SUGARBEETS

On root crops such as sugarbeets, different root parasitic nematodes will cause somewhat different symptoms. For example, both cyst nematode and root knot nematode infections will cause stunting of top growth and discoloration of leaves that become yellow and wilt with such additional stresses as hot weather or poor irrigation. Heavily infested plants may remain stunted throughout the season, and in parallel to this poor root stytems will develop. In root knot nematode infections complete loss of stand may occur because of secondary rot infection in the root. Infection of sugarbeet by stubby root nematodes will result in root system damage and aboveground symptoms will include stunting fairly early in the season. Often, stunted and healthy plants will be intermixed in a field causing a patchwork effect. Plants may appear to recover somewhat from mid- to late-season with enhanced top growth; a harvestable root system may not be present, however.

Root proliferation is a common plant response to attack by some nematodes. In particular, cyst nematodes (Heterodera species) induce such symptoms. For example H. schachtii and H. cruciferae will cause root proliferation on cole crops (cauliflower, broccoli, brussels sprouts, cabbage), and H. schachtii will cause root proliferation on sugarbeet. Extensive lateral-root production on the host will give root systems a "whiskery" appearance. Although it is not a plant-induced symptom, the presence of white females and yellow or brown cysts on the external surface of parasitized roots is a definite sign of cyst nematode. Stubby root, pin, and root knot nematodes are also known to cause root proliferation on some hosts.

From: McKenry, M.V. and P. A. Roberts. 1985. Phytonematology Study Guide. University of California, Division of Agriculture and Natural Resources. Publication 4045.

Heterodera schachtii on sugarbeet
Heterodera schachtii on sugarbeet
Heterodera schachtii on sugarbeet, Temik on right

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