Browsing by Author "Sasidharan Pillai, K"

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Comparative efficacy of different formulations of ethyl parathion
(Kerala Agricultural University, 1973) Sasidharan Pillai, K; Saradarnma, K; Das, N M
Influence of weather and rearing techniques on mulberry silk worm crops in Kerala
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1998) Krishnakumar, R; Sasidharan Pillai, K
Investigations were conducted on the effect of weather parameters on the mulberry silkworm crops reared in different seasons and to evolve suitable rearing technology for stress seasons in order to improve the rearing during these seasons and for developing suitable package of practices recommendations for silkworm rearing in Kerala. The study was conducted during 1992-1996 at College of Agriculture, Vellayani. The experiments conducted were  Effect of climatic factors on mulberry silkworm crops in different seasons.  Identifying rearing technology for stress seasons of high temperature and humidity.  Manipulation of feeding schedule with reference to stress seasons and types of silkworm rearing houses. To study the effect of climatic conditions on the mulberry silkworm crop, the silkworms were reared during different identified seasons viz December- January, February-April, May-July, August-September and October-November in 1993-94. The mulberry silkworms used for the study were bivoltine NB4Dz and crossbreed PM x NB4D2. Three brushing were done in each season at fortnightly intervals and fifteen continuous rearings were conducted. The important weather parameters recorded were maximum temperature, minimum temperature, maximum humidity and minimum humidity inside and outside the rearing house. The rearing characters like instarwise larval duration, moulting duration, larval weight, leaf consumption, silk gland weight, disease incidences, missing larval percentage and economic traits like cocoon weight, shell weight, shell ratio, effective rearing rate, filament length, reelability and computed parameters like growth index and growth rate were also recorded. Among the different seasons, August-September and December-January were identified as the favourable seasons. October-November, February-April and May-July seasons were found to be the stress seasons as the biological and economic traits of the different silkworm races during these seasons were not compromising in comparison with other seasons. Maximum temperature and minimum temperature show direct correlations whereas maximum humidity indirectly showed negative correlations with the economic traits like larval weight, silkgland weight, shell ratio, cocoon weight and yield. Second and third experiments were conducted to identify suitable cost effective and efficient rearing house for these stress seasons and also to evolve rearing technology so as to reduce cost of production. The treatments for the second experiment were five different rearing houses along with three different larval spacings. The rearings were conducted by using the same crossbreed and bivoltine race used in the first experiment. The rearings were carried out during 1995 and 1996 in the three stress seasons viz May-July, October-November and February-March. The observations were recorded in terms of the larval characters and economic traits of the silkworms NB4D2 and PM x NB4D2 in these seasons. The results revealed that wider spacing was superior to medium and close spacings in both races. The rearing houses made of mud brick and thatched roof and burnt brick and thatched roof were found superior to other rearing houses in all the three stress seasons during the two year period. Among the different feeding schedules studied in the third experiment, three feeding a day was mostly on par with four feeding a day but was advantageous in terms of convenience of feeding time over other feeding schedules though four feedings recorded higher values for some biological and economic traits in the different silkworm types during different seasons. The incorporation of new techniques of rearing the crossbreed silkworm types in thatched mud wall rearing house, medium spacing of worms and three feeding a day was found to be an ideal profitable package during unfavourable seasons as comparable to that of favourable seasons.
Management of pests of amaranthus and bhindi using plant extracts
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1990) Srinath, B; Sasidharan Pillai, K
Water extracts of eight locally available plants of known insect control potential were screened at 2 and 4 per cent concentrations against pests of amaranthus and bhindi in a pot culture experiment in comparison with carbaryl and tobacco decoction. T. nerifolia followed by A. indica, C. infortunatum and E. odoratum were highly effective against P. basalis on amaranthus and A. gossypii on bhindi. C. infortunatum and T. nerifolia followed by A. indica, N. oleander and E. odoratum were effective against A. biquttula biguttula. T. nerifolia and A. indica followed C. infortunatum and E. odoratum reduced damage caused by E. vittella. Carbaryl 0.2 per cent was superior to plant extracts and tobacco decotion was effective only against aphids. A laboratory study was undertaken for augmenting the toxicity of five aqueous plant extracts by adding with teepol, soap and coconut oil at varying concentrations and combinations. Toxicity of eight and four per cent extracts of C. infortunatum and eight per cent extract of T. nerifolia with teepol, coconut oil and soap reduced the adult emergence of S. litura. A. indica and T. nerifolia were more effective against A. gossypii when the extracts were mixed with soapwater. Teepol and coconut oil also had the same effect with eight per cent T. nerifolia. Field experiment was conducted with the extracts of A. indica, T. nerifolia and C. infortunatum at two and four per cent concentrations without and with soap against pests of amaranthus and bhindi using carbaryl and tobacco decoction as standards. Carbaryl was superior to plant extracts in controlling the population of pests. Four per cent extracts of A. indica, two and four per cent extracts of T. nerifolia and C. infortunatum protected amaranthus against A. crenulata and P. basalis. Toxicity of the extracts A. indica and T. nerifolia was augmented with soap at lower concentration. All the plant extracts increased the crop yield but lesser then carbaryl. Tobaco decoctin failed to control the pests incidence and to increase the yield. Two and four per cent extracts of T. nerifolia caused heavy mortality of A. gossypii. Four per cent extract of A. indica was more effective than carbaryl followed by C. infortunatum, and T. nerifolia against A. crenulata on bhindi. C. infortunatum with soap was efficient against A. biguttula biguttula. Four per cent extracts of T. nerifolia and A. indica were highly effective against E. vitella. T. nerifolia four per cent was effective against S. derogate. Plant extracts were not toxic as carbaryl to C. sexmaculata. All the plant extracts other than at 2 per cent concentration increased the yield and T. nerifolia recorded maximum, but lesser than carbaryl. Tobacco decoctin had no impact on yield. Toxicity of 2 per cent extract of T. nerifolia was augmented with soap against pests of bhindi.
Persistence of some systemic insecticides in cowpea when applied as granules in different soil types of Kerala
(Kerala Agricultural University, 1975) Das, N M; Dale, D; Sasidharan Pillai, K
A pot trial was conducted to study the persistent toxicity of phorate, car. bofuran, mephosfolan and disulfoton to the pea aphid, Aphis craccivota on cowpea grown in sandy, laterite, red, forest and black soils treated with the above insecticides as granule. The persistent toxicity was highest in plants treated with disulfoton in all types of soils. Mephosfolan was next best in sandy, red and forest soils whereas carbofuran was next to disulfoton in laterite and black soils. The yields obtained from treated plants were significantly higher than those of corresponding controls. But there was no direct correlation between the persistent toxicity of insecticides and the yield. The yield factor appears to be influenced by the impact of the insecticide on some soil factors favouring plant growth.
Relative susceptibility of the rice variety 'Rohini' grown under different levels of nitrogen, to the storage pests
(Kerala Agricultural University, 1973) Saradamma, K; Sasidharan Pillai, K; Das, N M
Use of synthetic pyrethroides for the control of pests of bitter gourd (Momordica charantia L) and snake gourd (Trichosanthes anguina L)
(Department of Entomology, College of Agriculture, Vellayani, 1982) Kosaraju Ravindra, Nath; Sasidharan Pillai, K
In a field experiment conducted at the Instructional Farm, College of Agriculture, Vellayani, during the summer season in 1982, the efficacy of four synthetic pyrethroids viz. permethrin, fenvalerate, cypermethrin and deltamethrin, on the pests of bitter gourd and snake gourd in comparision with the standard, malathion, was evaluated. Both the crops were sprayed thrice on need basis for controlling the various pests which infested the crops at different growth stages. Spotted beetle observed on bitter gourd at the time of first spraying was controlled by all the synthetic pyrethroids along with the standard for a period of 23 days after spraying. Fruit fly of the bitter gourd also was controlled by all the three sprayings and all the insecticides were effective in most occasions. Cypermethrin at higher dose was superior to the standard during the first spraying followed by fenvalerate and deltamethrin. In the second spraying deltamethrin was not so effective whereas permethrin was found more effective. Again in the third spraying deltamethrin and fenvalerate were more effective . The fruit fly damage observed for the entire crop season revealed the superiority of fenvalerate, permethrin and deltamethrin at their higher doses over the standard. Jassid on bitter gourd was controlled by all the insecticides except permethrin and cypermethrin at their lower dose for a period of 2 days after the spraying . But aphid could be controlled only with permethrin and fenvalerate at their higher dose along with the standard malathion for a period of 2 DAS. The fruit set and the flowering pattern were not affected by any of these insecticides.