Browsing by Author "Susamma Mathai"

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Control of the insect pests affecting cowpea Vigna Sinensis
(Kerala Agricultural University, 1977) Das, N M; Susamma Mathai; Christudas, S P
In a field experiment conducted in the red soil of Agricultural College Farm, Vellayani applying thimet, disulfotan, rnephosfolan and carbofuron granules at three different levels, applied at the' time of sowing, disulfoton at 1 kgai/ha was found an effective and economic method for controlling pea aphid upto 5 weeks after sowing. In another field experiment it was observed that spraying of different insecticides commencing from the time of flowering along with one application of disulfotan granules at the rate of 1 kg ai/ha at the time of sowing reduced the incidence of pea aphid and pod borers and increased the yield significantly. On a benefit cost ratio basis the effective insecticides could be ranked as follows: f enithion >f enitrothion > monocrotophos > carbaryl > phosalone > quinalphos.
Effect of entomopathogenic fungi on sucking pests and leaf feeders of vegetables under in vitro conditions
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2002) Jincy Simon; Susamma Mathai
Field evaluation of insecticides against pests of paddy
(Kerala Agricultural University, 1975) Susamma Mathai; Christudas, S P; Nair, M R G K
Fusarium pallidoroseum (Cooke) Sacc as a biocontrol agent for the pea aphid Aphis craccivora Koch
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1996) Sunitha, V S; Susamma Mathai
Detailed investigations were made on the entomogenous fungus Fusarium pallidoroseum (cooke) Sacc infecting cowpea aphid Aphis cracclvora koch. Field studies showed that spore suspension and wettable powder formulations were equally effective in controlling the pea aphid. 7 x 106 spores per ml suspension in water or a similar suspension of a wettable powder or quinalphos 0.05 per cent were found to be equally effective in controlling the aphids under field conditions. Spore suspension containing 3.5 x 106 spores per ml have shown similar results during the later half of the experimental period. Pot culture studies conducted to assess the influence of host plants of aphid on the efficacy of the pathogen revealed that there was no influence of host plant on the pathogenecity of F. pallidoroseum. The germination and viability of F. pallidoroseum in formulation was found to decrease with increase in storage period and the formulations retained its capacity for germination and viability for more than ten months under refrigeration. The fungus was found nonpathogenic to vegetables viz. as bhindi, brinjal, amaranths, tomato, chillies, snakegourd, bittergourd and medicinal plants, viz., adathoda, ocimum and notchi under field conditions. Besides it was found safe to natural enemies of aphids viz., Coccinella septumpunctata, Menochilus sexmaculata and Scymnus sp. The productive insects, honey bees and silkworms were not at all affected by this fungus. Cross inoculation studies using this pathogen showed that three species of aphids, viz., Toxoptera aurantii, Aphis gossypii and Aphis malvae were not infected. A strain of F. Pallidoroseum isolated from a weed plant water hyacinth(Eichhornia crassipes) was found to be non pathogenic to the aphid Aphis Crassivora. Similarly F. Pallidoroseum was observed non pathogenic to water hyacinth. These observations indicated that the above two strains of F. Pallidorosem are entirely different.
On the control of the jassid Amrasca Biguttula biguttula (Ishida) on bhindi using some new insecticides
(Kerala Agricultural University, 1976) Nair, M R O K; Christudas, S P; Susamma Mathai
On the toxicity of some newer insecticides to certain common crop pests
(Kerala Agricultural University, 1976) Susamma Mathai; Nair, M R G K
Production and evaluation of the fungus fusarium pallidorosium (coooke)saac. as a biopesticide againstpea aphid apphis craccivora koch.
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2001) Reji Rani, O P; Susamma Mathai
Studies on the effect of host nutrition on the larval parasite, Microbracon brevicornis Wesmael (Braconidae: Hymenoptera)
(Division of Entomology, Agricultural College and Research Institute, Vellayani, 1965) Susamma Mathai; Renga Ayyar, G
Literature on effect of nutrition on fecundity, development and longevity of insects with special reference to entomophagous forms has been reviewed. Comparative studies of eleven different nutrient media were made to ascertain their effect on the development and growth of the larvae of Corcyra cephalonica (Stainton) using coarsely ground wheat flour as a medium of basic diet. The larval duration was considerably reduced,by 10-14 days when the larvae were reared in a medium of basic diet containing coarsely ground wheat flour to which either fructose , or a combination of black gram powder and glucose fortified with yeast were added. The pupal duration of Corcyra cephalonica was not much affected by various nutrient media , through addition of bengal gram powder to basic diet in the larval nutrition shortened the pupal period by two days.
Studies on the entomogenous fungus associated with cowpea aphid
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1992) Faizal, M H; Susamma Mathai
Studies were conducted on the entomogenous fungus Fusarium pallidoroseum (Cooks) Sacc. infecting cowpea aphid Aphis craccivora Koch. The infected aphids turned pale and assumed brownish black discolouration. Death occurred in 24 to 72 hours after infection and mycelial growth appeared on the cadavers 24 to 48 hours after death. For mass production of the fungus, wheat bran and rice bran appeared to be comparatively suitable as they recorded maximum growth, sporulation and virulence of the pathogen. Maximum sporulation was noticed 8 days after inoculation. Culture substrates subjected to full heat sterilization produced maximum growth and sporulation of the fungus followed by those subjected to full solarization. A mortality per cent of 99.57 was observed when aphids were sprayed with culture filtrate of F. pallidoroseum grown in Richard’s medium indicating the presence of toxins. Studies on the effect of pesticides on the growth of the fungus showed that mercaptothion and monocrotophos were the least inhibitory. Fenthion showed the least inhibition of sporulation. HCH, captan and zineb completely inhibited the growth. Sporulation was completely inhibited in all the fungicidal treatments. Under laboratory conditions spore suspension of the fungus in water was found to be superior to the spore formulations tried. Among the formulations wettable powder with diatomaceous earth as inert material was found to cause more mortality followed by wettable powder with talc as inert material. Dust using talc as inert material was found to be the least effective. Spore suspension in water, wettable powder formulation of fungal spores with diatomaceoue earth as inert material and quinalphos 0.05 per cent were found to be equally effective in bringing down the population of aphids under field conditions. The virulence of spores of F. pallidoroseum in formulation was found to decrease with increase in storage period and it retained substantial virulence up to four days of storage.
Use of insecticides for control of pests of brinjal and bhindi
(Kerala Agricultural University, 1975) Christudas, S P; Susamma Mathai; Nair, M R G K