Browsing by Author "Hebsy Bai"

Now showing 1 - 10 of 10

Bare-root dip of brinjal seedlings in phytochemicals for the management of root-knot nematode (Meloidogyne Incognita)
(Kerala Agricultural University, 2000) Asha John; Hebsy Bai
Aqueous ncem leaf extract, neem oil and marotti oil at different concentrations were tested as bare-root dip treatments for their efficacy in containing root-knot nematode [Meloidogyne incognita (Kofoid and White, 1919) Chitwood, 1949] infestation in brinjal. Root-dip in neem leaf extract for 1 h resulted in significantly better height and number of leaves in the treated plants than neem oil and marotti oil. Among the different concentrations of nccm leaf extract tested, 6.25 and 25 per cent extracts proved more effective. Significant reduction in gall index was also seen in neem leaf extract treated plants. Higher concentrations of the extract (50 and 25 per cent) significantly reduced the number of egg masses produced. But none of the phytochemicals had any adverse effect on the hatching of the egg masses. All the three phytochemicals irrespective of the doses reduced population of the nematode in the soil. An overall assessment of the result established the superiority of neem leaf extract (25%) among the different phytochemicals in checking nematode infestation.
Efficacy and biosafety of new generation insecticides for the management of fruit borers of cowpea, brinjal and okra
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2013) Vijayasree, V; Hebsy Bai
Infestation of the pumpkin caterpillar, diaphania indica saunders in cucurbits and its management
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2011) Neena Lenin; Hebsy Bai
Integrated control of nematode pests of bhindi with special reference to root-knot nematode
(Department of Entomology, College of Agriculture, Vellayani, 1981) Hebsy Bai; Nair, M R G K
A field experiment was undertaken to ascertain the effect of the treatment with carbofuran and aldicarb treatment of soil, when applied individually and in combinations on the control of the root-knot nematode N. incognita infesting bhindi. A randomised block design was adopted for the experiment with eight treatments including control and four replications each . To ensure uniform population of the nematode in the different plots a crop was raised and the root system of the plants ploughed back into the soil on the forty-fifth day of sowing. Further , galled roots of bhindi collected from different parts of the farm were chopped and added to the soil to ensure a high and uniform initial population of the nematode. Deep ploughing was done to a depth of 20 cm. Seed treatment was done using the flowable concentrate of carbofuran, to give a 3 per cent deposit. Aldicarb was applied to the soil as granules, raked into it and sealed with a layer of water, a day prior to sowing.
Isolation of the bioactive pinciples of thevetia nerlifolia juss.(Apocynaceae) and determination of their biological activities
(Department of Entomology, College of Agriculture, Vellayani, 1996) Hebsy Bai; George Koshy
Major spiders in vegetable ecosystem and their predatory potential
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2005) Manu Mani, P; Hebsy Bai
Spider faunistic survey conducted in okra, brinjal, cowpea, bittergourd and amaranthus fields in Kalliyoor panchayat of Thiruvananthapuram district during the summer of 2004, revealed the prevalence of high density and diversity of spiders in the vegetable ecosystem. Hunting spiders were dominant in all the vegetable plots. Thirty species of spiders distributed in nine families were recorded with the number of species in each vegetable field ranging from 10 to17. Among the thirty species, 16 species were commonly seen in the different vegetable fields while 14 species were seen exclusively associated with a particular vegetable. Araneidae with ten species was the most represented family in the vegetable fields followed by Oxyopidae and Salticidae. The other families observed were Miturgidae, Thomisidae, Tetragnathidae, Corinnidae, Lycosidae and Clubionidae. Most of the spiders appeared during the vegetative and flowering stages of the crop. Few spiders were recorded in the early stage of the crops. Four spiders viz., O. javanus, C. danieli, N. mukerjei and T. mandibulata were dominant in all the vegetable plots among which O. javanus and C. danieli predominated. Studies on the seasonal influence showed no significant difference in the abundance of the spiders during summer and rainy seasons. Rather, the growth stages of the crops significantly influenced the build up of the spider population with higher population being observed during the reproductive phase. In general, the spiders preferred soft bodied insects like the hemipterans, lepidopterans, dipterans and coleopterans (eggs and grubs) for predation. While the spiders did not show any significant preference for the different hemipteran prey in a mixed diet, significant difference was shown for the different lepidopteran pests. O. javanus had the maximum preference for the lepidopteran pests Chemical insecticides were more toxic to the spiders than botanicals when tested at their recommended doses. Among the chemical insecticides, dimethoate 0.05 per cent, carbaryl 0.2 per cent and malathion 0.1 per cent were highly toxic. Even at different doses the insecticides were toxic to the spiders. Quinalphos 0.05 per cent and imidacloprid were less toxic. Between the two methods of application, topical application of insecticides was more detrimental to the spiders than release on treated plants. Among the spiders, T. mandibulata was more susceptible to the insecticides followed by C. danieli. O. javanus and N. mukerjei were less sensitive. While the fungal pathogens, M. anisopliae, P. lilacinus and Bt were safe to the spiders. F. pallidoroseum, Fusarium sp. and B. bassiana were pathogenic. Based on the results of the study, conservation of the spiders characteristic of the vegetable ecosystem would be a practical and ecologically and economically viable approach for pest suppression in vegetables. When there is a spurt in pest ravage, the protection afforded by the predator could be supplemented with judicious use of “spider friendly” insecticides.
Management of the american serpentine leaf miner Liriomyza trifolii (Burgess) Dietars on cowpea, Vigna unguiculata (L.) Walp
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2002) Reji, G V; Hebsy Bai
Survey conducted in Kailiyoor panchayat of Thiruvananthapuram district revealed that Liriomyza trifol ii caused maximum damage to cowpea at the reproductive phase of the crop III summer. Raising susceptible varieties, applying high doses of nitrogen and frequent use of insecticides were noted to intensify the pest incidence. The weeds, Achyranthus aspera, Amaranthus viridis, Cleome viscosa, Cleome monophylfa, Heliotropium indicum, Physalis minima and Desmodium gyrans were identified as host plants of the pest. Seven larval parasitoids were recorded of which Chrysonotomyia rexia and Asecodes sp. were predominant. Twenty accessions of ccwpea including trailing and bush types were screened in the laboratory for resistance to L. trifolii. Accessions of trailing type were more susceptible to the pest. VU-12 was least susceptible among the trailing type while Sharika and Vyjayanthi were highly susceptible. Among the bush type, VU-4, VU-6, VU-3 and Arka Garima were less susceptible. Four plant oils and four synthetic insecticides when evaluated in the laboratory at two doses along with neem oil (2.5 per cent) and dimethoate (0.05 per cent) showed no significant diffe. ence in efficacy between the doses. Neem oil, marotti oil and ilIupai oil at 2.5 per cent and abamectin, 0.003 per cent, thiamethoxam, 0.02 per cent and profenophos, 0.025 per cent were found to be effective in controlling the pest. All the treatments reduced the pest infestation significantly in the field. Abamectin, 0.003 per cent was significantly superior. Neem oil, marotti oil and illupai oil 2.5 per cent also reduced pest infestation. Considering the cost and safety to the natural enemies, the oils were found more advantageous to the farmers. Based on the results, cultivation of the tolerant accession VU -12 111 endemic areas, destruction of weed host plants, judicious application of nitrogen and need based application of neem oil / marotti oil / illupai oil at 2.5 per cent can be recommended for inclusion in rPM strategies of L. trifolii.
Phytochemicals and vam for management of nematodes in brinjal
(Department of Entomology, College of Agriculture, Vellayani, 1997) Asha John; Hebsy Bai
Aqueous neem leaf extract, neem oil and marotti oil at different concentrations were tested as bare root-dip treatments for their efficacy in containing root-knot nematode infestation in brinjal. Root-dip in neem leaf extract for one hour resulted in significantly better height and number of leaves in the treated plants than nee m oil and marotti oil. Among the different concentrations of neem leaf extract tested, 6.25 and 25 per cent extracts proved more effective. Significant reduction in gall index was also seen in neem leaf extract treated plants. Higher concentrations of the extract (50 and 25 per cent) significantly reduced the number of egg masses produced. But none of the phytochemicals had any adverse effect on the hatching of the egg masses. All the three phytochemicals irrespective of the doses reduced population of the nematode in the soil. An overall assessment of the result established the superiority of neem leaf extract (25 per cent) among the different phytochemicals tested in checking nematode infestation. Different isolates of V AM fungi like, G. fasciculatum, G. etunicatum, G. mosseae, G. constrictum G. monosporum and A. morroweae did not show any significant difference in the growth parameters of brinjal plants (height and number of leaves) at transplanting and one month after transplanting irrespective of the pot size. Later (45 and 60 days after transplanting) significant increase in height and number of leaves were observed in plants raised in soil inoculated with G.etunicatum and G. fasciculatum. Higher percentage of V A mycorrhizal colonisation was observed in plants artificially inoculated with V AM. Plants raised in G. etunicatum G. fasciculatum and G. monosporum recorded significantly lower root-knot indices. The fecundity of the nematode and the number of larvae hatching per eggmass was also significantly reduced in mycorrhizae treated plants. Irrespective of the pot size, G.fasciculatum registered the lowest population per gram root while G. fasciculatum and G. constrictum significantly lowered the nematode population in the soil. Overall assessment of the results revealed G. fasciculatum as the most effective mycorrhizae among the isolates tested for protecting brinjal plants from root-knot infestation. Field trial with bare-root dip in 25 per cent neem leaf extract and insecticides monocrotophos (500 and 250 ppm) and carbosulfan (500 and 250 ppm) nursery treatment with G. fasciculatum and root-dip of the mycorrhizal seedlings in neem leaf extract and nematicides did not show any significant effect on growth parameters of the plant like height, number of leaves and root weight But the . bare-root dip treatment in neem leaf extract and mycorrhizal nursery treatment and bare-root dip treatment in monocrotophos 500 ppm resulted in significant increase in shoot weight. Root-dip in nematicides was definitely superior to root- dip in neem leaf extract and nursery treatment with G. fasciculatum in increasing yield significantly. Bare-root dip in neem leaf extract, nursery treatment with G.fasciculatum also registered significantly higher yield. Root-dip of mycorrhizal seedlings in monocrotophos and carbosulfan were far more superior than the individual treatments in increasing the yield of brinjal. During the early stage (45 DAT) no significant difference was seen in the gall index, number of egg mass per plant and mycorrhizal colonization percentage. Later, as the plant matured a significant difference was seen in these parameters. Root -dip in neither nematicide nor neem leaf extract showed any deleterious effect on mycorrhizal colonisation.
Population dynamics and management of aphids in vegetable ecosystem
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2009) Thamilvel, D; Hebsy Bai
Yellow oleander (Thevetia neriifolia juss.) a bio-antifeedant for epilachna beetle (Henosepilachna vigintioctopunctata L.)
(Kerala Agricultural University, 1999) Hebsy Bai; George Koshy
Fresh and dried leaves and seeds of Thevetia neriifolia Juss. were evaluated for their antifeedant activity against Henosepilachna vigintioctopunctata L. using acetone, benzene, ethanol, hexane, methanol and water as extractants. Based on the percentage of leaf protection, seed extracts were found superior to the leaf extracts. Fresh and dried leaf extracts were on par. Among the solvents, ethanol and methanol gave maximum leaf protection closely followed by water. Based on larval starvation, seed extracts were superior to leaf extracts and fresh leaf extracts were significantly better than dried leaf extracts. Soaking of oowdered plant material in solvents for 48 h and filtration was found as effective as soxhlet method for extracting antifeedant components from leaves and seeds of T. neriifolia.