In surveys conducted in Coimbatore district during 2009-10, Okra fruit borers, Earias vittella Fabricius, Earias insulana Boisdual and Helicoverpa armigera (Hübner) were the serious pests causing 50 per cent loss. During the survey, three... more
In surveys conducted in Coimbatore district during 2009-10, Okra fruit borers, Earias vittella Fabricius, Earias insulana Boisdual and Helicoverpa armigera (Hübner) were the serious pests causing 50 per cent loss. During the survey, three hymenopteran parasitiods viz., Bassus spp., Brachymeria lasus Walker, Goryphus spp., of the families Braconidae, Chalcididae and Ichneumonidae against Earias spp. and the dipteran parasitoid, Carcelia illota (Tachinidae ) against H. armigera were recorded with 0.00 to 10.00 per cent parasitization. All the parasitoids recorded were not amenable for mass culturing, and hence, other braconid parasitoids viz., Bracon brevicornis Wesmael, Bracon hebetor Say and Chelonus blackburni Cameron were studied for their parasitic potential against fruit borer complex. Cent per cent parasitization was observed with B. brevicornis against all instars of E. vittella and H. armigera, higher parasitizaion of 100 and 97.50 per cent was observed by B. hebetor at a par...
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Attempts were made to establish new cell lines from the embryos of Helicoverpa armigera (Hübner) to study its susceptibility to baculoviruses. Three primary cell cultures were initiated from the embryo of H. armigera. Among the three... more
Attempts were made to establish new cell lines from the embryos of Helicoverpa armigera (Hübner) to study its susceptibility to baculoviruses. Three primary cell cultures were initiated from the embryo of H. armigera. Among the three cultures, HaE9 alone produced sufficient cell growth to allow subculturing and led to establishment. Population doubling time (PDT) of the cell line HaE9 ranged from 3.63 days to 4.75 days for five consecutive generations. Susceptibility studies of different baculoviruses revealed that HaE9 was permissive for HearNPV alone. Studies on the influence of incubation temperature regimes (26o, 27o and 28oC) on cell infection and polyhedral occlusion body (POB) yield of HearNPV in HaE9 cell line revealed that the temperature regime of 27oC could yield a maximum of 5.63 and 5.75x107 POB/ ml in 20th and 21st passage respectively. Bioassays with cell cultured viruses in comparison with in vivo produced virus had similar effects against 2nd instar H. armigera larv...
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The present study investigated the biology and morphometric analysis of rugose spiralling whitefly (RSW), Aleyrodicus rugioperculatus on coconut under mini net house condition at Department of Agricultural Entomology, Tamil Nadu... more
The present study investigated the biology and morphometric analysis of rugose spiralling whitefly (RSW), Aleyrodicus rugioperculatus on coconut under mini net house condition at Department of Agricultural Entomology, Tamil Nadu Agricultural University-Coimbatore during 2019-2020. The biology of rugose spiralling whitefly was studied by clip cage method and morphometrics were done using Leica image analyser. Total lifecycle of rugose spiraling whitefly was 56.23 ± 2.20 days. Developmental period of egg, nymphal, pupal and adult period was 8.47 ± 0.26, 17.46 ± 0.76, 10.30 ± 0.29 and 20.00 ± 1.00 days, respectively. In morphometrics, Length and width of egg (0.31 ± 0.01 mm and 0.11± 0.02 mm), nymphal (0.94 ± 0.01 mm and 0.82 ± 0.01 mm), pupal (1.23 ± 0.01 mm and 1.00 ± 0.01 mm) was recorded. A nymphal parasitoid, Encarsia guadeloupae can be potential natural enemy for effective management of rugose spiraling whitefly.
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Influence of nine UV protectants on the persistence of the entomopathogenic fungus B. bassiana (Bb 111) was evaluated in the laboratory. Among the UV protectants screened with the local B. bassiana (Bb 111) isolate, skimmed milk, yeast... more
Influence of nine UV protectants on the persistence of the entomopathogenic fungus B. bassiana (Bb 111) was evaluated in the laboratory. Among the UV protectants screened with the local B. bassiana (Bb 111) isolate, skimmed milk, yeast extract, starch, molasses and tinopal were found to be promising and offered good conidial protection with more than 70 per cent germination even after 60 minutes of UV exposure. Other UV protectants viz., folic acid (66.19%) and sucrose (61.91%) offered moderate protection of B. bassiana (Bb 111) conidia. Skimmed milk at 2 and 5 per cent concentration consistently recorded higher germination of 85.71 and 89.29 per cent respectively at 60 minutes of exposure. Upon 90 minutes of UV exposure, in B. bassiana (Bb 111) alone, the spore viability was drastically reduced to 27.38 per cent, whereas skimmed milk and starch at 5 per cent offered 71.43 and 53.85 per cent conidial germination respectively
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The use of conventional synthetic insecticides to manage mites population poses great difficulties owing to their cryptic nature and has, therefore led to growing interest in novel and effective alternatives like microbial bio-control... more
The use of conventional synthetic insecticides to manage mites population poses great difficulties owing to their cryptic nature and has, therefore led to growing interest in novel and effective alternatives like microbial bio-control agents. Successful usage of entomopathogenic fungi for pest control under field conditions includes delivery techniques, infectivity and persistence of their inoculum in the environment. Microplot experiment on chilli mite, Polyphagotarsonemus latus Banks revealed that the oil based formulation of B. bassiana (Bb 112) was significantly superior to all other treatments and recorded the highest cumulative mean population reduction of 39.80 percent. Two field experiments conducted against chilli mite, the cumulative mean percent reduction in the first field trial at Kumarapalayam and the second one at Ambilikkai showed that oil based formulation of B. bassiana, Bb 112 @ 108 spores mL-1 sprayed with CDA sprayer was significantly superior to other treatment...
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The present investigation was undertaken during the Kharif and Rabi seasons of 2019 to study the influence of different sowing windows and intercropping of legumes on the level of infestation of fall armyworm on maize crop. Three dates of... more
The present investigation was undertaken during the Kharif and Rabi seasons of 2019 to study the influence of different sowing windows and intercropping of legumes on the level of infestation of fall armyworm on maize crop. Three dates of sowing were adopted in each season and intercrops like cowpea, soybean, sunnhemp, and tephrosia were included besides sole maize with and without insecticide sprays. The results showed that the maize sown during July and October months has reported less FAW infestation and provided a higher grain yield than the rest of the sowing windows taken in Kharif and Rabi seasons, respectively. The maize intercropped with cowpea and sunnhemp has performed well in terms of yield and the leaf damage was also found to be lower apart from the insecticide applied maize crop.
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Background The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is a devastating pest of maize, difficult to manage using a single pest management tactic. The entomopathogenic fungus (EPF), Metarhizium... more
Background The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is a devastating pest of maize, difficult to manage using a single pest management tactic. The entomopathogenic fungus (EPF), Metarhizium anisopliae being an eco-friendly component, could be an effective tool for managing this notorious pest owing to its preferred habitat, principally the whorl region. Results Metarhizium anisopliae (TNAU-MA-GDU) isolated from FAW was evaluated against 2nd instar larvae of S. frugiperda reared under laboratory conditions. The pathogenicity and infection process were also studied through scanning electron microscope (SEM). The LC50 value for M. anisopliae isolate TNAU-MA-GDU was recorded as 5.8 × 104 spores ml−1 against the second instar larvae of S. frugiperda. SEM observations on the infection process revealed the adherence of the conidia on the head, cuticular ornamentations of the thorax, sensory seta, and legs at 24 h post-infection (hpi). Formation ...
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Population dynamics of sucking pests in cotton ecosystem were studied at Tamil Nadu Agricultural University, Coimbatore during winter (2021) and summer (2022) seasons. Weekly observations were recorded on 20 randomly selected plants... more
Population dynamics of sucking pests in cotton ecosystem were studied at Tamil Nadu Agricultural University, Coimbatore during winter (2021) and summer (2022) seasons. Weekly observations were recorded on 20 randomly selected plants representing top, middle and bottom canopy of the crop which was raised in regular planting dates of winter and summer and were maintained as per the recommended regular agronomic practices except insect management interventions. During winter season, sucking pests viz., leafhopper, aphids, thrips, and whitefly were first observed in field from 39th SMW i.e. one month after sowing. Mealybugs were first observed during 41st SMW i.e. 43 days after sowing (DAS) of crop. The highest population of leafhopper, aphids, thrips, whitefly and mealybug recorded was 4.7, 18.7, 4.6, 2.45 no. per 3 leaves and 13.7 no. per 3 twigs, respectively. The mean population of sucking pests was high in October, 2021 and coincided with square formation to flowering stage except ...
Research Interests: Agronomy, Biology, Environment and climate change, Population, Crop, and 3 moreThrips, Whitefly, and Sowing
Background: Entomopathogenic fungi are microorganisms that specifically infect and often kill insects and other arthropods. Most are non-pathogenic to plants and relatively non-toxic to humans and animals. Use of fungal entomopathogens... more
Background: Entomopathogenic fungi are microorganisms that specifically infect and often kill insects and other arthropods. Most are non-pathogenic to plants and relatively non-toxic to humans and animals. Use of fungal entomopathogens can be an alternative to insecticides and could help in bio-intensive pest management. The current study aimed to study the pathogenicity of entomopathogenic fungal isolates against two Spotted Spider Mites, Tetranychus urticae Koch in tomato and broad Mite, Polyphagotarsonemus latus (Banks) in chilli. Methods: An extensive survey for the natural occurrence of entomopathogenic fungi on insects and mites was made in different agro climatic regions of Tamil Nadu during 2013 and 2014. Survey revealed the occurrence of two entomopathogenic fungi viz., Beauveria bassiana (Balsamo) Vuillemin and Metarhizium flavoviride Gams and Rozsypal var. minus. Laboratory experiment was conducted to evaluate the pathogenicity of fourteen isolates of Beauveria bassiana, ...
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Laboratory experiments were conducted to test the efficacy of biopesticides viz., Emamectin benzoate, Spinosad and Azadirachtin against third, fourth and fifth instar larvae of Maruca vitrata on different pulses namely black gram, green... more
Laboratory experiments were conducted to test the efficacy of biopesticides viz., Emamectin benzoate, Spinosad and Azadirachtin against third, fourth and fifth instar larvae of Maruca vitrata on different pulses namely black gram, green gram, lablab, cowpea and pigeonpea. Among the three biopesticides tested, spinosad 45% SC was found to be highly effective against third, fourth and fifth instar larvae on all the pulses tested. The lowest LC50 values were recorded against third (24.20 ppm), fourth (30.69 ppm) and fifth instar (36.56 ppm) larvae on pigeonpea.
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Fungal pathogens particularly, Beauveria bassiana (Balsamo) Vuillemin, Metarhizium anisopliae (Metschinkoff), Verticillium lecanii (Zimmerm.) Zare and Games Nomuraea rileyi (Farlow) Samson had been found to be promising in the control of... more
Fungal pathogens particularly, Beauveria bassiana (Balsamo) Vuillemin, Metarhizium anisopliae (Metschinkoff), Verticillium lecanii (Zimmerm.) Zare and Games Nomuraea rileyi (Farlow) Samson had been found to be promising in the control of several agricultural pests (Lingappa et al., 2005). B. bassiana is a hyphomycete insect pathogenic fungus in the subdivision Deuteromycotina which occurs worldwide. Over 200 species of insects in nine orders, mainly Lepidoptera and coleoptera had since been recorded as hosts (Li and Yang, 1988). It is found naturally on some plants and in soils and is regarded as a safe biopesticide (Uma Devi et al., 2008). The appropriate use of environment-friendlymicrobial pesticides can play a significant role in sustainable crop production by providing a stable pestmanagement program. Because, biological control is generally perceived as providing both long-lasting insect control and having less potential for damage to the environment or non-target organisms th...
An extensive survey was made at different pulse growing blocks of Coimbatore District viz., Annur, Karamadai, Madhukkarai, Periyanayakkanpalayam, Pollachi, Sulur, Thondamuthur, Tamil Nadu Agricultural University (TNAU) - Orchard and... more
An extensive survey was made at different pulse growing blocks of Coimbatore District viz., Annur, Karamadai, Madhukkarai, Periyanayakkanpalayam, Pollachi, Sulur, Thondamuthur, Tamil Nadu Agricultural University (TNAU) - Orchard and Pudukkottai District viz., Arantangi, Gandarvakottai, Karambakudi, Thirumayam, Thiruvarankulam and National Pulses Research Centre (NPRC), Vamban on the incidence of natural enemies of Maruca vitrata. Survey revealed that the level of parasitism of legume pod borer under field conditions ranged from 0.00 to 30.00 per cent. Highest parasitization of 30.00 per cent was recorded in National Pulses Research Centre, Vamban. Ponnaviduthi village of Karambakudi block in Pudukkottai district recorded the second highest parasitization of 20.00 per cent followed by Irumborai village of Karamadai block in Coimbatore district. During the survey, four larval parasitoids belonging to the families viz., Braconidae and Ichneumonidae were recorded. The braconid parasitoi...
Research Interests: Biology and Ichneumonidae
Some of the main issues in the successful use of entomopathogenic fungi for pest control include the application, infectivity and persistence of their inoculum in the environment. In this connection, suspending entomopathogenic fungal... more
Some of the main issues in the successful use of entomopathogenic fungi for pest control include the application, infectivity and persistence of their inoculum in the environment. In this connection, suspending entomopathogenic fungal conidia in oil frequently improves their environmental persistence and virulence against insects, compared to water suspensions. In microplot, the quantification of viable spore load (in terms of CFU per sq.cm leaf disc) of oil based formulation of Beauveria bassiana Bals. (Vuill) (Bb 112) delivered through different delivery equipments revealed that the CFU load was invariably higher in onion (fully opened 4 leaf) (fully opened 4 leaf) and top leaves of chilli plants sprayed with CDA sprayer (Controlled Droplet Applicator) (434.23 and 453.21 CFU cm) on the day of application. This was followed by Avenger ULV sprayer > Aspee Maruyama Engine Sprayer > Aspee Knapsack Hand Sprayer > Aspee Hitech Hand Sprayer > Aspee Battery Sprayer.
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Aphis gossypii, Bemisia tabaci, Thrips tabaci are important sucking pests of horticultural crops. Fungal pathogen, Beauveria bassiana is known to cause high infection in sucking pest populations. The present investigation was undertaken... more
Aphis gossypii, Bemisia tabaci, Thrips tabaci are important sucking pests of horticultural crops. Fungal pathogen, Beauveria bassiana is known to cause high infection in sucking pest populations. The present investigation was undertaken to evaluate the safety of oil formulation of fungal pathogen B. bassiana (Bb 112) available at the Department of Agricultural Entomology, TNAU, Coimbatore against the eggs and grubs of Chrysoperla zastrowi sillemi under laboratory condition. The safety studies of B. bassiana to the eggs of C. zastrowi sillemi revealed that egg hatchability was 66.88 per cent in the highest dose of Bb 112 (108 spores ml-1) and per cent hatchability increased with lower doses of Bb 112. In case of grubs, survival was 95.71 per cent at 104 spores ml- 1 and it declined with increased spore load. Further research should focus on development of efficient mass production systems, formulation, and delivery systems of fungal pathogens.
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Investigations were carried out to evaluate the efficacy of formulations of Beauveria bassiana (Bb 112) against whitefly, Bemisia tabaci on tomato under microplot condition. Among the different formulations tested viz., crude, talc and... more
Investigations were carried out to evaluate the efficacy of formulations of Beauveria bassiana (Bb 112) against whitefly, Bemisia tabaci on tomato under microplot condition. Among the different formulations tested viz., crude, talc and oil formulations, B. bassiana (Bb 112) oil formulation was most effective against whitefly on tomato with 45.86 % reduction in population over control followed by talc (29.62 %) and crude formulations (21.63 %). Present study wide open the scope of using an oil formulation of B. bassiana (Bb 112) against other sucking pests also.
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The Helicoverpa armigera micleopolyhedrovirus (HaNPV) is widely distributed across the geographical regions of Indian subcontinent. Nine geographical isolates of HaNPV were compared by dose and time-mortality assays against second instar... more
The Helicoverpa armigera micleopolyhedrovirus (HaNPV) is widely distributed across the geographical regions of Indian subcontinent. Nine geographical isolates of HaNPV were compared by dose and time-mortality assays against second instar Helicoverpa armigera (Hubner) lairae. The results of the study showed distinct variation in biological activity of these isolates. Of the isolates tested, CBE 1, BAN 1, NEC. OOT, HYD and CTR showed higher virulence against second instar with LC50 values ranging from 0.012 - 0.059 poly ocular bodies (POB) /mm2 than MAH 1 and RHI with LC50 values 0.343 and 0.415 POB/mm2, respectively. Considering the time mortality response, isolate CBE I had the shortest LT50 of 93.77 h that was comparable to NEG and OOT (98.30 - 101.62 h). RAJ isolate recorded the highest LC50 values of 0.864 and 5.225 POB/mm2 and LT50 value of 130.89 and 132.81 h, respectively for both second and third instar H. armigera larvae and was significantly inferior to other isolates tested.
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Background: The groundnut leafminer (GLM), Aproaerema modicella is an important pest of several legume crops which causes 50 to 100 per cent yield loss in India. The exploration of indigenous natural enemies is crucial to the success of... more
Background: The groundnut leafminer (GLM), Aproaerema modicella is an important pest of several legume crops which causes 50 to 100 per cent yield loss in India. The exploration of indigenous natural enemies is crucial to the success of every biological control strategy. Besides, alternative host plants act as a source of both herbivorous pests and their natural enemies. In this view, occurrence of GLM and their parasitic fauna on groundnut, alternate leguminous hosts viz., redgram and babchi were recorded. Methods: Survey on damage potential of GLM and their parasitic fauna were recorded on groundnut at Sivagangai and Coimbatore districts of Tamil Nadu, India during 2016 to 2018. Survey was also conducted to find the damage potential of A. modicella on alternate leguminous hosts viz., redgram, babchi and their parasitic fauna at Coimbatore district. The damage potential of A. modicella, per cent parasitization and parasitoid emergence were assessed from A. modicella infested ground...
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The foliar application of oil based formulation of B.bassiana (Bb 112) @ 10 spores ml had significant influence on the induction of defense related enzymes against Thrips tabaci Lindeman infestation in onion. On four days after treatment... more
The foliar application of oil based formulation of B.bassiana (Bb 112) @ 10 spores ml had significant influence on the induction of defense related enzymes against Thrips tabaci Lindeman infestation in onion. On four days after treatment (DAT), maximum activity of phenylalanine ammonia-lyase (0.63 μmol trans-cinnamic acid min g of fresh tissue) and total phenol content of 7.60 μg of catechol g of fresh tissue was recorded. The maximum activity of lipoxygenase (0.21 min g of fresh tissue) was recorded on 6 DAT and on 10 DAT, peroxidase, polyphenol oxidase, catalase and super oxide dismutase (SOD) reached its maximum in thrips infested onion plants treated with foliar application of oil based formulation of Bb 112.
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Investigations on the natural epizootics of Cladosporium cladosporioides (Fresenius) de vries were carried out on Okra grown at Tamil Nadu Agricultural University, Coimbatore during 2010 and 2011. Observations on the incidence of mycosed... more
Investigations on the natural epizootics of Cladosporium cladosporioides (Fresenius) de vries were carried out on Okra grown at Tamil Nadu Agricultural University, Coimbatore during 2010 and 2011. Observations on the incidence of mycosed mites were monitored continuously on okra at weekly interval during the study period. Occurrence of mycosis on Tetranychus urticae Koch due to C. cladsoporioides was high during third week of August 2010 (67.58%) followed by first week of August 2011 (47.24%), respectively. Fungal infection on mites had significant positive correlation with relative humidity and negative correlation with sunshine hours during the study period. An epizootic incidence of Cladosporium cladosporioides recorded on T. urticae is the first report from Coimbatore, Tamil Nadu.
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Experiments were carried out with male and female adults of Spodoptera litura to ascertain the role of antennae in their mating and host selection behavior. The olfactory responses of S. litura larvae to odour emitted by different hosts... more
Experiments were carried out with male and female adults of Spodoptera litura to ascertain the role of antennae in their mating and host selection behavior. The olfactory responses of S. litura larvae to odour emitted by different hosts viz., castor, cauliflower, sunflower, tomato and lab lab were tested in multiarm olfactometer. The experiments to know the role of antennae in mate and host selection were carried out with the adults with antennae and without antennae showed that the treatments having adult males with antennae laid fertile eggs, whereas, male without antennae laid sterile eggs. As far as the host preference for oviposition was concerned, the treatments involving male without antennae and female with antennae and, both male and female with antennae preferred castor and sunflower, respectively. The results of multiarm olfactometer experiments showed that the larvae had more preference for castor and least preference for lab lab, while, adult female preferred sunflower ...
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Biopesticides based on baculoviruses offer great scope as promising viral insecticides against Helicoverpa armigera (Hubner). However, an important limitation in the use of baculoviruses is their reduced efficacy against grown up larvae.... more
Biopesticides based on baculoviruses offer great scope as promising viral insecticides against Helicoverpa armigera (Hubner). However, an important limitation in the use of baculoviruses is their reduced efficacy against grown up larvae. The infectivity of NPV against grown up larvae were reported to be enhanced by the presence of a viral enhancing factor (VEF) in granuloviruses (GV). Hence, we investigated the possible interaction of GVs of Spodoptera litura (SlGV), Agrotis segetum (AsGV), Plutella xylostella (PxGV), Achaea janata (AjGV) and Chilo infuscatellus (CiGV) separately with the NPV of H. armigera (HearNPV) against second, third, fourth and fifth instar H. armigera . Of the GVs tested with HearNPV, SlGV alone synergized HearNPV action with reduced LC 50 values. The integration of SlGV with HearNPV resulted in 9.38, 10.93, 10.70 and 13.32 fold reduction in LC 50 values against the second, third, fourth and fifth instars respectively. Tests conducted with heat inactivated (a...
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A field experiment was conducted during the year 2001 to evaluate the bio efficacy of certain newer insecticide molecules like applaud, etofenprox and danitol. The study revealed that application of applaud 25 SC registered more than 80... more
A field experiment was conducted during the year 2001 to evaluate the bio efficacy of certain newer insecticide molecules like applaud, etofenprox and danitol. The study revealed that application of applaud 25 SC registered more than 80 per cent reduction of hopper population over control, on the 14th day after first and second application at both the doses. Hence, applaud @ 1 ml/lit can be a better alternative to most of the conventional insecticide molecules currently in use.
Research Interests: Toxicology and Medicine
In this study, extensive survey was carried out for the occurrence of T. absoluta in different vegetable growing regions of Tamil Nadu during August, 2015 to April, 2016. Among the forty one localities surveyed, T. absoluta infestation... more
In this study, extensive survey was carried out for the occurrence of T. absoluta in different vegetable growing regions of Tamil Nadu during August, 2015 to April, 2016. Among the forty one localities surveyed, T. absoluta infestation was found nearly in 25 localities of Tamil Nadu. Among them, the incidence was highest in a polyhouse of Tamil Nadu Agricultural University (TNAU) orchard (92.50 %) followed by 89.70 per cent in Echampatti village of Krishnagiri district and 82.40 per cent in Magendra mangalam village of Dharmapuri district. Apart from tomato, T. absoluta damage was also recorded on brinjal at TNAU orchard (9.72%) and potato at wood house, Horticultural Research Station, Ooty (26.67%). Characterisation of Tuta absoluta populations from Coimbatore, Dharmapuri and Krishnagiri Districts using cytochrome c oxidase subunit I (COI) revealed that the Dharmapuri and Krishnagiri populations were closely related with NCBI accessions sourced from Pune, Maharashtra (Accession No....
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Rugose spiraling whitefly, Aleurodicus rugioperculatus Martin (RSW) is an invasive pest found in India. A nymphal parasitoid, Encarsia guadeloupae Viggiani is a potential natural enemy of RSW. Here, we evaluated the biology of RSW in four... more
Rugose spiraling whitefly, Aleurodicus rugioperculatus Martin (RSW) is an invasive pest found in India. A nymphal parasitoid, Encarsia guadeloupae Viggiani is a potential natural enemy of RSW. Here, we evaluated the biology of RSW in four different host plants, viz., coconut, banana, sapota, and guava. In addition, we performed studies on the parasitic potential of E. guadeloupae on RSW and its biological parameters in the above-mentioned host plants. The developmental period of RSW from egg to adult stage is 36.6 days in coconut and sapota, followed by 37.9 days in banana and 38.6 days in guava. The identification of E. guadeloupae was confirmed by molecular analysis using the mtCOI gene. The parasitization percentage of E. guadeloupae was found to be higher in the second (60.60%) followed by the third nymphal stages (50.50%) of RSW. A high level of parasitism was recorded in RSW grown on guava (46.50%) and a low level in RSW grown on sapota (34.00%). Hence, the biology of E. guadeloupae was studied on the preferred nymphal stages (second and third) of RSW. The results revealed that the developmental period of E. guadeloupae was shorter (10.60 days and 11.27 days) and that of adult longevity was longer (11.10 and 12.17 days) in the third nymphal stage of RSW grown on guava and banana plants. The results suggested that the release of E. guadeloupae coincided with these stages under field conditions for effective management of RSW.
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Tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the major destructive invasive pests spread from South America to several parts of Europe, Africa and to India. Its incidence causes up to 90% yield loss and... more
Tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the major destructive invasive pests spread from South America to several parts of Europe, Africa and to India. Its incidence causes up to 90% yield loss and reduction in fruit quality both under greenhouses and field conditions. Efficacy of certain new molecules viz., spinetoram 12% SC w/v (11.7% w/v) SC at different doses (30, 45 and 54 g ai ha−1), flubendiamide 48 SC @ 60 g ai ha−1 and lambda cyhalothrin 5 EC @ 15 g ai ha−1 were evaluated against T. absoluta in two locations viz., Kaduchittipatti and B. Thrungipatti villages of Dharmapuri District during 2016–17 under open field conditions on hybrids “Sivam” and “Sagar”, respectively. Spinetoram 12% SC w/v was effective at the higher dose of 54 g ai ha−1 with the maximum reduction of leaf (89.15 and 88.18%) and fruit damage (95.07 and 89.61%) in both the locations, respectively followed by flubendiamide 48SC@ 60 g ai ha−1. These insecticides can be utilized for the management of T. absoluta subject to label claims for use on tomato.
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Microplot field trial was conducted from March to May 2017 to assess the efficacy of various biopesticides, pathogen, predator and parasitoid against M. vitrata on lablab (var. Co Gb 14). The experiments were carried out in a randomized... more
Microplot field trial was conducted from March to May 2017 to assess the efficacy of various biopesticides, pathogen, predator and parasitoid against M. vitrata on lablab (var. Co Gb 14). The experiments were carried out in a randomized block design (RBD) with nine treatments and three replications. Results revealed that spinosad 45% SC @ 75 ml ha-1 was significantly superior to all other treatments by recording a cumulative mean population reduction of 72.58 per cent. The next in the order of efficacy were emamectin benzoate 5% SG @ 200 ml ha-1 (65.16 %) > sequential application of emamectin benzoate (200 ml ha-1) + Bracon brevicornis (2000 adults ha-1 released after fortnight) (63.70%) > emamectin benzoate (100 ml ha-1) + B. brevicornis (1000 adults ha-1) @ half the dose each (62.06 %) > azadirachtin 0.03% @ 2.5 L ha-1 (39.33 %) > B. brevicornis @ 2000 adults ha-1(32.77 %) > Crude suspension of B. bassiana (Bb 112) @ 108 Spores ml-1 (25.95 %) > Xylocoris flavipes...
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The studies with SEM clearly depicted that the antenna of female was longer than male antenna. Five types of sensilla namely trichodea, chaetica, styloconica, coeloconica and auricillica, and scales were observed on the flagellum of both... more
The studies with SEM clearly depicted that the antenna of female was longer than male antenna. Five types of sensilla namely trichodea, chaetica, styloconica, coeloconica and auricillica, and scales were observed on the flagellum of both sexes. Sensilla trichodea were distributed randomly on all segments and were the most frequent type. Six sensilla chaetica were observed on each flagellar segment in both sexes, except in the apical segment. A sensillum styloconicum was always found at the upper-middle region of each flagellar subsegment. This sensillum had a smooth petiole and a conic extremity with one to three apical structures. Sensilla coeloconica were situated from middle to the distal portion of segment. Sensilla auricillica were found among the scales and had the typical shape of rabbit’s ear. Sensilla squamiformia were present on dorsal part of the antenna among scales. They were shorter and finer than scales and were embedded in a socket and point distally. Sensilla basico...
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Field efficacy of seven geographical isolates of Helicoverpa armigera nucleopolyhedrovirus (HaNPV) along with an insecticide control was evaluated against H. armigera on cotton and chickpea in the Coimbatore district of Tamil Nadu, India.... more
Field efficacy of seven geographical isolates of Helicoverpa armigera nucleopolyhedrovirus (HaNPV) along with an insecticide control was evaluated against H. armigera on cotton and chickpea in the Coimbatore district of Tamil Nadu, India. Among the HaNPV isolates, CBE I (Coimbatore) and NEG (Negamum) applied at 3.0 × 1012 POB/ha to cotton and 1.5 × 1012 POB/ha to chickpea with an adjuvant, crude sugar, significantly reduced the H. armigera larval population and increased the yield. CBE I and NEG recorded the highest yield of 2038 kg/ha and 2033 kg/ha, which was on a par with endosulfan (2026.7 kg/ha) with cost/benefit ratios of 1:2.32, 1:2.48, and 1:1.12, respectively, on cotton. In chickpea grain yields of 980, 983, and 973.3 kg/ha and cost/benefit ratios of 1:1.36, 1:1.48 and 1:0.87, respectively, in CBE I, NEG and endosulfan treated plots were obtained. The isolate RAJ (Rajasthan) recorded the lowest yield comparable to that of the untreated control in both crops.
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ABSTRACT
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A study assessed the toxicity of insecticides on mycelial growth and spore production of Beauveria bassiana by poisoned food technique. Among the insecticides tested, profenophos 50 EC was the most toxic to mycelial growth and conidial... more
A study assessed the toxicity of insecticides on mycelial growth and spore production of Beauveria bassiana by poisoned food technique. Among the insecticides tested, profenophos 50 EC was the most toxic to mycelial growth and conidial germination followed by thiamethoxam 25 WG. Dimethoate 30 EC showed complete inhibition of vegetative growth and sporulation of the fungus at all the doses. On the contrary, imidacloprid 17.8 SL and neem oil 3% were significantly compatible and were found safe to conidial germination and growth.
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The two spotted spider mite (TSSM) Tetranychus urticae Koch is a serious pest injurious to many crops. The predatory mite Amblyseius longispinosus (Evans) was explored as a potential biocontrol agent against T. urticae in many polyhouse... more
The two spotted spider mite (TSSM) Tetranychus urticae Koch is a serious pest injurious to many crops. The predatory mite Amblyseius longispinosus (Evans) was explored as a potential biocontrol agent against T. urticae in many polyhouse experiments. An attempt has been made to determine the functional and ovipositional responses of, A. longispinosus under laboratory condition at temperatures ranging from 20 to 35oC. Functional response revealed that the handling time (Th) of the prey by the predators generally decreased with temperature, whereas successful attack rate (a) was almost uniform. Judging by a/Th values, A. longispinosus was most efficient against T. urticae at 30 and 35°C. The rate of oviposition of the predator increased linearly with prey density, and the number of eggs laid increased linearly with the number of prey consumed. The potential of A. longispinosus as a biocontrol agent against T. urticae is discussed.