番石榴(Psidiumguajava)根结线虫病的病原是南方根结线虫(Meloidogyneincognita),其典型症状是:新根上根结单个或呈念珠状串生,须根稀疏;老根重复侵染,形成较大的不规则瘤状突起,初期呈白色,后期变黑,腐烂,易脱落,裸露出白色的木质部.在显微镜下,剥开根结或瘤状突起,可见白色、球形或洋梨形根结线虫雌虫,或有线形雄虫或幼虫从根部游离出来,每100g土壤中2龄幼虫数达270条.地上部分,枝叶稀疏,结果少而小,最后整株死亡.发病严重的果园,发病株达90%,缺行断垄现象十分严重.春、秋季发病较严重. The pathogen of root knot nematode disease in guava (Psidium guajava) is Meloidogyne incognita, with the typical symptoms as follows: the new root root knot is single or a beaded pearl, the fibrous root is sparse; the old root is repeatedly infected to form larger Irregular nodules, initially white, late black, decay, easy to fall off, exposing the white xylem.Under the microscope, peel the root knot or tumor-like protrusions, showing white, spherical or pear-shaped root-knot nematode females , Or linear male or larvae free from the roots, the number of second instar larvae per 100g of 270. The aboveground parts, sparsely follicle, the results of small and small, and finally the whole plant died of serious orchards, the incidence of up to 90 %, Lack of line ruin phenomenon is very serious, spring, autumn more serious.