Sugar Beet Eelworm
Sugar Beet Eelworm
(Heterodera schachtii), also sugar beet nematode, a parasitic nematode of the family Heteroderi-dae. The sugar beet eelworm causes a beet disease that superficially resembles plant starvation, a condition resulting from a deficiency of phosphorus and potassium. The nematode also parasitizes cabbage, turnips, radishes, and other plants of the family Cruciferae.
The sugar beet eelworm is found in all beet-growing areas. The threadlike males, which reach 1.6 mm in length, are mobile; the lemon-shaped immobile females are covered by a thick cuticle and reach a length of 1.2 mm. In the spring, larvae emerge from eggs buried in the soil and enter young beet roots. Sexually mature males enter the soil, seek out the females, and, after fertilization, die. Before fertilization the young females break the beet’s cortex, and their posterior end protrudes onto the surface of the roots.
Sugar beet eelworms lay their eggs in a mucous egg sac on the posterior end of the body. After 30 to 60 days a new generation is produced; there are two to three generations produced annually. The rest of the eggs remain in the female’s body, which by winter turns into a brown cyst that preserves its vitality for several years. The female usually produces 100 to 150 eggs; sometimes as many as 600 eggs are laid.
Plants infected by the sugar beet eelworm develop slowly. Their root system acquires a peculiar beardlike appearance because of the large number of secondary lateral roots replacing those that have been damaged. Leaf curling is observed, and the root crops are small and have a reduced sugar content. Control measures include doubling or tripling doses of phosphorus and potassium fertilizer and returning beets to the same field after four to five years. Other effective measures include raising graińs, legumes, and timothy in the crop-rotation plan and gathering and removing postharvest remains from the field.
REFERENCESKir’ianova, E. S., and E. L. Krall’. Paraziticheskie nematody rastenii i mery bor’by s nimi, vol. 2. Leningrad, 1971.
Decker, H. Nematody rastenii i bor’ba s nimi. Moscow, 1972. (Translated from German.)