Inhibition Of Adult Emergence Research Articles

FUNCTIONAL RESPONSE, HOST STAGE PREFERENCE AND DEVELOPMENT OF RHYNOCORIS FUSCIPES (FAB.) (HETEROPTERA: REDUVIIDAE) FOR TWO COTTON PESTS

The rice weevil, Sitophilus oryzae is a major stored grain insect pest that causes both quantitative and qualitative damage to cereals. Hence, the study was conducted to evaluate the insecticidal efficacy of Clerodendrum multiflorum, Clerodendrum viscosum, Vitex negundo, Argemone mexicana and Withania somnifera leaves essential oil against S. oryzae in laboratory conditions. The essential oil isolated from V. negundo and A. mexicana at 2.0 μL/gm of wheat was found to be toxic, causing 100% mortality as compared to other plant essential oils. The percentage of oviposition deterrence increased from 20% to 90% by increasing the concentrations of essential oils. Interestingly, all plant essential oils were inhibited F1 adult emergence at lower dose. Essential oils of V. negundo and A. mexicana revealed significant toxicity, oviposition deterrence and inhibition of F1 adult emergence of S. oryzae at lower concentrations. Thus, these plant essential oils may be suggested as admixtures in the integrated management of rice weevil during the storage of grains.

FIELD ASSESSMENT OF AUTODISSEMINATION OF PYRIPROXYFEN BY CONTAINER-INHABITING AEDES MOSQUITOES IN FLORIDA

Domestic mosquito control for container-inhabiting Aedes vectors of Zika, chikungunya, yellow fever, and dengue viruses is challenging, and novel methods are needed. Autodissemination strategies are one such method. In this control method, females are attracted to stations treated with an insect growth regulator (IGR), become treated, and subsequently deposit the IGR in natural oviposition sites, preventing pupal emergence. We developed and tested treatment stations in semi-field conditions based on number of captured mosquitoes in the treatment stations. The modified treatment station attracted gravid females with oak leaf infusion and mosquito passage through exit chutes granted access to sucrose and topical contamination of IGR (pyriproxyfen) for 25% of released mosquitoes. Although a majority of released mosquitoes were uncaptured (75%), sufficient amounts of pyriproxyfen contaminated female mosquitoes to result in 75% inhibition of adult emergence in larval bioassays. These stations were then used in a field experiment to test the efficacy using sentinel cups with mosquito larvae. Three treatments which included varied numbers of autodissemination stations (control, low density, and high density) were compared. Both low and high density of stations provided high inhibition of adult emergence from sentinel cups relative to controls. We did not observe differences in mosquito emergence inhibition whether sites contained low or high densities of stations (i.e., similar rates of mosquito inhibition). Two additional field trials showed that topically contaminated mosquitoes were traveling further than expected and causing mortality in sentinel cups at least as far as 80 meters from the autodissemination stations. The development and implementation of autodissemination of IGRs is an additional tool for use in integrated mosquito management.

Efficacy of Mentha Piperita L. and Verbascum Thapsus L. Extracts Against Callosobruchus Chinensis L. in Horse Gram

In view of the insecticidal properties of Mentha piperita (peppermint) and Verbascum thapsus (jungle tambakoo) these were evaluated for their efficacy against pulse beetle Callosobruchus chinensis (L.) infesting horse gram. Extracts of leaves, roots and inflorescence were prepared with acetone and methanol and these evaluated by considering adult mortality, oviposition and emergence of F1 progeny. The results revealed significant effects on oviposition and emergence of adults, with extracts from leaves providing the best protection. It was observed that 20% extract of M. piperita resulted in 100% inhibition of adult emergence.

The effects of exposure to pyriproxyfen and predation on Zika virus infection and transmission in Aedes aegypti.

Zika virus (ZIKV) is an emerging mosquito-borne pathogen that can cause global public health threats. In the absence of effective antiviral medications, prevention measures rely largely on reducing the number of adult mosquito vectors by targeting juvenile stages. Despite the importance of juvenile mosquito control measures in reducing adult population size, a full understanding of the effects of these measures in determining mosquito phenotypic traits and in mosquito-arbovirus interactions is poorly understood. Pyriproxyfen is a juvenile hormone analog that primarily blocks adult emergence, but does not cause mortality in larvae. This mechanism has the potential to work in combination with other juvenile sources of mortality in nature such as predation to affect mosquito populations. Here, we experimentally evaluated the effects of juvenile exposure to pyriproxyfen and predatory mosquito Toxorhynchites rutilus on Aedes aegypti phenotypes including susceptibility to ZIKV infection and transmission. We discovered that combined effects of pyriproxyfen and Tx. rutilus led to higher inhibition of adult emergence in Ae. aegypti than observed in pyriproxyfen or Tx. rutilus treatments alone. Adult body size was larger in treatments containing Tx. rutilus and in treatments mimicking the daily mortality of predation compared to control or pyriproxyfen treatments. Susceptibility to infection with ZIKV in Ae. aegypti was reduced in predator treatment relative to those exposed to pyriproxyfen. Disseminated infection, transmission, and titers of ZIKV in Ae. aegypti were similar in all treatments relative to controls. Our data suggest that the combination of pyriproxyfen and Tx. rutilus can inhibit adult Ae. aegypti emergence but may confer a fitness advantage in survivors and does not inhibit their vector competence for ZIKV relative to controls. Understanding the ultimate consequences of juvenile mosquito control measures on subsequent adults’ ability to transmit pathogens is critical to fully understand their overall impacts.

Assessment of the susceptibility status of Aedes aegypti (Diptera: Culicidae) populations to pyriproxyfen and malathion in a nation-wide monitoring of insecticide resistance performed in Brazil from 2017 to 2018

BackgroundChemical mosquito control using malathion has been applied in Brazil since 1985. To obtain chemical control effectiveness, vector susceptibility insecticide monitoring is required. This study aimed to describe bioassay standardizations and determine the susceptibility profile of Ae. aegypti populations to malathion and pyriproxyfen, used on a national scale in Brazil between 2017 and 2018, and discuss the observed impacts in arbovirus control.MethodsThe diagnostic-doses (DD) of pyriproxyfen and malathion were determined as the double of adult emergence inhibition (EI) and lethal doses for 99% of the Rockefeller reference strain, respectively. To monitor natural populations, sampling was performed in 132 Brazilian cities, using egg traps. Colonies were raised in the laboratory for one or two generations (F1 or F2) and submitted to susceptibility tests, where larvae were exposed to the pyriproxyfen DD (0.03 µg/l) and adults, to the malathion DD determined in the present study (20 µg), in addition to the one established by the World Health Organization (WHO) DD (50 µg) in a bottle assay. Dose-response (DR) bioassays with pyriproxyfen were performed on populations that did not achieve 98% EI in the DD assays.ResultsSusceptibility alterations to pyriproxyfen were recorded in six (4.5%) Ae. aegypti populations from the states of Bahia and Ceará, with Resistance Ratios (RR95) ranging from 1.51 to 3.58. Concerning malathion, 73 (55.3%) populations distributed throughout the country were resistant when exposed to the local DD 20 µg/bottle. On the other hand, no population was resistant, and only 10 (7.6%) populations in eight states were considered as exhibiting decreased susceptibility (mortality ratios between 90 and 98%) when exposed to the WHO DD (50 µg/bottle).ConclusionsThe feasibility of conducting an insecticide resistance monitoring action on a nation-wide scale was confirmed herein, employing standardized and strongly coordinated sampling methods and laboratory bioassays. Brazilian Ae. aegypti populations exhibiting decreased susceptibility to pyriproxyfen were identified. The local DD for malathion was more sensitive than the WHO DD for early decreased susceptibility detection.

Residual Activity of Pyriproxyfen Against Mosquitoes in Catch Basins in Northwestern Riverside County, Southern California.

A field study was carried out on the year-long residual activity of the insect growth regulator (IGR) pyriproxyfen (Nylar 0.5G) in comparison with methoprene (Altosid® XRP Pellets) against mosquito developmental stages in catch basins in northwestern Riverside County, southern California. Pyriproxyfen was applied at 75, 100, 125, 150, 175 g per catch basin and methoprene at 3.5 g per catch basin. A total of 80 catch basins (10 per each treatment and 20 for control) were used. Posttreatment observations of catch basins were carried out at weekly intervals, with all pupal collections reared to adults. Mosquito species composition in this study, consisting mostly of Culex species (693), was predominated by Cx. quinquefasciatus (92.8%), followed by Cx. erythrothorax (5.5%), Cx. tarsalis (1.2%), Cx. stigmatosoma (0.3%), and Cx. thriambus (0.2%). Activity of both IGRs was expressed as percent inhibition of adult emergence (% IAE). Data generated on % IAE showed that, like methoprene, pyriproxyfen provided complete control of mosquitoes at 75, 125, and 175 g per catch basin up to 50 wk posttreatment at the Riverside amusement park, whereas its activity against mosquitoes in catch basins treated with 100 g and 150 g at the Eastvale site was short-lived, up to 48 wk. Water samples, bioassayed against laboratory-reared, 4th-stage larvae of Cx. quinquefasciatus 1-2 wk after the 50-wk-long study, showed evidence of significant % IAE (∼50) by pyriproxyfen at the 2 higher rates (125 g, 175 g) used at the amusement park. In conclusion, pyriproxyfen can be used to effectively control mosquitoes in catch basins for 48-50 wk, depending on the rate of application.

Deployment and Fact Analysis of the In2Care® Mosquito Trap, A Novel Tool for Controlling Invasive Aedes Species.

During April-October 2019, the West Valley Mosquito and Vector Control District (Ontario, CA) deployed large numbers of In2Care® mosquito traps in a preliminary study to evaluate the trap's potential effectiveness at controlling invasive Aedes aegypti (L.) and Ae. albopictus (Skuse) in 6 cities of San Bernardino County, CA. The trap was used to attract ovipositing females, expose them to the juvenile hormone mimic pyriproxyfen and the entomopathogenic fungus Beauveria bassiana, and autodisseminate pyriproxyfen to other water sources prior to their death from fungal infection. The trap attracted Ae. aegypti and Culex quinquefasciatus, with the latter species predominating at much higher larval densities in the trap reservoirs. Field-collected larvae and pupae from the trap reservoirs showed complete adult emergence inhibition. Furthermore, the trap reservoirs retained high levels of residual larvicidal, pupicidal, and emergence inhibition activity after they were retrieved from the field, as indicated by laboratory bioassays against laboratory colony of Cx. quinquefasciatus. Results of this study support more detailed quantitative local evaluations on trap efficacy to measure the impact of the In2Care mosquito trap on wild invasive Aedes and Culex populations in future mosquito control efforts.

Pathogenicity of entomopathogenic fungus Isaria fumosorosea on rugose spiralling whitefly Aleurodicus rugioperculatus and its effect on parasitoid Encarsia guadeloupae

ABSTRACT Highly polyphagous rugose spiralling whitefly (RSW), Aleurodicus rugioperculatus Martin (Hemiptera: Aleyrodidae) invaded India during 2016. Pathogenicity of two strains (ICAR-NBAIR Pfu-1 & Pfu-5) of entomopathogenic fungus Isaria fumosorosea Wize were evaluated against RSW, however, only Pfu-5 showed virulence. Further dose mortality studies were carried out with re-isolated Pfu-5 strain with five different concentrations ranging from 1×104–1 × 108 spores/mL on A. rugioperculatus and its dominant parasitoid Encarsia guadeloupae (Hymenoptera: Aphelinidae). The Pfu-5 strain showed mean mortality of 44.03, 44.80, 36.42 and 28.82% on the eggs, first, third and fourth instar nymphs, respectively. The LC50 values of I. fumosorosea for eggs, first, third and fourth instar nymphs were 2.6 × 104, 2.3 × 104, 3.5 × 105 and 9.5 × 105 spores/mL, respectively, and the LT50 values were 50.39, 41.39, 67.54 and 68.31 h, respectively, for corresponding life stages for the concentration of 1 × 108 spores/mL. The impacts of I. fumosorosea on the parasitoid showed the inhibition of adult emergence was much lower in the Pfu-5 strain (5.8–19.6%) at a concentration of 1 × 108 spores/mL at different exposure times. The present study indicated the pathogenicity of Pfu-5 against A. rugioperculatus and warrant further studies on the compatibility of these biocontrol agents to be evaluated for the simultaneous utilisation under field conditions.

Effects of interaction between cowpea variety and the application of plant powders on Callosobruchus maculatus (Fabricius) (Coleoptera: Chrysomelidae) infestation of stored cowpea seeds

An integrated pest management scheme involving seed resistance and the application of powder of Cymbopogon citratus, Alstonia boonei, Hyptis suaveolens, Azadirachta indica, Loranthus braunii and Lycopersicum esculentum as protectant against the seed bettle, Callosobruchus maculatus (Fabricius), was evaluated in the laboratory at ambient temperature (29±3°C) and relative humidity (65±5%). Six resistant cowpea accessions selected from previous studies were treated with the six plant powders at 1.25% w/w in a 6×7 factorial arrangement fitted into a completely randomized design with five replicates. Seed treatment with any of the six plant powders on six accessions resulted in significantly higher adult mortality, lower oviposition rate, adult emergence inhibition, lower seed damage and higher seed germination over the control, Protection ability of the plant powders was influenced by the cowpea accessions used.

Effect of edible oils on different stages of pulse beetle (Callosobruchus chinensisL.) on chickpea grains

Among the five edible oils viz. olive oil (Olea europaea L), coconut oil (Cocos nucifera L.), groundnut oil (Arachis hypogaea L.), mustard oil (Brassica spp L.) and sesame oil (Sesamum indicum L.) @ 3, 6 and 9 ml kg-1 grains were evaluated as protectants of C. arietinum against oviposition, adult mortality and adult emergence. Pulse beetles favoured untreated rather than treated grains. Similarly, irrespective of these oils, at the rate of 3 ml kg-1 was less effective in inhibiting the oviposition, adult mortality and adult emergence inhibition than 6 and 9 ml kg-1. Among the oils, coconut oil at 9 ml kg-1 grains was found to be most effective in inhibiting the oviposition (26.43 eggs), adult mortality (44.52%) and adult emergence inhibition (96.34%) and did not affect germination of chickpea grains till four months. Sesame oil also provided excellent results giving in the same parameters as 26.62 eggs, 40.95 and 96.08.percent, respectively. Oils of groundnut and olive were least effective in performing the above parameter in the process of the investigation.

Synthesis by silver nanoparticle activity of Larvicidal Useing leaf extracts of Andrographis alata against Culex quinquefasciatus

In the present study, the Larvicidal activity of biosynthesized silver nanoparticle using leaf extracts of Andrographis alata was used against Culex quinquefasciatus in order to carry out larvicidal activity. Methanolic leaf extract of Andrographis alata along with AgNPs was significantly inhibits the adult emergence. The percentage of adult emergence inhibition were 08.0±1.3, 14.0±1.3, 30.0±1.5, 45.5±1.5, 58.0±3.2, 76.0±2.4 and 96.0±2.3 % at different concentration viz., 0.1, 0.2, 0.3, 0.4 and 0.5 ppm against the larvae of Cx.quinquefasciatus. The LC50 values of the methanolic leaf extract of Andrographis alata along with silver nanoparticle was 460.05 ppm against late third larva Cx. quinquefasciatus. The chi-square value 0.25 was significant at p

Harmaline ingestion effect on development, metabolites and midgut of the red flour beetle, Tribolium castaneum

Abstract Alkaloids constitute an interesting family of molecules synthesized and accumulated by certain plants and it suggested that they participate in plant defences. In this study, we determined the ingestion effect of the alkaloid, harmaline, on the insect pest Tribolium castaneum Herbst (Coleoptera: Tenebrionidae). When incorporated into the diet at 400, 1000, and 2000 ppm, harmaline provoked larval weight loss, larval mortality and adult emergence inhibition. Spectrophotometric analyses showed that harmaline ingestion caused a significant diminution in the rate of protein, glycogen and lipid. Besides, the activity of the enzyme α-amylase was also significantly reduced in treated larvae. In addition, by using the optical and electron microscopy, we have showed that harmaline ingestion induced a marked cytotoxic effect on the midgut epithelial cells. They exhibited rare microvilli and an extensive disorganization and vacuolisation of the cytoplasm and the nucleus. In conclusion, the results obtained from this study prove and show potent insecticidal effect of Alkaloids such as harmaline on Tribolium castaneum.

Pyriproxyfen treated surface exposure exhibits reproductive disruption in dengue vector Aedes aegypti.

BackgroundReduced susceptibility of mosquito vectors to currently used insecticides hampers control interventions. Recently pyriproxyfen, an insect growth regulator has been demonstrated to effectively reduce the reproductive potential in vector mosquitoes.MethodsPyriproxyfen (PPF), in different concentrations (0.75%, 0.075%, 0.0075%, and 0.00075%) was applied on papers and Indian wild type Aedes aegypti female mosquitoes (N ≥ 20 for each treatment) were exposed onto it as per WHO guidelines, to study the reproductive disruption. PPF concentration on treated papers was quantitatively cross-determined using HPLC method. Reduction in fecundity, fertility and adult emergence in exposed female Ae. aegypti was determined. Abnormal development in ovary and eggs of exposed females was studied microscopically after different time intervals.ResultsEggs laid, eggs hatched, pupae formed and adults emerged per female exposed in both before blood meal and after blood meal groups declined significantly from lowest to highest concentration of PPF (F ≥ 5.2; p < 0.02). Adult emergence inhibition in females exposed to PPF before and after blood meal groups ranged from 58.8% [OR = 0.18 (95% CI = 0.09–0.36)] to 79.2% [OR = 0.04 (95% CI = 0.02–0.10)] and 64.4% [OR = 0.12 (95% CI = 0.05–0.28)] to 77.1% [OR = 0.05 (95% CI = 0.02–0.14)] respectively in different concentrations. The probit model used suggested that FI50 (50% fertility inhibition) and EI50 (50% emergence inhibition) were 0.002% (p = 0.82) and 0.0001% (p = 0.99) for females exposed before blood meal, while 0.01% (p = 0.63) and <0.0001% (p = 0.98) for the females exposed after blood meal, respectively. The eggs laid by the females exposed to PPF-treated surface showed altered body organization, desegmentation and disoriented abdominal and cervical regions in the developing embryo. Quantification of PPF on impregnated papers showed that it was uniformly distributed throughout the matrix.ConclusionsThe present study has shown that tarsal contact to PPF-treated surface for a small time drastically influenced the fecundity, fertility and adult emergence in Indian wild Ae. aegypti mosquitoes. Results suggest that a certain minimum concentration of PPF through contact exposure can reduce the abundance of vector mosquitoes to a considerable level. The formulations based on combination of PPF and other compatible insecticides may be an impactful approach where susceptible mosquitoes are killed by the insecticide component while resistant mosquitoes are sterilised by PPF.

Inhibitory effect of Zingiberaceae essential oils against Conopomorpha cramerella (Snellen) Lepidoptera: Gracillariidae

Zingiberaceae (Order: Zingiberales) is recognized as the essential herbaceous species in the tropics. Several species of Zingiberaceae have shown potential in managing some Lepidopteran and Dipteran pests. Currently, there is no report in Malaysia explores the potential use of Zingiberaceae in managing cocoa pests, particularly the Cocoa pod borer (CPB), Conopomorpha cramerella. The study was conducted to evaluate the potential of Zingiberaceae as an adult emergence inhibition of C. cramerella using three locally grown species in Malaysia; Alpinia galanga (galanga), Curcuma longa (turmeric), and Zingiber officinale (ginger). Different ages of the CPB pupa (Days 1, 2, 3, 4, and 5) were selected and were sprayed with Zingiberaceae essential oils (EOs). Pupa was sprayed with EOs at four different concentrations; 100, 200, 400, and 800 ppm. Observations were carried out after 5 to 7 days, where the percentage of the unhatched pupa and healthy adult was recorded. The percentage of the deformed adults were examined based on the abdomen, the antenna, the wings, and overall deformities. The study was repeated four times for each EOs. Results denoted that the percentage of the unhatched pupa was the highest at C. longa (49.75 % a) and significantly different (p&lt;0.05) with A. galanga (48.00 % b), Z. officinale (40.97 % c) and control treatment (13.59 % d). The highest healthy adult emergence was recorded under the control treatment (75.77 % a), and significantly different with all Zingiberaceae EOs. The overall results denoted that most of the deformities occurred after pupa were treated with the Zingiberaceae EOs at high concentrations (400 and 800 ppm), and engaged with the body and wing deformities. The symptom of adult deformities after treating with EOs may indicate the potential of Zingiberaceae as an adult emergence inhibitor of C. cramerella, and can be possibly used for the development of Zingiberaceae based botanical pesticide in the future.&#x0D; J Bangladesh Agril Univ 17(3): 349–354, 2019

Evaluation of Effectiveness and Persistence of three Slow Release Formulations against Aedes Aegypti (L) (Diptera: Culicidae) under Laboratory Conditions

A laboratory evaluation of three slow-release formulations (SRFs) of spinosad tablets, sumilarv granules and du-dim tablets was carried out in 20 liters plastic containers. The tested formulations were applied according to recommended doses to evaluate their efficacy and longevity against Ae. aegypti. The results revealed that the tested SRFs achieved complete inhibition of adult stages emergence of Ae. aegypti in the first four weeks and gave continuous effective with 50-100% for 98, 86 and 78 days post -treatment by using spinosad tablets, sumilarv granules and du-dim tablets respectively. The highest larval mortality was observed for spinosad followed by sumilarv and du-dim, it gave 1.3 folds than sumilarv and 1.1 folds with du-dium, whereas sumilarv and du-dium were more effective on pupal mortality than spinosad. On the other hand, morphological abnormalities were observed in larval and pupal stages of Ae. aegypti as delayed effects by tested formulations. This study highlighted that these SRFs could be used as potential larvicidal compounds in mosquito control programs as a single treatment and provide satisfactory results and continuous control against the dengue vector Ae. aegypti for several weeks.

Truck-mounted area-wide applications of larvicides and adulticides for extended suppression of adult Aedes albopictus.

Given the lack of vaccines for most vector-borne diseases, vector control is often the primary option for disease control. Aedes albopictus are difficult to control because the immatures primarily develop in containers ubiquitous in residential properties. Conventional adulticide campaigns often result in brief, rebounding population declines, so incorporating new techniques into an integrated pest management program is imperative. We performed combined area-wide applications of the larvicides Bacillus thuringiensis var. israelensis and pyriproxyfen with the adulticide sumithrin and prallethrin to achieve extended suppression of Ae. albopictus populations in Trenton, NJ, USA. We deployed bioassay cups to assess the spatial penetration and efficacy of the applications. Inhibition of adult emergence was significantly higher in the treatment bioassay cups than in laboratory controls (z = 4.65, P < 0.0001) and field control bioassay cups (z = 8.93, P < 0.0001). We observed a lower trend in adult numbers following season-long combined application of pyriproxyfen and adulticide, with numbers of adult Ae. albopictus at the treatment site up to five times lower than at the control site. Pyriproxyfen is a powerful mosquito larvicide and pupacide with low mammalian toxicity that shows promise for area-wide vehicle-mounted (either ground or airborne) applications. © 2018 Society of Chemical Industry.

Influence of abiotic factors on the efficacy of insect growth regulators against Trogoderma granarium (Everts)(Coleoptera: Dermestidae): Presentation

Present study was designed to investigate the effects of different combinations of three temperatures (20, 25 and 30?) and three relative humidity levels (55, 65 and 75%) on the efficacy of three synthetic IGRs i.e., pyriproxyfen, lufenuron and buprofezin at concentrations of 1, 5 and 10ppm on fecundity and adult emergence inhibition of T. granarium under controlled laboratory conditions. This study was conducted at Grain Research Training and Storage management Cell, Department of Entomology, University of Agriculture, Faisalabad, Pakistan. All the treatments were replicated three times using Completely Randomized Design. Larvae of T. granarium were exposed to IGRs at different levels of temperature and relative humidity. F1 adult emergence results showed that at temperature 20°C, the highest percent reduction in adult emergence (84.38, 70.65 and 79.94%) was recorded after exposure to lufenuron, buprofezin and pyriproxyfen treated diet, respectively. At 75% relative humidity, lufenuron, buprofezin and pyriproxyfen caused 77.53, 80.00 and 80.32% reduction in adult emergence, respectively. Adults were exposed to IGRs at different temperature and relative humidity to evaluate the oviposition inhibition. The results revealed that at temperature 20°C, maximum percent reduction in fecundity (87.95, 80.45 and 70.55%) was recorded after exposure to buprofezin, pyriproxyfen and lufenuron treated diet, respectively. At 75% relative humidity buprofezin, pyriproxyfen and lufenuron caused 86.73, 83.72 and 69.11% reduction in fecundity, respectively. It is concluded that temperature and relative humidity play an important role in the effectiveness of insect growth regulators.

Laboratory Evaluation of the Toxicity of Silver Nanoparticles Against Housefly, Musca Domestica (Diptera: Muscidae)

The synthesis of nanomaterials is currently one of the most active in nanoscience branches; especially those help improve the human quality life. Silver nanoparticles (AgNPs) are an example of this as it is known to have inhibitory and bactericidal effects and as one of the famous metal nanomaterials in broad Sectors especially in agriculture. It was synthesized by a chemical method and characterized by UV-visible spectroscopy, TEM, and SEM in this present study. The nanoparticles were ranged between 20-50 nm and the shape seem grain with rough ends. The larvicidal activity of silver nanoparticles AgNPs were tested against the third instar larvae of housefly, M. domestica. Six concentrations were used over two different application methods (Dipping and Feeding methods) under laboratory conditions. In general, it was noticed that the larvicidal effects based on LC50 of either method against the housefly. The LC50 value for AgNPs was 45.5 mg/ml by feeding method in a different concentration (60,40,32,24,16,8 µg/ml). Data showed the moderate effect in larval mortality % and high effect of inhibition of pupation% and inhibition of adult emergence%. Furthermore, the treatment caused some morphological effects such; abnormalities of larvae and pupae, larval pupal intermediates, deformed adult with crumpled wings. Also, some

Evaluation of bio-efficacy and residual activity of pyriproxyfen against field collected aedes aegypti and aedes albopictus from Gujranwala (Punjab), Pakistan

Background: Abstract Background: Dengue disease is a major health problem in tropical and subtropical region of the world. Pakistan has also serious issues on this infectious disease in the form of DF, DHF & DSS since 1994 when it was declared the first epidemic in Pakistan. Since then, many epidemics in different cities of Pakistan have been occurring on regular basis. The ever worst epidemic was occurred in 2011 in Punjab province where more than 286857 suspected cases and 21685 confirmed cases with 350 deaths were reported by Health Department. There is an urgent need for entomological and epidemiological studies on large scale to control the disease. Methods & Materials: Methodology: The recent study was conducted in district Gujranwala-Punjab, Pakistan to evaluate the Bio-efficacy of pyriproxyfen (a juvenile hormone analogue) against field collected mosquitoes (larvae) of dengue vectors. Aedes aegypti and Aedes albopictus were collected from three different localities of Aroop Town. Collected mosquitoes were reared to get fresh larvae according to the WHO recommended rearing procedure. Larvae were treated with pyriproxyfen (Predator 0.5 WDG) at the WHO recommended dose of 0.01 mg/l of a.i. The tests were conducted in triplicate form along with a control. A fresh lot of 25 larvae were added in all treated as well as in control cups on every ten days interval to determine the residual activity of the tested product. Results: Result: The bio-efficacy of pyriproxyfen was found effective against field collected Aedes aegypti and Aedes albopictus. The complete Inhibition of Adult Emergence (EI) was observed 58 days and 47 days for Aedes aegypti and Aedes albopictus respectively. The results also show that the residual activity of pyriproxyfen against Aedes aegypti is greater than Aedes albopictus as 68 days and 59 days (up to 80% EI) respectively. Conclusion: Conclusions: Pyriproxyfen can be used to control the dengue vectors (Aedes aegypti and Aedes albopictus) and it can be included in integrated vector control strategy. It is very effective and safer to use for vector control as non-conventional usage of chemical insecticides.

Development of an autodissemination strategy for the deployment of novel control agents targeting the common malaria mosquito, Anopheles quadrimaculatus say (Diptera: Culicidae)

BackgroundThe reduced efficacy of current Anopheline mosquito control methods underscores the need to develop new methods of control that exploit unique target sites and/or utilizes novel deployment methods. Autodissemination methodologies using insect growth regulators (IGRs) is growing in interest and has been shown to be effective at controlling Aedes mosquitoes in semi-field and field environments, yet little information exists for Anopheline mosquitoes. Therefore, we tested the hypothesis that female-driven autodissemination of an IGR combined with a new mechanism of action insecticide (Kir channel inhibitor) could be employed to reduce Anopheline populations.MethodologyWe studied the ability of three IGRs to be transferred to the larval habitat during oviposition in laboratory and semi-field environments. Adult mosquitoes were exposed to the chemicals for 4 hours immediately after blood feeding and efficacy was tested using classical methodologies, including adult emergence inhibition and High Performance Liquid Chromatography (HPLC). A complete autodissemination design was tested in a semi-field environment.Principal findingsLarval survivability and adult emergence were significantly reduced in habitats that were visited by novaluron treated adults, but no statistical differences were observed with pyriproxyfen or triflumuron. These data suggested novaluron, but not pyriproxyfen or triflumuron, was horizontally transferred from the adult mosquito to the larval habitat during oviposition. HPLC studies supported the toxicity data and showed that novaluron was present in the majority of larval habitats, suggesting that novaluron can be horizontally transferred by Anopheles quadrimaculatus. Importantly, the combination of novaluron and the Kir channel inhibitor, VU041, was capable of reducing adult and larval populations in semi-field environments.ConclusionsNovaluron can be transferred to the adult at a greater efficacy and/or is not degraded as quickly during the gonotropic cycle when compared to pyriproxyfen or triflumuron. Pending field confirmation, autodissemination approaches with novaluron may be a suitable tool to manage Anopheles populations.