Dimethyl Dichlorovinyl Phosphate Research Articles

Water in liquid crystal emulsion-based sensing platform for colorimetric detection of organophosphorus pesticide

Development of a simple and convenient method for the rapid detection of organophosphorus pesticides (OPs) is particular important for the safety of environmental water and agriculture products. In this work, the water/liquid crystal (W/LC) emulsion is obtained via dispersing an aqueous solution of sodium dodecyl sulfate (SDS) and peroxidase from horseradish (HRP) into a water-immiscible nematic LC and employed as a sensing platform for the detection of dichlorvos (2, 2-dichlorovinyl dimethyl phosphate, DDVP) that is a typical OP with acute toxicity. Remarkably, the stepwise release of the encapsulated cargo HRP from the W/LC emulsion can be triggered upon the addition of the cationic surfactant myristoylcholine chloride (Myr) due to the strong interfacial charge interactions with the anionic surfactant SDS. The released HRP induces an obvious color change of the overlaying bulk aqueous solution via the H2O2-HRP-TMB reaction system. As Myr can be enzymatically cleaved by AChE, the detection of AChE is fulfilled successfully. This approach is also employed to detect DDVP that can irreversibly inhibit the activity of AChE. This assay shows a linear response between the absorbance of the oxidized TMB solution and the DDVP concentration in the range of 0.001–10 μg/mL (R2 = 0.99). The limit of detection (LOD) and the limit of quantity (LOQ) of DDVP are determined to be 1.9 ng/mL and 6.3 ng/mL, respectively. In addition, this strategy also demonstrates excellent performance for the DDVP detection in real samples, the detection recovery rate of DDVP in water samples (lake water and tap water) and vegetables (tomatoes and cole) by this method is 88.0 % ∼112.6 %, the relative standard deviation (RSD) ≤ 7.5 %. These results suggest the W/LC emulsion-based sensing platform shows great potential for visual detection of DDVP in real samples. In conclusion, the proposed approach is scalable for practical application in food safety as well as environmental monitoring fields, and will provide promising solutions for the assay of pesticide residues.

Ameliorative effects of palm oil on sniper induced toxicity on the cerebral cortex of adult male Wistar rats

Introduction: Sniper insecticide is a highly toxic, water soluble, synthetic organophosphate belonging to the DDVP (2, 2 — dichlorovinyl dimethylphosphate) compound family of chemicals. It’s wide spread indiscriminate indoor usage and more recently, an effective instrument for suicide related mortality which has been a source of great concern. Red palm oil, on the other hand, is an edible vegetable oil from the fleshy pulp of the oil palm that contains antioxidants; carotenoids that is responsible for its color (pigmentation) and Vitamin E that support brain health. This palm oil is consumed widely, used as an antidote in Nigeria and so is used for various ingested poisons. Aim: This study is aimed at investigating the ameliorative effects of palm oil on sniper induced toxicity on the cerebral cortex. Materials and methods: Sixteen adult male Wistar rats were randomly assigned to 4 groups (n = 4 per group). Group A was the Control, while Group B was administered just sniper (5 mg/kg), Group C was administered 2 ml of Red oil and Group D received 5 mg/kg of sniper + 2 ml of red oil. At the end of the experiment, the rats were sacrificed, their brains extracted and fixed in 10% formal saline for routine histological analysis. Results: There was significant increase in the body weight of Groups A, B, C and D. The relative organ weight of Wistar rats showed an insignificant decrease in the relative brain weight of Group B compared to the Control. Groups C and D also had a relative decrease in comparison to the control. The cerebral cortex reveals neuronal damage and proliferation of glial cells in the sniper-induced group and the mild recovery of neuronal cells in the rats treated with sniper and palm oil. Conclusion: The results from this study shows that there was a significant reduction in organ weight in Group B [Sniper only] when compared to the control group. When palm oil was administered, there was mild recovery of neuronal cells. This shows the ameliorative effects/ impact of Palm Oil in Neurotoxicity.

Investigating the effect of Mimosa Pudica on dichlorvos induced hippocampal neurodegeneration in mice

BackgroundDichlorvos, the Dimethyl Dichlorovinyl Phosphate (DDVP) poisoning is common due to its frequent usage as a food preservative. This is determining to assessing the reversal of DDVP-induced neurodegeneration by Mimosa pudica MethodsFifty (50) adult BALB/c mice were randomly assigned to five groups (A-E) of 10 mice each. Group A mice were given normal feed and water, Group B mice were treated orally with 400 mg/kg body weight (b.wt.) of Mimosa pudica, Group C mice were fed with 2.5% of 2, 2- DDVP poisoned feed (7ml of DDVP in 300ml of water, sprayed on the feed), Group D mice were fed 2.5% DDVP poisoned feed simultaneously with 400mg/kg b.wt. of Mimosa pudica (MP) orally; and Group E mice were fed 2.5% DDVP poisoned feed for 14 days and then treated orally with 400mg/kg b.wt. of Mimosa pudica for the remaining 14 days. The exposure lasted for 28 days through oral administration. Behavioural studies to assess spatial and non-spatial memory of the mice were carried out on the 27th day using the Y-Maze and Novel Object Recognition (NOR) test. On the 28th the mice were sacrificed using chloroform as anaesthesia. Immunohistochemical studies were perfused transcardially using normal saline followed by perfusion with 10% formal saline.Values were analyzed using Graphpad prism version 5.0. P values was set at 0.05, 0.01 and 0.001. ResultsNeurodegeneration was observed in animals exposed to DDVP contaminated feed while treatment with MP after DDVP exposure ameliorated the degeneration taken together. ConclusionIt was concluded that exposure to DDVP contaminated feed induces damage in the hippocampus which leads to synaptic loss and neurodegeneration.

Invitro Toxicity of Binary Mixtures of Glyphosate and 2, 2 Dichlorovinyl Dimethyl Phosphate on Bacterial Isolates

The in vitro toxicity of glyphosate (Gly) and 2, 2 Dichlorovinyl dimethyl phosphate (DDVP) single compound and binary mixtures was assessed against Pseudomonas sp. and Bacillus sp. isolated from Otamiri River, Imo state, Nigeria was investigated. The toxicity response was assessed using the inhibitory effect of the single and binary mixtures on isolates dehydrogenase activity; and 2,3,5 triphenyltetrazolium chloride (TTC) was used as the artificial electron acceptor. The binary mixtures were composed using fixed ratios of glyphosate and 2, 2 Dichlorovinyl dimethyl phosphate in ratios of 20% Gly:80% DDVP, 40% Gly: 60% DDVP, 50% Gly: 50% DDVP, 60% Gly: 40% DDVP and 80% Gly: 20% DDVP. Results obtained showed that the isolates exhibited different degrees of logistic and sigmoidal toxicity trends with areas of hormesis at low concentrations of the toxicants. Furthermore, isobolographic analysis on the toxic interaction of the mixtures presented both synergism and antagonism, based on the relative ratio of the component mixtures. Increasing concentration of glyphosate in the binary mixture caused a shift in the interaction effect from antagonism to synergism. Our findings showed that isolates exhibited tolerance to glyphosate and 2,2 dichlorovinyl dimethyl phosphate and their binary mixtures exposure at concentration range of 0-1000mg/L; above which has deleterious effects on the aquatic organisms. It is evident that there are considerable differences in pesticide sensitivity among the bacterial species and that the presence of glyphosate and 2, 2-dichlorovinyl dimethyl phosphate in the aquatic environment may present toxicological risk to microbial diversity.

Synthesis, characterization and investigation of chitosan-functionalized ZnFe2O4 for the removal of dichlorvos from aqueous solution

Chitosan was successfully functionalized with zinc ferrites (Cs-ZnFe2O4), the composite was characterized using powder X-ray Diffraction, (XRD), scanning electron micrograph (SEM) and Fourier transform infrared spectroscopy (FTIR) and used as adsorbent for removal of 2, 2-dichlorovinyl dimethyl phosphate (DDVP) insecticide from aqueous solutions in batch processes. The equilibrium data were subjected to Langmuir, Freundlich, Dubinin-Radushkevich (R-D), Tempkin, Redlich-Peterson and Sips isotherms models. Pseudo-first order, second order, Elovich and intra particle diffusion models were used to analyzed the kinetics data. The composite was able to remove DDVP from aqueous solution by 90.10 to 99.85 % as the pH was increased from 1 to 8, while an increase in removal efficiency from 6.80 to 88.9 % was observed as the dosage was increased 0.01 to 0.1 g/100 mL. Langmuir isotherms best described the adsorption process with maximum capacities of 119.86 mg/g which compared favorably with other adsorbents in the same category. The adsorption process followed pseudo second-order kinetics with correlation coefficient (R2) values > 0.9 and error margin of 0.003 to 0.009% between Qe(cal.) and Qe(exp). The average ΔG, ΔH and ΔS values of −22.65, 84.51 kJ mol-1 and 339.9 J mol-1K-1 respectively obtained revealed that the adsorption process was spontaneous and endothermic with increase entropy at adsorbate surface. Thus, chitosan modified with zinc ferrites is an efficient adsorbent for the removal of DDVP insecticide from aqueous solution

Impacts of changes in temperature and exposure time on the median lethal concentrations (LC50) of a combination of organophosphate and pyrethroid in the control of Culex quinquefasciatus, say (Diptera: Culicidae)

Climate change factors such as rainfall, heat waves, rising temperatures and flooding have positively impacted insect vector population. This scenario poses considerable demand on chemical control. This study was carried out with the specific aim to examine the influence of changes in temperature and exposure time of C. quinquefasciatus to toxicities of pyrethroid (Cypermethrin), organophosphate (2, 2- dichlorovinyl dimethyl phosphate) and their mixtures. Eggs of C. quinquefasciatus were collected at the Federal University of Technology, Akure, Nigeria, in an area far from residential and cultivated zones, with a remote chance of the mosquitoes being exposed to insecticides. The eggs were allowed to hatch into larvae/pupae in the field at 27–29 °C temperature, 70–85% RH, 14:10 (L: D) photoperiod. F3 adult generation reared were transferred to the Entomology Laboratory and exposed to different concentrations of Cypermethrin and DDVP applied singly and in mixtures at varying temperatures and exposure time with mortality recorded. The median lethal concentration (LC50) values for the insecticides were higher when the insecticides were applied singly than when applied as mixtures. Therefore, mixtures of cypermethrin and DDVP have enhanced toxicity. Again, temperature changes also affect insecticide toxicity and because climate change has a characteristic temperature variability, it poses a barrier to insecticide toxicity. Hence, it is expedient to have a climate change adaptation policy in synergy with modality of chemical applications. Further study of toxico-kinetic of the insecticides in mosquito control is also recommended.

Quantification of Pesticide Residues in Retail Samples of Cowpea - Vigna unguiculata (L.) Walp

Quantification of pesticide residues in retail samples of food is one way to determine the level of human exposure to these chemicals and hence their potential health hazards. The study was aimed at quantifying the level of some known pesticides in retail samples of Vigna unguiculata (L.) Walp. (Cowpea) from two cropping seasons. Five cultivars of cowpea from two different harvest seasons (2016/2017 and 2017/2018) were purchased from Ogige Market, Nsukka, Enugu State, Nigeria. The cowpeas were identified based on city/state where they were cultivated. Two foreign samples were also purchased from London, UK. The pesticide residues were determined using gas chromatography coupled with electron capturing detector (GC-ECD). The results showed that the retail samples of cowpea contained residues of one or more organochlorines and organophosphates. The levels of post-harvest pesticides, 2, 2-dichlorovinyl dimethyl phosphate (DDVP) in 2016/17 season (0.02 μg/g) exceeded the international permissible standards (0.01 μg/g). The levels of the pre-harvest pesticides, glyphosate was low in both seasons (0.01 μg/g) when compared to the international permissible standards (0.1 μg/g). The DDVP was not detected in the two foreign samples. HCB (Hexachlorobenzene), α-HCH (alpha-Hexachlorocyclohexane), Chlorpyrifos, g-chlordane, t-nonachlor, p-p’-DDT (Dichlorodiphenyltrichloroethane), p-p’-DDE (Dichlorodiphenyldichlo-rowthylene), and p-p’-DDD (Dichlorodiphenyldichloroethane) were detected in the cowpea from two cropping seasons despite being banned from agricultural use. This could be due to the additional application of pesticides during storage of the cowpeas. The findings concludes that the levels of some of the residues exceeded the safety limits while some were below the safety limits, suggesting that some of samples of the cowpea were not safe for human consumption as bioaccumulation, persistence, and toxicity of these residues was likely to pose serious health risks to the consumers. Generally, cowpea from the 2016/17 season contained higher pesticide residues than those from the 2017/18 season.

Quantification of Pesticide Residues in Retail Samples of Cowpea - Vigna unguiculata (L.) Walp

Quantification of pesticide residues in retail samples of food is one way to determine the level of human exposure to these chemicals and hence their potential health hazards. The study was aimed at quantifying the level of some known pesticides in retail samples of Vigna unguiculata (L.) Walp. (Cowpea) from two cropping seasons. Five cultivars of cowpea from two different harvest seasons (2016/2017 and 2017/2018) were purchased from Ogige Market, Nsukka, Enugu State, Nigeria. The cowpeas were identified based on city/state where they were cultivated. Two foreign samples were also purchased from London, UK. The pesticide residues were determined using gas chromatography coupled with electron capturing detector (GC-ECD). The results showed that the retail samples of cowpea contained residues of one or more organochlorines and organophosphates. The levels of post-harvest pesticides, 2, 2-dichlorovinyl dimethyl phosphate (DDVP) in 2016/17 season (0.02 μg/g) exceeded the international permissible standards (0.01 μg/g). The levels of the pre-harvest pesticides, glyphosate was low in both seasons (0.01 μg/g) when compared to the international permissible standards (0.1 μg/g). The DDVP was not detected in the two foreign samples. HCB (Hexachlorobenzene), α-HCH (alpha-Hexachlorocyclohexane), Chlorpyrifos, g-chlordane, t-nonachlor, p-p’-DDT (Dichlorodiphenyltrichloroethane), p-p’-DDE (Dichlorodiphenyldichlo-rowthylene), and p-p’-DDD (Dichlorodiphenyldichloroethane) were detected in the cowpea from two cropping seasons despite being banned from agricultural use. This could be due to the additional application of pesticides during storage of the cowpeas. The findings concludes that the levels of some of the residues exceeded the safety limits while some were below the safety limits, suggesting that some of samples of the cowpea were not safe for human consumption as bioaccumulation, persistence, and toxicity of these residues was likely to pose serious health risks to the consumers. Generally, cowpea from the 2016/17 season contained higher pesticide residues than those from the 2017/18 season.

Non-linear model analysis of the relationship between cholinesterase activity in rats exposed to 2, 2-dichlorovinyl dimethylphosphate (dichlorvos) and its metabolite concentrations in urine

Urinary dialkylphosphates (DAPs) are measured to assess exposure to organophosphorus pesticides (OPs), but they are common metabolites of OPs and not specific indices for individual agents. Biomonitoring (BM) of urinary DAPs has been widely adopted as an assessment of individual exposure in general environments, however, guidance values for DAPs based on health effects have yet to be established. The present study aimed to clarify the relationship between the amount of urinary dimethylphosphate (DMP), a metabolite of dichlorvos (DDVP), and the inhibition of cholinesterase (ChE) activity in rats exposed to DDVP. The relationship was analyzed using a nonlinear model analysis, and the excretion level of urinary DMP equivalent to ChE 20 % inhibition (EL20) and the lower limit of the 95 % confidence interval of EL20 (ELL20) were estimated. EL20 and ELL20 (mg/24 h urine) of brain, erythrocyte, and plasma ChE activities after 10-day administration of DDVP were 0.21 and 0.15, 0.11 and 0.06, and 0.23 and 0.09, respectively. Extrapolating ELL20 of the brain ChE to humans, the range of 24 h urinary DMP concentration according to the 20 % inhibition of cholinesterase activity was estimated to be 20.5–30.8 mg/l. In conclusion, the amount of urinary DMP as ELL20 for DDVP exposure was identified and could probably be used as a novel index for the assessment of risk from OP exposure. Further studies are needed to clarify the ELL20 s derived from OPs other than DDVP, for informing efforts to establish guidance values of urinary OP metabolites that should prevent neurotoxicity.

Forensic Identification of Air Freshener Components from the Toxicological Samples by GC-MS : A Case Report

Indoor air fresheners are commonly used to deodorize rooms and cars. A case of air freshener intoxication by oral ingestion was forwarded to the forensic laboratory to determine the components and cause of death. The presumptive tests were conducted for organo-phosphorus and organo-chloro compounds, formaldehyde, carbolic acid, drugs and aromatic compounds. Gas Chromatography–Mass Spectroscopy (GC-MS) was used as a confirmatory test for all these compounds. Presence of toxic substances like dichlorvos (2,2 di-chlorovinyl dimethyl phosphate), phenol, formaldehyde, naphthalene was confirmed in the air freshener that led to the person’s death. Laboratory analysis also confirmed the presence of alprazolam in the viscera as per case history. The methodology used can be utilized as a reference for TLC and GC-MS based analysis of such cases

Effects of Ozonated Water on Microbial Growth, Quality Retention and Pesticide Residue Removal of Fresh-cut Onions

ABSTRACT The native microflora survival and quality retention of fresh-cut onions treated by ozonated water (OW) with ozone concentration of 1.4 mg L−1, for 1, 3, and 5 min during storage at 4°C for 14 days were investigated. The pesticide residue removal effect of OW treatment for 5 min was also determined. The results show that all OW treatments significantly inhibited the growth of aerobic bacteria, coliforms, and yeasts during storage, with the OW treatment for 5 min allowing the lowest growth rates. OW treatment for 1 min significantly reduced the weight loss of fresh-cut onions during a longer storage time (8–14 d). All OW treatments reduced the respiration rate and the softening of fresh-cut onions, exhibiting better overall quality retention than the control samples. In addition, OW treatment for 5 min significantly reduced the residual levels of five tested pesticides (dimethyl dichlorovinyl phosphate, cypermethrin, chlorpyrifos, methomyl, and omethoate) compared with water treatment. These results indicate that treatment with OW is a promising strategy to control the microbial growth, preserve the quality and reduce pesticide residual of fresh-cut onions. Abbreviations OW: ozonated water; PCA: plate count agar; VRBA: violet red bile agar; PDA: potato dextrose agar; DDVP: dimethyl dichlorovinyl phosphate

Degradation of 2, 2-Dichlorovinyl dimethyl phosphate (dichlorvos) through the rhizosphere interaction between Panicum maximum Jacq and some selected fungi

Many fungi have been reported to enhance the plant responses and degradation of several persistent pollutants in soils. In this study, five dominant fungi strains were identified from a pesticides polluted soil in Nigeria and screened for the expression of phosphoesterase (opd and mpd) and catechol 1, 2-dioxygenase (afk2 and afk4) genes using Reverse Transcriptase-PCR technique. Their rhizosphere interaction with plant (Panicum maximum) was further studied for the degradation of 2, 2 Dichlorovinyl dimethyl phosphate (dichlorvos). Fungal strains were mixed with Spent Mushroom Compost (SMC) of Pleurotus ostreatus in 1:100 w/w and then applied to a sterilized pesticide polluted soil (5 kg) at increasing concentrations of 10, 20, 30 and 40% with two controls (plant only and fungi-SMC mixture only). Degradation efficiency (DE), degradation rate (K1) and half-life (t1/2) of dichlorvos was calculated in each treatment after 90-day of planting. All the strains were registered at NCBI gene-bank with accession numbers KY693969, KY488464, KY488465, KY693971 and KY693972: they all possess the tested genes although mpd and opd were over-expressed in all the strains while afk2 and afk4 were moderately expressed. The plant-fungi-SMC interaction synergistically sped-up dichlorvos degradation rate in less time period, appreciable loss of dichlorvos at 72.23 and 82.70% DE were observed in 30 and 40% treatments respectively as compared to controls 1 and 2 having 62.20 ± 3.07 and 62.33 ± 4.69% DE respectively. In the same way, the 40% treatment gave the best k1 and t1/2 of 1.755 and 0.40 ± 0.02/day respectively.

Non-Linear Model Analysis of the Relationship between Cholinesterase Activities in Rats Exposed to 2, 2-Dichlorovinyl Dimethylphosphate and its Metabolite Concentrations in Urine

Background and aim2, 2-dichlorovinyl dimethylphosphate (DDVP) is an organophosphate (OP) widely used for the insect pest control operation and to maintain the household environment. However, there ...

The Role of 2, 2-Dichlorovinyl Dimethyl Phosphate and the Dynamics of Heavy Metals Absorption/Translocation in Plants: Emphasis on Sorrel and Spinach

The Role of 2, 2-Dichlorovinyl Dimethyl Phosphate and the Dynamics of Heavy Metals Absorption/Translocation in Plants: Emphasis on Sorrel and Spinach

Effects of 2, 2-Dichlorovinyl Dimethyl Phosphate (DDVP) on leukocyte profiles in juveniles and adult sizes of Tilapia guineensis

Effects of 2, 2-Dichlorovinyl Dimethyl Phosphate (DDVP) on leukocyte profiles in juveniles and adult sizes of Tilapia guineensis

Mortality Rate of Clarias gariepinus Fingerlings Exposed to 2, 3- dichlorovinyl dimethyl Phosphate

Mortality Rate of Clarias gariepinus Fingerlings Exposed to 2, 3- dichlorovinyl dimethyl Phosphate

Role of α7-Nicotinic Acetylcholine Receptors of B Cells in the Immunotoxic Effect of Organophosphorus Compounds.

Experiments on white non-inbred rats demonstrated that treatment with organophosphorus compound dimethyl dichlorovinyl phosphate (DDVP) decreased T cell-independent antibody production by B cells and blood levels of IL-10 and IL-12; a similar effect was produced by GTS-21, a selective agonist of α7-nicotinic acetylcholine receptor. N-nicotinic receptor antagonist chlorisondamine in combination with DDVP partially prevented suppression of antibody production in comparison with the effect observed during intoxication with DDVP.

Effect of surfactant concentration on the spreading properties of pesticide droplets on Eucalyptus leaves

The area wetted by 500-μm diameter droplets of pesticide and deionised water placed at different positions on Eucalyptus urophylla × E. grandis (E.u × E.g) and Eucalyptus tereticornis (E.t) leaves was determined at an air temperature of 30 °C and a relative humidity of 60%. Dimethyl dichlorovinyl phosphate (DDVP), and efficient cypermethrin (EC) were diluted 1000 times in deionised water. Solutions the pesticides were prepared with surfactant concentrations (SC) of 0.1%, 0.25%, 0.5%, and 1%. For comparison SC solutions with water and deionised water were also used. Droplet deposition positions were located in the interveinal area, midrib, and secondary vein on both adaxial and abaxial surfaces. Without surfactant, all droplets remained nearly spherical and did not spread on the leaf surfaces. With surfactant, the deionised water and pesticide droplets had distinct spreading properties. For deionised water, both the wetted area and spread effectiveness peaked at 0.1% SC, while for pesticide droplets the wetted area peaked at 1% SC. However, the optimum SC was 0.25%. Compared with droplets on E.u × E.g leaves, droplets spread more on E.t leaves. The adaxial surface had better wettability than the abaxial surface. For pesticide droplets, the wetted area was a minimum on the midrib and the wetted area on the secondary vein was slightly larger than that on the interveinal area.

Determination of dichlorvos residue levels in vegetables sold in Lusaka, Zambia.

IntroductionSmall scale and large scale farmers around Lusaka, the capital city of Zambia grow vegetables using intensive agriculture methods to satisfy the ever increasing demand. To ensure maximum yield they apply various types of pesticides to control pests and diseases that attack these vegetables. Organophosphate pesticides are widely used in agriculture for the control of various insect pests mainly in developing countries. The purpose of the study was to determine the residual levels of the most commonly used organophosphate, 2, 2-Dichlorovinyl dimethyl phosphate, in three commonestvegetables supplied at various markets around Lusaka.MethodsSamples of 9 bunches of rape, 14 bunches lettuce and 15 rolls cabbage were randomly picked from several study sites around Lusaka. The vegetables were chopped into small pieces which were chemically treated to get methanol extracts. The extracts were then dissolved in an appropriate solvent and using Shimadzu High Performance Liquid Chromatography-Ultra-violet detector (HPLC-UV) levels of 2, 2-Dichlorovinyl dimethyl phosphate were determined.ResultsThe analysis showed that the average levels of dichlorvos were significantly above the maximum accepted limit as set by Zambian Food and Drugs Act on vegetables.ConclusionLocally grown vegetables from around Lusaka have higher than maximum acceptable limits. This may have implications on human health as the cumulative effect of organophosphates in human body has potential to cause long term health problems.

Weathering and Chemical Degradation of Methyl Eugenol and Raspberry Ketone Solid Dispensers for Detection, Monitoring, and Male Annihilation of Bactrocera dorsalis and Bactrocera cucurbitae (Diptera: Tephritidae) in Hawaii.

Solid male lure dispensers containing methyl eugenol (ME) and raspberry ketone (RK), or mixtures of the lures (ME + RK), and dimethyl dichloro-vinyl phosphate (DDVP) were evaluated in area-wide pest management bucket or Jackson traps in commercial papaya (Carica papaya L.) orchards where both oriental fruit fly, Bactrocera dorsalis (Hendel), and melon fly, Bactrocera cucurbitae (Coquillett), are pests. Captures of B. dorsalis with fresh wafers in Jackson and bucket traps were significantly higher on the basis of ME concentration (Mallet ME [56%] > Mallet MR [31.2%] > Mallet MC [23.1%]). Captures of B. cucurbitae with fresh wafers in Jackson and bucket traps were not different regardless of concentration of RK (Mallet BR [20.1%] = Mallet MR [18.3%] = Mallet MC [15.9%]). Captures of B. dorsalis with fresh wafers, compared with weathered wafers, were significantly different after week 12; captures of B. cucurbitae were not significantly different after 16 wk. Chemical analyses revealed presence of RK in dispensers in constant amounts throughout the 16-wk trial. Degradation of both ME and DDVP over time was predicted with a high level of confidence by nonlinear asymptotic exponential decay curves. Results provide supportive data to deploy solid ME and RK wafers (with DDVP) in fruit fly traps for detection programs, as is the current practice with solid TML dispensers placed in Jackson traps. Wafers with ME and RK might be used in place of two separate traps for detection of both ME and RK responding fruit flies and could potentially reduce cost of materials and labor by 50%.