Encapsulation of Meloidogyne incognita Eggs in Carrageenan.

Nematologists need a method to maintain single species populations of Meloidogyne spp. for prolonged periods without significant loss of viability. As a standard practice, isolates of MeIoidogyne populations are identified, characterized, and maintained on the same host plant species. Ex t reme precaut ions are necessary to maintain them free of contamination from other nematode populations. Sterile root culture techniques also are used for culturing and maintaining single species populations (2), but both systems require periodic subcuhuring which after many years can select for certain characters that are uncommon in the original isolated population. Hydrocolloids extracted from seaweeds are being used to encapsulate various chemicals and biological organisms. Sodium alginate has been used (via gelation with Ca ++ ) to formulate sustained-release herbicides (1) and mycoherbicides (8) and to encapsulate somatic plant embryos (5) and entomogenous nematodes (4). In our laboratory, eggs of Meloidogyne incognita (Kofoid & White) Chitwood and Filipjevimermis &ipsandra Poinar & Welch encapsulated in calcium alginate gels were kept viable for about 2 months (Fassuliotis, unpubl.). Some calcium alginate gels, however, have an undesirable property of extreme syneresis after capsule preparation. After the excess water is removed, the relative humidity must be controlled to pre-