Northern root-knot nematode (Meloidogyne hapla) is a species of vegetable pathogens which produces tiny galls on around 550 crop and weed species. They invade root tissue after birth. Females are able to lay up to 1,000 eggs at a time in a large egg mass. By surviving harsh winters, they can survive in cold climates (hence, the name, Northern).
Hosts and symptoms
Meloidogyne hapla (Northern root-knot nematode) has a wide host range. It is polyphagous and affects over 550 crops and weeds. It feeds on many agricultural and horticultural plants (vegetables, fruits, ornamentals), but few grasses or cereals. A list of known hosts can be found at the bottom of this page.
alt=|thumb|185x185px|Symptom of nematode Meloidogyne hapla on carrot
Symptoms can be seen in the roots, leaves, and the overall growth of the infected plant. In roots, there may be stunting, wilting, and the formation of abnormal growths called galls. Galls are usually small and spherical and are situated near many small roots. The end result is stunted, wilted, and yellowing plants (characteristic of nutrient deficiency) and a decreased yield. In potato tubers (special stems), brown spots will appear on areas of the tubers where the females have laid their eggs. The males are able to move freely and leave the root after they become adults, while the females stay sedentary and feed on cells next to the vascular system Nematodes in cooler regions usually have longer life cycles. Eggs may remain inside root tissue or may be released into the soil matrix and survive for up to one year. However, using a combination of control practices, known as integrated pest management plant (IPM), has been proven to be effective.