Objective: To determine abundance, distribution and diversity of potential breeding container habitats of the dengue vectors in public places including schools, restaurants,mosques and parks in southwest areas of Pena...Objective: To determine abundance, distribution and diversity of potential breeding container habitats of the dengue vectors in public places including schools, restaurants,mosques and parks in southwest areas of Penang Island, Malaysia.Methods: Premises at restaurants, schools, parks and mosques were surveyed simultaneously and inspected visually for container habitats and production of immature mosquitoes from March 2015 to March 2016. Abundance(mean ± SE) of breeding containers between sites was compared using One-way ANOVA. Independent sample ttest was used to compare total number of Aedes albopictus(Ae. albopictus) and Aedes aegypti(Ae. aegypti) surveyed.Results: The surveyed locations yielded a total of 3 741 breeding containers and 19 537 immature mosquitoes from four areas. Concurrent artificial and natural containers produced 78.4% immature Ae. albopictus and 6.3% Ae. aegypti mosquitoes in wet season,with 14.2% Ae. albopictus and 1.1% Ae. aegypti mosquitoes in dry season. Artificial containers accounted for 98.1% of the total containers recorded, with restaurants being the most productive locations(8 012) and schools being the least productive(2 234).Conclusions: It was concluded that public places are good sources of potential container habitats of Aedes mosquitoes in Penang Island, Malaysia and Ae. albopictus has exclusively replaced the home-grown Ae. aegypti even in urban areas. Therefore, treatment of artificial containers in such locations is critical in Aedes mosquito control campaigns during dengue outbreaks.展开更多
Objective: To explore the larvicidal activities of different plant parts of Melanochyla fasciculiflora(M. fasciculiflora), Gluta renghas(G. renghas), Anacardium occidentale and Mangifera indica from family Anacardiace...Objective: To explore the larvicidal activities of different plant parts of Melanochyla fasciculiflora(M. fasciculiflora), Gluta renghas(G. renghas), Anacardium occidentale and Mangifera indica from family Anacardiaceae against the laboratory and field strains of dengue vectors Aedes aegypti and Aedes albopictus(Ae. albopictus).Methods: Leaves and bark parts of study plants were collected from Taman Nageri,Bukit Pancor and Teluk Bahang National Park, Penang, Malaysia. Leaves and stem barks were separated, air dried, ground and extracted with methanol by Soxhlet apparatus.Crude extract was obtained by evaporating the extra solvent in rotary evaporator. The 4th instar larvae from laboratory and field strains were exposed to 50–1 300 mg/L concentrations according to World Health Organization standard larval bioassay. Larval mortality was recorded after 24 h of exposure.Results: Highest larvicidal activity was exhibited by G. renghas bark extract against Ae.albopictus laboratory strain at 600 mg/L. G. renghas also showed the highest larvicidal activities for other strains as compared to other plant extracts, followed by Mangifera indica and M. fasciculiflora and Anacardium occidentale.Conclusions: Ae. albopictus has been found to be more susceptible as compare to Aedes aegypti in both laboratory and field strains in this study. G. renghas and M. fasciculiflora were tested for the first time and exhibited prompting larvicidal activities against dengue vectors. These results revealed that all the plants especially G. renghas and M. fasciculiflora have the higher larvicidal activities and can be used for the control of dengue vector as a new environment friendly, target specific and low cost phytochemical.展开更多
Objective:To monitor the current duration of the application rates in vector programme and the level of Aedes albopictus larvae susceptibility from three selected areas in northeast district of Penang on two selected ...Objective:To monitor the current duration of the application rates in vector programme and the level of Aedes albopictus larvae susceptibility from three selected areas in northeast district of Penang on two selected larvicides,temephos and Bacillus thuringiensis subsp.israelensis(Bti) which are commonly used by Penang Health Department for vector control.Methods:The mosquito larvae were tested against two types of larvicides:(1) temephos(Abate®) with diagnostic dosage(0.012 mg/L) and operational dosage(1 mg/L) and(2)Bacillus thuringiensis subsp.israelensis(Vecto Bac®WG) with operational dosage ranging from 6 000 international toxic units per L to 24 000 international toxic unit per L.A total of 20 late third and early forth instar larvae were selected and transferred into paper cup sized 300 m L using wide-mouthed pipette.The larvae were distributed into each 300 m L paper cup containing 50 m L of aged tap water.The experiment was replicated five times for each concentration tested.Each test was repeated three times.The mortality was recorded after 24 h of exposure and recorded lethal time was based on 2 h for temephos and 6 h for Bti.The control consisted of ethanol for temephos and only seasoned water for Bti.Results:The result showed that Aedes albopictus from Flat Hamna,Kampung Sungai Gelugor and Kampung Tanjung Tokong were still susceptible to Bti and temephos.However,higher lethal time and resistance ratio were detected in strain from Flat Hamna which was a known dengue hot spot area in northeast of Penang.Conclusions:The application of temephos and Bti in vector control activity in these selected localities is still relevant in the control of Aedes larvae populations.展开更多
Objective: To test the effectiveness of conidial spore formulations [Aspergillus tubingensis(A.tubingensis) and Trichoderma harzianum(T.harzianum)] against tropical bed bugs, Cimex hemipterus.Methods: Spore formulatio...Objective: To test the effectiveness of conidial spore formulations [Aspergillus tubingensis(A.tubingensis) and Trichoderma harzianum(T.harzianum)] against tropical bed bugs, Cimex hemipterus.Methods: Spore formulations were made from two fungal strains, T.harzianum and A.tubingensis.The bed bugs were exposed to the conidial spores placed soaked onto a fabric cloth for 1 h and the mortality counts were recorded daily until 14 days.Results: Mean survival times based on Kaplan–Meier survival analysis showed no significant differences between all the concentrations in both the fungal isolates:T.harzianum and A.tubingensis.However, the evaluation of both the isolates in terms of virulence resulted in low lethal hours in all the concentrations except for the high concentration of A.tubingensis(LT_(50)= 44.629 h) at the conidial exposure of 1 × 10~6 spores/mL.Rapid mortality of the bed bugs was observed from Day 6 to Day 12, ranging from 13% to 90% in all three concentrations of A.tubingensis.With reference to the T.harzianum exposure, the concentration of 1 × 10~4 spores/mL displayed a gradual increase in the percentage mortality of 90 on Day 14.Conclusions: Approaches to the bed bugs treatment should be explored in-depth using a natural biological agent like fungus especially A.tubingensis to reduce this pest population, in order to replace chemical methods.展开更多
Objective: To evaluate the lethal concentration, oviposition deterrence and ovicidal activity of acetone extracts of Melanochyla fasciculiflora(M. fasciculiflora) leaf and Gluta renghas(G. renghas) leaf against Aedes ...Objective: To evaluate the lethal concentration, oviposition deterrence and ovicidal activity of acetone extracts of Melanochyla fasciculiflora(M. fasciculiflora) leaf and Gluta renghas(G. renghas) leaf against Aedes albopictus(Ae. albopictus). Methods: To determine the lethal concentration of Anacardiaceae, ten test concentrations of the extracts ranging from 200 to 650 mg/L were selected for larvicidal bioassays and 25 early fourth instar larvae were exposed to the extracts for 24 h. The sub-lethal concentrations used for oviposition deterrence was the value of LC25, LC50 and LC75 from above study which is 235 mg/L, 470 mg/L and 705 mg/L for M. fasciculiflora extract and 187.5 mg/L, 375 mg/L and 562.5 mg/L for G. renghas extract, respectively. Twenty gravid Ae. albopictus were allowed to oviposit in different treated concentrations. For oviciding procedure, a total of 300 eggs of Ae. albopictus were soaked in solution with each treated concentration as mentioned above for 24 h. After 24 h, eggs were sieved and soaked in seasoned water, and hatching rates were calculated. For comparison, only seasoned water was used in control experiment.Results: G. renghas demonstrated lower LC50 value of 372.80 mg/L compared to M. fasciculiflora(467.90 mg/L). The activity index of negative oviposition revealed the deterrent effect and thus, caused a remarkable negative response resulting in oviposition of fewer eggs compared with control(without plant extract). The acetone extract of M. fasciculiflora was more effective than G. renghas extract in displaying oviposition deterrence potential since the latter did not possess the deterring effect within the concentration range tested. However, both plant extracts exhibited excellent oviciding effect as 92.33% of eggs failed to be hatched when treated with 705.0 mg/L of M. fasciculiflora and 86.67% with 562.5 mg/L of G. renghas. The oviposition deterrence and percentage of egg mortality were directly proportional to the concentrations of extracts in both plants tested. Conclusions: These results clearly indicate that the acetone extract of G. renghas could be served as potential larvicide, whereas M. fasciculiflora has better sub-lethal effect for oviposition deterrence and against Ae. albopictus as an oviciding agent.展开更多
The harmful effects of chemical-based termiticides and the increased incidence of termite resistance have resulted in the need for safer and more effective termiticides.Therefore,the screening of antitermiticidal acti...The harmful effects of chemical-based termiticides and the increased incidence of termite resistance have resulted in the need for safer and more effective termiticides.Therefore,the screening of antitermiticidal activity of naturally-occurring products could possibly hamper an alternative means in termite control strategies.The aims of this study were to determine the toxicity and repellency of L.leucocephala,A.paniculata,Az.indica and P.niruri crude extracts against two subterranean termites,G.sulphureus and C.gestroi.Bioassays were conducted by applying varying concentrations of the plant extracts(10,000 ppm,5000 ppm and 500 ppm)on both termite species under laboratory conditions.All extracts exhibited a significant antitermiticidal activity in time-and concentration-dependent manners after 14 days of exposure.The highest mortality of G.sulpureus and C.gestroi were noted in all methanolic extracts of P.niruri,L.leucocephala,A.paniculata,Az.indica at 10,000 ppm.High repellent activity was also noted in the choice bioassay when both termites were treated with all methanolic extracts at 10,000 ppm.展开更多
基金Funded by a grant from Universiti Sains Malaysia(Grant No.1001/PBIOLOGI/811277)
文摘Objective: To determine abundance, distribution and diversity of potential breeding container habitats of the dengue vectors in public places including schools, restaurants,mosques and parks in southwest areas of Penang Island, Malaysia.Methods: Premises at restaurants, schools, parks and mosques were surveyed simultaneously and inspected visually for container habitats and production of immature mosquitoes from March 2015 to March 2016. Abundance(mean ± SE) of breeding containers between sites was compared using One-way ANOVA. Independent sample ttest was used to compare total number of Aedes albopictus(Ae. albopictus) and Aedes aegypti(Ae. aegypti) surveyed.Results: The surveyed locations yielded a total of 3 741 breeding containers and 19 537 immature mosquitoes from four areas. Concurrent artificial and natural containers produced 78.4% immature Ae. albopictus and 6.3% Ae. aegypti mosquitoes in wet season,with 14.2% Ae. albopictus and 1.1% Ae. aegypti mosquitoes in dry season. Artificial containers accounted for 98.1% of the total containers recorded, with restaurants being the most productive locations(8 012) and schools being the least productive(2 234).Conclusions: It was concluded that public places are good sources of potential container habitats of Aedes mosquitoes in Penang Island, Malaysia and Ae. albopictus has exclusively replaced the home-grown Ae. aegypti even in urban areas. Therefore, treatment of artificial containers in such locations is critical in Aedes mosquito control campaigns during dengue outbreaks.
基金Supported by USM Research University Grant(1001/PBIOLOGI/815079)Ministry of Higher Education Commission,Malaysia(MOHE)
文摘Objective: To explore the larvicidal activities of different plant parts of Melanochyla fasciculiflora(M. fasciculiflora), Gluta renghas(G. renghas), Anacardium occidentale and Mangifera indica from family Anacardiaceae against the laboratory and field strains of dengue vectors Aedes aegypti and Aedes albopictus(Ae. albopictus).Methods: Leaves and bark parts of study plants were collected from Taman Nageri,Bukit Pancor and Teluk Bahang National Park, Penang, Malaysia. Leaves and stem barks were separated, air dried, ground and extracted with methanol by Soxhlet apparatus.Crude extract was obtained by evaporating the extra solvent in rotary evaporator. The 4th instar larvae from laboratory and field strains were exposed to 50–1 300 mg/L concentrations according to World Health Organization standard larval bioassay. Larval mortality was recorded after 24 h of exposure.Results: Highest larvicidal activity was exhibited by G. renghas bark extract against Ae.albopictus laboratory strain at 600 mg/L. G. renghas also showed the highest larvicidal activities for other strains as compared to other plant extracts, followed by Mangifera indica and M. fasciculiflora and Anacardium occidentale.Conclusions: Ae. albopictus has been found to be more susceptible as compare to Aedes aegypti in both laboratory and field strains in this study. G. renghas and M. fasciculiflora were tested for the first time and exhibited prompting larvicidal activities against dengue vectors. These results revealed that all the plants especially G. renghas and M. fasciculiflora have the higher larvicidal activities and can be used for the control of dengue vector as a new environment friendly, target specific and low cost phytochemical.
基金Funded by FGRS Grant by Ministry of Education and Universiti Sains Malaysia(203/PBIOLOGI/6711359)
文摘Objective:To monitor the current duration of the application rates in vector programme and the level of Aedes albopictus larvae susceptibility from three selected areas in northeast district of Penang on two selected larvicides,temephos and Bacillus thuringiensis subsp.israelensis(Bti) which are commonly used by Penang Health Department for vector control.Methods:The mosquito larvae were tested against two types of larvicides:(1) temephos(Abate®) with diagnostic dosage(0.012 mg/L) and operational dosage(1 mg/L) and(2)Bacillus thuringiensis subsp.israelensis(Vecto Bac®WG) with operational dosage ranging from 6 000 international toxic units per L to 24 000 international toxic unit per L.A total of 20 late third and early forth instar larvae were selected and transferred into paper cup sized 300 m L using wide-mouthed pipette.The larvae were distributed into each 300 m L paper cup containing 50 m L of aged tap water.The experiment was replicated five times for each concentration tested.Each test was repeated three times.The mortality was recorded after 24 h of exposure and recorded lethal time was based on 2 h for temephos and 6 h for Bti.The control consisted of ethanol for temephos and only seasoned water for Bti.Results:The result showed that Aedes albopictus from Flat Hamna,Kampung Sungai Gelugor and Kampung Tanjung Tokong were still susceptible to Bti and temephos.However,higher lethal time and resistance ratio were detected in strain from Flat Hamna which was a known dengue hot spot area in northeast of Penang.Conclusions:The application of temephos and Bti in vector control activity in these selected localities is still relevant in the control of Aedes larvae populations.
基金Supported by Universiti Sains Malaysia(Grant No.304/PBIOLOGI/6313030)
文摘Objective: To test the effectiveness of conidial spore formulations [Aspergillus tubingensis(A.tubingensis) and Trichoderma harzianum(T.harzianum)] against tropical bed bugs, Cimex hemipterus.Methods: Spore formulations were made from two fungal strains, T.harzianum and A.tubingensis.The bed bugs were exposed to the conidial spores placed soaked onto a fabric cloth for 1 h and the mortality counts were recorded daily until 14 days.Results: Mean survival times based on Kaplan–Meier survival analysis showed no significant differences between all the concentrations in both the fungal isolates:T.harzianum and A.tubingensis.However, the evaluation of both the isolates in terms of virulence resulted in low lethal hours in all the concentrations except for the high concentration of A.tubingensis(LT_(50)= 44.629 h) at the conidial exposure of 1 × 10~6 spores/mL.Rapid mortality of the bed bugs was observed from Day 6 to Day 12, ranging from 13% to 90% in all three concentrations of A.tubingensis.With reference to the T.harzianum exposure, the concentration of 1 × 10~4 spores/mL displayed a gradual increase in the percentage mortality of 90 on Day 14.Conclusions: Approaches to the bed bugs treatment should be explored in-depth using a natural biological agent like fungus especially A.tubingensis to reduce this pest population, in order to replace chemical methods.
基金Supported by Universiti Sains Malaysia Research University Grant(Grant No.1001/PBIOLOGI/815079)
文摘Objective: To evaluate the lethal concentration, oviposition deterrence and ovicidal activity of acetone extracts of Melanochyla fasciculiflora(M. fasciculiflora) leaf and Gluta renghas(G. renghas) leaf against Aedes albopictus(Ae. albopictus). Methods: To determine the lethal concentration of Anacardiaceae, ten test concentrations of the extracts ranging from 200 to 650 mg/L were selected for larvicidal bioassays and 25 early fourth instar larvae were exposed to the extracts for 24 h. The sub-lethal concentrations used for oviposition deterrence was the value of LC25, LC50 and LC75 from above study which is 235 mg/L, 470 mg/L and 705 mg/L for M. fasciculiflora extract and 187.5 mg/L, 375 mg/L and 562.5 mg/L for G. renghas extract, respectively. Twenty gravid Ae. albopictus were allowed to oviposit in different treated concentrations. For oviciding procedure, a total of 300 eggs of Ae. albopictus were soaked in solution with each treated concentration as mentioned above for 24 h. After 24 h, eggs were sieved and soaked in seasoned water, and hatching rates were calculated. For comparison, only seasoned water was used in control experiment.Results: G. renghas demonstrated lower LC50 value of 372.80 mg/L compared to M. fasciculiflora(467.90 mg/L). The activity index of negative oviposition revealed the deterrent effect and thus, caused a remarkable negative response resulting in oviposition of fewer eggs compared with control(without plant extract). The acetone extract of M. fasciculiflora was more effective than G. renghas extract in displaying oviposition deterrence potential since the latter did not possess the deterring effect within the concentration range tested. However, both plant extracts exhibited excellent oviciding effect as 92.33% of eggs failed to be hatched when treated with 705.0 mg/L of M. fasciculiflora and 86.67% with 562.5 mg/L of G. renghas. The oviposition deterrence and percentage of egg mortality were directly proportional to the concentrations of extracts in both plants tested. Conclusions: These results clearly indicate that the acetone extract of G. renghas could be served as potential larvicide, whereas M. fasciculiflora has better sub-lethal effect for oviposition deterrence and against Ae. albopictus as an oviciding agent.
文摘The harmful effects of chemical-based termiticides and the increased incidence of termite resistance have resulted in the need for safer and more effective termiticides.Therefore,the screening of antitermiticidal activity of naturally-occurring products could possibly hamper an alternative means in termite control strategies.The aims of this study were to determine the toxicity and repellency of L.leucocephala,A.paniculata,Az.indica and P.niruri crude extracts against two subterranean termites,G.sulphureus and C.gestroi.Bioassays were conducted by applying varying concentrations of the plant extracts(10,000 ppm,5000 ppm and 500 ppm)on both termite species under laboratory conditions.All extracts exhibited a significant antitermiticidal activity in time-and concentration-dependent manners after 14 days of exposure.The highest mortality of G.sulpureus and C.gestroi were noted in all methanolic extracts of P.niruri,L.leucocephala,A.paniculata,Az.indica at 10,000 ppm.High repellent activity was also noted in the choice bioassay when both termites were treated with all methanolic extracts at 10,000 ppm.
