Browsing by Author "Thomas Biju Mathew"

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Bio-ecology of coconut eriophyid mite, aceria guerreronis keifer and yield loss due to its infestation on popular coconut cultivars
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2001) Ambily Paul; Thomas Biju Mathew
Studies were conducted to understand the biology, ecology, population dynamics and rr .te-host interactions of A. guerreronis and to assess the yield loss on popular cultivars of coconut as influenced by nut characters and weather parameters. An abstract of the work done and the results are given below. Biology of A. guerreronis was studied under both laboratory and field conditions. The study indicated that a total period of 9.8 days was required for completing one generation under laboratory condition. Population dynamics of A. guerreronis in young buttons of susceptible and tolerant palms of variety WeT and Komadan was studied from February 2000 to January 2001. Population of mites under each tepal was counted by using cello tape embedding method. The results revealed that the population was the highest in nuts sampled from fifth bunch followed by fourth and sixth bunches in both susceptible and tolerant palms. The present study indicated that age of developing nut was the most critical factor in the study of population dynamics. Monthly mean population of A. guerreronis was correlated with weather parameters viz., temperature, relative humidity and rainfall prevailed during the time of sampling, probable time of mite entry and the total duration of critical age of the bunch. The results indicated that the relative humidity prevailed at the probable time ofmite entry alone had a positive correlation with population in the susceptible type of Ko mad an. The length to circumference ratio of young nuts and its influence on mite injury was observed. The results showed that round nuts having a length to circumference ratio of 1 :1.90 to 1 :2.29 suffered less damage. The study gave an indication that elongated nuts were more susceptible to mite attack than round ones. The expansion of feeding scar on coconut husk due to mite injury in relation to growth of nuts was studied in young nuts with different degree of injury in terms of number of triangular lesions. The study indicated that the age of buttons / nuts at which the colonization started w~ the most critical factor in deciding whether the nut will finally become economically damaged (category 4 and 5) or not. Yield loss studies were carried out from the nuts obtained from ten consecutive harvests by categorizing them into five damaged categories and the yield loss was calculated by deducting actual yield from potential yield. No significant variation was observed among the five varieties studied, viz. WeT, Komadan, T X YD, Laccadive Ordinary and Dwarf Orange Yield loss in terms of reduction in weight ofcopra ranged from 11 to 39 percentage and reduction in weight of husk ranged from 12 to 40 percentage. Additional labour requirement for de husking infested nuts was studied in a separate experiment. Study revealed that an extra time of 25.05 to 41.75 minutes was required to dehusk 100 damaged nuts over healthy nuts. Another experiment was conducted to assess the effect of mite injury on the quality and quantity of fibre and coir. Husk obtained from fifty harvested nuts representing the damage categories 1 to 5 were subjected to natural retting practices. Fibre obtained from nuts coming under damage category 4 and 5 resulted in 47-53 per cent reduction in length.
Bioefficacy and safety evaluation of biorational insecticides for the management of sucking pest complex of chilli (capsicum annuum L. )
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2011) Thania Sara Varghese; Thomas Biju Mathew
Characterization and management of insecticide resistance in spodoptera litura (fabricius) (lepidoptera:noctuidae)
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2017) Pattapu Sreelakshmi; Thomas Biju Mathew
Chemical control of thrips stenchaetothrips biformis Bagnall using synthetic pyrethroids in rice nursery
(Kerala Agricultural University, 1988) Reghunath, P; Premila, K S; Thomas Biju Mathew; Nandakumar, C
Degradation of mancozeb residues in pepper and the effect of processing on the removal of residues
(Kerala Agricultural University, 1997) Naseema Beevi, S; Thomas Biju Mathew; Visalakshi, A; Nalina Kumari, T
Dissipation of endosulfan in cowpea
(Kerala Agricultural University, 1997) Naseema Beevi, S; Thomas Biju Mathew; Visalakshi, A
In an experiment to study the dissipation of endosulfan in cowpea pods following application @ 0.07 and 0.14 per cent at flowering and paid formation stage, the residues dissipated below detectable level on 15th day in the lower dose while 0.3 mg kg'1 could be detected in the higher dose. A waiting period of 2.85 and 5.21 days are fixed for the lower and higher dose respectively. Washing of green pods removed 39.78% of the initial deposit while washing followed by cooking removed up to 67.93% in the lower dose.
Dissipation of lindane residues in cowpea
(Kerala Agricultural University, 1999) Naseema Beevi, S; Thomas Biju Mathew; Sudhanna, K; Nalinakumari
Dissipation ok quinalphos and monocrotophos residues in cardamom Capsules
(Kerala Agricultural University, 1998) Thomas Biju Mathew; Visalakshi, A; Naseema Beevi, S; Rajan Asari, P A; Rajagopal, B
The paper describes the results of a field experiment conducted in the Cardamom Research Station, Pampadumpara, to study the dissipation of two insecticides used for controlling cardamom thrips and to fix their waiting periods. The results showed that the residues of quinalphos reached below the tolerance limit of 0.25 ppm within 23 to 24 days in fresh cardamom and within 20 to 21 days in cured cardamom. The corresponding periods for monocrotophos did not differ between fresh and cured cardamom (22 to 23 days) because of the systemic nature of the residues.
Insecticide deposits and residues on paddy with reference to volume of spray fluid applied at different growth stages of the crop
(Department of Entomology, College of Agriculture, Vellayani, 1982) Thomas Biju Mathew; Mohan Das, N
A set of experiments were conducted for assessing the optimum volumes of carbaryl suspension required to spray rice at different growth stages of the crop, using a pneumatic knapsack sprayer and a mist blower. The levels of pesticide deposit formed by spraying the crop at varying levels of pesticide suspension were taken as the indices of bio efficacy and these were also correlated with the leaf area indices of the crop at different growth stages . The level of contamination of the rice eco-system was assessed in terms of pesticide residue in irrigation water of the treated plots. A correlation between different levels of pesticide deposits caused by varying the volumes of the spray fluid was assessed by trials conducted against leaf roller and case worm infesting rice. In the first experiment , the crop was sprayed with 100, 150, 200, 250, 300, 350, 400, 450, 500, 550 and 600 1/ha of 0.2% carbaryl suspension on using a pneumatic knapsack sprayer. Deposit on leaf and stalk of the plants, two hours after spraying , was estimated from the representative samples adopting the chemical assay method of Benson and Finocchiare (1965). The experiment was repeated at four different growth stages of the cropviz. 30, 45, 60 and 75 days after sowing. The results showed that the minimum levels of carbaryl suspension required to cause significantly higher levels of deposit on the leaves were 200, 300, 400 and 500 1/ha for the crop at 30, 45,60 and 75 days after sowing respectively.
Insecticide residues in market samples of vegetables and method of their decontamination
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1997) Santhosh Kumar, S R; Thomas Biju Mathew
Management of pesticide residues in select spices
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2016) Aaruni, P S; Thomas Biju Mathew
The present study entitled “Management of pesticide residues in select spices” was carried out at Department of Agricultural Entomology, College of Agriculture, Vellayani during 2014-16. The main objective of the work was to standardize household techniques to decontaminate pesticide residues in select spices. Investigation was conducted to evaluate the efficacy of different decontamination techniques in removing pesticide residues of organophosphate and synthetic pyrethroid from six select spices viz., peppermint leaves, coriander leaves, red chilli (dry), cumin, fennel and ginger
Management of pests and pesticide residues in vegetable amaranth (Amaranthus tricolor L.)
(Department of Agricultural Entomology, College of Agriculture, 2015) Pooru Muralikrishna; Thomas Biju Mathew
Monitoring and decontamination of pesticide residues in agricultural commodities
(Department of agricultural entomology, College of agriculture, Vellayani, 2013) Pallavi Nair, K; Thomas Biju Mathew
Optimum spray volume requirements for rice at different stages of growth
(Kerala Agricultural University, 1984) Thomas Biju Mathew; Mohan Das, N; Visalakshi, A
Field experiments were conducted for two seasons in 1980-'81 at the College of Agriculture, Vellayani for assessing the optimum volumes of insecticide suspension required for treating rice crop at different growth stages of the crop using a pneumatic knapsack sprayer and mist blower. The results showed that the optimum volumesof 0.2",, carbaryl suspension required to give highest deposits on leaves were 200, 300, 500 and 500 I/ha in the case of a pneumatic knapsack sprayer and 90, 1 20, 1 80 and 1 80 I/ha in the case of a mist blower at 30, 45, 60 and 75 days after sowing respectively. The optimum volumes thus obtained were correlated with the leaf area indices of the respective stages of growth and relevant statistical models were fitted for both the type of sprayers.
Population dynamics and management of erythrina gall wasp quardrastichus erythrinae kim.
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2008) Beena, M P; Thomas Biju Mathew
. Studies were conducted to understand the population dynamics and management of Erythrina Gall Wasp (EGW)Quadrastichus erythrinae. An abstract of the work done and the results are given below. Population dynamics of Q.erythrinae was studied by observing weekly emergence of male and female insects from leaflets and petioles collected from field during the period from January 2006 to June 2007. The results showed that population was high in the months of July 2006, January 2007, April 2007 and June 2007.The present study indicated that the emergence od adult EGW was the highest from petioles. The increase in weight due to EGW infestation and gall production was the highest in the left lateral leaflets. Weekly mean population of EGW emerged during the period of study showed that the total number of male EGW (1096.36) was higher than the female insects emerged (763.13). Weekly mean population of the male and female emerged from the leaflets and petioles was correlated with weather parameters viz. maximum and minimum temperature. Maximum and minimum relative humidity and rainfall prevailed during the time of sampling, previous one week, previous 14 days,week 21 days before and week 28 days before. The results showed significant and positive correlation between population of male EGW and the minimum temperature, while no correlation existed between female population and other parameters studied. Comparison of biometric observation of uninfested and infested plant parts indicated that the weight of the leaflets and petioles increased significantly due to an increase in biomass. Due galling by EGW, the girth of the petioles was shortened to about one third of uninfested petioles. The emergence of EGW was maximum from petioled scored in the damage category ‘9’. Among the four groups of Erythrina stricta Roxb..stricta trees studied, based on the height of the trees, no group turned out to withstand the damage by EGW. Thiomethoxam, imidacloprid, carbaryl and acephate proved superior among the chemical tested insecticides tried against female and male EGW in the laboratory . Neem oil 2 per cent and neem oil-garlic 2 per cent proved superior among the botanical insecticides tried for protecting the newly formed side shoots. Among the systemic /translaminar insecticides applied on the galled plant parts, triazophos 0.05 per cent and imidacloprid .002 per cent were significantly superior in controlling the EGW emergence. In the field experiment conducted to evaluate insecticide-fungicide combination for EGW infestation and protection of the new side shoots, carbaryl 0.1 per cent and combination of imidacloprid 0.002 per cent and carbendazim 0.2 per cent effectively protected the side shoots up to 8 weeks after spraying. Residue analysis of dry pepper berries collected from pepper vines trailed, on the insecticide sprayed crythrina standards showed that residues at the time of harvest from trees sprayed with acephate 0.05 per cent dimethoate 0.05 per cent were below detectable limit. Where as the residues in pepper collected from lamda cyhalothrin 0.05 per cent and triazophos 0.05 percent treated trees was 1.38 ppm and 1.16ppm respectively. An overall analysis and interpretation of the data on population in relation to phenology to E.stricta foliar growth showed that there existed a six monthly cycle of damage by gall wasp resulting in complete defoliation of the trees by about six month followed by the next cycle of regrowth and re infestation .
Resurgens of brown planthopper Nilaparvata lugens (Stal) on rice treated with various insecticides
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1989) Thomas Biju Mathew; Mohan das, N