申嗪霉素对烟草黑胫病的毒力及防治效果

为探明申嗪霉素防治烟草黑胫病的潜力，在室内离体条件下测定其对烟草黑胫病菌菌丝生长、孢子囊形成和游动孢子释放的毒力，并通过温室盆栽和大田药效试验明确其对烟草黑胫病菌的防效及对烟草生长的影响。结果表明，申嗪霉素对沂水烟区黑胫病菌孢子囊的形成和游动孢子的释放抑制效果最好，EC₅₀值分别为0.31和0.35 μg/mL。室内防效结果表明，1%申嗪霉素悬浮剂（15 g a.i./hm²）对烟草黑胫病的防效为84.37%，显著高于25%甲霜灵可湿性粉剂（56.33%）和50%烯酰吗啉可湿性粉剂（80.55%），而田间药效试验结果与室内防效基本一致，在冕宁和诸城两地1%申嗪霉素田间防效分别为90.49%和82.93%，显著高于对照药剂甲霜灵（71.89%，38.87%）和烯酰吗啉（78.42%，69.01%）。除此之外，申嗪霉素较甲霜灵和烯酰吗啉在提高株高、茎粗、有效叶片数及光合速率等指标效果更好。可见，申嗪霉素是防治烟草黑胫病的有效制剂，可作为甲霜灵和烯酰吗啉的轮换药剂使用。

Effect of Shenqinmycin on Growth and Development of Phytophthora nicotianae and Its Control Effect on Tobacco Black Shank

To explore the potential of antibiotic biocontrol agents Shenqinmycin to control tobacco black shank disease, the inhibitory effects of Shenqinmycin on mycelial growth, sporangia formation and zoospores release of Phytophthora nicotianae was investigated in vitro. The effects of Shenqinmycin on the control of tobacco black shank and the growth of tobacco plant were determined based on greenhouse experiments and field trials. The results showed that Shenqinmycin had the best inhibitory effect on sporangia formation and zoospores release of P. nicotianae in Yinshui with EC₅₀ of 0.31 and 0.35 μg/mL, respectively. The results of greenhouse pot experiment indicated that the control effect of 1% Shenqinmycin suspension on tobacco black shank at 15 g a.i./ha was 84.37%, which was significantly higher than that of 25% metalaxyl (56.33%) and 50% dimethomorph (80.55%), whereas the field trial results were basically consistent with the control effect of greenhouse experiments. Field efficacy trials in Mianning and Zhucheng showed that the application of Shenqinmycin can significantly reduce tobacco black shank to occurrence, and the control effect on tobacco black shank in Liangshan and Zhucheng was 90.49% and 82.93%, which was significantly higher than the control agents metalaxyl (71.89%, 38.87%) and dimethomorph (78.42%, 69.01%). In addition, Shenzinmycin has better effects on the increase of plant height, stem diameter, effective leaf number and photosynthetic rate than that of metalaxyl and dimethomorph. The results of the present study indicate that Shenqinmycin can be used as an alternative agent for metalaxyl and dimethomorph to control tobacco black shank.