Mealybug, Planococcus lilacinus Cockerell, is a primary surface-feeding insect pest of fruit and ... more Mealybug, Planococcus lilacinus Cockerell, is a primary surface-feeding insect pest of fruit and flowering plants and also transmits plant viruses, resulting in economic crop loss. Inappropriate and recurrent use of pesticides for mealybug control results in resistance building and deleterious effects on humans and the environment. Essential oils are the most excellent choice for insecticides. Insecticidal activities of pure compounds of essential oils against P. lilacinus are not reported. The present study aims to study the insecticidal activities of some pure active compounds and their binary mixture’s action by topical application against P. lilacinus. Results showed that the pure compounds of L-limonene, β-myrcene, and ocimene revealed toxicity (each at LD50 = 0.37 µg/insect) after 96 h. The binary mixtures of geraniol + L-menthol and L-limonene + geraniol exhibited synergistic effects (each at LD50 = 0.03 µg/insect) after 96 h. The monoterpenes of ocimene and β-myrcene at the ...
Tea, Camellia sinensis (L.) O. Kuntze is grown within the tropics and in diverse agro ecological ... more Tea, Camellia sinensis (L.) O. Kuntze is grown within the tropics and in diverse agro ecological conditions such as temperatures from -12ºC to 40ºC, annual rainfall from 938 to 6000 mm and relative humidity from 30 to 90%. It is grown on over 2.71 million ha in more than 34 countries (Hazarika et al. 2009). In India, tea is grown in Darjeeling, Assam and Nilgiri (Tamil Nadu), Meghalaya and in the adjacent plain areas of Dooars and Terai of West Bengal. Tea consisting of genetically diverse cultivars, and is a perennial mono-culture crop. It provides a relatively steady microclimate and food supply for insect and mite pests. Each tea growing country has its own distinctive insect and mite pests, diseases and weeds. However, several of them are common. Globally, 1031 species of arthropods are associated with tea mono-culture (Hazarika et al. 2009) and is attacked by nearly 250 insect species (Barthakur 2011). Tea plantations roughly resemble a "single species forest" and ins...
Aqueous extract of neem seed kernel (NKAE) was tested in laboratory condition to evaluate its ant... more Aqueous extract of neem seed kernel (NKAE) was tested in laboratory condition to evaluate its antifeedant, ovicidal, nymphl duration and hatching performance on tea mosquito bug (Helopeltis theivora).Different concentrations of NKAE used were 1,2,3,4and 5%. In F1 population NKAE was significantly superior in antifeedant activity, hatching percentage ,oviposition period and nymphal duration @ 5% (248.2), (50%) , (8days) (5 day in 4 th inster). The number of eggs laid by female was significantly less in 5% (23.33 Nos.) compared to other treatments.
Litchi chinensis is the “queen of fruits”, and pollination is an essential requirement for fruit ... more Litchi chinensis is the “queen of fruits”, and pollination is an essential requirement for fruit set and production. The present study was conducted in litchi orchards to study the diversity/abundance of insect visitors, the impact of pollination on quantitative parameters, and different modes of pollination. The results showed that 75 insect species during flowering were reported including Hymenoptera, Lepidoptera, Diptera, and Coleoptera. In natural pollination, the abundance of insect visitors of Hymenoptera was more during morning and evening (50.25% and 44.89%, respectively) compared to Lepidoptera (21.83 and 26.67%) and Diptera (24.37 and 23.33%). Similarly, natural pollination with one Apis mellifera colony also showed higher abundance of insect visitors of Hymenoptera during morning and evening (50.15 and 57.31%, respectively) as compared to Lepidoptera and Diptera. The Dipteran insect visitors under natural pollination showed significant positive correlation with temperatur...
Pulse beetle is the most harmful pest attacking stored grains and affecting quality and marketabi... more Pulse beetle is the most harmful pest attacking stored grains and affecting quality and marketability. Continuous use of chemical-based pesticides against pulse beetle led to the development of insecticidal resistance; essential oils (EOs) can be an effective natural alternative against this pest. The main objective was to study the chemical composition of seven EOs viz., Acorus calamus, Hedychium spicatum, Lavandula angustifolia, Juniperus recurva, Juniperus communis, Cedrus deodara and Pinus wallichiana, their insecticidal and enzyme inhibition activities against pulse beetle. The primary compounds present in these EOs were cis-asarone, 1,8-cineole, linalyl isobutyrate, 2-β-pinene, camphene, α-dehydro-ar-himachalene and camphene. A. calamus oil showed promising fumigant toxicity to Callosobruchus maculatus and C. chinensis (LC50 = 1357.86 and 1379.54 µL/L, respectively). A combination of A. calamus + L. angustifolia was effective against C. maculatus and C. chinensis (LC50 = 108.5...
The apple pomace (AP) was standardized for the multiplication of Lecanicillium lecanii and evalua... more The apple pomace (AP) was standardized for the multiplication of Lecanicillium lecanii and evaluated against Aphis craccivora. Results showed that AP medium at 2% recorded more mycelial growth and were at par with AP 3%, 4%, and 5% as compared to other concentrations. The spore yield of L. lecanii also significantly higher in AP 5% (16 Â 10 6 spores ml À1) and was at par with AP 0.5%. L. lecanii at 1 Â 10 9 spores ml À1 showed maximum mortality (43.33-93.33% mortality) against A. craccivora and was followed by 1 Â 10 8 spores ml-1 (36.67-86.67% mortality).
The effect of Tagetes minuta oil on the morphology of Aphis craccivora is reported in the scannin... more The effect of Tagetes minuta oil on the morphology of Aphis craccivora is reported in the scanning electron microscopy (SEM). Results showed that, flagellar segments of antenna treated with T. minuta showed filamentous and knotted without losing the setae after 96 h of treatment. The sensilla (Type I and II) showed remarkable deformation, reduction in the length and width. Morphometric measurements also helped to identify the deformed sensilla on cuticle and antenna. Type I and antennal sensilla reduced its length by 30% and type II sensilla by 42%. The breadth of type I and II sensilla also reduced by 35%.
Essential oil (EO) of ginger and oleoresins isolated from extraction solvents by GC-MS. Zingibere... more Essential oil (EO) of ginger and oleoresins isolated from extraction solvents by GC-MS. Zingiberene was the major constituent in all the samples, and ethanol could extract the maximum quantity (21.2%) from the dried de-oiled cake (EDD) followed by EO (20.3%) as compared to oleoresins. Hydro-distilled EO contains higher oxygenated monoterpenes (22.4%) than oleoresins. EDD showed more toxicity to larvae of Plutella xylostella (LC 50 ¼ 4957.9 mg L À1) after 96 h and was followed by EDW (LC 50 ¼ 5067.6 mg L À1) and EF (LC 50 ¼ 6631.2 mg L À1). EO also showed promising efficacy (LC 50 ¼ 5875.9 mg L À1) and repellency (97.1%) against P. xylostella.
Essential oil (EO) from aerial parts of Eupatorium adenophorum Spreng was extracted by steam dist... more Essential oil (EO) from aerial parts of Eupatorium adenophorum Spreng was extracted by steam distillation and characterized by Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). a-epi-cadinenol (16.63%), O-cymene (13.54%), bornyl acetate (7.70%), b-phellandrene (7.46%), and r-2-carene (5.77%) were the major terpenoids. The EO showed promising toxicity (median lethal concentration, LC 50 ¼ 3176.54 mg L À1) and repellent activity (median repellent concentration, RC 50 ¼ 2070.99 mg L À1) to larvae of Plutella xylostella within 24 h. Among fractions, hexane fraction was more effective to P. xylostella (LC 50 ¼ 5056.74 mg L À1), whereas methanol fraction to Aphis craccivora (LC 50 ¼ 1175.83 mg L À1).
Eleven essential oils (EOs) were screened for their fumigant and repellent activity against twosp... more Eleven essential oils (EOs) were screened for their fumigant and repellent activity against twospotted spider mite, Tetranychus urticae Koch (Acarina: Tetranychidae) under laboratory conditions. Results showed that, in fumigant toxicity assay, Mentha longifolia L. showed more toxic to T. urticae (LC 50 ¼ 11.08 mg L À1 air) and was followed by Mentha piperita L. (LC 50 ¼ 15.86 mg L À1 air), Cymbopogon flexuosus (Nees ex Steud.) W. Watson (LC 50 ¼ 17.23 mg L À1 air) and Chrysopogon zizanioides (L.) (LC 50 ¼ 18.82 mg L À1 air). In repellent activity test, Acorus calamus (L.), M. piperita and C. flexuosus showed 100% repellent activity to T. urticae as compared to Cedrus deodara (Roxb.) and Aegle marmelos (L.) (76.67%).
Plutella xylostella L. is one of the world’s major pests of cruciferous crops. The indiscriminate... more Plutella xylostella L. is one of the world’s major pests of cruciferous crops. The indiscriminate use of synthetic insecticides has led to insecticide resistance and resurgence, and has been harmful to non-target organisms and the environment. Botanical insecticides are the best alternatives to synthetic pesticides for the management of pests in organic agriculture and integrated management. T. sebifera is an invasive species and has good potential as an insecticide due to the availability of plant material in some parts of India. The antifeedant activities of T. sebifera have not been reported against P. xylostella and other lepidopteron insects to date. Therefore, the current study targeted the characterization of leaf and bark extracts, feeding deterrence, synergistic and detoxification enzyme activities of leaf/bark ethanolic extracts/fractions, seed oil, and isolated compounds. UHPLC-QTOF-IMS analysis showed that shikimic acid, xanthoxylin, quercetin, kaempferol, methyl gallate...
Field survey was conducted in muga culture (rearings) from different locations of Upper Assam dur... more Field survey was conducted in muga culture (rearings) from different locations of Upper Assam during peak period of infestation i.e. Jarua (Dec.09-Jan.2010) and Chotua (Feb.-Mar. 2010) to record the present status of uzi fly incidence in muga culture during fifth instar larval stage and at harvesting of cocoons. The results show that, maximum incidence of uzi fly on 5th instar larvae was more during Chotua crop (43.0%) followed by Jarua crop (19.0%). Similarly, the uzi fly incidence at harvesting (cocoon stage) was more during Chotua crop (35.0%) followed by Jarua (27.50%). Muga silkworm, Antheraea assamensis Helfer (Lepidoptera: Saturniidae), yields golden yellow silk, is unique to Brahmaputra river valley of Assam. It is polyphagous, multivoltine, producing 117 million tonnes of raw silk, accounting to 0.65% of raw silk produced in the country, while rest of the production contributed by other North-Eastern states (Anon, 2009). The silkworm has 5-6 generations in a year viz., Jeth...
Apple pomace (AP), the left over waste after extraction of juice, is often dumped in open field a... more Apple pomace (AP), the left over waste after extraction of juice, is often dumped in open field and that adds to environmental pollution. In this context and a rich source of carbohydrates, we tried to standardize the AP as a substrate for growth and spore production of entomopathogenic fungi (EPF) viz., Lecanicillium lecanii, Beauveria bassiana and Paecilomyces fumosoroseus by adding water, ammonium nitrate, as well as using different temperatures and pH. Results have shown that addition of 40 mL of water, 4 g of ammonium nitrate, and maintaining temperature at 30C and pH alkaline (pH 8 & 10) in AP recorded significantly higher spore production of L. lecanii (50.53, 52.81, 151.2 and 50.26-52.2 lakh spores/mL, respectively), B. bassiana (50.44, 51.87, 152.2 and 50.14-51.66 spores/mL, respectively) and P. fumosoroseus (50.56, 52.18, 149.3 and 50.1452.31 lakh spores/mL, respectively) as compared to positive control, potato dextrose agar (41.76-43.8 lakh spores/mL).
Incidence of insect pests on ferns, particularly sap suckers, needs attention as it causes more d... more Incidence of insect pests on ferns, particularly sap suckers, needs attention as it causes more damage indirectly. Here, we recorded seasonal incidence of black scale, Saissetia oleae (Olivier) on Thelypteris tylodes (Kunze) (Thelypteridaceae) for a period of one year from May 2012 to April 2013 at weekly interval. Results have shown that incidence of S. oleae first occurs in the first week of May 2012 (5.4 scales/rachis).The infestation increases gradually from second week of May (6.6 scales/rachis) and attains its peak during the last week of July 2012 (27.8 scales/rachis) due to high temperature (20–27°) and relative humidity (74-83%). The infestation starts declining gradually from August 2012 to November 2012 (24.7 scales/ rachis to 3.4 scales/rachis). The lowest scale incidence was observed during the last week of December 2012 (0.50 scales/ rachis) and second week of January 2013 (0.2 scales/rachis). The scale infestation was not observed from third week of January 2013 to en...
Efficay of imidacloprid and thiamethoxam was evaluated on okra leafhopper, Amrasca bigutlula big... more Efficay of imidacloprid and thiamethoxam was evaluated on okra leafhopper, Amrasca bigutlula bigutlula (Ishida). Field experiments were conducted at the Indian Institute of Horticultural Research (IIHR) Bangalore on okra variety, Arka Anamika during khartf 1999 and summer, 2000. Results indicated that thiamoxam 25 WG was on par with imidacloprid (Gaucho 600 FS) seed treatment @ 12 ml/kg of seed in reducing the leafhcpper infestation. Lower concentrations of imidacloprid seed treatment were less effective. All the doses of imidacloprid and thiamoxam had no phytotoxic effect on okra. The utility of imidacloprid for the control of okra lealhopper is discussed.
The larvicidal activity of essential oils of four species of Piper from the Amazon Forest was tes... more The larvicidal activity of essential oils of four species of Piper from the Amazon Forest was tested using third-instar larvae of Aedes aegypti. The oils were extracted by steam distillation and analyzed by GC and GC–MS. The main components isolated from each Piper species were as follows: viridiflorol (27.50%), aromadendrene (15.55%) and β-selinene (10.50%) from Piper gaudichaudianum; β-selinene (15.77%) and
Aphis craccivora Koch is a polyphagous and major pest of leguminous crops causing significant dam... more Aphis craccivora Koch is a polyphagous and major pest of leguminous crops causing significant damage by reducing the yield. Repeated application of synthetic insecticides for the control of aphids has led to development of resistance. Therefore, the present study aimed to screen the insecticidal activity of root/stem extracts/fractions, and pure molecules from Cissampelos pareira Linnaeus against A. craccivora for identification of lead(s). Among root extract/fractions, the n-hexane fraction was found most effective (LC50 = 1828.19 mg/L) against A. craccivora, followed by parent extract (LC50 = 2211.54 mg/L). Among stem extract/fractions, the n-hexane fraction (LC50 = 1246.92 mg/L) was more effective than the water and n-butanol fractions. Based on GC and GC-MS analysis, among different compounds identified in the n-hexane fraction of root and stem, ethyl palmitate (known to possess insecticidal activity) was present in the highest concentration (24.94 to 52.95%) in both the fractio...
Mealybug, Planococcus lilacinus Cockerell, is a primary surface-feeding insect pest of fruit and ... more Mealybug, Planococcus lilacinus Cockerell, is a primary surface-feeding insect pest of fruit and flowering plants and also transmits plant viruses, resulting in economic crop loss. Inappropriate and recurrent use of pesticides for mealybug control results in resistance building and deleterious effects on humans and the environment. Essential oils are the most excellent choice for insecticides. Insecticidal activities of pure compounds of essential oils against P. lilacinus are not reported. The present study aims to study the insecticidal activities of some pure active compounds and their binary mixture’s action by topical application against P. lilacinus. Results showed that the pure compounds of L-limonene, β-myrcene, and ocimene revealed toxicity (each at LD50 = 0.37 µg/insect) after 96 h. The binary mixtures of geraniol + L-menthol and L-limonene + geraniol exhibited synergistic effects (each at LD50 = 0.03 µg/insect) after 96 h. The monoterpenes of ocimene and β-myrcene at the ...
Tea, Camellia sinensis (L.) O. Kuntze is grown within the tropics and in diverse agro ecological ... more Tea, Camellia sinensis (L.) O. Kuntze is grown within the tropics and in diverse agro ecological conditions such as temperatures from -12ºC to 40ºC, annual rainfall from 938 to 6000 mm and relative humidity from 30 to 90%. It is grown on over 2.71 million ha in more than 34 countries (Hazarika et al. 2009). In India, tea is grown in Darjeeling, Assam and Nilgiri (Tamil Nadu), Meghalaya and in the adjacent plain areas of Dooars and Terai of West Bengal. Tea consisting of genetically diverse cultivars, and is a perennial mono-culture crop. It provides a relatively steady microclimate and food supply for insect and mite pests. Each tea growing country has its own distinctive insect and mite pests, diseases and weeds. However, several of them are common. Globally, 1031 species of arthropods are associated with tea mono-culture (Hazarika et al. 2009) and is attacked by nearly 250 insect species (Barthakur 2011). Tea plantations roughly resemble a "single species forest" and ins...
Aqueous extract of neem seed kernel (NKAE) was tested in laboratory condition to evaluate its ant... more Aqueous extract of neem seed kernel (NKAE) was tested in laboratory condition to evaluate its antifeedant, ovicidal, nymphl duration and hatching performance on tea mosquito bug (Helopeltis theivora).Different concentrations of NKAE used were 1,2,3,4and 5%. In F1 population NKAE was significantly superior in antifeedant activity, hatching percentage ,oviposition period and nymphal duration @ 5% (248.2), (50%) , (8days) (5 day in 4 th inster). The number of eggs laid by female was significantly less in 5% (23.33 Nos.) compared to other treatments.
Litchi chinensis is the “queen of fruits”, and pollination is an essential requirement for fruit ... more Litchi chinensis is the “queen of fruits”, and pollination is an essential requirement for fruit set and production. The present study was conducted in litchi orchards to study the diversity/abundance of insect visitors, the impact of pollination on quantitative parameters, and different modes of pollination. The results showed that 75 insect species during flowering were reported including Hymenoptera, Lepidoptera, Diptera, and Coleoptera. In natural pollination, the abundance of insect visitors of Hymenoptera was more during morning and evening (50.25% and 44.89%, respectively) compared to Lepidoptera (21.83 and 26.67%) and Diptera (24.37 and 23.33%). Similarly, natural pollination with one Apis mellifera colony also showed higher abundance of insect visitors of Hymenoptera during morning and evening (50.15 and 57.31%, respectively) as compared to Lepidoptera and Diptera. The Dipteran insect visitors under natural pollination showed significant positive correlation with temperatur...
Pulse beetle is the most harmful pest attacking stored grains and affecting quality and marketabi... more Pulse beetle is the most harmful pest attacking stored grains and affecting quality and marketability. Continuous use of chemical-based pesticides against pulse beetle led to the development of insecticidal resistance; essential oils (EOs) can be an effective natural alternative against this pest. The main objective was to study the chemical composition of seven EOs viz., Acorus calamus, Hedychium spicatum, Lavandula angustifolia, Juniperus recurva, Juniperus communis, Cedrus deodara and Pinus wallichiana, their insecticidal and enzyme inhibition activities against pulse beetle. The primary compounds present in these EOs were cis-asarone, 1,8-cineole, linalyl isobutyrate, 2-β-pinene, camphene, α-dehydro-ar-himachalene and camphene. A. calamus oil showed promising fumigant toxicity to Callosobruchus maculatus and C. chinensis (LC50 = 1357.86 and 1379.54 µL/L, respectively). A combination of A. calamus + L. angustifolia was effective against C. maculatus and C. chinensis (LC50 = 108.5...
The apple pomace (AP) was standardized for the multiplication of Lecanicillium lecanii and evalua... more The apple pomace (AP) was standardized for the multiplication of Lecanicillium lecanii and evaluated against Aphis craccivora. Results showed that AP medium at 2% recorded more mycelial growth and were at par with AP 3%, 4%, and 5% as compared to other concentrations. The spore yield of L. lecanii also significantly higher in AP 5% (16 Â 10 6 spores ml À1) and was at par with AP 0.5%. L. lecanii at 1 Â 10 9 spores ml À1 showed maximum mortality (43.33-93.33% mortality) against A. craccivora and was followed by 1 Â 10 8 spores ml-1 (36.67-86.67% mortality).
The effect of Tagetes minuta oil on the morphology of Aphis craccivora is reported in the scannin... more The effect of Tagetes minuta oil on the morphology of Aphis craccivora is reported in the scanning electron microscopy (SEM). Results showed that, flagellar segments of antenna treated with T. minuta showed filamentous and knotted without losing the setae after 96 h of treatment. The sensilla (Type I and II) showed remarkable deformation, reduction in the length and width. Morphometric measurements also helped to identify the deformed sensilla on cuticle and antenna. Type I and antennal sensilla reduced its length by 30% and type II sensilla by 42%. The breadth of type I and II sensilla also reduced by 35%.
Essential oil (EO) of ginger and oleoresins isolated from extraction solvents by GC-MS. Zingibere... more Essential oil (EO) of ginger and oleoresins isolated from extraction solvents by GC-MS. Zingiberene was the major constituent in all the samples, and ethanol could extract the maximum quantity (21.2%) from the dried de-oiled cake (EDD) followed by EO (20.3%) as compared to oleoresins. Hydro-distilled EO contains higher oxygenated monoterpenes (22.4%) than oleoresins. EDD showed more toxicity to larvae of Plutella xylostella (LC 50 ¼ 4957.9 mg L À1) after 96 h and was followed by EDW (LC 50 ¼ 5067.6 mg L À1) and EF (LC 50 ¼ 6631.2 mg L À1). EO also showed promising efficacy (LC 50 ¼ 5875.9 mg L À1) and repellency (97.1%) against P. xylostella.
Essential oil (EO) from aerial parts of Eupatorium adenophorum Spreng was extracted by steam dist... more Essential oil (EO) from aerial parts of Eupatorium adenophorum Spreng was extracted by steam distillation and characterized by Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). a-epi-cadinenol (16.63%), O-cymene (13.54%), bornyl acetate (7.70%), b-phellandrene (7.46%), and r-2-carene (5.77%) were the major terpenoids. The EO showed promising toxicity (median lethal concentration, LC 50 ¼ 3176.54 mg L À1) and repellent activity (median repellent concentration, RC 50 ¼ 2070.99 mg L À1) to larvae of Plutella xylostella within 24 h. Among fractions, hexane fraction was more effective to P. xylostella (LC 50 ¼ 5056.74 mg L À1), whereas methanol fraction to Aphis craccivora (LC 50 ¼ 1175.83 mg L À1).
Eleven essential oils (EOs) were screened for their fumigant and repellent activity against twosp... more Eleven essential oils (EOs) were screened for their fumigant and repellent activity against twospotted spider mite, Tetranychus urticae Koch (Acarina: Tetranychidae) under laboratory conditions. Results showed that, in fumigant toxicity assay, Mentha longifolia L. showed more toxic to T. urticae (LC 50 ¼ 11.08 mg L À1 air) and was followed by Mentha piperita L. (LC 50 ¼ 15.86 mg L À1 air), Cymbopogon flexuosus (Nees ex Steud.) W. Watson (LC 50 ¼ 17.23 mg L À1 air) and Chrysopogon zizanioides (L.) (LC 50 ¼ 18.82 mg L À1 air). In repellent activity test, Acorus calamus (L.), M. piperita and C. flexuosus showed 100% repellent activity to T. urticae as compared to Cedrus deodara (Roxb.) and Aegle marmelos (L.) (76.67%).
Plutella xylostella L. is one of the world’s major pests of cruciferous crops. The indiscriminate... more Plutella xylostella L. is one of the world’s major pests of cruciferous crops. The indiscriminate use of synthetic insecticides has led to insecticide resistance and resurgence, and has been harmful to non-target organisms and the environment. Botanical insecticides are the best alternatives to synthetic pesticides for the management of pests in organic agriculture and integrated management. T. sebifera is an invasive species and has good potential as an insecticide due to the availability of plant material in some parts of India. The antifeedant activities of T. sebifera have not been reported against P. xylostella and other lepidopteron insects to date. Therefore, the current study targeted the characterization of leaf and bark extracts, feeding deterrence, synergistic and detoxification enzyme activities of leaf/bark ethanolic extracts/fractions, seed oil, and isolated compounds. UHPLC-QTOF-IMS analysis showed that shikimic acid, xanthoxylin, quercetin, kaempferol, methyl gallate...
Field survey was conducted in muga culture (rearings) from different locations of Upper Assam dur... more Field survey was conducted in muga culture (rearings) from different locations of Upper Assam during peak period of infestation i.e. Jarua (Dec.09-Jan.2010) and Chotua (Feb.-Mar. 2010) to record the present status of uzi fly incidence in muga culture during fifth instar larval stage and at harvesting of cocoons. The results show that, maximum incidence of uzi fly on 5th instar larvae was more during Chotua crop (43.0%) followed by Jarua crop (19.0%). Similarly, the uzi fly incidence at harvesting (cocoon stage) was more during Chotua crop (35.0%) followed by Jarua (27.50%). Muga silkworm, Antheraea assamensis Helfer (Lepidoptera: Saturniidae), yields golden yellow silk, is unique to Brahmaputra river valley of Assam. It is polyphagous, multivoltine, producing 117 million tonnes of raw silk, accounting to 0.65% of raw silk produced in the country, while rest of the production contributed by other North-Eastern states (Anon, 2009). The silkworm has 5-6 generations in a year viz., Jeth...
Apple pomace (AP), the left over waste after extraction of juice, is often dumped in open field a... more Apple pomace (AP), the left over waste after extraction of juice, is often dumped in open field and that adds to environmental pollution. In this context and a rich source of carbohydrates, we tried to standardize the AP as a substrate for growth and spore production of entomopathogenic fungi (EPF) viz., Lecanicillium lecanii, Beauveria bassiana and Paecilomyces fumosoroseus by adding water, ammonium nitrate, as well as using different temperatures and pH. Results have shown that addition of 40 mL of water, 4 g of ammonium nitrate, and maintaining temperature at 30C and pH alkaline (pH 8 & 10) in AP recorded significantly higher spore production of L. lecanii (50.53, 52.81, 151.2 and 50.26-52.2 lakh spores/mL, respectively), B. bassiana (50.44, 51.87, 152.2 and 50.14-51.66 spores/mL, respectively) and P. fumosoroseus (50.56, 52.18, 149.3 and 50.1452.31 lakh spores/mL, respectively) as compared to positive control, potato dextrose agar (41.76-43.8 lakh spores/mL).
Incidence of insect pests on ferns, particularly sap suckers, needs attention as it causes more d... more Incidence of insect pests on ferns, particularly sap suckers, needs attention as it causes more damage indirectly. Here, we recorded seasonal incidence of black scale, Saissetia oleae (Olivier) on Thelypteris tylodes (Kunze) (Thelypteridaceae) for a period of one year from May 2012 to April 2013 at weekly interval. Results have shown that incidence of S. oleae first occurs in the first week of May 2012 (5.4 scales/rachis).The infestation increases gradually from second week of May (6.6 scales/rachis) and attains its peak during the last week of July 2012 (27.8 scales/rachis) due to high temperature (20–27°) and relative humidity (74-83%). The infestation starts declining gradually from August 2012 to November 2012 (24.7 scales/ rachis to 3.4 scales/rachis). The lowest scale incidence was observed during the last week of December 2012 (0.50 scales/ rachis) and second week of January 2013 (0.2 scales/rachis). The scale infestation was not observed from third week of January 2013 to en...
Efficay of imidacloprid and thiamethoxam was evaluated on okra leafhopper, Amrasca bigutlula big... more Efficay of imidacloprid and thiamethoxam was evaluated on okra leafhopper, Amrasca bigutlula bigutlula (Ishida). Field experiments were conducted at the Indian Institute of Horticultural Research (IIHR) Bangalore on okra variety, Arka Anamika during khartf 1999 and summer, 2000. Results indicated that thiamoxam 25 WG was on par with imidacloprid (Gaucho 600 FS) seed treatment @ 12 ml/kg of seed in reducing the leafhcpper infestation. Lower concentrations of imidacloprid seed treatment were less effective. All the doses of imidacloprid and thiamoxam had no phytotoxic effect on okra. The utility of imidacloprid for the control of okra lealhopper is discussed.
The larvicidal activity of essential oils of four species of Piper from the Amazon Forest was tes... more The larvicidal activity of essential oils of four species of Piper from the Amazon Forest was tested using third-instar larvae of Aedes aegypti. The oils were extracted by steam distillation and analyzed by GC and GC–MS. The main components isolated from each Piper species were as follows: viridiflorol (27.50%), aromadendrene (15.55%) and β-selinene (10.50%) from Piper gaudichaudianum; β-selinene (15.77%) and
Aphis craccivora Koch is a polyphagous and major pest of leguminous crops causing significant dam... more Aphis craccivora Koch is a polyphagous and major pest of leguminous crops causing significant damage by reducing the yield. Repeated application of synthetic insecticides for the control of aphids has led to development of resistance. Therefore, the present study aimed to screen the insecticidal activity of root/stem extracts/fractions, and pure molecules from Cissampelos pareira Linnaeus against A. craccivora for identification of lead(s). Among root extract/fractions, the n-hexane fraction was found most effective (LC50 = 1828.19 mg/L) against A. craccivora, followed by parent extract (LC50 = 2211.54 mg/L). Among stem extract/fractions, the n-hexane fraction (LC50 = 1246.92 mg/L) was more effective than the water and n-butanol fractions. Based on GC and GC-MS analysis, among different compounds identified in the n-hexane fraction of root and stem, ethyl palmitate (known to possess insecticidal activity) was present in the highest concentration (24.94 to 52.95%) in both the fractio...
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Papers by Eswara Reddy