Effects of Meloidogyne javanica and organic amendments, inorganic fertilisers and nematicides on carrot growth and nematode abundance

Abstract

Nematode pathogenicity and control methods were evaluated in pot experiments. Six USDA selections (crosses of Brasilia and Nantes inbred) of carrots suppressed multiplication of Meloidogynejavanica and were less galled than a susceptible cultivar. Lower population densities of M. javanica were observed in soil used to grow rapeseed cv Dwarf Essex and sorghum/sudangrass cv Jumbo as green manure crops compared with sorghum cv Pacific Supergraze, and carrot growth was inhibited in soil used to grow the latter. Although M. javanica egg masses were observed on Dwarf Essex roots, and juveniles were detected in roots of both Dwarf Essex and Jumbo, growth of the subsequent carrot crop was not inhibited compared to carrots grown in fallowed soil. Lucerne pellets at high rates alone or combined with urea, poultry manure or gypsum were shown consistently to stimulate carrot growth without increasing forking and to reduce both carrot galling and M. javanica population density. Poultry manure also reduced galling and population density of M. javanica in soil but not in roots. Fenamiphos effectively controlled M. javanica at an initial population density of 108 J2/175 cm3 of soil but not at 717 J2/175 cm3. Cadusafos was highly effective in controlling M. javanica but it suppressed carrot emergence. Resistant carrot selections and soil amendments have potential value for the control of M. javanica in carrot production.