Distribution of phytonematodes and their management in ornamental crops in Thiruvanantharpuram district

Abstract

A random survey was. conducted in Thiruvananthapuram district to gather information about the nematodes associated with cut flowers( anthurium and orchid), traditional flowers( rose and jasmine) and ornamental foliage plants ( begonia and croton). The root - knot nematode M incognita and burrowing nematode, R. similis were found associated with these plants. Other nematodes observed were the lance nematode Hoplolaimus spp.,spiral nematode Helicotylenchus spp. and ring nematode Criconemoides sp. Among the cut flowers, anthurium was found to be highly susceptible to root - knot nematode. In ornamental foliage, begonia and traditional flowers, jasmine were found susceptible to the nematode. Small terminal galls were seen in anthurium whereas comparatively large sized galls spread throughout the root system were seen in begonia and croton . Histopathological studies were conducted in anthurium, jasmine and begonia .The xylem vessels were highly damaged in these crops due to nematode attack affecting translocation of nutrients and water. Studies on nematode management conducted in anthurium revealed no significant difference in the biometric characters of the plant. Significant reduction in root weight was observed in plants receiving different treatments. Treatment of soil with carbofuran 2 kg ai ha' gave maximum reduction of nematode population in soil. Neem cake 0.5 per cent w/w ,carbofuran lkg ai ha+ neem cake 0.25 per cent w/w and carbofuran 1 kg ai hal+neem cake 0.25 per cent w/w +G.fasciculatum 200 spores per pot were equally effective in reducing population of nematode in the soil. G. fasciculatum 200 spores per pot +neem cake 0.25 per cent w/w gave maximum reduction of nematode in root. A low gall index of 1.25 was observed in plants treated with carbofuran @ 2 kg ai ha:' and carbofuran @ 1 kg ai hal+neem cake 0.25 per cent w/w.