EFFECTS OF CONTAINER BASES ON THE SPREAD OF MELOIDOGYNE-INCOGNITA IN A HAWAIIAN ORNAMENTAL NURSERY

The influence of container bases on nematode spread from infested pots or ground in an ornamental foliage nursery was investigated with Melo idogyne incognita as the test nematode and cowpea as the indicator pla nt. The container bases examined were black cloth, concrete masonry bl ocks, gravel, crushed cinders, and bare ground. Masonry blocks raised 46 cm above ground (raised bench) served as the control treatment. Und er the standard nursery practice of irrigation by rainfall and supplem ental overhead sprinkler, nematodes spread from contaminated pots or g round to adjacent nematode-free pots an all tested container bases. In cidence of spread, measured as the percentage of nematode-free pots th at became contaminated, increased over time and occurred more extensiv ely from ground to pot than from pot to pot. Ground to pot spread incr eased rapidly following heavy rains, indicating rain was an important contributing factor. On the M. incognita-infested nursery ground, the nematode was found more frequently associated with weeds than with bar e soil, suggesting that weeds were important reservoirs of nematode in oculum for rain-splash dispersal. Placement of containers on a raised bench was more effective than on any of the unraised container bases i n preventing the ground to pot spread.