Tylenchulus semipenetrans

Zasada I A and Ferris H (2003), Sensitivity of Meloidogyne javanica and Tylenchulus semipenetrans to isothiocyanates in laboratory assays , Phytopathology, 93, 747-750. 

The latest development in the field of citrus pests involves nematodes. The citrus nematode (Tylenchulus semipenetrans Cobb) has been known for many years in California, Florida, and Argentina and probably exists in most other areas. Whether it could do much damage to healthy citrus trees is a moot point. In recent years, however, more and more workers in California have been inclined to blame it for poor tree condition and their inability to replant citrus with citrus satisfactorily. The idea that nematodes are of importance has been stimulated by the finding in Florida that the cause of spreading decline is the burrowing nematode, Radopholus similis (Cobb) Thorne. This nematode, hitherto unknown as a citrus pest, destroys the feeder roots particularly below a depth of about 2 feet and has been found to a depth of 14 feet. In the course of this work a number of other nematodes, hitherto unreported on citrus, have been found and at least some of these appear to damage citrus roots. The indications are that nematodes are going to be one of the real citrus problems of the future. 

Van Gundy SD, Bird AF, Wallace HR. Aging and Starvation of Maloidogyne javanica and Tylenchulus semipenetrans. Phytopathology 1967 57 559-571. 

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