抑制效果明显,但随着菌核基数的依次增大,抑制效果逐渐减弱。三年的小区试验(2008-2010年)结果表明：105孢子/ml、106孢子/ml、107孢子/ml的盾壳霉孢子溶液对油菜菌核病的病指防效和病株降低率会随着浓度的提高而具有增强的趋势。一般情况下,105孢子/ml的盾壳霉病指防效和病株降低率显著低于106孢子/ml、107孢子/ml(P＜0.05),106孢子/ml和107孢子/ml的防效差异不显著(P＜0.05)。盾壳霉106孢子/ml、107孢子/ml的病指防效和病株降低率中,至少有一个与化学药剂无显著差异或显著高于化学药剂(P＜0.05)。通过三年(2008-2010年)盾壳霉防治油菜菌核病的田间示范试验,结果表明：苗期喷雾106孢子/ml-107孢子/ml的盾壳霉制剂效果不理想,平均病指防效为12.8%,平均病株降低率为0。花期喷雾效果较好,除了2008年孝感市示范区的病株降低率为1级,其他示范区的平均病指防效和病株降低率都可达到2级或3级。上述研究结果表明,水旱轮作可以一定程度上减轻油菜菌核病的发生,盾壳霉制剂对防治油菜菌核病具有巨大的生防潜力。更多还原

【Abstract】 Sclerotinia stem rot of oilseed rape (SSR) is one of the most common fungal disease of rapeseed with losses of 10%-30% frequently reported. In these years, losses caused by SSR in this area have increased because of the lightened and simpilfied cultivation(LSC). There are no sclerotinia-resistant rape varieties and control is reliant on use of fungicides which have been known to have adverse effects on food. Therefore, the concerns about pesticide residues have prompted interest in agricultural measures and biological control. In order to characterize epidemics of SSR in field and evaluate the efficacy of Coniothyrium minitans in two types fields (cotton-rapeseed succession fields and rice-rapeseed succession fields) in Hubei province under LSC, we investigated the occurrence of SSR in fields, efficacy of C. minitans in suppression of SSR.Firstly, the survival of sclerotinia in different depth of soil in the indoor test simulation was studied. The results showed the sclerotinias were buried in the depth of 1-9cm have 100% survival for 18 consecutive months. The sclerotinias survived 20 days under flooded condition in indoor in autumn, survived 45 days under flooded condition in indoor in winter. The occurrence of SSR in field was investigated during 2008-2010 growing seasons in Wuxue County and Huanggang County. In cotton-rapeseed succession fields, the number of apothecia was generally higher than in rice-rape succession fields, and the subsequent disease severity on leaf and stem was obviously higher except Huanggang County in 2009.The study demonstrated that apothecia in cotton-rapeseed succession fields was appeared in early March, peak time was in late march or early April. The occurrence of SSR had no obvious difference with above two types of fields. Disease appeared on leaf in fields in mid-March, disease appeared on stem in end of March or early April. The correlation analysis between disease incidence and 5 climatic factors (daily minimum temperature, maximum temperature, daily average temperature, daily rainfall and rainy days) during the blooming period showed that there was no statistic difference (P＜0.05).Laboratory tests showed disease suppression on leaf and stem with applications of C. minitans at 107 conidia/ml was 60%,68.8%respectively. Inhibitory effect on sclerotinia germination with applications of C. minitans at 106 conidia/ml was obviously. But with increasing concentration of the sclerotinia, inhibitory effect was decreased. The field studies indicated that with increased spore concentrations of C. minitans (C. minitans at concentrations of 105,106, or 107 conidia/ml), efficacy was increased in the both types of succession fields. Efficacy of C. minitans at concentrations of 105 conidia/ml was significantly lower than that of 106, or 107 conidia/ml in most conditions (P<0.05). Efficacy of C. minitans between 105 conidia/ml and 106 conidia/ml has not significant difference (P<0.05). There was at least one efficacy between 106 conidia/ml and 107 conidia/ml has not significant difference with fungicide or be significantly higer than fungicide (P<0.05).In demonstration field trials (2008-2010), control effect by C. minitans sprayed in seedling stage at concentrations of 106 to 107 conidia/ml was not good, mean disease index control effect was 12.8%, mean disease incidence effect was 0. Efficacy of C. minitans at 106conidia/ml-107 conidia/ml sprayed at early bloom was much better. The level of control effect in all demonstration field trials was 2 or 3 level.Based on the results of this studys, paddy-upland rotation can reduce SSR, Coniothyrium minitans was an effective antagonist and biocontrol agent of the plant pathogen Sclerotinia sclerotiorum.更多还原