Browsing by Author "Rajamohanan, K"

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Effect of certain biopesticides and irradiation on the developmental stages of myiasis producing flies
(Department of Parasitology, College of Veterinary and Animal Sciences,Mannuthy, 1998) Subramanian, H; Rajamohanan, K
A study was undertaken on the prevalence of cutaneous myiasis in domestic animals and its control using bio-pesticides and gamma irradiation. The prevalence of cutaneous myiasis in domestic animals was found to be 205 (2.08 per cent) among .the 9861 animals screened. The peak of infestation was noted in the month of January. In host-wise and parasite-wise the highest incidence was noted in cattle (63.41 per cent) and the majority of infestation was produced by Chrysomya bezziana larvae (90.73 per cent). Methoprene at 1 to 50 ppm concentration caused only moderate mortality on larvae but significantly increased the mortality rate on eggs, prolonged the larval phase, increased the formation of larval pupal intermediaries and adult deformities and reduced the adult emergence. Diflubenzuron at 0.5 to 5 ppm caused 55 to 100 per cent larvicidal effect due to lowered chitin content of 18.42 to 52.11 per cent in larval cuticle. Bacillus thuringiensis var israelensis produced only moderate larval mortality at 160 to 800 ppm in myiasis producing flies. Azadirachtin at 10.5 to 15 ppm produced 100 per cent mortality in eggs and larvae. Significant antifeedant, ovipositional deterrent and repellant effects were also produced by Azadirachtin. Among the extracts of Acarus calamus, studied, petroleum ether extract at 2.5 per cent concentration gave 82.5 to 100 per cent mortality of the larvae. Moderate antifeedant, ovipositional deterrent and repellant effects were also noticed. The petroleum ether extract produced 100 per cent sterility at 0.1 to 1 per cent concentration by preventing the development of ovarian follicles. Three day old pupae of myiasis producing flies exposed to r-rays gave excellent sterility effect at 2000 to 4000 rads radiation exposure without any other deleterious effect in the flies. Diflubenzuron at 5 ppm concentration showed the highest larvicidal effect (88.5 per cent) in natural cases of cutaneous myiasis.
Immune response of cattle to Boophilus annulatus (Acari : Ixodoidea)
(Department of Parasitology, College of Veterinary and Animal Sciences, Mannuthy, 1992) Sreekrishnan, R; Rajamohanan, K
A study was undertaken to assess the nature and degree of development of acquired resistance in calves against the cattle tick Boophilus annulatus. Observations were made mainly on the development of natural resistance against repeat infestations and the effect of artificial immunization using the tick antigen. Tissue reactions induced by the ticks at the site of bite were also studied. The results indicated the development of resistance in the host, which was gradual and varying in degrees. Immunodiffusion test failed to reveal the presence of tick antibodies in the sera of calves after repeated infestations, indicating that easily demonstrable quantities of antibodies are not developed even after repeated infestations. The cellular reactions at the site of tick – bite revealed the development of a resistant reaction at the site of bite. Studies made on artificial immunization using the whole – tick extract gave varying results. However, the immunodiffusion test using sera of immunized calves revealed that there is a steady maintenance of antibody level throughout the infestation period. Thus, the results obtained in the present study indicate that antibodies are developed against the tick Boophilus annulatus in calves on natural infestations and using the tick antigen, and that there is a clear possibility of immunizing calves against B. annulatus artificially.
Package of practices recommendations: crops 1996
(Directorate of extension, Kerala Agricultural University, 1996) Rajamohanan, K
Paradarogangal kannukalikalil : 100 chodyangalum utharangalum
(Kerala Agricultural University, 1997-01) Rajamohanan, K