线虫对小麦纹枯病影响的初步研究

EFFECTS OF NEMATODE ON DISEASE SHARP EYE SPOT OF WHEAT

在小麦成株期,调查植株茎基部线虫量,结果表明:茎基部0～5cm处存在大量线虫,感染纹枯病的植株线虫量高于健株,病株(茎鲜重)线虫量为93.9～102.7条·g^(-1),健株(茎鲜重)为15.8～43.4条·g^(-1)。以杀线虫剂克百威处理小麦根部土壤后,植株线虫量明显下降,病株(茎鲜重)降至57.5～84.6条·g^(-1),健株(茎鲜重)降至1.6～33.8条·g^(-1),但纹枯病随着植株线虫量的下降而明显加重,病株率较未施用杀线虫剂田块上升1.32倍。将线虫与小麦纹枯菌混合接种小麦植株,病株率无明显变化,但病斑平均长度降低34.80％,说明线虫对小麦纹枯菌的浸染、扩展有一定干扰作用。经初步识别,小麦茎基部的线虫中90％以上为腐生线虫,少数为植物寄生线虫和捕食线虫。

Large number of nematodes were observed on the stem foots (0-5 cm above the ground) of adult wheat plants. More nematodes were found on the plants infected by disease sharp eye spot of wheat than on the non-infected plants. The amount of nematodes on the stem foot per gram of fresh plant was 93. 9-102. 7 for infected plants and 15. 8-43. 4 for non-infected plants, respectively. Treating soil with nematicide carbofuran, the amount of nematodes dropped to 57. 5-84. 6 on the infected plants, and 1. 6-33. 8 on the non-infected plants. However, with the reduction of nematodes after nematicide treatment, the disease was getting more serious. In field experiment, the disease incidences rose 1. 32 times after nematicide treatment, compared with the non-nematicide treatment. Combined inoculating plants with nematode and pathogen (Rhizoctonia cerealis), the disease incidences didn't obviously change, but the average length of lesions reduced 34. 8%. The result indicated that nematode had some interference effect on the invasion and spread of the pathogen. On the stem foots of wheat plant, more than 90% of the nematodes identified was saprophytic nematode, others were plant-parasitic nematode and predatory nematode.