Neoplastic Growths in Preparasitic Juveniles of Meloidogyne incognita.

A b e r r a n t morpholog ica l forms have been reported for a number of free-living and plant-parasitic nematodes. In some cases aberrancy is genetic (4) and in others it is environmentally induced (5,6). More than 200 mutant genes known to control aberrant phenotypes of Caenorhabclitis elegans (Maupas) Dougherty have been reported (4). Some of these mutants affect collagen synthesis and cuticle formation (4). Anal protrusions of C. briggsae (Dougherty & Nigon) Dougherty occurred when a cellfree extract of Flavobacterium was incorporated into the culture medium (6). Aberrant second-s tage larvae of Heterodera schachtii (A. Schmidt) developed when this nematode was reared on insecticide-treated hosts (5). In the current study, external growths were observed on freshly hatched juveniles (J2) of Meloidogyne incognita (Kofoid & White) Chitwood from a single egg-mass population that had been maintained in the greenhouse continuously for more than 15 years. Aberrant specimens were examined by light and electron microscopy to determine cytological details of the deformations. Eggs ofM. incognita (7) were collected (8) f rom g reenhouse cul tures of eggplant (Solanum melongena L. cv. Black Beauty) and hatched in distilled water on nylon cloth (TETKO, Inc., Elmsford, NY) with a pore size of 20 ~m. Infective J2 that hatched and migrated through the nylon cloth were