Studies on fusarium solani meloidogyne javanica disease complex in coleus forskohlii and its management

Abstract

The present work deals with Studies on Fusarium solani - newlineMeloidogyne javanica disease complex in Coleus forskohlii and its management . Aspect wise abstract of the results is presented below: To determine the inoculum threshold level of root - knot nematode, Meloidogyne javanica, the cuttings of coleus, Coleus forskohlii var. newlineSelection - K plants were separately inoculated with different inoculums levels of M. javanica (250, 500, 1000, 2000, 4000 and 8000 J2 / kg soil). newlineIt was observed that with an increase in the level of inoculum there was a progressive increase in host infestation by root - knot nematode as indicated by the number of galls / root system as well as the population ofnematode. Moreover, the rate of nematode multiplication was reduced with the increase in the inoculum density of M. javanica. The galls of varying size developed on both lateral as well as tuberous roots of the plants. Besides galling in roots, some other typical symptoms in the form of forking of tuberous roots and appearance of galls at the base of the stem near the soil level were also observed at and above 2000 J2 / kg soil. The nematode density particularly at 1000 J2 and above inoculums levels also exhibited varying degree of stunted growth in plants accompanied with premature yellowing, drying and shedding of leaves, giving the infected plants an unhealthy appearance. In the highest inoculum level, the diseased plants also showed temporary day time wilting during hot hours even in the presence of enough soil moisture. The damaging threshold level of M. javanica on Coleus forskohlii was 1000 J2 / kg soil as the population at this level was associated with the significant decline in plant growth parameters including yield of tuber and forskolin. Irrespective of inoculum levels, the root - rot fungus, Fusarium solani neither caused any damage nor produced any symptoms in coleus, the reason being that this fungus is not pathogenic to coleus. Coleus seedlings were inoculated with M. javanica (1000 J2 / kg soil) and F.