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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
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
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%).
Open Access
Eco - Friendly management strategies against pod borer complex of Cowpea vigna unguiculata var.sesquiedalis (L) Verdcourt
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2013) Subhasree, S; KAU; Maicykutty Mathew, P
The investigations on “Eco-friendly management strategies against pod borer complex of cowpea, Vigna unguiculata var. sesquipedalis (L.) Verdcourt” was taken up at Department of Agricultural Entomology, College of Horticulture, Vellanikkara during October 2012 to January 2013. The short duration bushy variety of cowpea, Bhagyalakshmi susceptible to pod borers was used for the study. The experiment aimed at, evaluating the efficacy of a botanical viz., azadirachtin (0.005%), bioagents viz., Beauveria bassiana (1%), Metarhizium anisopliae (1%), Bacillus thuringiensis (0.2%) along with their sequential application (azadirachtin followed by B. bassiana, azadirachtin followed by M. anisopliae, azadirachtin followed by B. thuringiensis), a safer chemical viz., flubendiamide 480SC (0.008%) and a standard check (quinalphos 0.05%) against pod borer complex of cowpea under field conditions, studying the species composition of pod borer complex of cowpea and the natural enemies associated with them. Considering the three consecutive sprays at fortnightly intervals starting from flowering, flubendiamide was found to be highly effective in managing the larval population of pod borers compared to azadirachtin and bioagents. A single application of the same reduced the population of pod borers significantly. In the case of quinalphos the population of pod borers showed a decreasing trend up to seven days after each spraying and increased thereafter. Azadirachtin, M. anisopliae and B. thuringiensis recorded larval population below economic threshold level starting from 14th day after first spraying till the end of cropping period. With respect to per cent pod damage (in terms of number and weight) flubendiamide was found to be significantly superior over control and all other treatments were on par. Though quinalphos recorded the highest total yield both in terms of weight and number, application of flubendiamide resulted in the highest number of marketable pods. The total yield recorded in terms of weight was higher in B. thuringiensis than other bioagents. Azadirachtin followed by B. thuringiensis application resulted in high marketable yield among bioagents and botanical, followed by B. bassiana and were on par with the two chemical insecticides. Flubendiamide recorded the highest B: C ratio followed by quinalphos. Among the bioagents B. bassiana recorded a B: C ratio next to quinalphos and was followed by B. thuringiensis, azadirachtin followed by B. thuringiensis and M. anisopliae. Two species of pod borers were recorded on cowpea viz., spotted pod borer (Maruca vitrata) and pea blue butterfly (Lampides boeticus). M. vitrata was the major species of pod borer under Vellanikkara conditions compared to L. boeticus. The population of L. boeticus increased when there were more pods in the field compared to flowers. Two species of hymenopteran larval parasitoids belonging to the family Braconidae observed on M. vitrata were Apanteles sp. and Phanerotoma sp.
Open Access
Novel bioformulations of entomopathogenic fungi and their efficacy aganist banana weevils
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2018) Remya, S; KAU; Reji Rani, O P
The study entitled ‘Novel bioformulations of entomopathogenic fungi and their efficacy against banana weevils’ was carried out at Dept. of Agrl. Entomology, College of Agriculture, Vellayani during 2016-2018, with the objective to develop novel formulations of entomopathogenic fungi, Metarhizium anisopliae (Metch.) Sorokin, Beauveria bassiana (Bals.) Vuillemin and to evaluate their efficacy in managing banana weevils. It was intended to develop capsule and gel formulations. Experiment to standardize a coating material for developing capsules revealed that Hard Gelatin Transparent (HGT), Hard Gelatin Coloured (HGC) and Hydroxy Propyl Methyl Cellulose (HPMC), were equally stable under ambient conditions of storage (26 -33°C and RH 60-80%). On testing their ability to disintegrate under field conditions, it was noted that chitosan filled HGT capsules easily disintegrated at 20% soil moisture after 36 h and after 24 h at 30 % soil moisture. It took 144 h for all capsules to disintegrate in sheath or leaf axil and 24 h in bore holes. Talc and chitosan were superior, in maintaining storage stability as well as degradability. A trial conducted to determine the moisture content of capsules, revealed that 10 % was the ideal moisture level content of the ingredient, to maintain storage stability as well as viability of the formulation. Viability noticed after three months was 2.29 × 107 cfu mL-1 and 2.27 × 107 cfu mL-1 in chitosan based capsules of M. anisopliae and B. bassiana and 2.10 × 107 cfu mL-1 and 0.76 × 107 cfu mL-1 in talc based capsules. Therefore, capsules were developed with HGT coating, with chitosan / talc as carrier at 10 % moisture content. Shelf life studies revealed that chitosan was the best carrier material compared to talc in retaining viability of Metarhizium capsules, with a mean cfu of 2.51 × 107 mL-1 and 1.77× 107 mL-1. During a period of three months of storage, there was no decline in the number of viable colonies, cfu ranging from 1.72 × 107 mL-1 to 2.79 × 107 mL-1. . Storage under refrigeration had better retention of viability (2.63 × 107 cfu mL-1) than at room temperature (1.64× 107 cfu mL-1). In Beauveria capsules, the viability did not differ in both chitosan and talc based capsules. Here also, the number of viable colonies did not decline statistically, till three months of storage, with mean cfu values ranging from 1.85 × 107 mL-1 to 2.36 × 107 mL-1. In general, shelf life of capsules could be extended by two months when chitosan was used as the carrier material. Low temperature storage could also improve the shelf life by two months. Shelf life studies of gel formulations indicated that both Metarhizium and Beauveria gels exhibited high viability in chitosan at room temperature and under refrigeration. The mean number of viable colonies observed was 2.39 × 106 cfu mL-1 in chitosan based gels of Metarhizium and 2.17 × 106 cfu mL-1 in Beauveria gels. The number of viable colonies of Metarhizium and Beauveria observed throughout the experimental period did not vary significantly over three months of storage. The mean number of cfu being 2.26 × 107 mL-1 on the 15th day and 1.41 x 106 mL-1 on the 90th day . It was also inferred that chitosan when used for formulating gels could extend the shelf life of both organisms by one month. Pathogenicity test disclosed the affinity of M. anisopliae to rhizome weevil and B. bassiana to pseudostem weevil. Pot culture studies to evaluate chitosan and talc based capsules of B. bassiana revealed that both the capsules of Beauveria were effective as chlorpyriphos 20 EC 0.05% for pseudostem weevil, in prophylactic and curative methods. The damage index (DI) was one each and reduction in pest population was 91.67 % in prophylactic control and 91.67-100 % in curative control. Metarhizium capsules reduced the damage caused by rhizome significantly, but the reduction in pest population was only to the tune of 47-55 % in prophylactic and 50- 58 % in curative control. Chitosan based gel of Metarhizium tested against rhizome weevil, reduced the damage significantly (DI 46.67 and 30, in prophylactic and curative methods). The pest population was reduced by 61.11 % in prophylactic and 36.11 % in curative methods. The study could standardize the protocol for capsule and gel formulations of entomopathogenic fungi, retaining the viability and infectivity upto three months of storage. It is concluded that placement of Beauveria capsules in leaf axils prophylactically and curatively can effectively control pseudostem weevil and Metarhizium capsules and gels placed in the rhizosphere could manage the rhizome weevil moderately.
Open Access
Biorational management of major pests in brinjal (Solanum Melongena L.)
(Department of Agricultural Entomology, College of Agriculture, Padannakkad, 2014) Gowrish, K R; KAU; Ramesha, B
Brinjal (Solanum melongena L.) is a plant of considerable conomic importance in many tropical and sub tropical parts of the world. It is a popular vegetable grown as poor man’s crop in India. It is a native of India and is grown throughout the country. The brinjal crop is usually infested by a number of pests right from nursery stage till harvest. Among the insect pests, the most important and destructive ones are shoot and fruit borer, Leucinodes orbonalis; epilachna beetle, Epilachna vigintioctopunctata; leaf roller, Antoba olivacea and hairy caterpillar, Selepa docilis. For the management of these pests, the conventional pest management practices often provide unsatisfactory results. Further, the use of chemical pesticide results in insecticide resistance, pest resurgence, destruction of natural enemies and pesticide residue in the harvested produce and related environment and health hazards. Hence, there is an impetus for research and development of eco-friendly and biorational alternative for the sustainable management of major pests of brinjal. A survey was conducted in the three agro climatic regions of Kasargod district viz., low, mid and high land area. The survey revealed that per cent incidence of pests like L. orbonalis, E. vigintioctopunctata and A. olivacea were severe on brinjal in low, mid and high land area of Kasargod district. However, severe infestation of S. docilis was noticed in low land, compared to mid and high land area of Kasargod district. Spinosad 45 SC was found to be effective in controlling the shoot and fruit borer of brinjal during both summer and kharif season. Azadirachtin 1% was found to be most effective in controlling E. vigintioctopunctata adults as well as grubs. It was also found to be effective in reducing mean per cent of leaf infestation during both summer and kharif season. The Bt formulation was found to be highly effective for early instar larvae of A. olivacea. However, for older instar caterpillars, malathion 50 EC was found to be effective during both summer and kharif season. The azadirachtin 1% was found to be highly effective against S. docilis as compared to other treatments during both summer and kharif season. The spinosad 45 SC was safer to natural enemies like predatory coccinellids and spiders in brinjal ecosystem. The yield of brinjal plant was higher in spinosad 45 SC treated plots and a higher return was obtained worth Rs. 2.52 and Rs. 2.67 during both summer and kharif season respectively for every one rupee invested. Effect and compatibility of spinosad 45 SC on entomopathogenic fungi using poisoned food technique under in vitro condition revealed that spinosad 45 SC is not compatible with M. anisopliae and B. bassiana in terms of colony development, sporulation and spore germination. Residue of major and minor component of spinosad 45 SC were below the maximum residue limit.
Open Access
Ecological Management of Coconut root grub, Leucopholis coneophora Burm
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Melvin Mohan, S; KAU; SanthoshKumar, T
The study entitled ‘Ecological management of coconut root grub, Leucopholis coneophora Burm.’ was conducted at the Department of Agricultural Entomology, College of Agriculture, Vellayani, and College of Agriculture, Padannakkad during 2017 to 2019. The main objectives were to study the efficacy of botanical insecticides and biocontrol agents against coconut root grub, L. coneophora. The entire study consisted of two parts, laboratory evaluation and pot culture experiment. The laboratory experiment was conducted for screening various entomopathogenic fungi (EPF), entomopathogenic nematodes (EPN), botanicals and chemical insecticides against coconut root grub. Metarhizium anisopliae (Ma 4) and Beauveria bassiana (Bb 5) at different concentrations (1 x 108, 1 x 109 and 1 x 1010 spores mL-1) were tested. Entomopathogenic nematodes Steinernema carpocasae and Heterorhabditis bacteriophora at 100, 500 and 1000 IJ mL-1 were used for screening. The botanicals such as Azadirachta indica, Gliricidia maculata, Clerodendron infortunatum and Chromolaena odorata @ 25 g kg-1 of soil were screened for their efficacy against root grub. The chemicals used for the experiment comprised of chlorantraniliprole 0.4% G @ 75g a.i ha-1, fipronil 0.3% G @ 75g a.i ha-1 and spinosad 45% SC @ 73g a.i ha-1. Chlorpyriphos 25 % EC @ 225 g a.i ha-1 was used as a chemical check along with untreated control. Fifteen kilograms of sterilized moist soil was taken in a plastic basin and fresh potato tubers were given as feed for root grub. Three grubs were released into the basin and treatments were given one week after the release of grubs. The screening experiment using EPF consisted of eight treatments with three replications. The application of M. anisopliae @ 1 x 1010 spores mL-1 was found to be the most effective (100 % mortality) EPF against root grub and was on par with chemical check at 14 days after treatment (DAT). At 21 DAT, B. bassiana @ 1 x 1010 spores mL-1 resulted 100 per cent mortality and was on par with M. anisopliae @ 1 x 1010 spores mL-1 and the chemical check. At 28 DAT, M. anisopliae @ 1 x 1010 spores mL-1 and B. bassiana @ 1 x 1010 spores mL-1 brought about 100 per cent mortality of grubs, which were on par with the chemical check chlorpyriphos 20 % EC @ 225g a.i ha-1 (100 %), followed by M. anisopliae @ 1 x 109 spores mL-1 (92.58 %) and B. bassiana @ 1 x 109 spores mL-1 (85.17 %). The screening experiment with EPN consisted of eight treatments with three replications and the results revealed that all the treatments except chemical check failed to cause infection on grubs upto 10 DAT. Among the botanicals, A. indica application showed 48.14 per cent mortality of root grubs followed by C. infortunatum (37.03 %) at 30 DAT. The effect of chemical insecticides on root grub was conducted with five treatments and four replications. Fipronil 0.3% G @ 75g a.i ha-1 exhibited 97.22 per cent mortality and was on par with the chemical check at nine DAT followed by chlorantraniliprole 0.4% G @ 75g a.i ha-1 (74.99 %). Promising treatments viz. M. anisopliae (1 x 1010 spores mL-1, 1 x 109 spores mL-1), B. bassiana (1 x 1010 spores mL-1, 1 x 109 spores mL-1), chlorantraniliprole 0.4% G @ 75g a.i ha-1, and Fipronil 0.3% G @ 75g a.i ha-1 from laboratory experiments were selected and evaluated in a pot culture experiment and were laid out in CRD with eight treatments and three replications. Chlorpyriphos 25 % EC @ 225 g a.i ha-1 was used as a chemical check along with untreated control. Fodder grass variety CO-3 was raised in pots and first instar grubs were released after the establishment of the crop. The results of the pot culture experiment indicated that the application of fipronil 0.3% G @ 75g a.i ha-1 resulted in 100 per cent mortality and was on par with the chemical check at 28 DAT followed by M. anisopliae @ 1 x 1010 spores mL-1 (85.17 %). The treatments B. bassiana @ 1 x 1010 spores mL-1 (77.77 %), chlorantraniliprole 0.4 % G @ 75g a.i ha-1 (74.06 %) and M. anisopliae @ 1 x 109 spores mL-1 (74.06 %) were found to be on par at 28 DAT. From the present study, it can be concluded that the application of entomopathogenic fungi M. anisopliae @ 1 x 1010 spores mL-1 is a promising option for the management of first instar grubs of L. coneophora followed by B. bassiana @ 1 x 1010 spores mL-1. Soil application of neem leaves @ 25 g kg-1 of soil can enhance the suppression of root grubs. The results clearly indicate the possibility of reducing the use of chemical insecticides by resorting to botanicals and biocontrol agents.

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