Browsing by Author "Jim Thomas"

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Biodiversity of the termite (isoptera) fauna in crop environments
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2011) Jyothy Narayanan; Jim Thomas
Bioecology and management of mulberry leaf roller diaphania pulverulentalis(hampson)(lepidoptera: pyralidae)
(Department of Entomology, College of Horticulture, Vellanikkara, 2005) Ramalakshmaiah, C; Jim Thomas
Investigations were carried out on the “ Bioecology and management of mulberry leaf roller, Diaphania pulverulentalis (Hampson) (Pyralidae : Lepidoptera ) simultaneously in the department of Entomology, College of Horticulture, Vellanikkara and in Kottat village of Chalakkudy area of Thrissur district during April 2004 to March 2005. The objectives of the study were to find out the biological aspects of leaf roller namely, fecundity, duration of each life stage, number of larval instars as well as bioecological aspects like identification of collateral hosts, natural enemy complex and the correlation of weather parameters on leaf roller incidence and also the pest management issues like population counts at before and after treatments and per cent leaf damage per harvestable shoot. Relative humidity at morning and evening was negatively correlated to larval population and shoot damage in both the open and intercropped system of cultivation. Photo phase showed significant positive relation on larval population in open and intercropped system of cultivation. Precipitation showed significant negative correlation on the larval population in the intercropping system of cultivation. The number of larvae per plant and shoot damage varied from month to month on mulberry. The number of larvae per plant was 1.56 in June, ascended to 5.37 by December. It came down to 1.47 in the following March in open system of cultivation. The number of larvae per plant was 1.94 in June, ascended to 7.26 by December. It came down to 2.25 per plant by the following March in intercropping system of cultivation. The shoot damage increased from 37.13 (June) to 72.83 (December). It came down to 36.96 by the following March in inter cropped system of cultivation. The shoot damage ascended from 28.5 (June ) to 75.83 (December). It came down to 45.46 per cent by the following March in open system of cultivation. The biological studies on the leaf roller revealed that the fecundity was 157 eggs with a range of 117 to 211eggs per female. The biological studies in peak season (October to December) recorded the egg period as 4 days, individual larval periods as 1.714, 2.5, 3.214, 3.28 and 3.92 days for the I, II, III, IV and V instar larvae respectively. The pupal period was 7.95 days, the adult male longevity was 8.15 days and the adult female longevity as 10.225 days. The biology in lean season (February – March) recorded the incubation period of egg as 3.3 days, individual larval periods as 1.516, 2.009, 2.471, 2.52 and 3.5 days for I, II, III, IV and V instar larvae respectively. The pupal period was 7.95 days. The adult male longevity was 8.15 days and female longevity was 10.225 days. The total development period varied from 23.25 days during the lean season to 28.01 days during peak season. There are many natural enemies affecting different life stages of leaf roller. Bracon hebetor, Chelonus sp. and a mermithid nematode parasitizes the larvae. Tetrastichus howardi attacks the pupae. The spiders Tetragnatha sp. and Philodromus sp. predated on the leaf roller. The experiments on the collateral hosts showed that the existing weed flora in and around mulberry garden, were not the hosts of leaf roller. The leaf roller did not feed on the leaves of related plant species to mulberry like Jack, Hibiscus and Cucurbits. The evaluation of different management practices against leaf roller showed that the integration of the practices like clipping of top leaves, inert soil dust application and the application of dichlorvos 0.1 per cent as the best treatment than the individual treatments concerned for the reduction in larval population and shoot damage. The management practices were not pronounced in summer season (February to April). The results were almost similar in open, intercropped system of cultivation. The chemical treatment with dichlorvos at 0.1 per cent afforded greater reduction in pupal population than other treatments. Dichlorvos exhibited greater ovicidal action by recording the hatchability of 43.33 and 16.67 per cent at 0.1 and 0.2 per cent concentrations respectively. The probit analysis if dose mortality response of dichlorvos at different concentrations showed that 1.73 per cent as the LC50 value. The time mortality response of dichlorvos at 0.1 per cent showed that 17.12 hours as the LT 50 value. The experiments on food consumption and utilization indices recorded that the approximate digestibility (AD), efficiency of conversion of ingested food into body tissue (ECI) and the efficiency of digested fool into body matter (ECD) were 53.3, 37.34 and 25.23 per cent respectively.
Biology of banana Pseudostem weevil, Odoiporus longicollis Oliv. (Coleoptera:Cucur lionidae)
(Department of Agricultural Entomology , College of Horticulture, Vellanikkara, 1992) Jayasree, T V; Jim Thomas
The Banana Pseudostem Weevil, Odoiporus longicollis Oliv., considered as one of the destructive pests in North and North East India is very recently found to be causing wide spread damage in the banana growing tracts of Ernakulam and Trissur districts of Kerala. The present investigation was envisaged to properly understand about the nature of attack, symptomatology, bio-ecology, morphology and the preliminary control measures of the pest species under both field and laboratory conditions. The insect pest is associated with the banana plants throughout the year in Kerala in overlapping generations with its maximum population during both the monsoon periods. This insect has a very congenial condition in Kerala for their survival and multiplication in general and its hot spots of infestation were identified to be around Alwaye-Perumbavoor regions in Ernakulam District. Of late the infestation was observed to be spreading to other Districts also. The banana varieties more susceptible to its attack were found to be Nendran, Palayankodan and Poovan while; Njalipoovan was relatively tolerant. The adult weevils preferred to oviposit on the outersheaths on 3-4 months old plants coinciding with the peduncle formation at a height ranging from 3-4 meter above ground level. The weevil grubs bored into the pseudostem portions and cause extensive tunnelling and riddling leading to weakening of growth, delayed flower emergence, smalling of bunches and finally breakage and lodging leading to partial or complete loss of the crop. The biology, morphology and biomorphometrics of the insect under laboratory conditions were worked out in detail. Because of the peculiar nature of the plant and the fruit produce, as well as the type and nature of the pest species, chemical means of control by spray impregnation of natural products, injection of systemic insecticide through root, rhizome and pseudostem portions and padding technique with fumigant insecticide gave inconclusive results. Bio-control with the parasitic nematode, DD-136, Steinernema sp. eventhough showed good in vitro mortality under lab conditions, it was not successful under field condition. From the above studies, it was found that, to contain the pseudostem weevil infestation effectively, an integrated pest management strategy with special emphasis on cultural techniques on a community basis should be evolved and practiced.
Evaluation of potential botanical pesticides gainst tobacco cutworm
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2002) Suresh, S; Jim Thomas
Evaluation of the active principles of the rhizome extracts of L. for the management of melon fly
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1996) Shakunthala Nair; Jim Thomas
The melon fruit fly Bactrocera cucurbitae : Diptera) is one of the highly destructive pest species attacking cucurbits. The larvae hatching from eggs deposited within the fruits, tunnel and feed on the internal contents. As a result of this, the fruits are severely damaged, rot and fall to the ground, where pupation takes place. As the recommended management practices against the melon fly are still proving inadequate, there is a need to devise newer and safer means to solve this problem. The latest trend in pest control is the use of natural products derived from plant and animal sources. Among the various plants tested, Acorus calamus L., is gaining importance owing to its insecticidal and insectistatic properties. The present study was carried out at the Department of Agricultural Entomology, College of Horticulture, Vellanikkara, during 1993-94, with the objective of evaluating the extracts of A. calamus for the management of the melon fly, B. cucurbitae. The experiments were conducted in order to assess effects like repellency, feeding deterrency, oviposition deterrency, ovicidal action, topical contact toxicity to larvae, pupae and adults and chemosterilant action. Water and organic solvents were used to prepare the A. calamus extracts. Among the organic solvents tested, methanol was selected, owing it’s the better effect. Melon flies (B. cucurbitae ) reared in the laboratory were used for all the tests, and the following results were obtained. The repellent and feeding deterrent effects of the extracts was proved by reduced alightment of flies on the treated substrates. The aqueous extracts were effective at 5%, while the methanol extract at 0.1% was highly repellent., proving the superiority of the methanol extract. In the oviposition deterrency test, the number of ovipunctures as well as the fecundity realization, showed a decreasing trend with the increase in concentration of the extracts. The methanol extract was found to be superior to the aqueous extract in deterring oviposition also, as it was effective at 0.25 %, while in case of the aqueous extract a significant effect was produced only at a concentration of 5 %. Toxicity tests were conducted on all life stages of the melon fly. The eggs were not affected by the aqueous extract upto 10%, but there was 100% egg mortality (inhibition of hatching) when 0.1% methanol extract was used. The LC50 of methanol extracts to the eggs was found to be 0.03%. Both the aqueous extract and the methanol extract were found to be ineffective in causing mortality to larvae and pupae, upto 10%. In the case of adult flies, there was no mortality upto 10% of the aqueous extract by topical application or residue film technique. Topical application with methanol extract could not be followed, as the solvent itself caused 100% mortality. However by residual film application, it was possible to obtain a range of mortalities, and the LC50 of methanol extract to adult flies was found to be 0.07%. The methanol extracts were found to inhibit mating completely, in adult flies fed with the extracts at 0.1 to 0.01 % from the day of emergence. The average survival period of these flies was also significantly lower, because of which, fecundity realization was not see. The sizes of reproductive organs in the treated flies were found to be considerably reduced, probably due to regression or oosorption in the ovaries, or general atrophy of the organs, caused by the feeding of the extracts. This damage to the reproductive organs might have caused a hormonal imbalance, which resulted in the mating being inhibited
On the chemical control of 'udbatta' disease of rice incited by Ephelis Oryzae Sydow
(Kerala Agricultural University, 1981) Indrasenan, G; Jim Thomas; Sreekumar, V; Mammen, M K
Population dynamics and biorational management of melon fly, (bactrocera cucurbitae (coquillet)) in bitter gourd (momordica charantia L.)
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2006) Rameash, K; Jim Thomas
Resistance of some rice varieties to 'udbatta' disease in Wynad
(Kerala Agricultural University, 1982) Indrasenan, G; Sreekumar, V; Jim Thomas; Mammen, M K
Saccolepis interrupta, an alternate host for the rice leaf folder, Cnaphalocrocis medinalis Guen. (Pyralidae: Lepidoptera)
(Kerala Agricultural University, 1982) Thomas, M J; Jim Thomas; Nandakumar, C
Species diversity of the orchard fruit fly complex and the biorational management of the mango fruit fly, bactrocera dorsalis (hendel) (diptera: tephritidae)
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2008) Thiyagarajan, P; Jim Thomas
Trapping of red palm weevil in coconut gardens
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1999) Ramesha, B; Jim Thomas
Experiments were undertaken in the Department of Agricultural Entomology, College of Horticulture, Vellanik:kara during 1997-1998 to evaluate the efficacy of the male aggregation pheromone Ferrolure (4-Methyl-5 nonanol) in mass trapping the redpalm weevil of coconut Rhynchophorus ferrugineus F (Oliv.) in the coconut plantations of Thrissur district. A survey was conducted in Thrissur district in three regions representing three geographical zones viz., coconut plantations in coastal zones, midland regions and upland conditions with the respective red palm weevil damage incidence of 5.33 per cent, 7.66 per cent and five per cent with an average incidence of six per cent. A convenient and suitable bucket trap was designed and fabricated for the mass trapping of the adult weevils from the field and for further laboratory experiments. Out of the different food attractants tried pineapple waste and toddy gave increased trapping efficiency of the weevils with the pheromone sachet. The food attractants was necessarily to be renewed afresh once in three to four days interval so as to keep the trap effective. At this rate of change of the food attractant a single pheromone sachet was found to be actively performing to trap the weevils for a period of 10-12 weeks. The Ferrolure tried was found to be predominently a male aggregation pheromone but with reasonable attraction to female weevils as well. The best exposure height of the pheromone trap was at a height range of one to two meters from the ground level within the coconut plantations to offer maximum trapping efficiency.' An DV light source at night was found to supplement the weevil trapping along with the pheromone trap giving 2.85 times more catch. In conclusion the experimental observation proves the overall efficacy of the ferrolure with pineapple as a food attractant coupled with the bucket trapping device. If the traps are installed at one to two meter above the ground level in the plantation, this gives good performance in trapping the male and female adult weevils for an effective period of nine to 10 weeks. A large number of weevils could be trapped which will probably reduce the damage of this weevil below the existing six per cent of damage. Food substance should be changed periodically at an interval offour days to retain the efficiency.