Senthil-Nathan, Sengottayan | Manonmaniam Sundaranar University (original) (raw)

Papers by Senthil-Nathan, Sengottayan

Research paper thumbnail of Effect of Botanical Insecticides and Bacterial Toxins on the Gut Enzyme of the Rice Leaffolder Cnaphalocrocis medinalis

The effect of botanical insecticides and bacterial toxins on gut enzyme activity of larvae of the... more The effect of botanical insecticides and bacterial toxins on gut enzyme activity of larvae of the rice leaffolder Cnaphalocrocis medinalis (Guen´ee) (Insecta: Lepidoptera: Pyralidae) was investigated. Gut enzyme activities were affected by botanical insecticides and bacterial toxin individually and in combination. When fed a diet of rice leaves treated with botanical insecticides and bacterial toxins, in bioassays the activities of gut tissue enzymes - acid phosphatases (ACP), alkaline phosphatases (ALP) and adenosine triphosphatases (ATPase) – of rice leaffolder larvae were affected. When combined, the effect was more severe at
a low concentration. Larvae that were chronically exposed to botanical insecticides and bacterial toxins showed a reduction in weight (59–89%) and exhibited a signicant reduction
in ACP, ALP and ATPase activities. The combination of Bacillus thuringiensis kurstaki and botanical insecticides caused a decrease of twofold in enzyme activity even at reduced concentration. A synergistic effect was found when botanical insecticides and bacterial toxins were combined at low doses. These effects were most pronounced in early instars. Clear dose–response relationships were established with respect to enzyme activity. In conclusion: (i) biopesticides are relatively safe and biodegradable; (ii) a synergistic effect of botanical insecticides and bacterial toxins was found; (iii) less expensive, readily available and naturally occurring biopesticides could be an alternative for organic and inorganic
pesticides in controlling RLF.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effect of Biopesticides Applied Separately or Together on Nutritional Indices of the Rice Leaffolder Cnaphalocrocis medinalis

Laboratory assays were done to evaluate the effect of neem seed kernel extract (Azadirachta indic... more Laboratory assays were done to evaluate the effect of neem seed kernel extract (Azadirachta indica A. Juss), Vitex negundo L. (Lamiales: Verbenaceae) leaf extract, and Bacillus thuringiensis (Berliner), applied separately or together, on nutritional indices of the rice leaffolder Cnaphalocrocis medinalis (Guen´ee) (Lepidoptera: Pyralidae). All three biopesticides suppressed feeding and larval growth and low concentrations affected the larval performance. The combined effect of the three biopesticides resulted in a considerable
decrease in nutritional indices, indicating strong deterrence. Dose response relationships were established with respect to frass production and larval growth. The efciency of conversion of ingested and digested food was considerably reduced.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effects of neem limonoids on the malaria vector Anopheles stephensi Liston (Diptera: Culicidae)

The effects of the neem (Azadirachta indica A. Juss) limonoids azadirachtin, salannin, deacetylge... more The effects of the neem (Azadirachta indica A. Juss) limonoids azadirachtin, salannin, deacetylgedunin, gedunin, 17- hydroxyazadiradione and deacetylnimbin on Anopheles stephensi Liston (Diptera: Culicidae) were investigated. In exploring advantages of pure neem limonoids, we studied the larvicidal, pupicidal, adulticidal and antiovipositional activity of neem
limonoids. Azadirachtin, salannin and deacetylgedunin showed high bioactivity at all doses, while the rest of the neem limonoids
were less active, and were only biologically active at high doses. Azadirachtin was the most potent in all experiments and produced
almost 100% larval mortality at 1 ppm concentration. In general, first to third larval instars were more susceptible to the neem limonoids. Neem products may have benefits in mosquito control programs.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The effects of azadirachtin and nucleopolyhedrovirus on midgut enzymatic profle of Spodoptera litura Fab. (Lepidoptera: Noctuidae)

The effects of azadirachtin (AZA) and nucleopolyhedrovirus (NPV) on midgut enzyme activity in Spo... more The effects of azadirachtin (AZA) and nucleopolyhedrovirus (NPV) on midgut enzyme activity in Spodoptera litura Fabricius (Lepidoptera: Noctuidae) (Tobacco cutworm) were evaluated. Gut enzyme activities were decreased by AZA and NPV individually and in combination. When S. litura larvae were fed a diet of castor leaves treated with AZA and NPV in bioassays, gut enzyme—acid phosphatases, alkaline phosphatases, adenosine triphosphatases, and lactate dehydrogenase-activities were decreased. There were statistically signiWcant diVerences (P60.05) in enzyme activities
between combined and individual treatment. A synergistic eVect of botanical insecticides and virus was found when combined in low doses. These effects are most pronounced in early instars. Maximum weight loss (59–72%) occurred, when AZA and NPV were combined.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Efficacy of neem limonoids on Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae) the rice leaffolder

In leaf cut choice assay and topical application experiments, the neem (Azadirachta indica) limon... more In leaf cut choice assay and topical application experiments, the neem (Azadirachta indica) limonoids azadirachtin, salannin,
deacetylgedunin, gedunin, 17-hydroxyazadiradione, and deacetylnimbin showed strong antifeedant and growth inhibitor activity against fifth instar larvae of Cnaphalocrocis medinalis, the rice leaffolder, a serious pest of rice in Asian countries. The parameters, used to evaluate the activity of the limonoids were larval food utilization, quantity of ingested and digested food; consumption index and feeding deterrence index. Azadirachtin, salannin, deacetylgedunin showed high bioactivity at all doses, while the other neem limonoids proved to be less active, and only at the higher doses did they display antifeedant activity. Azadirachtin was the most potent in all experiments. Gross dietary utilization (efficiency of conversion of ingested food) of C. medinalis was also decreased after treatment with limonoids. Our results suggest that neem limonoids may be used in IPM programs for rice leaffolder and should be evaluated for efficacy under field conditions.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The toxicity and physiological effect of neem limonoids on Cnaphalocrocis medinalis (Guenee) the rice leaffolder

The effect of neem (Azadirachta indica) limonoids azadirachtin, salannin, deacetylgedunin, geduni... more The effect of neem (Azadirachta indica) limonoids azadirachtin, salannin, deacetylgedunin, gedunin, 17-hydroxyazadiradione,
and deaceytlnimbin on gut enzyme activity of the rice leaffolder larvae was investigated. When fed a diet of rice leaves treated with limonoids in bioassays, gut tissue enzymes—acid phosphatases (ACP), alkaline phosphatases (ALP), and adenosine triphosphatases (ATPase) activities of rice leaffolder (Cnaphalocrocis medinalis) larvae are affected. Azadirachtin was most potent in all experiments. Larvae that were chronically exposed to limonoids showed a reduction in weight (59–89%) and exhibited a significant reduction in ACP, ALP, and ATPase activities. These results indicate neem limonoids affects gut enzyme activities. These effects are most pronounced in early instars. 

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Efficacy of nucleopolyhedrovirus and azadirachtin on Spodoptera litura Fabricius (Lepidoptera: Noctuidae)

Spodoptera litura Fabricius (Lepidoptera: Noctuidae) is a destructive pest of subtropical and tro... more Spodoptera litura Fabricius (Lepidoptera: Noctuidae) is a destructive pest of subtropical and tropical agriculture, and has the potential to be a serious pest of forage crops in Asia. The effects of azadirachtin (AZA) and nucleopolyhedrovirus (NPV) on feeding and mortality of S. litura were evaluated in the laboratory. The nutritional indices were significantly affected. Gross dietary utilization (efficiency of conversion of ingested and digested food) of S. litura was also decreased after treatment with AZA and NPV. Food consumption, efficiency of conversion of ingested and digested food, relative growth rate, and consumption index values declined significantly, but at the same time an increase in approximate digestibility was also observed. Maximum larval weight (fifth instar) loss (68%) occurred, when AZA and NPV were combined. When consumed together (AZA and NPV) larvae died significantly faster compared with larvae that consumed NPV or AZA. Dose and larval instar dependent growth retardation was observed after treatment with NPV and AZA. Upon combination of AZA with NPV, nutritional indices decreased twofold even at reduced concentration of both.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effects of Melia azedarach on nutritional physiology and enzyme activities of the rice leaVolder Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae)

Laboratory assays were done to evaluate the effect of Melia azedarach L. (Rutales: Meliaceae) see... more Laboratory assays were done to evaluate the effect of Melia azedarach L. (Rutales: Meliaceae) seed extract on nutritional
indices and gut enzymes acid phosphatases, alkaline phosphatases, adenosinetriphosphatases, and lactate dehydrogenase of
the rice leaffolder (RLF) Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae). Larvae were fed a treated rice-leaf diet
containing the seed extract and their midgut was used for enzyme determination. Laboratory experiments showed that the seed extract suppressed the larval activity of C. medinalis even at a low dose. Gross dietary utilization (effciency of conversion of ingested and digested food) of RLF decreased after ingesting the treated rice-leaf diet. Food consumption, digestion, relative consumption rate, effciency of conversion of ingested food, effciency of conversion of digested food, and relative growth rate values declined significantly. As compared to the control, consumption of the extract containing rice-leaf diet resulted in a 69% reduction of the acid phosphatases activity, a 71% reduction of the alkaline phosphatases activity, a 46% reduction of the adenosine triphosphatases activity, and a 52% inhibition of the lactate dehydrogenase activity.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effects of Millet, Wheat, Rice, and Sorghum Diets on Development of Corcyra cephalonica (Stainton) (Lepidoptera: Galleriidae) andIts Suitability as a Host for Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae)

Emergence and survival of adults for 24 h was compared for Trichogramma chilonis Ishii reared on ... more Emergence and survival of adults for 24 h was compared for Trichogramma chilonis Ishii reared on eggs of Corcyra cephalonica (Stainton) adults whose larval growth and development had been monitored on broken grains of four different cereals: finger millet (Eleusine coracana L. Gaertn),
soft white wheat (Triticum aestivum L), short-grained white rice (Oryza sativa L.), and durra sorghum (Sorghum bicolor L. Moench). For C. cephalonica, the percentage adult emergence and several fifth-instar food use indices (consumption index, relative growth rate, and efficiencies of conversion of ingested and digested food) were significantly higher for millet-reared than for sorghum-reared larvae. The nutritional indices for wheat- and rice-reared C. cephalonica larvae were intermediate
between the indices for larvae reared on millet and sorghum. The percentage adult emergence and percentage 24-h survival of T. chilonis were significantly higher on eggs of C. cephalonica hosts reared on millet than on eggs of those reared on sorghum. These results suggest that the rearing of
C. cephalonica larvae on a high-quality nutritional source resulted in high-quality eggs, which ultimately resulted in high-quality T. chilonis reared on those eggs. Such an effect has been modeled in ecological theory as a “bottom up cascade.” Improved knowledge of the nutritional ecology of parasitoids and hosts can lead to improved understanding of the ecological mechanisms affecting host plant, host, and parasitoid abundance, as well as to improved efficiency and quality of Trichogramma production in mass rearing programs.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effects of Dysoxylum malabaricum Bedd. (Meliaceae) extract on the malarial vector Anopheles stephensi Liston (Diptera: Culicidae)

In recent years, use of environmentally friendly and biodegradable natural insecticides of plant ... more In recent years, use of environmentally friendly and biodegradable natural insecticides of plant origin have received renewed attention as agents for disease vector control. Methanol extracts of leaves from the Indian white cedar Dysoxylum malabaricum Bedd. (Meliaceae) were tested against mature and immature Anopheles stephensi Liston (Diptera) mosquitoes under laboratory conditions. The extract
showed strong larvicidal, pupicidal, adulticidal, and antiovipositional activity. The maximum leaf extract concentration tested in this study was 4%, which produced pronounced effects. In general, first and second instars were more susceptible to leaf extract than older insects. Clear dose–response relationships were established, with the highest dose of 4% plant extract causing 97% mortality of first
instars.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Behavioural responses and changes in biology of rice leaffolder following treatment with a combination of bacterial toxins and botanical insecticides

Ingestion of the bacterial toxins Bacillus thuringiensis (Berliner) sub sp kurstaki, neem seed ke... more Ingestion of the bacterial toxins Bacillus thuringiensis (Berliner) sub sp kurstaki, neem seed kernel extract and Vitex negundo L. (Lamiales: Verbenaceae) leaf extract to the rice leaffolder (RLF), Cnaphalocrocis medinalis (Guene´e) (Lepidoptera: Pyralidae), resulted in altered leaf-folding behaviour and biology. In laboratory experiments, treatment with plant extracts and bacterial toxins suppressed leaf folding behaviour of C. medinalis. Larvae fed lower doses moulted into progressive instars, but in the late fourth to early fifth instars, spinning behaviour completely stopped, feeding was reduced and larvae regurgitated a sticky, semisolid substance that occluded the tunnel in which the pupae were formed. With the combination of Btk and botanicals, average leaf consumption was decreased by a factor of two even at reduced concentrations when compared with controls. Duration of larval and pupal stages, adult longevity and fecundity were more affected by treatment with the combination of bacterial toxins and both botanicals than by the treatment with the bacterial toxins or botanicals individually. All larvae died in the treatment of bacterial toxins and both botanicals combined.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effect of biopesticides on the lactate dehydrogenase (LDH) of the rice leaffolder, Cnaphalocrocis medinalis (Guenee) (Insecta: Lepidoptera: Pyralidae)

The effects of bacterial toxins (Bacillus thuringiensis) and botanical insecticides (Azadirachta ... more The effects of bacterial toxins (Bacillus thuringiensis) and botanical insecticides (Azadirachta indica and Vitex negundo) on lactate dehydrogenase (LDH) activity in Cnaphalocrocis medinalis (Guene´ e) (the rice leaffolder) were evaluated. Bacterial toxins and botanical insecticides affected the LDH activity individually and in combination. When they were combined, the effect was more severe at low concentration. There was a decrease in enzyme activity over controls at all concentrations tested. The combined effect of the three biopesticides resulted in a considerable decrease in enzyme activity, indicating strong enzyme inhibition. Clear dose–response relationships were established with respect to enzyme activity.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Efficacy of Melia azedarach L. extract on the malarial vector Anopheles stephensi Liston (Diptera: Culicidae)

Methanolic extracts of leaves and seeds from the chinaberry tree, Melia azedarach L. (Meliaceae) ... more Methanolic extracts of leaves and seeds from the chinaberry tree, Melia azedarach L. (Meliaceae) was tested against mature and immature mosquito vector Anopheles stephensi Liston (Diptera) under laboratory condition. The extract showed strong larvicidal, pupicidal, adulticidal, antiovipositional activity, repellency and biting deterrency. The M. azedarach seed and leaf extracts were used to determine their effect on A. stephensi adults and their corresponding oviposition and consequent adult emergence in comparison with the control. The seed extracts showed high bioactivity at all doses, while the leaf extracts proved to be active, only in the higher
dose. Results obtained from the laboratory experiment showed that the seed extracts suppressed the pupal and adult activity of A. stephensi even at low dose. In general, first and second instar larvae were more susceptible to both leaves and seed extracts. Clear dose–response relationships were established with the highest dose of 2% plant extract evoking 96% mortality. Entire development of A. stephensi was inhibited by M. azedarach treatment. Less expensive (less than US$0.50 per 1 kg seed), naturally accruing biopesticide
could be an alternative for chemical pesticides.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Combined effect of biopesticides on the digestive enzymatic profiles of Cnaphalocrocis medinalis (Guene´ e) (the rice leaffolder) (Insecta: Lepidoptera: Pyralidae)

Plant extracts, especially botanical insecticides, are currently studied more and more because of... more Plant extracts, especially botanical insecticides, are currently studied more and more because of the possibility of their use in plant protection. Many of the natural plant compounds and organic compounds used in the control of insect pests are known to affect digestive enzymes. When fed a diet of rice leaves treated with botanical insecticides and bacterial toxins in bioassays, activities of the digestive enzymes protease, amylase, and lipase in the rice leaffolder larvae are affected. Digestive enzyme activities were affected by botanical insecticides and bacterial toxins individually and in combination. When combined, the effect was more severe at low concentration. There were statistically significant differences (Pp0:05) in enzyme activities in combined and individual treatments. The combination of Btk and botanical insecticides caused a two-fold decrease in enzyme activity even at reduced concentration. Clear dose–response relationships were established with respect to enzyme activity. A synergistic effect of botanical insecticides and bacterial toxins was found when combined in low doses. These effects are most pronounced in early instars.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The toxicity and behavioural effects of neem limonoids on Cnaphalocrocis medinalis (Guene´e), the rice leaffolde

Meliaceae plant products have been shown to exert pesticidal properties against a variety of inse... more Meliaceae plant products have been shown to exert pesticidal properties against a variety of insect species. In agricultural
pest control programs, such products may have the potential to be used successfully as botanical insecticides. The effect of the neem (Azadirachta indica) limonoids azadirachtin, salannin, deacetylgedunin, gedunin, 17-hydroxyazadiradione and deacetylnimbin on the biology and mortality of rice leaffolder larvae was investigated. In laboratory experiments, treatment with neem limonoids suppressed leaf folding behaviour of C. medinalis. Biological parameters (larval duration, pupal duration adult longevity and fecundity) were also affected by the treatment. Azadirachtin, salannin, and deacetylgedunin showed high bioactivity at all doses, while the rest of the neem limonoids were less active, and were only biologically active at high doses. Azadirachtin was most potent in all experiments and produced almost 100% larval mortality at 1 ppm concentration. These results indicate neem limonoids affect the larval behaviour. These effects are most pronounced in early instars.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effect of neem limonoids on lactate dehydrogenase (LDH) of the rice leaffolder, Cnaphalocrocis medinalis (Guenee) (Insecta: Lepidoptera: Pyralidae)

Neem is derived from the neem tree Azadirachta indica A. Juss. (Meliaceae), and its primary insec... more Neem is derived from the neem tree Azadirachta indica A. Juss. (Meliaceae), and its primary insecticidal component is the tetranortriterpenoid azadirachtin and other limonoids. The effect of neem limonoids azadirachtin, salannin, deacetylgedunin, gedunin, 17-hydroxyazadiradione and deacetylnimbin on enzyme lactate dehydrogenase (LDH) activity
of the rice leaffolder (RLF) Cnaphalocrocis medinalis (Lepidoptera: Pyralidae) larvae was investigated. There was a
decrease in enzyme activity relative to the control at all concentrations tested. When fed a diet of rice leaves treated with neem limonoids in bioassays, gut tissue enzyme, LDH levels in rice leaffolder larvae are affected. These results indicate neem limonoids affect LDH activity. These effects are most pronounced in early instar larvae. Azadirachtin was the
most potent in of all the limonoids in all experiments indicating strong enzyme inhibition. Clear dose–response relationships
were established with respect to LDH activity.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effects of Melia azedarach L. extract on the teak defoliator Hyblaea puera Cramer (Lepidoptera: Hyblaeidae)

Methanolic extracts from leaves and seeds of chinaberry tree, Melia azedarach L. (Meliaceae) were... more Methanolic extracts from leaves and seeds of chinaberry tree, Melia azedarach L. (Meliaceae) were tested against the larvae of
Hyblaea puera (H. puera) Cramer (Lepidoptera: Hyblaeidae) under laboratory conditions. This insect defoliates teak, and is
considered as a major pest that strongly influences the development of the teak tree. Chinaberry extracts were found to affect the growth, feeding and oviposition of H. puera. In general, the seed extracts showed high bioactivity at all doses, while the leaf extract, proved to be active, only at the higher doses. Our laboratory experiment showed that the seed extract suppressed the larval activity of H. puera even at low doses. Gross dietary utilization (efficiency of conversion of ingested and digested food) of H. puera decreased after treatment in the diet. The growth of surviving larvae decreased, and no late fourth and early fifth instars completed development on higher dose treatment of both leafs and seed extracts. Food consumption, digestion, relative consumption rate (RCR), efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD), and relative growth rate (RGR) values declined significantly, but concurrently a significant increase in approximate digestibility (AD) was observed. Clear dose–response relationships were established, with the highest dose of 4% seed extract evoking 94% feeding deterrence. Larvae that were chronically exposed M. azedarach extract showed a reduction in weight (65–84%). The less expensive and naturally occurring biopesticide may be an alternative for synthetic pesticides in order to protect forest trees.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Combined effects of azadirachtin and nucleopolyhedrovirus (SpltNPV) on Spodoptera litura Fabricius (Lepidoptera: Noctuidae) larvae

Abstract The effects of azadirachtin (AZA) and Spodoptera nucleopolyhedrovirus (SpltNPV) on devel... more Abstract
The effects of azadirachtin (AZA) and Spodoptera nucleopolyhedrovirus (SpltNPV) on development and mortality of Spodoptera litura Fabricius (tobacco cutworm) were evaluated in the laboratory. The effective concentrations for AZA and SpltNPV were determined and tested as single and combination treatments. AZA and SpltNPV produced synergistic effects on tobacco cutworm mortality in higher dose combination treatment. Combinations of AZA + SpltNPV at 0.25 ppm + 1×103 OBs and 0.50 ppm + 1×106 OBs resulted in a significantly higher larval mortality than treatment with either virus/botanical insecticide alone at the corresponding concentrations. When consumed together (AZA and SpltNPV) larvae died significantly faster compared with larvae consuming SpltNPV or AZA. These results suggest that treatments with AZA and SpltNPV at appropriate combinations of concentration levels may result in improved control of tobacco cutworm compared with treatment with either AZA or virus alone.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Food consumption, utilization, and detoxification enzyme activity of the rice leaffolder larvae after treatment with Dysoxylum triterpenes

The toxicity and physiological (enzyme and nutritional indices) effect of Dysoxylum triterpenes 3... more The toxicity and physiological (enzyme and nutritional indices) effect of Dysoxylum triterpenes 3,24,25-trihydroxycycloartane and beddomei lactone were evaluated on the rice leaffolder Cnaphalocrocis medinalis (Guenée). The LC50 [6.66ppm (SDD0.31), 5.79 ppm
(SDD0.33) for 3,24,25-DHCL and BL, respectively] and LC 90 [14.63 ppm (SDD0.36), 13.49 ppm (SDD0.27) for 3,24,25-DHCL and BL, respectively] were identifed by probit analysis. Fourth instars were exposed to various concentrations (1.5, 3, 6, and 12 ppm) of Dysoxylum
triterpenes. Results showed that treated larvae exhibited reduced food consumption and enzyme activity. Food consumption, digestion, relative consumption rate, efficiency of conversion of ingested food, efficiency of conversion of digested food, and relative growth rate values declined siginificantly but the approximate digestibility of treated larvae was significantly higher as a result of treatment (in particular 6 and 12 ppm). Likewise, the gut enzymes acid phosphatases, alkaline phosphatases, and adenosine triphosphatases were signifcantly inhibited by the Dysoxylum triterpenes. The high biological activity of these triterpenes from Dysoxylum sp. could be used as an active principle during the preparation of botanical insecticides for insect pest like rice leaffolder.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The use of Eucalyptus tereticornis Sm. (Myrtaceae) oil (leaf extract) as a natural larvicidal agent against the malaria vector Anopheles stephensi Liston (Diptera: Culicidae)

Secondary metabolites obtained from the indigenous plants with proven mosquito control potential ... more Secondary metabolites obtained from the indigenous plants with proven mosquito control potential can be used as an alternative to synthetic insecticides under the integrated vector control. The essential oil extract from the forest redgum, Eucalyptus tereticornis Sm. (Myrtaceae) was tested against mature and immature mosquito vector Anopheles stephensi Liston (Diptera) under laboratory condition. The extract showed strong larvicidal, pupicidal and adulticidal activity. The leaf oil extracts showed high bioactivity at high doses. Results obtained from the laboratory experiment showed that the leaf extracts suppressed the pupal and adult activity of Anopheles stephensi at higher doses. In general, first and second instar larvae were more susceptible to all treatments. Clear dose –response relationships were established with the highest dose of 160 ppm plant extract evoking almost 100% mortality. The results obtained suggest that, in addition to their medicinal activities, E. tereticornis can also serve as a natural mosquitocide.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effect of Botanical Insecticides and Bacterial Toxins on the Gut Enzyme of the Rice Leaffolder Cnaphalocrocis medinalis

The effect of botanical insecticides and bacterial toxins on gut enzyme activity of larvae of the... more The effect of botanical insecticides and bacterial toxins on gut enzyme activity of larvae of the rice leaffolder Cnaphalocrocis medinalis (Guen´ee) (Insecta: Lepidoptera: Pyralidae) was investigated. Gut enzyme activities were affected by botanical insecticides and bacterial toxin individually and in combination. When fed a diet of rice leaves treated with botanical insecticides and bacterial toxins, in bioassays the activities of gut tissue enzymes - acid phosphatases (ACP), alkaline phosphatases (ALP) and adenosine triphosphatases (ATPase) – of rice leaffolder larvae were affected. When combined, the effect was more severe at
a low concentration. Larvae that were chronically exposed to botanical insecticides and bacterial toxins showed a reduction in weight (59–89%) and exhibited a signicant reduction
in ACP, ALP and ATPase activities. The combination of Bacillus thuringiensis kurstaki and botanical insecticides caused a decrease of twofold in enzyme activity even at reduced concentration. A synergistic effect was found when botanical insecticides and bacterial toxins were combined at low doses. These effects were most pronounced in early instars. Clear dose–response relationships were established with respect to enzyme activity. In conclusion: (i) biopesticides are relatively safe and biodegradable; (ii) a synergistic effect of botanical insecticides and bacterial toxins was found; (iii) less expensive, readily available and naturally occurring biopesticides could be an alternative for organic and inorganic
pesticides in controlling RLF.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effect of Biopesticides Applied Separately or Together on Nutritional Indices of the Rice Leaffolder Cnaphalocrocis medinalis

Laboratory assays were done to evaluate the effect of neem seed kernel extract (Azadirachta indic... more Laboratory assays were done to evaluate the effect of neem seed kernel extract (Azadirachta indica A. Juss), Vitex negundo L. (Lamiales: Verbenaceae) leaf extract, and Bacillus thuringiensis (Berliner), applied separately or together, on nutritional indices of the rice leaffolder Cnaphalocrocis medinalis (Guen´ee) (Lepidoptera: Pyralidae). All three biopesticides suppressed feeding and larval growth and low concentrations affected the larval performance. The combined effect of the three biopesticides resulted in a considerable
decrease in nutritional indices, indicating strong deterrence. Dose response relationships were established with respect to frass production and larval growth. The efciency of conversion of ingested and digested food was considerably reduced.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effects of neem limonoids on the malaria vector Anopheles stephensi Liston (Diptera: Culicidae)

The effects of the neem (Azadirachta indica A. Juss) limonoids azadirachtin, salannin, deacetylge... more The effects of the neem (Azadirachta indica A. Juss) limonoids azadirachtin, salannin, deacetylgedunin, gedunin, 17- hydroxyazadiradione and deacetylnimbin on Anopheles stephensi Liston (Diptera: Culicidae) were investigated. In exploring advantages of pure neem limonoids, we studied the larvicidal, pupicidal, adulticidal and antiovipositional activity of neem
limonoids. Azadirachtin, salannin and deacetylgedunin showed high bioactivity at all doses, while the rest of the neem limonoids
were less active, and were only biologically active at high doses. Azadirachtin was the most potent in all experiments and produced
almost 100% larval mortality at 1 ppm concentration. In general, first to third larval instars were more susceptible to the neem limonoids. Neem products may have benefits in mosquito control programs.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The effects of azadirachtin and nucleopolyhedrovirus on midgut enzymatic profle of Spodoptera litura Fab. (Lepidoptera: Noctuidae)

The effects of azadirachtin (AZA) and nucleopolyhedrovirus (NPV) on midgut enzyme activity in Spo... more The effects of azadirachtin (AZA) and nucleopolyhedrovirus (NPV) on midgut enzyme activity in Spodoptera litura Fabricius (Lepidoptera: Noctuidae) (Tobacco cutworm) were evaluated. Gut enzyme activities were decreased by AZA and NPV individually and in combination. When S. litura larvae were fed a diet of castor leaves treated with AZA and NPV in bioassays, gut enzyme—acid phosphatases, alkaline phosphatases, adenosine triphosphatases, and lactate dehydrogenase-activities were decreased. There were statistically signiWcant diVerences (P60.05) in enzyme activities
between combined and individual treatment. A synergistic eVect of botanical insecticides and virus was found when combined in low doses. These effects are most pronounced in early instars. Maximum weight loss (59–72%) occurred, when AZA and NPV were combined.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Efficacy of neem limonoids on Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae) the rice leaffolder

In leaf cut choice assay and topical application experiments, the neem (Azadirachta indica) limon... more In leaf cut choice assay and topical application experiments, the neem (Azadirachta indica) limonoids azadirachtin, salannin,
deacetylgedunin, gedunin, 17-hydroxyazadiradione, and deacetylnimbin showed strong antifeedant and growth inhibitor activity against fifth instar larvae of Cnaphalocrocis medinalis, the rice leaffolder, a serious pest of rice in Asian countries. The parameters, used to evaluate the activity of the limonoids were larval food utilization, quantity of ingested and digested food; consumption index and feeding deterrence index. Azadirachtin, salannin, deacetylgedunin showed high bioactivity at all doses, while the other neem limonoids proved to be less active, and only at the higher doses did they display antifeedant activity. Azadirachtin was the most potent in all experiments. Gross dietary utilization (efficiency of conversion of ingested food) of C. medinalis was also decreased after treatment with limonoids. Our results suggest that neem limonoids may be used in IPM programs for rice leaffolder and should be evaluated for efficacy under field conditions.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The toxicity and physiological effect of neem limonoids on Cnaphalocrocis medinalis (Guenee) the rice leaffolder

The effect of neem (Azadirachta indica) limonoids azadirachtin, salannin, deacetylgedunin, geduni... more The effect of neem (Azadirachta indica) limonoids azadirachtin, salannin, deacetylgedunin, gedunin, 17-hydroxyazadiradione,
and deaceytlnimbin on gut enzyme activity of the rice leaffolder larvae was investigated. When fed a diet of rice leaves treated with limonoids in bioassays, gut tissue enzymes—acid phosphatases (ACP), alkaline phosphatases (ALP), and adenosine triphosphatases (ATPase) activities of rice leaffolder (Cnaphalocrocis medinalis) larvae are affected. Azadirachtin was most potent in all experiments. Larvae that were chronically exposed to limonoids showed a reduction in weight (59–89%) and exhibited a significant reduction in ACP, ALP, and ATPase activities. These results indicate neem limonoids affects gut enzyme activities. These effects are most pronounced in early instars. 

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Efficacy of nucleopolyhedrovirus and azadirachtin on Spodoptera litura Fabricius (Lepidoptera: Noctuidae)

Spodoptera litura Fabricius (Lepidoptera: Noctuidae) is a destructive pest of subtropical and tro... more Spodoptera litura Fabricius (Lepidoptera: Noctuidae) is a destructive pest of subtropical and tropical agriculture, and has the potential to be a serious pest of forage crops in Asia. The effects of azadirachtin (AZA) and nucleopolyhedrovirus (NPV) on feeding and mortality of S. litura were evaluated in the laboratory. The nutritional indices were significantly affected. Gross dietary utilization (efficiency of conversion of ingested and digested food) of S. litura was also decreased after treatment with AZA and NPV. Food consumption, efficiency of conversion of ingested and digested food, relative growth rate, and consumption index values declined significantly, but at the same time an increase in approximate digestibility was also observed. Maximum larval weight (fifth instar) loss (68%) occurred, when AZA and NPV were combined. When consumed together (AZA and NPV) larvae died significantly faster compared with larvae that consumed NPV or AZA. Dose and larval instar dependent growth retardation was observed after treatment with NPV and AZA. Upon combination of AZA with NPV, nutritional indices decreased twofold even at reduced concentration of both.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effects of Melia azedarach on nutritional physiology and enzyme activities of the rice leaVolder Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae)

Laboratory assays were done to evaluate the effect of Melia azedarach L. (Rutales: Meliaceae) see... more Laboratory assays were done to evaluate the effect of Melia azedarach L. (Rutales: Meliaceae) seed extract on nutritional
indices and gut enzymes acid phosphatases, alkaline phosphatases, adenosinetriphosphatases, and lactate dehydrogenase of
the rice leaffolder (RLF) Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae). Larvae were fed a treated rice-leaf diet
containing the seed extract and their midgut was used for enzyme determination. Laboratory experiments showed that the seed extract suppressed the larval activity of C. medinalis even at a low dose. Gross dietary utilization (effciency of conversion of ingested and digested food) of RLF decreased after ingesting the treated rice-leaf diet. Food consumption, digestion, relative consumption rate, effciency of conversion of ingested food, effciency of conversion of digested food, and relative growth rate values declined significantly. As compared to the control, consumption of the extract containing rice-leaf diet resulted in a 69% reduction of the acid phosphatases activity, a 71% reduction of the alkaline phosphatases activity, a 46% reduction of the adenosine triphosphatases activity, and a 52% inhibition of the lactate dehydrogenase activity.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effects of Millet, Wheat, Rice, and Sorghum Diets on Development of Corcyra cephalonica (Stainton) (Lepidoptera: Galleriidae) andIts Suitability as a Host for Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae)

Emergence and survival of adults for 24 h was compared for Trichogramma chilonis Ishii reared on ... more Emergence and survival of adults for 24 h was compared for Trichogramma chilonis Ishii reared on eggs of Corcyra cephalonica (Stainton) adults whose larval growth and development had been monitored on broken grains of four different cereals: finger millet (Eleusine coracana L. Gaertn),
soft white wheat (Triticum aestivum L), short-grained white rice (Oryza sativa L.), and durra sorghum (Sorghum bicolor L. Moench). For C. cephalonica, the percentage adult emergence and several fifth-instar food use indices (consumption index, relative growth rate, and efficiencies of conversion of ingested and digested food) were significantly higher for millet-reared than for sorghum-reared larvae. The nutritional indices for wheat- and rice-reared C. cephalonica larvae were intermediate
between the indices for larvae reared on millet and sorghum. The percentage adult emergence and percentage 24-h survival of T. chilonis were significantly higher on eggs of C. cephalonica hosts reared on millet than on eggs of those reared on sorghum. These results suggest that the rearing of
C. cephalonica larvae on a high-quality nutritional source resulted in high-quality eggs, which ultimately resulted in high-quality T. chilonis reared on those eggs. Such an effect has been modeled in ecological theory as a “bottom up cascade.” Improved knowledge of the nutritional ecology of parasitoids and hosts can lead to improved understanding of the ecological mechanisms affecting host plant, host, and parasitoid abundance, as well as to improved efficiency and quality of Trichogramma production in mass rearing programs.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effects of Dysoxylum malabaricum Bedd. (Meliaceae) extract on the malarial vector Anopheles stephensi Liston (Diptera: Culicidae)

In recent years, use of environmentally friendly and biodegradable natural insecticides of plant ... more In recent years, use of environmentally friendly and biodegradable natural insecticides of plant origin have received renewed attention as agents for disease vector control. Methanol extracts of leaves from the Indian white cedar Dysoxylum malabaricum Bedd. (Meliaceae) were tested against mature and immature Anopheles stephensi Liston (Diptera) mosquitoes under laboratory conditions. The extract
showed strong larvicidal, pupicidal, adulticidal, and antiovipositional activity. The maximum leaf extract concentration tested in this study was 4%, which produced pronounced effects. In general, first and second instars were more susceptible to leaf extract than older insects. Clear dose–response relationships were established, with the highest dose of 4% plant extract causing 97% mortality of first
instars.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Behavioural responses and changes in biology of rice leaffolder following treatment with a combination of bacterial toxins and botanical insecticides

Ingestion of the bacterial toxins Bacillus thuringiensis (Berliner) sub sp kurstaki, neem seed ke... more Ingestion of the bacterial toxins Bacillus thuringiensis (Berliner) sub sp kurstaki, neem seed kernel extract and Vitex negundo L. (Lamiales: Verbenaceae) leaf extract to the rice leaffolder (RLF), Cnaphalocrocis medinalis (Guene´e) (Lepidoptera: Pyralidae), resulted in altered leaf-folding behaviour and biology. In laboratory experiments, treatment with plant extracts and bacterial toxins suppressed leaf folding behaviour of C. medinalis. Larvae fed lower doses moulted into progressive instars, but in the late fourth to early fifth instars, spinning behaviour completely stopped, feeding was reduced and larvae regurgitated a sticky, semisolid substance that occluded the tunnel in which the pupae were formed. With the combination of Btk and botanicals, average leaf consumption was decreased by a factor of two even at reduced concentrations when compared with controls. Duration of larval and pupal stages, adult longevity and fecundity were more affected by treatment with the combination of bacterial toxins and both botanicals than by the treatment with the bacterial toxins or botanicals individually. All larvae died in the treatment of bacterial toxins and both botanicals combined.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effect of biopesticides on the lactate dehydrogenase (LDH) of the rice leaffolder, Cnaphalocrocis medinalis (Guenee) (Insecta: Lepidoptera: Pyralidae)

The effects of bacterial toxins (Bacillus thuringiensis) and botanical insecticides (Azadirachta ... more The effects of bacterial toxins (Bacillus thuringiensis) and botanical insecticides (Azadirachta indica and Vitex negundo) on lactate dehydrogenase (LDH) activity in Cnaphalocrocis medinalis (Guene´ e) (the rice leaffolder) were evaluated. Bacterial toxins and botanical insecticides affected the LDH activity individually and in combination. When they were combined, the effect was more severe at low concentration. There was a decrease in enzyme activity over controls at all concentrations tested. The combined effect of the three biopesticides resulted in a considerable decrease in enzyme activity, indicating strong enzyme inhibition. Clear dose–response relationships were established with respect to enzyme activity.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Efficacy of Melia azedarach L. extract on the malarial vector Anopheles stephensi Liston (Diptera: Culicidae)

Methanolic extracts of leaves and seeds from the chinaberry tree, Melia azedarach L. (Meliaceae) ... more Methanolic extracts of leaves and seeds from the chinaberry tree, Melia azedarach L. (Meliaceae) was tested against mature and immature mosquito vector Anopheles stephensi Liston (Diptera) under laboratory condition. The extract showed strong larvicidal, pupicidal, adulticidal, antiovipositional activity, repellency and biting deterrency. The M. azedarach seed and leaf extracts were used to determine their effect on A. stephensi adults and their corresponding oviposition and consequent adult emergence in comparison with the control. The seed extracts showed high bioactivity at all doses, while the leaf extracts proved to be active, only in the higher
dose. Results obtained from the laboratory experiment showed that the seed extracts suppressed the pupal and adult activity of A. stephensi even at low dose. In general, first and second instar larvae were more susceptible to both leaves and seed extracts. Clear dose–response relationships were established with the highest dose of 2% plant extract evoking 96% mortality. Entire development of A. stephensi was inhibited by M. azedarach treatment. Less expensive (less than US$0.50 per 1 kg seed), naturally accruing biopesticide
could be an alternative for chemical pesticides.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Combined effect of biopesticides on the digestive enzymatic profiles of Cnaphalocrocis medinalis (Guene´ e) (the rice leaffolder) (Insecta: Lepidoptera: Pyralidae)

Plant extracts, especially botanical insecticides, are currently studied more and more because of... more Plant extracts, especially botanical insecticides, are currently studied more and more because of the possibility of their use in plant protection. Many of the natural plant compounds and organic compounds used in the control of insect pests are known to affect digestive enzymes. When fed a diet of rice leaves treated with botanical insecticides and bacterial toxins in bioassays, activities of the digestive enzymes protease, amylase, and lipase in the rice leaffolder larvae are affected. Digestive enzyme activities were affected by botanical insecticides and bacterial toxins individually and in combination. When combined, the effect was more severe at low concentration. There were statistically significant differences (Pp0:05) in enzyme activities in combined and individual treatments. The combination of Btk and botanical insecticides caused a two-fold decrease in enzyme activity even at reduced concentration. Clear dose–response relationships were established with respect to enzyme activity. A synergistic effect of botanical insecticides and bacterial toxins was found when combined in low doses. These effects are most pronounced in early instars.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The toxicity and behavioural effects of neem limonoids on Cnaphalocrocis medinalis (Guene´e), the rice leaffolde

Meliaceae plant products have been shown to exert pesticidal properties against a variety of inse... more Meliaceae plant products have been shown to exert pesticidal properties against a variety of insect species. In agricultural
pest control programs, such products may have the potential to be used successfully as botanical insecticides. The effect of the neem (Azadirachta indica) limonoids azadirachtin, salannin, deacetylgedunin, gedunin, 17-hydroxyazadiradione and deacetylnimbin on the biology and mortality of rice leaffolder larvae was investigated. In laboratory experiments, treatment with neem limonoids suppressed leaf folding behaviour of C. medinalis. Biological parameters (larval duration, pupal duration adult longevity and fecundity) were also affected by the treatment. Azadirachtin, salannin, and deacetylgedunin showed high bioactivity at all doses, while the rest of the neem limonoids were less active, and were only biologically active at high doses. Azadirachtin was most potent in all experiments and produced almost 100% larval mortality at 1 ppm concentration. These results indicate neem limonoids affect the larval behaviour. These effects are most pronounced in early instars.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effect of neem limonoids on lactate dehydrogenase (LDH) of the rice leaffolder, Cnaphalocrocis medinalis (Guenee) (Insecta: Lepidoptera: Pyralidae)

Neem is derived from the neem tree Azadirachta indica A. Juss. (Meliaceae), and its primary insec... more Neem is derived from the neem tree Azadirachta indica A. Juss. (Meliaceae), and its primary insecticidal component is the tetranortriterpenoid azadirachtin and other limonoids. The effect of neem limonoids azadirachtin, salannin, deacetylgedunin, gedunin, 17-hydroxyazadiradione and deacetylnimbin on enzyme lactate dehydrogenase (LDH) activity
of the rice leaffolder (RLF) Cnaphalocrocis medinalis (Lepidoptera: Pyralidae) larvae was investigated. There was a
decrease in enzyme activity relative to the control at all concentrations tested. When fed a diet of rice leaves treated with neem limonoids in bioassays, gut tissue enzyme, LDH levels in rice leaffolder larvae are affected. These results indicate neem limonoids affect LDH activity. These effects are most pronounced in early instar larvae. Azadirachtin was the
most potent in of all the limonoids in all experiments indicating strong enzyme inhibition. Clear dose–response relationships
were established with respect to LDH activity.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effects of Melia azedarach L. extract on the teak defoliator Hyblaea puera Cramer (Lepidoptera: Hyblaeidae)

Methanolic extracts from leaves and seeds of chinaberry tree, Melia azedarach L. (Meliaceae) were... more Methanolic extracts from leaves and seeds of chinaberry tree, Melia azedarach L. (Meliaceae) were tested against the larvae of
Hyblaea puera (H. puera) Cramer (Lepidoptera: Hyblaeidae) under laboratory conditions. This insect defoliates teak, and is
considered as a major pest that strongly influences the development of the teak tree. Chinaberry extracts were found to affect the growth, feeding and oviposition of H. puera. In general, the seed extracts showed high bioactivity at all doses, while the leaf extract, proved to be active, only at the higher doses. Our laboratory experiment showed that the seed extract suppressed the larval activity of H. puera even at low doses. Gross dietary utilization (efficiency of conversion of ingested and digested food) of H. puera decreased after treatment in the diet. The growth of surviving larvae decreased, and no late fourth and early fifth instars completed development on higher dose treatment of both leafs and seed extracts. Food consumption, digestion, relative consumption rate (RCR), efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD), and relative growth rate (RGR) values declined significantly, but concurrently a significant increase in approximate digestibility (AD) was observed. Clear dose–response relationships were established, with the highest dose of 4% seed extract evoking 94% feeding deterrence. Larvae that were chronically exposed M. azedarach extract showed a reduction in weight (65–84%). The less expensive and naturally occurring biopesticide may be an alternative for synthetic pesticides in order to protect forest trees.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Combined effects of azadirachtin and nucleopolyhedrovirus (SpltNPV) on Spodoptera litura Fabricius (Lepidoptera: Noctuidae) larvae

Abstract The effects of azadirachtin (AZA) and Spodoptera nucleopolyhedrovirus (SpltNPV) on devel... more Abstract
The effects of azadirachtin (AZA) and Spodoptera nucleopolyhedrovirus (SpltNPV) on development and mortality of Spodoptera litura Fabricius (tobacco cutworm) were evaluated in the laboratory. The effective concentrations for AZA and SpltNPV were determined and tested as single and combination treatments. AZA and SpltNPV produced synergistic effects on tobacco cutworm mortality in higher dose combination treatment. Combinations of AZA + SpltNPV at 0.25 ppm + 1×103 OBs and 0.50 ppm + 1×106 OBs resulted in a significantly higher larval mortality than treatment with either virus/botanical insecticide alone at the corresponding concentrations. When consumed together (AZA and SpltNPV) larvae died significantly faster compared with larvae consuming SpltNPV or AZA. These results suggest that treatments with AZA and SpltNPV at appropriate combinations of concentration levels may result in improved control of tobacco cutworm compared with treatment with either AZA or virus alone.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Food consumption, utilization, and detoxification enzyme activity of the rice leaffolder larvae after treatment with Dysoxylum triterpenes

The toxicity and physiological (enzyme and nutritional indices) effect of Dysoxylum triterpenes 3... more The toxicity and physiological (enzyme and nutritional indices) effect of Dysoxylum triterpenes 3,24,25-trihydroxycycloartane and beddomei lactone were evaluated on the rice leaffolder Cnaphalocrocis medinalis (Guenée). The LC50 [6.66ppm (SDD0.31), 5.79 ppm
(SDD0.33) for 3,24,25-DHCL and BL, respectively] and LC 90 [14.63 ppm (SDD0.36), 13.49 ppm (SDD0.27) for 3,24,25-DHCL and BL, respectively] were identifed by probit analysis. Fourth instars were exposed to various concentrations (1.5, 3, 6, and 12 ppm) of Dysoxylum
triterpenes. Results showed that treated larvae exhibited reduced food consumption and enzyme activity. Food consumption, digestion, relative consumption rate, efficiency of conversion of ingested food, efficiency of conversion of digested food, and relative growth rate values declined siginificantly but the approximate digestibility of treated larvae was significantly higher as a result of treatment (in particular 6 and 12 ppm). Likewise, the gut enzymes acid phosphatases, alkaline phosphatases, and adenosine triphosphatases were signifcantly inhibited by the Dysoxylum triterpenes. The high biological activity of these triterpenes from Dysoxylum sp. could be used as an active principle during the preparation of botanical insecticides for insect pest like rice leaffolder.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The use of Eucalyptus tereticornis Sm. (Myrtaceae) oil (leaf extract) as a natural larvicidal agent against the malaria vector Anopheles stephensi Liston (Diptera: Culicidae)

Secondary metabolites obtained from the indigenous plants with proven mosquito control potential ... more Secondary metabolites obtained from the indigenous plants with proven mosquito control potential can be used as an alternative to synthetic insecticides under the integrated vector control. The essential oil extract from the forest redgum, Eucalyptus tereticornis Sm. (Myrtaceae) was tested against mature and immature mosquito vector Anopheles stephensi Liston (Diptera) under laboratory condition. The extract showed strong larvicidal, pupicidal and adulticidal activity. The leaf oil extracts showed high bioactivity at high doses. Results obtained from the laboratory experiment showed that the leaf extracts suppressed the pupal and adult activity of Anopheles stephensi at higher doses. In general, first and second instar larvae were more susceptible to all treatments. Clear dose –response relationships were established with the highest dose of 160 ppm plant extract evoking almost 100% mortality. The results obtained suggest that, in addition to their medicinal activities, E. tereticornis can also serve as a natural mosquitocide.

Bookmarks Related papers MentionsView impact