Browsing by Author "Sosamma Jacob"

Now showing 1 - 12 of 12

Bioecology, population dynamics and integrated management of rice blue beetle, Leptispa pygmaea Baly (Chrysomelidae:Coleoptera)
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2007) Karthikeyan, K; Sosamma Jacob
Bioefficacy of neonicotinoid insecticides against insect pests of Okra (Abelmoschus esculentus(L.) Moench)
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2014) Jijisha, P K; Sosamma Jacob
An investigation on “Bioefficacy of neonicotinoid insecticides against insect pests of okra (Abelmoschus esculentus (L.) Moench)” was undertaken in the Department of Agricultural Entomology, College of Horticulture, Vellanikkara, Kerala Agricultural University during 2013- 2014. The study was carried out by conducting two field experiments at the Instructional Farm, College of Horticulture in two seasons viz., April 2013 to July 2013 and October 2013 to January 2014. Two neonicotinoid insecticides - thiamethoxam and imidacloprid - were fieldevaluated for their biological efficiency against major insect pests of okra, safety to naturaenemies, influence on plant growth parameters and terminal residues in okra fruits. The twoinsecticides were applied in three methods viz., seed treatment (ST), two foliar treatments (2FT) and a combination of seed treatment followed by a single foliar treatment (ST+FT). Thetreatments comprised of ST thiamethoxam 30FS @ 3 g a.i. kg -1 (T1) and ST imidacloprid48FS @ 6 g a.i. kg -1 (T2) before sowing, two foliar sprayings ( 2FT) with thiamethoxam25WG @ 25g ai ha -1 (T3) and imidacloprid 70WG @ 25 g a.i. ha-1 (T4) at 15 and 30 daysafter sowing (DAS) and a combination of seed treatment followed by a foliar spraying(ST+FT) with thiamethoxam (T5) and imidacloprid (T6) at 30 DAS. A standard checkinsecticide quinalphos 25EC @ 250 g a.i. ha -1 as two foliar sprayings (FT) at 15 and 30DAS (T7) along with an untreated control (T8) were also included in the field experiment. Both thiamethoxam and imidacloprid were found to be significantly effective than quinalphos against Amrasca biguttula biguttula Ishida in okra. All the three methods of application with thiamethoxam and imidacloprid showed equal effectiveness upto 30 DAS. However, both the foliar treatment and the combination of seed treatment followed by a single foliar treatment with thiamethoxam proved to be equally effective throughout the season to A. biguttula biguttula. Thiamethoxam and imidacloprid by all the three application methods (seed treatment, foliar treatment and combination of seed treatment followed by foliar treatment) were equally effective against Aphis gossypii Glover upto 25 DAS. From 30 to 50 DAS, two foliar sprayings at 25 g a.i. ha -1 revealed a highest reduction of 88.49 per cent in the population of A. gossypii. Two foliar sprayings with imidacloprid 70 WDG @ 25 g a.i. ha-1 at 15 and 30 DAS recorded the lowest population of Bemisia tabaci Gennadius and least leaf damage by Sylepta derogata Fabricius in okra. Thiamethoxam 25WDG with two foliar sprayings (2 FT) @ 25 g a.i. ha -1 at 15 and 30 DAS significantly reduced the shoot and fruit damage by Earias vitella Fabricius. With regard to the impact of thiamethoxam and imidacloprid on natural enemies, two foliar sprayings with thiamethoxam at 25 g a.i. ha -1 showed highest coccinellid population in the first season. In the second season, seed treatment with thiamethoxam @ 3 g a.i. kg indicated the highest population of coccinellids. However, imidacloprid was found to be safer than the standard check quinalphos to coccinellids in both seasons. But the spider population was observed to be relatively less in all the treatments of thiamethoxam and imidacloprid as compared to the untreated control. Thiamethoxam and imidacloprid showed no adverse effect on other predators such as syrphids, chrysoperla and rove beetles in okra field. Thiamethoxam and imidacloprid indicated phytotonic effects on okra plant for they exhibited significant effects on plant growth parameters. Two foliar sprayings of thiamethoxam significantly increased the plant height, number of leaves, flowers per plant, fruit weight and fruit length. Seed treatment with both thiamethoxam and imidacloprid reduced the days for flower initiation. Terminal residue in fruits was below detectable limit at 15 days after spraying in all the treatments with thiamethoxam and imidacloprid.
Bioefficiency persistence and residue dynamics of carbofuran in bittergourd (Momordica charantia L.)
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1989) Cherian Thomas; Sosamma Jacob
Studies were undertaken to assess the bioefficiency, persistence and residue dynamics of carbofuran in bittergourd (Momordica eharantia L.). Carbofuran was applied at two doses, 0.75 and 1.5 kg ai/ha at different growth stages, namely sowing, vining, flowering and at all the above three stages of the bittergourd crop. An untreated control was also maintained to compare the effects of various treatments. All the treatments recorded lower population of epilachna beetle (Henosepilachna 28 punctata Fab.) than control. But the treatment wherein carbofuran ® 1.5 kg ai/ha applied at the time of sowing, vining and flowering was found to be the most effective one in controlling the epilachna beetles with 95,79 per cent reduction over control 80 days after sowing. In controlling the red pumpkin beetle Raphidopalpa feveicollis Lucus. and melon fruit fly Dacus cucurbitae Coq. also the same above treatment was found to be the most effective one. The percentage of reduction in incidence of fruit fly was of the order of 79.72 over control in terms of fruit damage by number and 83.35 by weight. The treatment in which carbofuran Q 0.75 kg ai/ha applied at the time of sowing was found to be least effective in controlling the above pests.
Decontamination of bhindi (Abelmoschus Esculentus Moench) treated with quinalphos
(Kerala Agricultural University, 1985) Sosamma Jacob; Shashi Varma
In an experiment to study the effect of different decontamination processes on the reduction of quinalphos residues on bhindi, it was found that water washing of the fruit resulted in the reduction of initial residues to the extent of 61.86 and 64.35% in the case of fruit treated with spray application of quinalphos at 0.03 and 0.05% respectively on the same day. The residues on washed fruit was below the maximum residue limit at the zero day of the treatment making it safe for consumption on the same day of harvest. Saltwater washing and cooking also, helped to bring down the residues below the MRL at the zero day itself. Out of the three processes of decontamination cooking was found to bring out the maximum reduction of residues.
Impact of novel insecticides on Trichogramma chilonis Ishii (Hymenoptera:Trichogrammatidae)
(Department of agricultural entomology, College of horticulture, Vellanikkara, 2013) Uma, S; Sosamma Jacob
Orientational response of leaf hoppers, epilachna beetles and aphids to brinjal plants treated with the sublethal concentrations of decamethrin and carbaryl
(Kerala Agricultural University, 1992) Sheila, M K; Abraham, C C; Sosamma Jacob
Potency of bioinsecticides against the cowpea bruchid, Callosobruchus maculatus (F.) (Coleoptera:Cysomelidae) in storage
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2011) Amritha Kumari, S; Sosamma Jacob
Regulation of fecundity, progeny production and female-male composition of Bracon Brevicornis Wesmael (Hymenop Tera : Braconidae)
(Kerala Agricultural University, 1980) Sosamma Jacob; Abraham, C C; Joy, P J
The fecundity, progeny production, female-male ccmposition offhe progeny of Bracon brevicorn/s Wesmael as influenced b/ density and weight of host larvae of Corcyra caphalonica Stainton and the sex-ratio of the parent parasite population were studied at three temperature-humidity combinations, namely, 28°C-75% RH (TH,), 30aC-60% RH (THJ and 32°C-50% RH {TH3) • The effect of the main factors on parasite development was found to be modified by the temperature humidity conditions of rearing. The maximum fecundity of the parasite was registered consistently at all the three TH levels at a host density level of two larvae per female parasite and when the parental parasite sex ratio was kept at 2.1 and 3:1 (femalermale). The highest progeny production was attained at the THt and TH^ levels under a host density le/e! of two heavie' (30-35 mg) larvae per female parasite, The influence of host larva! density on the proportion of females was pronounced only at the TH^ level and a density of two larvae per female parasite was found to be better for the production of higher proportion of females. The parental sex-ratios of 1:3 (female : male) produced higher proportion of females at the THLJ and TH3 levels.
Relative susceptibility of population of Amrasca biquttula biquttula (Ishida) infesting bittergourd Momordica charantia L. collected from different locations to insecticides
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1992) Sabitha, R; Sosamma Jacob
Relative susceptibility of populations of Amrasca biguttula biguttula (ISHIDA) infesting Bittergourd (memordica charantia L.) collected from different locations to insecticides part II
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1994) Jyothi Bindu, P; Sosamma Jacob
A study was undertaken at the college of Horticulture, Vellanikkara during 1993-94 to evaluate the relative susceptibility of eight different populations of Amrasca biguttula biguttula (Ishida) on bittergourd collected from four districts of Kerala state to six insecticides belonging to different chemical groups. Two different localities were selected for the collection of the leaf hopper, from each district. The selected localities were, Pattikadu and Nedupuzha (Thrissur district), Pothappara and Odanallur (Palakkad district), Wandoor and Chattipparambu (Malappuram district) and Vempalli and Kurichi (Kottayam district). All the populations were collected from farmers fields which were subjected to regular insecticidal spraying. The insecticides selected for the study belong to different chemical groups viz. organophosphorus compounds (quinalphos, monocrotophos and phosphamidon), organochlorine compounds (endosulfan), synthetic pyrethroid (deltamethrin) and CHO compound (ethofenporx). Among these insecticides, the organophosphorus compounds were widely used by the farmers for controlling this pest in the field. Relative toxicity of different insecticides to different populations were found by leaf dipping technique of bioassay and the results were subjected to probit analysis (Finney, 1971). Based on the relative toxicity studies it was clear that endosulfan was the most toxic insecticide against A.biguttula biguttula collected from all the eight localities. Monocrotophos ranked second in toxicity against populations from Thrissur district while deltamethrin was proved to be the second highly toxic insecticide to Palakkad and Kottayam hopper populations. Against Malappuram populations of A.biguttula biguttula highest toxicity of endosulfan was followed by ethofenprox. Phosphamidon was found to be relatively less toxic to this pest. Quinalphos, the commonly used organophosphorus insecticide was found to have least toxicity and thereby it was observed to be ineffective in controlling this pest in bitttergourd in all the four districts. Great variation was observed in the relative toxicity values of different insecticides indicating their difference in toxicity level to A. biguttula biguttula. The order of toxicity of different insecticides was found to be the same between the two populations from each district but varied with populations from different districts. Organophosphorus compounds were found to be relatively less toxic than endosulfan, deltamethrin and ethofenprox belonging to other groups. Therefore, the use of quinalphos against A.biguttula biguttula among the farmers has to be discouraged and endosulfan can be advocated against A. biguttula biguttula in bitterfourd as an alternative. Carbaryl was proved to be ineffective against leaf hopper populations in bittergourd earlier (Sabitha, 1992). The relative susceptibility studies with populations of A. biguttula biguttula from the four districts revealed that all the eight populations were highly susceptible to endosulfan. The LC50 value of endosulfan was found to be very low, ranging from 0.00022 to 0.00041 per cent. At the same time all the populations were least susceptible to the most commonly used organophosphorus insecticide quinalphos. All the populations showed higher susceptibility to endosulfan, deltamethrin and ethofenprox than the organophosphorus insecticides. Thrissur population was more susceptible to monocrotophos next to endosulfan. Palakkad and Kottayam populations were more susceptible to deltamethrin while Malappuram populations indicated more susceptibility to ethofenprox, next to endosulfan. The LC50 value of phosphamidon ranged from 0.02 to 0.06 and all the eight populations of A.biguttula biguttula manifested lower susceptibility to this insecticide in comparison with the other chemicals
Screening of cowpea varieties for the rice fallows
(Kerala Agricultural University, 1978) Varkey, P A; Sosamma Jacob
Toxicity of insecticides against populations OE Amrasca Biguttula biguttula (Ishida) infesting bittergourd from four districts of Kerala
(Kerala Agricultural University, 1994) Sabitha, R; Sosamma Jacob; Rao, D S
A study was undertaken to assess the relative toxicity of five insecticides against different populations of Amrasca Iriguttula bigiittula collected from four districts of Kerala. Variations were observed in the toxicity of insecticides against different populations.