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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
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
Integrated insect pest management (IIPM) and Biological Control based integrated pest management (BIPM) in rice
(Department of Agricultural Entomology, College of Horticulture,Vellanikkara, 2012) Pramod Kumar, KAU; Ranjith, A M
Rice is the staple food of India and most parts of the world. India has a history of pest outbreaks resulting in extensive losses in rice production, with a lot of factors contributing to it. For managing pests in rice many farmers use only the parasitoid Trichogramma (available as trichocards) and sometimes with the addition of Pseudomonas fluorescens. Trichogramma will manage only yellow stem borer and leaf folder (YSB and LF). Other lepidopteran pests and sucking pests have to be tackled by adopting other management practices. Even trichocards are wasted due to wrong application techniques. Light traps can be used to monitor the incidence of YSB and LF to aid in the placement of trichocards. Hence the present study “Integrated insect pest management (IIPM) and biological control based integrated pest management (BIPM) in rice” was taken up with the objectives of separating/fractionating the contribution of biological control based integrated pest management (BIPM), need based super imposition of integrated insect pest management(IIPM) over BIPM, synchronizing trichocard with moth emergence to explore the possibility of reducing trichocard numbers, evaluation of trichocard dispensing technologies and economic analysis of these operations. The experiment was conducted in transplanted rice and direct sown rice at State Seed Farm, Mannuthy. Both BIPM and IIPM strategies were implemented. Two light traps were installed in the field. The trichocards @ 5cc ha-1 were released four times in treated plots to suppress the yellow stem borer and leaf folder based on moth emergence. Other treatments included application of Beauveria bassiana and neem oil garlic extract 2% in BIPM plot and need based application of insecticides in IIPM plot for managing the pests. Results revealed that the relationship between light trap catches of yellow stem borer (Scirpophaga incertulas) and dead heart/white ear head damage did not differ significantly between transplanted and direct sown rice and trap catches were also low in both the cases. Considering the percentage damage, it was seen that control plot shows significantly high damage compared to other treatments. After sixth fortnight, the application of insecticides in IIPM and botanicals in BIPM plots reduced the damage and resulted in more yield. While observing the relationship between light trap catches of leaf folder (Cnaphalocrocis medinalis) and number of leaves damaged in transplanted and direct sown rice, less damage was observed in BIPM plot compared to other treatments. Considering the percentage damage, it was observed that control plot showed significantly high damage. After sixth fortnight , when other pests started infesting the crop, application of insecticides in IIPM and botanicals in BIPM plots reduced the damage and resulted in more yield. The yield data of various treatments indicate that the IIPM plot recorded highest yield i.e. 9,150 kg ha-1 in transplanted and 8,600 kg ha-1 in direct sown rice in comparison to BIPM (8,425 kg ha-1 and 7,975 kg ha-1) and control (6,115 kg ha-1 and 5,225 kg ha-1). The highest benefit cost ratio was recorded in IIPM (1.49 and 1.53:1) followed by BIPM (1.36 and 1.41:1). In the experiment to synchronize trichocard release with moth emergence for possible reduction of trichocard numbers, four releases starting from second to fifth fortnight could suppress both yellow stem borer and leaf folder. Different trichocard dispensing techniques have an important role in suppressing the yellow stem borer and leaf folder. In the cup method adults are restricted inside the cup and hence, leaf clipping method or coconut leaf method are recommended and also discourage the use of cup method. The results reveal that for minimizing pest incidence, providing protection and for phytotonic effects, seed treatments with insecticides and Pseudomonas is best suited. Major rice pests can be monitored by installing the light trap in the field and it is possible to synchronize the trichocard releases with moth emergence of yellow stem borer and leaf folder. Egg parasitoids T. japonicum and T. chilonis are effective against yellow stem borer and leaf folder only. BIPM method is best for managing leaf folder and IIPM for yellow stem borer. It is necessary to use need based application of insecticides, neem oil garlic extract and other biocontrol methods in controlling insect pests. Maximum yield is attained in IIPM plot followed by BIPM in transplanted and direct sown rice and benefit cost ratio was high in IIPM followed by BIPM method.
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
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
Bio-ecology and management of papaya mealybug on mulberry
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2014) Rajan, V P; KAU; Krishnakumar, R
The experiment entitled “Bio-ecology and management of papaya mealybug on mulberry” was carried out at College of Agriculture, Vellayani, Kerala Agricultural University and in farmers’ fields at Agali, Sholayur and Puthur panchayats during October 2009 to July 2012. The main objectives of the study were to identify and assess the extent of infestation of papaya mealybug on mulberry, its role in disease transmission and population dynamics and to evolve an Integrated Pest Management (IPM) strategy to contain the pest. Preliminary survey conducted in sericulture practising districts of Kerala revealed heavy infestation of the pest in three panchayats of Palakkad district in Kerala. The mealybugs identified in the survey were papaya mealybug, Paracoccus marginatus Williams and Granara de Willink, pink hibiscus mealybug, Maconellicoccus hirsutus (Green) and breadfruit mealybug, Icerya aegyptiaca (Douglas). The occurrence of papaya mealybug and its egg masses were found to be high during the period of May to August. The competition between these three mealybugs and also the influence of weather parameters on the population of the papaya mealybug was studied. The mealybug population showed positive correlation with maximum temperature, sunshine and wind speed and negative correlation with minimum temperature, rainfall and humidity. The different plants belonging to families Asteraceae, Euphorbiaceae, Malvaceae and Solanaceae were observed to be the most preferred hosts for papaya mealybug. The highest number of all life stages of papaya mealybug was observed on Parthenium, Parthenium hysterophorus L., which augmented the perpetuation of papaya mealybug in the absence of other crop hosts. Sprouted potatoes were the host material used for studying the biology of the papaya mealybug, pink hibiscus mealybug and breadfruit mealybug. The average number of eggs laid by an adult papaya, pink hibiscus and breadfruit mealybug were 361.50, 281.30 and 141.30 respectively. The mean larval period of papaya, pink hibiscus and bread fruit mealybugs were found to be 16.7, 21.2 and 47.1 days respectively. DAC-ELISA was performed with infected mulberry plants using antibodies of SCBMV and BSV showed the absence of virus in the infected samples collected from the mealybug infested mulberry gardens. The phenol content was also assessed in the infested samples to get an indication of the level of resistance showed by the host plant against mealybug. The level of resistance of the plant found to be increasing with the increase in the per cent damage. The fifth instar larvae of the predator, Spalgis epius was found as the most active feeder with a feeding potential of 21.69, 118.88, 40.88 and 20.49 of ovisacs and first, second and third instars of papaya mealybug respectively. Third instar larvae of green lacewing, Chrysoperla carnea (Stephens) and fourth instar grubs of ladybird predator, Cryptolaemus montrouzieri (Mulsant) were the most voracious feeders and they consumed significantly higher number of ovisacs, first, second and third instar nymphs of papaya mealybug as compared with first and second instar larvae of the predators. Among the different insecticides evaluated in the laboratory against the first instar and adult papaya mealybugs, dimethoate 0.1% was superior followed by imidacloprid 0.01%. Among the combinations, dimethoate 0.05% + econeem plus 2 ml L-1 was found to be superior with the highest per cent mortality of 93.33% and 96.67% for adult and first instar papaya mealybugs respectively. The silkworm larvae fed with the leaves after 15 days of treatment with the combination of dimethoate 0.05% + econeem plus 2 ml L-1 gave the highest yield of (91 /100 larva reared) cocoons with a total larval duration of 576 hours. Single cocoon weight was found to be high (1.56 g) with the highest shell ratio (22.09). The mean larval weight of different instars were 0.54, 0.87, 1.16, 8.80 and 36.61 gram respectively in first, second, third, fourth and fifth. In the above treatment, effective rearing rate (ERR) by number and weight were 9050.00 and 13744.69 g respectively. Field evaluation with the combination of pruning and weeding along with application of dimethoate (0.05%) 1.7 ml + econeem plus 2 ml L-1 and also providing a second spraying with dichlorvos (0.05%) 2 ml + econeem plus 2 ml L-1 was observed to be superior among all the treatments with minimum leaf damage, shoot damage and highest leaf yield per plant. B: C ratio worked out also confirmed the superiority of this treatment. Hence this treatment can be recommended as an IPM strategy for the management of papaya mealybug on mulberry.
Open Access
Diversity of predatory mite fauna in vegetable ecosystem
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2015) Maheswary, J; KAU; Haseena, Bhaskar
Mites constitute the most important group of non-insect pests in agriculture. Vegetable crops in particular, are subjected to infestation by a number of mite species, leading to heavy economic loss. The average yield loss in vegetable crops due to mite pests in India has been estimated to be around 25 per cent (Gupta, 1991). Predatory mites play a major role in reducing the populations of phytophagous mites and are able to feed on alternate sources of food and can survive in the absence of prey mites. The present study was undertaken at the Acarology Laboratory, Department of Agricultural Entomology, College of Horiculture, Vellanikkara during 2014 – 2015 to explore the diversity of predatory mite fauna in the vegetable ecosystems of Thrissur district, Kerala. The objectives of the study were to document the species diversity of predatory mites associated with phytophagous mites in vegetable ecosystems in Thrissur and also to develop a taxonomic key for the identification of predatory mite fauna in vegetable ecosystems. A purposive survey was undertaken to explore the mite fauna associated with the vegetable crops viz. amaranthus, brinjal, bhindi, bittergourd, chilli, cowpea, coccinia, cucumber, snakegourd and snap melon in major vegetable growing tracts of Thrissur district, Kerala. The taxonomic characters of the collected mite specimens were studied and were classified upto species level. Based on the characters studied and the species identity established, a detailed dichotomous key to the identification of the predatory mites studied was prepared. A total of 18 species of predatory mites belonging to six families were encountered in the study. The predatory mite families included Phytoseiidae, Stigmaeidae, Cunaxidae, Bdellidae, Tydeidae, and Acaridae represented by the genera Neoseiulus, Amblyseius, Typhlodromips, Euseius, Paraphytoseius, Phytoseius, Scapulaseius, Agistemus, Cunaxa, Bdella, Tydeus and Pronematus. The associated phytophagous prey mite families recorded were Tetranychidae, Tenuipalpidae and Tarsonemidae represented by the genera Tetranychus, Eutetranychus, Brevipalpus and Polyphagotarsonemus. Faunal studies in ten vegetable crops revealed highest species richness of predatory mites in brinjal, with a total of 18 species belonging to five different families. Mites in the family Phytoseiidae were found to be the most common predators in the vegetable fields of Thrissur district. Among the phytoseiid mites, Neoseiulus longispinosus was identified as the major species, associated with phytophagous mites in all the vegetable fields surveyed. Other species were Amblyseius paraaerialis, Amblyseius largoensis, Euseius macrospatulatus, Euseius sp. nr. prasadi, Typhlodromips syzygii, Paraphytoseius orientalis, Phytoseius intermedius and Scapulaseius sp. Occurence of Euseius sp. nr. prasadi and Phytoseius intermedius are new reports for Kerala. Predatory mites, Cunaxa sp. of the family Cunaxidae and Bdella khasyana of the family Bdellidae were recorded in chilli, cowpea and snap melon. Bdella khasyana is a new report for Kerala. Four species of mites belonging to the family Stigmaeidae viz., Agistemus gamblei, A. fleschneri, A. garrulus and A. macrommatus were recorded on bhindi, bitter gourd, brinjal, chilli and snake gourd. Occurence of A. fleschneri, A. garrulus and A. macrommatus are new reports for Kerala. The predatory mites Tydeus gossabaensis and Pronematus anconai of the family Tydeidae recorded in amaranthus, bhindi, brinjal, chilli, cowpea and snake gourd are new reports from Kerala. One species of astigmatid mite in the family Acaridae was also collected from brinjal and cowpea during the study.
Open Access
Management of pests of cowpea using red ant, oecophylla smaragdina (fab.)
(Department of agricultural entomology, College of agriculture, Padannakkad, 2015) Amida, Saparya; KAU; Sreekumar, K M
The experiment entitled “Management of pests of cowpea using red ant, Oecophylla smaragdina (Fab.)” was undertaken at the College of Agriculture, Padannakkad during the period from March 2014 to June 2015. The seasonal variation in population of red ant was measured by counting the number of live nests over one year and the ant activity was measured during 3 seasons for a period of 30 days in each. The interaction was measured by colonizing red ant on plants dominated by other ants. The effect of food provisioning was studied by counting the live nests constructed on host plants provided with and without artificial food. The experiment on the eradication of competitive ants was done on cashew and cowpea. Pest management efficacy and impact of commonly used pesticides on red ant were also studied. In the study on seasonal variation in red ant population, it was observed that there was a general tendency of decrease in the number of nests during monsoon period. The mean ant activity, temperature and relative humidity in each season show that relation between ant activity and temperature was positively correlated. The ant activity was found less during morning hours when temperature was less. The interaction between O. smaragdina and Tetraponera nigra and Paratrchina longicornis was found submissive and they coexist. The yellow crazy ant Anoplolepis gracileps was found dominant over O. smaragdina and severely affected red ant colony establishment. On an average, the number of nests on cashew trees provisioned with food increased 10 times where as it was only 1.35 times when food was not provided over a period of 33 days. In the competitive ant eradication experiment, Azadirachtin 0.1 % sprayed on the entire crop was observed as best on cashew and DDVP 76 EC @ 0.076 % sprayed on entire crop in cowpea. In the pest management efficacy study, maximum number of pods and leaves were attacked by aphids in control and red ant harboured plants and POP treated plants were on par. The result on yield parameters shows that there is no significant difference between the treatments in the case of pod number and pod length. Fresh weights of the pods were significantly low in control but POP treated and red ant colonized plants were on par. In the study on the impact of pesticides on red ant, DDVP 0.076 % treatment most adversely affected the red ant nest building and activity followed by Azadirachtin 0.03 % and Bordeaux mixture 1 % and least by Tobacco decoction 2.5 %
Open Access
Taxonomic studies on indian belonnotus (coleoptera: curculionidae: ceutorhynchinae)
(Department of agricultural entomology, College of agriculture, Padannakkad, 2015) Shruthi, C; KAU; Ramesha, B
The study entitled “Taxonomic studies on Indian Belonnotus (Coleoptera: Curculionidae: Ceutorhynchinae)” was undertaken in the Department of Entomology, College of Agriculture, Padannakkad during 2013-2015. The members of the tribe Mecysmoderini of the subfamily Ceutorhynchinae are one of the very large, diversely represented group of weevils in India, compared to other geographical regions of the world. Amongst the diverse genera representing of this tribe in India, genera Belonnotus and Mecysmoderes are important as it is distributed in Oriental region. A total of eighteen species are reported worldwide, out of which ten species are known from India in genus Belonnotus, whereas 26 species are known to be reported from worldwide in genus Mecysmoderes, of which five are known from India. Some of these species are major pests on economically important crops such as cucurbitaceous and cruciferous vegetables, as they cause pitting on the leaves and fruits. Some ceutorhynchine species feed on weeds and therefore are considered as biological control agents. The only substantial work on these weevil groups had come from Pajni and Kohli (1982). The available information is limited and lacking in essential diagnostics especially genitalia and morphometric observations. Hence, the present study was undertaken with objectives of survey and collection, study of morphological characters, redescription of species and formulation of taxonomic keys for the identification of the species. The present study was based on the collections from Malabar Insect Repository, College of Agriculture, Kerala Agricultural University, Padannakkad, Kerala and the specimens loaned from National Pusa Collection, Indian Agricultural Research Institute, New Delhi. Collections were also made through surveys from different parts of Kerala and Karnataka. The study constitutes five species belonging to two genera. All the species known so far under genera Belonnotus and Mecysmoderes have been taxonomically described. The descriptions of all the species studied are supplemented with taxonomic characters of genitalia and morphometric observations. An annotated checklist of the world Ceutorhynchinae had been prepared and these covered a total of 1316 species in worldwide distributed under 90 genera while the number of species reported from India is 45 distributed under 5 tribe and 13 genera. The geographic distribution of these species had been documented by taking up to date literature. The discrepancies in the description of the genera and species had been corrected and descriptions standardized to a uniform format loaded with morphometric ratios. Taxonomic keys to the species of all these two genera have been formulated and augmented with valid characters. Thus the present study fulfills to bridge a glaring lacuna of knowledge on these weevils and to keep its taxonomy on International standards.

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