Browsing by Author "Arthur Jacob, J"

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Distribution of phytonematodes and their management in ornamental crops in Thiruvanantharpuram district
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2001) Mahesh, T; Arthur Jacob, J
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.
Effect of root-knot nematode meloidogyne incognita (Kofoid and White) chitwood and reniform nematode rotylenchulus reniformis linford and oliveria on cowpea
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1989) Anitha, N; Arthur Jacob, J
Three pot culture experiments were laid out with the objectives (i) to study the effect of M. incognita on cowpea, (ii) to study the effect of R. reniformis on cowpea and (iii) to study their combind effect. The individual effects were assessed with nine population levels ranging from 0 – 1000 larvae/100 ml soil each replicated thrice. In the combined experiment three population levels, 100, 200 and 400 and their three combinations were tried each replicated four times. The results indicated that at initial inoculam levels of 100, 200, 400 and 600 larvae/ 100 ml of soil of the two nematodes, M. incognita and R. reniformis extered severe damaging influence on cowpea. The higher inoculum levels of 800 and 1000 larvae/100 ml soil did not show a progressive increase in crop loss. It is evident that the threshold levels of the nematodes will fall within the range of 100 to 600 larvae/100 ml soil. In the combined inoculation of the nematodes, an inoculum level of 400 M. incognita followed by 400 R. reniformis/100 ml soil 15 days later exerted a highly deleterious effect on cowpea. Simultaneous inoculation did not lag for behind in its debilitating effect. Considering the nematode population in soil, multiplication rate of both nematodes were found higher in lower inoculum levels than in the higher inoculum levels. In the combined inoculation, reniform nematode dominated root - knot nematode. Reniform nematode had an adverse effect on the multiplication of root-knot nematode. Both nematodes thrived well when M. incognita was inoculated prior to R. reniformis.
Pathogencity, yield loss assessment and management of root -knot nematode, meloidogyne incognita (kofoid and white) chitwood on chilli (capsicum annum L.)
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2003) Rajitha, R; Arthur Jacob, J
A study was conducted in pots to determine the pathogenicity of the root-knot nematode, Meloidogyne incognita (Kofoid and White, 1919) Chitwood, 1949 on chilli (Capsicum annuum L.). A significant reduction was seen in the growth parameters' at 30, 60 DAT and final harvest when chilli plants were inoculated with 50, 100, 200 and 300 hllOO g soil. A progressive reduction in yield was also observed wi th increase in the inoculum levels, the reduction in yield ranging from 17.59 to 62.99 per cent. Multiplication of the nematode was high at 50 and 100 hll 00 g soil. Considering the importance of the crop in the state, 40 per cent loss in .- yield and multiplication of the nematode in relation to its initial density at 100 Jz 11 00 g soil, the damage threshold of the nematode was fixed as 100 lj100 g soil. Thirteen accessions including high yielding varieties and local accessions were screened in pots for resistance to M. inco gnita. Pusa Sadabahar and Khandari were moderately resistant to the nematode. Pusa Sadabahar,Pusa Jwala and Pant C-l were moderately resistant to infestation of chilli thrips, Scirtothr ips dorsalis and chilli mite, Polyphagotarsonemus latus. The high yielding varieties, Jwalamukhi and Jwalasakhi released by Kerala Agricultural University were susceptible to , the nematode but moderately resistant to pest infestation. Three bioagents viz., AMF @ 250 spores per plant, fluorescent pseudomonads 2 per cent and Trichoderma sp. 5 per cent and oilcakes viz., neem cake and mustard cake @ 1 t ha-l were evaluated for their efficacy in controlling M. incognita in comparison with carbofuran @l kg ai ha-l in pots. Treatment with the bioagents protected chilli plants better from the infestation of the nematode while amendment of soil with oilcakes resulted in better growth of plants. Yield was also higher in plants treated with bioagents. Among the bioagents, application of AMF @ 250 spores per plant and Trichoderma sp. 5 per cent were equally effective 111 reducing nematode infestation and increasing yield of chilli. Based on the results of the study. M. incognito can be considered as a potential threat to the cultivation of chilli at 100 hll 00 g soil. Cultivation of the varieties Pusa Jwala or Pusa Sadabahar would be a viable option in areas where root-knot nematode and chilli mite and thrips are a major problem. Application of the vermiculite formulation of AMF @ 250 spores per plant or Trichoderma sp. 5 per cent at planting can be recommended for inclusion 111 integrated nematode management programmes in chilli.
Screening of pepper varieties for resistance against root-knot nematode Meloidogyne incognita
(Kerala Agricultural University, 1979) Arthur Jacob, J; John Kurian
Studies on the root-knot nematode of pepper (Piper nigrum L.)
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1977) Arthur Jacob, J; John Kuriyan, K
Nematodes have recently been observed to constitute a major threat and limiting factor to the pepper production in Kerala State, Among the nematodes, neloidecyne spp, causing root-knots on pepper is one of the most important. Investigation on this nematode in pepper was not done in this state, Therefore, to gather some information on the extent of damage done by this nematode and pepper and to evolve control measures the present work was carried out