EFFECTS OF FOUR CROPPING SYSTEMS ON POPULATlON DENSITIES OF MELOIDOGYNE INCOGNITA (ROOT-KNOT NEMATODE) ON CARROT

The research was conducted on two farms previously under carrot {Decucus cerote) monoculture and intercropped sweet potato (Ipomoea betetes) and carrot, respectively, for the past three years. The pre-plant population densities of Meloidogyne incognita were highly significantly reduced (P =0.001) under cabbage-carrot, chives-carrot and onion-carrot, as compared to sole cropping of carrot, after four months' growth. The initial root-knot nematode population densities in both farms combined were increased by 235% when carrot was grown in pure stands. Under the three crop combinations there was also a significant 40-60% reduction in root-knot gall indices of carrots, compared with carrots grown in monoculture. The potential of the three intercropping systems to manage the root-knot nematode on carrot in small farms in St. Vincent is discussed. ----- La investigacioh se llevd"a cabo, en dos fincas cultivadas an teriormente con zanahoria [Deucus cerote) en monoculti') o y, con rel(vo de camote (Ipomoea betetesl y znnahotia respectiveamente, durante los Gltimos tres anos. EI numero de Me!oidogyne incognita antes del plando, fue'reducido eonsiderablemente (p:: 0.001) cuando S(;' plantcf cultivos mixtos de: repollo-zanahoria, ccbollino-zanahoria y cebolla-zanahoria, comparados con el monucultivo de zanahoria, despues de cuatro meses de creeimiento. La cantidad inicial del Nodulador, en ambas fincas cornbinadamente fut! incrementada por un 235% cuando zanahoria solamente, fue" plantada. Durante el cultivo de las tres cornbinacionces mencionadas anteriormente se observe, un fudice de reduccioh notable, del 40 al 60'7<, del Nodulador en la zanahoria, comparado con zanahoria cultivada en monocultivo. En esta prcsentacidu discutirernos e1 potencial! de contro!ar el Nodulador en la zanahoria, que tienen los tres cultivos ell asociacion en pequenas fineas en la isla de St. Vincent.