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Open Access
Morphological variations of root knot nematode in vegetables and banana
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2017) Chinchu, P Babu; KAU; Narayana, R
The study entitled “Morphological variations of root knot nematode in vegetables and banana” was conducted at College of Agriculture, Vellayani during 2015-17 with the objective to study the morphological and morphometric variations of root-knot nematode in brinjal, okra, tomato and banana in Kerala. Morphological and morphometrical studies of females, perineal pattern, second stage juveniles and males of root knot nematodes collected from Dhanuvachapuram, Kattakada and Vellayani of Thiruvananthapuram district; Balagram, Pampadumpara and Thovalappady of Idukki district; Chazhoor, Thalikulam and Thaniyam of Thrissur district infecting brinjal, okra, tomato and banana were done and the data was analysed to identify the species. M.incognita (Kofoid & White, 1919) Chitwood, 1949, M. javanica (Treub, 1885) Chitwood, 1949, M. arenaria (Neal, 1889) Chitwood, 1949 and M. chitwoodi Golden, O'Bannon, Santo & Finley 1980 were identified from brinjal, okra, tomato and banana in Thiruvananthapuram, Idukki and Thrissur districts of Kerala. The study indicated M. incognita as the major species of root knot nematode in Thiruvananthapuram district (91.66%) with highest percentage of occurrence in brinjal and tomato (27.77). In Idukki district, the major species of root knot nematode was M. javanica (66.66%) with highest percentage of occurrence from brinjal and banana (33.33). In Thrissur district, M. arenaria was found to be the major species (66.66%) with highest percentage of occurrence in okra (37.5). M. incognita was found to be the major species in brinjal (55.55%), okra (44.44%), tomato (55.55%) and banana (44.44%) in Thiruvananthapuram, Idukki and Thrissur districts. The extent of parthenogenesis of root knot nematode was found to be very high (97.22%) in these populations. Intraspecific morphological variations were observed within M. incognita, M. javanica and M. arenaria with respect to shape of females, length and position of neck, perineal pattern morphology, tail characters including rectum dilation. Interpopulation comparison of mature females, perineal pattern and second stage juveniles of M. incognita showed that the characters length, width, neck length, stylet length, LMB, WMB and ratio a of females, LVS, AVS, ATT and IPD of perineal pattern and body length, stylet length, H-MB, ABW, tail length, ratio c and c’ were recorded as stable characters. Interpopulation comparison of mature females, perineal pattern and second stage juveniles of M. javanica showed that all the characters of females, perineal pattern and second stage juveniles were stable characters and in M. arenaria, the characters like body length, width, neck length, stylet length, LMB and WMB of females, LVS, AVS, ATT and IPD of perineal pattern and length, stylet length, H-MB, ABW and tail length were recorded as stable characters and found useful in characterizing species. Intraspecific morphological and morphometric variations of M. incognita, M. javanica, M. arenaria were recorded from four host plants in three districts in Kerala. M. arenaria and M. javanica showed high variability between the populations compared to M. incognita in Kerala. The study indicated that M. incognita, M. javanica and M. arenaria were the major species infesting vegetables and banana in Kerala. Among the sampled populations, M. hapla was not identified which shows that M. hapla is not common in Kerala conditions. The study recorded the first report of species having morphological and morphometrical characters similar to M. chitwoodi from okra in Thiruvananthapuram which opens way to molecular studies in future.
Open Access
Biotic agents for the management of American serpentine leaf miner, Liriomyza trifolii(Burgess) (Diptera:Agromyzidae)
(Department of agricultural entomology, College of horticulture, Vellanikkara, 2014) Jyothi Sara, Jacob; KAU; Maicykutty P, Mathew
A study on “Biotic agents for the management of American serpentine leaf miner, Liriomyza trifolii (Burgess) (Diptera: Agromyzidae)” was carried out at the Department of Agricultural Entomology, College of Horticulture, K.A.U., Vellanikkara during 2011-2013 with the objectives of collection and identification of indigenous natural enemies and to assess the pathogenicity of the entomopathogens to explore the feasibility of utilizing them for its management. Surveys were conducted in the vegetable fields for the collection and identification of natural enemies associated with L. trifolii in three districts, namely, Thrissur, Ernakulam and Kottayam from January to March, 2011. The surveys revealed the occurrence of nine species of hymenopteran parasitoids. The per cent parasitism varied from 10.96 to 58.99 per cent among the crops surveyed. Three species of eulophids, namely, Cirrospilus acadius Narendran, C. brevicorpus Shafee & Rizvi and Aprostocetus sp. as well as the braconid, Toxares sp. are new reports for India. Among the parasitoids, Closterocerus spp. were the dominant group followed by Chrysonotomyia sp. All parasitoids were solitary, larval endoparasitoids except Toxares sp. which was larval-pupal in nature. One species each of small ants (Formicidae) and a dipteran fly (Dolichopodidae) were observed as predators on L. trifolii. In the study, no entomopathogens were observed from L. trifolii. Considering the level of pesticide consumption in vegetable crops that undermine the potential of insect parasitoids and also that no entomopathogens could be observed during the survey, it was decided to evaluate entomopathogenic nematodes (EPNs) as biocontrol agents against L. trifolii. Isolation of EPNs from 72 soil samples from Thrissur, Ernakulam and Kottayam districts yielded four isolates of Steinernema carpocapsae. Bioefficacy studies carried out on these four isolates along with Steinernema bicornutum and Heterorhabditis indica showed that S. carpocapsae Isolate - 1 had the lowest LC 50 , LC 90 and LT values indicating their higher effectiveness against the maggots of the pest. 50 Pot culture study conducted to compare the potential of S. carpocapsae Isolate - 1 with other treatments showed that azadirachtin 1 EC at 0.005% was the most effective causing 84.51 per cent mortality to the maggots of L. trifolii. This was followed by the foliar application of H. indica at 32 infective juveniles (IJs)/ maggot which caused 18.98 per cent mortality. Application of Beauveria bassiana at 1×10 7 spores/ ml was not effective. In the field evaluation, fipronil 5 SC at 0.002% was found to be the most effective treatment for controlling L. trifolii followed by azadirachtin 1 EC at 0.005%. Compatibility of the IJs of the S. carpocapsae Isolate - 1, S. bicornutum and H. indica was studied with ten commonly used insecticides in the laboratory by direct exposure method. Chlorantraniliprole 18.5 SC at 0.005% was found to be the most compatible insecticide with S. carpocapsae isolate - 1 causing only 0.17 per cent mortality to IJs at 72 hours after treatment (HAT). Quinalphos 25 EC at 0.05% and chlorpyriphos20 EC at 0.05% were highly incompatible, causing 96.17 and 92.87 per cent mortality of the nematodes. Dimethoate 30 EC at 0.04% was the most compatible insecticide with S. bicornutum and caused only 0.60 per cent mortality at 72 HAT and was followed by azadirachtin 1 EC at 0.005% with 0.78 per cent mortality to the IJs. Quinalphos 25 EC at 0.05% caused 99.93 per cent mortality at 72 HAT. Heterorhabditis indica was compatible with all insecticides except quinalphos 25 EC at 0.05% which was moderately toxic resulting in 39.6 per cent mortality. The virulence, pathogenicity and multiplication of the survived IJs were not affected by the insecticide treatments. Parasitoids and EPNs were observed as potential candidates for the management of L. trifolii. Hence future studies on the bio-ecology and mass production of dominant parasitoids and standardization of methods to improve the efficacy of EPNs are suggested for the successful control of L. trifolii in polyhouses as well as in the field.
Open Access
Major spiders in vegetable ecosystem and their predatory potential
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2005) Manu Mani, P; KAU; Hebsi Bai
Spider faunistic survey conducted in okra, brinjal, cowpea, bittergourd and amaranthus fields in Kalliyoor panchayat of Thiruvananthapuram district during the summer of 2004, revealed the prevalence of high density and diversity of spiders in the vegetable ecosystem. Hunting spiders were dominant in all the vegetable plots. Thirty species of spiders distributed in nine families were recorded with the number of species in each vegetable field ranging from 10 to17. Among the thirty species, 16 species were commonly seen in the different vegetable fields while 14 species were seen exclusively associated with a particular vegetable. Araneidae with ten species was the most represented family in the vegetable fields followed by Oxyopidae and Salticidae. The other families observed were Miturgidae, Thomisidae, Tetragnathidae, Corinnidae, Lycosidae and Clubionidae. Most of the spiders appeared during the vegetative and flowering stages of the crop. Few spiders were recorded in the early stage of the crops. Four spiders viz., O. javanus, C. danieli, N. mukerjei and T. mandibulata were dominant in all the vegetable plots among which O. javanus and C. danieli predominated. Studies on the seasonal influence showed no significant difference in the abundance of the spiders during summer and rainy seasons. Rather, the growth stages of the crops significantly influenced the build up of the spider population with higher population being observed during the reproductive phase. In general, the spiders preferred soft bodied insects like the hemipterans, lepidopterans, dipterans and coleopterans (eggs and grubs) for predation. While the spiders did not show any significant preference for the different hemipteran prey in a mixed diet, significant difference was shown for the different lepidopteran pests. O. javanus had the maximum preference for the lepidopteran pests Chemical insecticides were more toxic to the spiders than botanicals when tested at their recommended doses. Among the chemical insecticides, dimethoate 0.05 per cent, carbaryl 0.2 per cent and malathion 0.1 per cent were highly toxic. Even at different doses the insecticides were toxic to the spiders. Quinalphos 0.05 per cent and imidacloprid were less toxic. Between the two methods of application, topical application of insecticides was more detrimental to the spiders than release on treated plants. Among the spiders, T. mandibulata was more susceptible to the insecticides followed by C. danieli. O. javanus and N. mukerjei were less sensitive. While the fungal pathogens, M. anisopliae, P. lilacinus and Bt were safe to the spiders. F. pallidoroseum, Fusarium sp. and B. bassiana were pathogenic. Based on the results of the study, conservation of the spiders characteristic of the vegetable ecosystem would be a practical and ecologically and economically viable approach for pest suppression in vegetables. When there is a spurt in pest ravage, the protection afforded by the predator could be supplemented with judicious use of “spider friendly” insecticides.
Open Access
Pathogenicity of indigenous entomopathogenic fungi against select lepidopteran pests
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2016) Praveena, A; KAU; Sudharma, K
The present study entitled “Pathogenicity of indigenous entomopathogenic fungi against select lepidopteran pests” was carried out in the Department of Agricultural Entomology, College of Agriculture, Vellayani during 2014-2016 with the objective to identify indigenous entomopathogenic fungi and evaluate their pathogenicity to lepidopteran pests of banana and vegetables. Survey was conducted in five agroecological zones of Thiruvananthapuram district at bimonthly intervals during 2015-16, for the isolation of fungi. Fungi from mycosed cadavers and 900 soil samples, collected from cultivated and uncultivated fields were isolated. Of the ten isolates of fungi selected from the 115 fungal isolates obtained, three were from mycosed cadavers which consisted of two isolates of Beauveria bassiana (Balsamo) Vuillemin (SP2 and SP4) and one isolate of Fusarium oxysporum Schlecht (SP1). Of the seven isolates from soil, one isolate was Fusarium solani (Mart.) Sacc. (SP6), five were isolates of Metarhizium anisopliae Metschnikoff (Sorokin) and one isolate was Purpureocillium lilacinum Thorn (Samson). Four isolates of M. anisopliae were trapped using larvae of Galleria melonella L. and one was trapped using grubs of Odoiporous longicollis Olivier. The isolate, S10 was obtained through soil plate method, with selective media. Symptoms of fungal infection varied, which was mainly reflected in the mycelial colour and growth of the isolates. Morphological and cultural characteristics also varied among the fungal isolates. Further, molecular characterization of the fungi was done through ITS sequencing. GenBank accession numbers for all the ten isolates were obtained on submission of nucleotide sequence in National Center for Biotechnology Information (NCBI). Among the various indigenous isolates, highest spore count was recorded in the M. anisopliae isolate, SP11 (28.01 x 107 spores mL-1) at 14 days after inoculation. The pathogenicity of the ten indigenous isolates and two isolates from National Bureau of Agricultural Insect Resources (NBAIR) were evaluated against five lepidopteran insects infesting banana and vegetables at different concentrations. The isolate M. anisopliae (SP8) recorded the highest mortality of 83.33 to 100 per cent and 64.44 to 95.83 per cent against the second instar larvae of Diaphania indica Saunders and first instar larvae of Leucinodes orbonalis Guenee at 107 to 109 spores mL-1 at seven days and five days after treatment respectively. The isolates SP11 and Ma4 of M. anisopliae that caused mortality of 83.33 to 100 per cent and 63.33 to 100 per cent were the most effective isolates against second instar larvae of Sylepta derogata Fabricius and Hymenia recurvalis Fabricius respectively. All the isolates except M. anisopliae (SP11) and B. bassiana (Bb5a) were non pathogenic to the larvae of Spodoptera litura Fabricius. The colour of the mycelial growth varied with isolates. A pot culture experiment was conducted in the Instructional Farm, Vellayani during April to June 2016, for the evaluation of seven indigenous isolates and two NBAIR isolates against leaf webbers in amaranthus, variety Arun. The lowest number of plants infested by webbers, webbings plant-1 and larvae web-1 at 14 days after treatment and the highest yield was recorded in the isolate M. anisopliae (SP11) @ 108 spores mL-1 and it was followed by M. anisopliae Ma4 and SP8 . To conclude, ten indigenous isolates of entomopathogenic fungi were collected from mycosed cadavers and soil and were identified as B. bassiana (SP2, SP4), F. oxysporum (SP1), F. solani (SP6), M. anisopliae (SP7, SP8, SP9, SP11 and SP13) and P. lilacinum (S10) through morphological, cultural characters and molecular characterization. Pathogenicity test to five lepidopteran pests showed that M. anisopliae (SP7, SP8, SP9, SP11, SP13) and NBAIR isolates of B. bassiana (Bb5a) and M. anisopliae (Ma4) were pathogenic to D. indica, H. recurvalis, L. orbonalis and S. derogata. Results of pot culture experiment showed that the indigenous isolates M. anisopliae (SP11) and (SP8) and NBAIR isolate M. anisopliae (Ma4) can be exploited for the management of leaf webbers in amaranthus.
Open Access
Major spiders in vegetable ecosystem and their predatory potential
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2005) Manu Mani, P; KAU; Hebsi, Bai
Spider faunistic survey conducted in okra, brinjal, cowpea, bittergourd and amaranthus fields in Kalliyoor panchayat of Thiruvananthapuram district during the summer of 2004, revealed the prevalence of high density and diversity of spiders in the vegetable ecosystem. Hunting spiders were dominant in all the vegetable plots. Thirty species of spiders distributed in nine families were recorded with the number of species in each vegetable field ranging from 10 to17. Among the thirty species, 16 species were commonly seen in the different vegetable fields while 14 species were seen exclusively associated with a particular vegetable. Araneidae with ten species was the most represented family in the vegetable fields followed by Oxyopidae and Salticidae. The other families observed were Miturgidae, Thomisidae, Tetragnathidae, Corinnidae, Lycosidae and Clubionidae. Most of the spiders appeared during the vegetative and flowering stages of the crop. Few spiders were recorded in the early stage of the crops. Four spiders viz., O. javanus, C. danieli, N. mukerjei and T. mandibulata were dominant in all the vegetable plots among which O. javanus and C. danieli predominated. Studies on the seasonal influence showed no significant difference in the abundance of the spiders during summer and rainy seasons. Rather, the growth stages of the crops significantly influenced the build up of the spider population with higher population being observed during the reproductive phase. In general, the spiders preferred soft bodied insects like the hemipterans, lepidopterans, dipterans and coleopterans (eggs and grubs) for predation. While the spiders did not show any significant preference for the different hemipteran prey in a mixed diet, significant difference was shown for the different lepidopteran pests. O. javanus had the maximum preference for the lepidopteran pests Chemical insecticides were more toxic to the spiders than botanicals when tested at their recommended doses. Among the chemical insecticides, dimethoate 0.05 per cent, carbaryl 0.2 per cent and malathion 0.1 per cent were highly toxic. Even at different doses the insecticides were toxic to the spiders. Quinalphos 0.05 per cent and imidacloprid were less toxic. Between the two methods of application, topical application of insecticides was more detrimental to the spiders than release on treated plants. Among the spiders, T. mandibulata was more susceptible to the insecticides followed by C. danieli. O. javanus and N. mukerjei were less sensitive. While the fungal pathogens, M. anisopliae, P. lilacinus and Bt were safe to the spiders. F. pallidoroseum, Fusarium sp. and B. bassiana were pathogenic. Based on the results of the study, conservation of the spiders characteristic of the vegetable ecosystem would be a practical and ecologically and economically viable approach for pest suppression in vegetables. When there is a spurt in pest ravage, the protection afforded by the predator could be supplemented with judicious use of “spider friendly” insecticides.
Open Access
Bionomics and ecological management of coconut eriophyid mite
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2001) Vidya, CV; KAU; Ranjith, A M
The bionomics and ecological management of coconut eriophyid mite, Aceria guerreronis (Keifer) was studied under the Department of Entomology, College of Horticulture, Vellanikkara. The preference of mites to bunches of different maturity, symptoms of damage, population dynamics, relationship of mite population with weather factors and the distribution pattern of mites based on plant morphology were considered for the study. Some ecological management practices were also tried along with this. The experiment was laid out as completely randomised design. Mites were absent in male and female flowers and also on buttons of first bunch. Initiation of infestation starts from buttons of second bunch and population increases further and maximum population is noticed in buttons of third and fourth bunches and thereafter it decreases. This is because after fourth bunch, the meristematic tissue becomes necrotic due to feeding of mites and hence mites cannot feed further easily. Traces of population were noticed even on nuts of ninth bunch. Predatory mites were also seen along with eriophyid mites even though they are very negligible. Symptoms of damage were seen outside from second bunch onwards. The symptom initially appears as whitish streak or triangular patch and it increases further in length and breadth and becomes brownish and later necrotic. In some cases, cracks, cuts and gummosis can be seen on the husk. The relationship between surface damage and mite population was worked out. Maximum mite population was noticed when the surface damage was 1-3 and 3-6 cm2 before and after the removal of perianth respectively and the percentage of damage was 1-3 per cent. Mite population was found to vary with different weather parameters. Minimum temperature of current week, current, -1 and -2 fortnights and maximum temperature of -2 fortnight were positively related with mite population. Morning humidity is also positively related with mite population. Mite population was negatively related with wind speed of zero current, current, -I and -2 fortnights. There is no direct relation between mite population and rainfall, number of rainy days, evening humidity and sunshine hours. Mite infestation was irrespective of the height of the palm, crown shape and perianth arrangement. The intensity of infestation varies between each inner tepals. Maximum infestation was under fourth tepal followed by fifth and sixth tepa\. The preference of mites to different portions under each tepal also varies with maximum entry through the 'outer edge' of fourth tepal followed by 'outer edge' of fifth tepal, 'middle' portion of sixth tepal, 'middle' portion of fifth and fourth tepal, and 'inner edge' of sixth and fifth tepa\. Infestation was found to be less in round shaped nuts compared to oval and oblong nuts. Maximum incidence was in green coloured nuts followed by greenish yellow and orange coloured nuts. There was no reduction in mite damage by different water regimes (rainfed, channel and drip irrigated) fertilizer regimes (0.34:0.17:0.68 kg NPK/palm, 0.5:0.32:1.2 kg NPKlpalm and 0.25:0.32:1.2 kg NPKlpalm) micronutrients (MgS04, ZnS04, MnS04, Borax and Micronutrient mixture) and crown cleaning (once and twice in an year).
Open Access
Bioefficacy of Quisqualis indica L. and Samadera indica gaetrn against tobacco caterpillar, spodoptera litura fabricius (LEPIDOPTERA: NOCTUIDAE) in poly house condition
(Depatment of Agricultural Entomology, College of Agriculture, Vellayani, 2016) Anusree, S S; KAU; Nisha, M S
An investigation entitled “Bioefficacy of Quisqualis indica L. and Samadera indica Gaetrn. against tobacco caterpillar, Spodoptera litura Fabricius (Lepidoptera: Noctuidae) in polyhouse condition” was conducted at College of Agriculture, Vellayani during 2014-16. The main objectives were to evaluate the effect of aqueous and solvent extracts of Q. indica flower and S. indica leaf on behavioural and physiological changes of S. litura and to test the potential of the selected plant extracts against S. litura infesting cowpea under polyhouse condition. Aqueous and solvent extracts of Q. indica flower and S. indica leaf were tested for antifeedant and insecticidal action against larvae of S. litura under in vitro condition. Antifeedant activity of aqueous extracts of Q. indica flower and S. indica leaf at 5, 10 and 15 % concentrations showed percentage leaf protection ranging from 0 to 10.98. Solvent extracts viz., ethyl acetate and methanol extracts of Q. indica flower and S. indica leaf at 1.25, 2.5 and 5 % concentrations showed percentage leaf protection ranging from 13.23 to 45.62. Maximum antifeedant activity (45.62 %) was exhibited by methanol extract 5 % of S. indica leaf at 24 hours after treatment. The extracts obtained through cold and soxhlet extraction methods were compared for the antifeedant activity against S. litura. Cold extraction was significantly superior to soxhlet extraction giving leaf protection of 12.72 % for Q. indica flower extract and 21.12 % for S. indica leaf extract. Decreasing trend of antifeedant action with increased exposure time was noticed for both the plants. The insecticidal effect of the extracts was assessed through two application methods, spraying and leaf dip method. Spraying method was effective for both the plant extracts, while leaf dip method was effective for S. indica leaf extract only. Cold extract of Q. indica flower 5% with methanol was found to be highly toxic to S. litura larvae with maximum percentage mortality of 93.51 in spraying method. Methanol cold extract 5 % of S. indica leaf exhibited 73.55 % mortality in spraying method and 41.67 % mortality in leaf dip method. Cold extraction method was found to be significantly superior for both Q. indica flower (70.05 %) and S. indica leaf (50.37 %) than soxhlet extraction in spraying method. The insecticidal effect assessed through dry film method showed that cold extracts of Q. indica flower and S. indica leaf exhibited larval mortality of 36.05 % and 13.52 % respectively. An increase in mortality with increased exposure was observed for both plant extracts. Effect on adult emergence of S. litura (deformation and mortality of larvae, pupae and adults, time taken for pupation, pupal duration, pupal weight and adult longevity) showed that the aqueous and solvent extracts of both plants did not have any influence on larvae, pupae and adults. Cold extracts of Q. indica flower and S. indica leaf exhibited significant larval and pupal mortality ranging from 8.33 to 30 % and 11.67 to 31.98 % respectively. Effect on fecundity and egg hatchability revealed that the plant extracts did not possess significant effect on number of eggs laid and number of eggs hatched. To assess the potential of the selected treatments, methanol extract (5 %) of Q. indica flower and S. indica leaf, a pot culture experiment was done under polyhouse condition on cowpea. It was compared with quinalphos 25 EC 0.05 % and biocontrol agent, Beauveria bassiana (Bb 5) 20 g/L. The percentage leaf area damage in 5 % methanol extract of Q. indica flower and S. indica leaf was 48.56 and 63.64 respectively. Maximum larval mortality of 84.07% was observed in quinalphos 0.05 % followed by 5 % methanol extract of Q. indica flower (61.45 %) and S. indica leaf (40.35 %). . From the above study it is concluded that methanol cold extract (5 %) of flowers of Q. indica and leaves of S. indica have insecticidal action against earlier instars of S. litura. These plants can be exploited for formulating potential green pesticides.
Open Access
Taxonomy of rhynchophorinae (COLEOPTERA: DRYOPHTHORIDAE) of Kerala
(Department of Agricultural Entomology, College of Agriculture, Padannakkad, 2016) Arun Kumar, Singh; KAU; Ramesha, B
The taxonomy of weevils under the subfamily Rhynchophorinae (Coleoptera: Dryophthoridae) was carried at the College of Agriculture Padannakkad, Kasargod, Kerala and seven different agro ecological zones of Kerala during 2014-2016. Study was based on survey carried out in agro and forest ecosystems of Kerala and the samples collected from these ecosystems. Commercially available pheromone traps for the collection of red palm weevil, banana pseudostem weevil and banana rhizome weevil were installed in five agroclimatic regions viz., Northern Zone, (RARS, Pilicode); High range (RARS, Ambalavayal); Central Zone (RARS, Pattambi); Problem zone (RARS, Kumarakom) and Southern Zone (RARS, Vellayani). Traps were also installed in the fields of BRS, Kannara and ORARS, Kayamkulam. The other two weevils, i.e. Diocalandra frumenti and Sitophilus oryzae were collected from households and fields of the aforesaid seven regions. The study also includes specimen stored in Malabar Insect Repository (MIR) and the specimens of Rhynchophorus ferrugineus collected from CPCRI regional station, Kayamkulam, Kerala. An annotated checklist of world Rhynchophorinae was prepared and results revealed that the subfamily Rhynchophorinae includes 955 species under 124 genera and 6 tribes. The distribution of these weevils is more concentrated in Oriental and Neotropical regions (70%). Maximum number of species was described during the 1851-1950. Highest contribution from coleopterists was by Heller (89 species) followed by Chevrolat (76 species), Faust (76 species), Guenther (68 species). Taxonomy ultimately narrowed down to focus on the 770 specimens of five species under five genera viz., Cosmopolites sordidus, Diocalandra frumenti, Odoiporus longicollis, Rhynchophorus ferrugineus and Sitophilus oryzae. Collected specimens of individual species were segregated into different populations according to the morphological variations within the species. The present study of economically important five species had 249 illustrations and 149 line diagrams.Detailed description of all the taxonomic characters like head, rostrum, (dorsal and lateral), antennae, pronotum, elytron, femur, tibia, tarsus, venter and genitalia were studied and presented with line diagrams. Taxonomic description of all the five species were supplemented with standard taxonomic terminology along with genital characters and loaded with the morphometric ratios. The taxonomic key was prepared for all the known species under genera Cosmopolites, Diocalandra, Odoiporus and Rhynchophorus. Based on the morphological characters all five species were segregated in different groups. The taxonomic study revealed that, morphological variations present among the groups may be due to environmental conditions, availability of food, and life stage of the plant on which they are feeding on. All the variations within the species were depicted with the differential distinguishing characters along with line diagrams. Among all five species, major difference was observed within the three groups of Odoiporus longicollis which may be a new species. More morphological and molecular level studies are needed for the confirmation of new species if any.
Open Access
Pesticide use pattern and monitoring of residues in cardamom in Idukki district
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2013) Seena, S M; KAU; Naseema Beevi, S
The field survey conducted among the farmers of Idukki district revealed that major pest infesting cardamom were shoot and capsule borer and cardamom thrips. For the timely management of these pests, farmers are following strict plant protection measures at an interval of 15 to 40 days with conventional insecticides. Farmers are widely applying heavy doses of chemicals especially the organophosphorus insecticides like phorate, chlorpyriphos, quinalphos, profenophos, methyl parathion and synthetic pyrethroids like cypermethrin and lambda cyhalothrin. Majority of the farmers resort to prophylactic spraying of plant protection chemicals rather than remedial measures. Adoption of IPM strategies are also negligible. Most of the farmers used their own spraying schedules for pest management. The pesticide use pattern in cardamom growing tracts of Idukki district shows that the farmers are applying plant protection chemicals aggressively and the liberal and continual use of pesticides has disturbing consequences on the ecosystem. In multiresidue mehod validation cardamom samples were spiked at five different levels viz. 0.01 µg g-1, 0.05 µg g-1 , 0.10 µg g-1 0.50 µg g-1 and 1 µg g-1 and extraction was carried out using various solvent/ solvent system and the modified QuEChERS method which gave 69.7–110% per cent recovery with RSD < 20 was selected and the same method was adopted for the estimation of pesticide residues from cardamom samples. In order to assess the residue level and to study the extend of contamination due to pesticides in cardamom, samples were collected from the cardamom growing plantations of Idukki district. Three major cardamom growing zones were selected namely Vandanmedu, Udumbanchola and Poopara in Idukki district and ten samples were collected from each location for a period of six months. Data on monitoring of pesticide residues in cardamom samples collected from the study regions for a period of six months revealed varying level of residues of several pesticides. Out of the total 180 samples analyzed, residues were detected in 173 samples and only seven samples were free of residues. Out of the 173 samples detected with pesticide residues, 160 contained multiple residues of pesticides whereas only 13 contained residues of single pesticide. Cardamom capsules contained residues of 16 different pesticide molecules belonging to organochlorines, organophosphates and synthetic pyrethroids. The most common contaminant was quinalphos which was detected in 121 out of 180 samples analysed. Other major contaminants include lambda cyhalothrin (104), cypermethrin (100), chlorpyriphos (87) and profenophos (64). Pesticides detected in cardamom which have no label claim in cardamom include Beta cyfluthrin (5), bifenthrin (3), fenpropathrin (4), fenvalerate (5), lambda cyhalothrin (104), methyl parathion (64) and triazophos (4) . A field experiment was carried out in order to study the curing process on removal of residues of quinalphos, chlorpyriphos, triazophos, cypermethrin, lambda cyhalothrin and imidacloprid. Curing process removed the residues of pesticides at varying levels. Processing factor was worked out for each chemical. Extent of removal of residues as a result of curing were: quinalphos (61.78-67.78%), chlorpyriphos (70.23-76.66%), triazophos (49.62-55.02%), cypermethrin (65.71-67.63%), lambda cyhalothrin (13.15-40.00%) and imidacloprid (75.56-77.32%).

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