根据森林病理学家С.Михкелъсон真的报导,1962—1963年在爱沙尼亚一些森林苗圃中发生了云杉苗干枯与死亡的现象。在植株的根部和其周围的土壤中进行植物蠕虫分析时,发现了线虫或蠕虫。它们是由圆形蠕虫这一组所组成的微观生物体。在土壤中以及在不同植物的根上和根内都有发现。线虫钻入植物的根部或地上部分,给许多植物的根、茎、叶都带来很大危害。 According to the forest pathologist С.Михкелъсон, it was reported that the dry and dead spruce seedlings occurred in some forest nurseries in Estonia from 1962 to 1963. Nematodes or worms were found when analyzing plant worms in the roots of plants and in the soil around them. They are microscopic organisms composed of a group of round worms. Found in soil and in roots and roots of different plants. Drilling nematodes into the roots or shoots of plants gives great harm to the roots, stems and leaves of many plants.