ALGINATE FILMS FOR DELIVERY OF ROOT-KNOT NEMATODE INOCULUM AND EVALUATION OF MICROBIAL INTERACTIONS

A method was developed for utilizing alginate films to deliver inoculu m into soil and evaluate microbial antagonistic activity against nemat ode eggs. Eggs of Meloidogyne incognita were harvested from galled tom ato roots (Lycopersicon esculentum), surface disinfested, suspended in 2% (w/v) aqueous sodium alginate, and applied to 2.5 x 5.0 cm polyvin yl chloride coated fiberglass screens (1.5 mm(2) mesh size) at a unifo rm thickness of 0.5 mm. The alginate solution was gelled by dipping in 0.25 M CaCl2. Films containing eggs were observed in vitro and egg de velopment was evaluated. The number of immature eggs and eggs with fir st stage juveniles declined linearly over time while the number of emp ty eggs shells, and hatched juveniles increased over time, indicating that the alginate gel did not inhibit development and motility of M. i ncognita juveniles. In a greenhouse experiment using cucumber (Cucumis sativus) the number of galls g(-1) root was correlated with the numbe r of eggs in alginate films placed in each pot at planting. Films cont aining M. incognita eggs were buried in field soil containing organic amendments, incubated, removed from soil, rinsed with water, and obser ved. The number of immature eggs in grids from soil amended with chiti n or flax seed meal were lower than in untreated soil; percent parasit ized eggs was also greater in films from amended soil than from untrea ted soil.