ECTOPARASITES

A reduction in root growth is commonly caused by ectoparasitic nematodes, sometimes without any other recognizable symptoms. However, in many cases, roots appear short, stubby, and malformed. The feeding on root tips often causes swelling and cessation of elongating growth. Feeding on root tips of the taproot may stop elongation of the taproot or cause the formation of a multiple tap or storage root that is forked. Feeding of many nematodes at points where lateral roots emerge results in lateral- and feeder-root stunting or destruction.

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

Trichodorus on corn
Trichodorus on onion
Xiphinema diversicaudatum on rose, healthy on right
Criconemella xenoplax on grape, healthy roots
Criconemella xenoplax on grape, infested roots

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