Fruit Fly Mortality Research Articles

Divergent effects of entomopathogenic fungi and medicinal mushroom species on Drosophila melanogaster lifespan

We tested the effect of entomogenous fungi isolated from the Coleoptera species Ophrida xanthospilota and of the medicinal mushroom Lentinula edodes on the lifespan of Drosophila melanogaster. All the four analyzed strains of entomogenous fungi showed pathogenicity to D. melanogaster by causing 100% mortality of fruit flies within 20 culture days. The shortest lifespan was recorded in flies treated with Fusarium verticillioides (15 days). On the contrary, L. edodes showed a remarkable lifespan-extending effect on the model organism, with fruit fly individuals surviving for 55 culture days. Fungal growth was microscopically observed on the bodies of dead fruit flies treated with the four entomogenous fungal species, confirming that the tested fungi were responsible for the mortality of the model insects. Our findings showed that the four fungal species previously found on the body of Coleoptera individuals are entomopathogenic and could be exploited in agriculture applications for the biocontrol of noxious pests. The significant lifespan extending effect on Drosophila produced by the analyzed L. edodes strain could represent very important experimental evidence of the anti-aging and lifespan prolonging effects of this medicinal mushroom species.

Soursop leaf extract (Annona muricata L) as a biochemical pesticide against fruit flies (Bactrocera sp)

Background: The citrus cultivation industry is commonly operated by the government, private sector, or individual owners from small, medium, to large scales. The fruit flies (Bactrocera sp) insect was reported to attack citrus crops in almost every region in Indonesia. Objective: To determine the effectiveness of soursop leaf extract (Annona muricata L) as a plant-derived insecticide against fruit flies. Methods: This study used true experimental with Posttest Only Control Design to analyse the difference in the average mortality of fruit flies for 24 hours. Results: The data generated through the Kruskal Wallis test showed that at a concentration of five per cent and 10% the effect of the mortality in fruit flies equals p > 0.939. However, at a concentration of 15%, the number decreased to p < 0.001. This finding showed that the compound has evolved its function to antifeedant only or as a secondary metabolite that does not result in immediate death but rather gives discomfort to insects. Conclusion: The use of an antifeedant compound as a biopesticide can inhibit fruit flies’ attack on citrus crops.

Pathogenicity of Aspergillus Airborne Fungal Species Collected from Indoor and Outdoor Public Areas in Tianjin, China.

Airborne fungi play an important role in air pollution and may have various negative effects on human health. In particular, Aspergillus fungi are pathogenic to humans and several domestic animals. In this work, Aspergillus strains isolated from airborne fungal communities sampled from different indoor and outdoor environments in Tianjin University were tested for pathogenicity on Drosophila melanogaster. Airborne fungi were sampled using an HAS-100B air sampler, over a one-year sampling period. Isolated fungal strains were identified based on morphological and molecular analysis. The Aspergillus-centered study was conducted as part of a larger work focusing on the total airborne fungal community in the analyzed environments, which yielded 173 fungal species. In this context, the genus Aspergillus showed the second-highest species richness, with 14 isolated species. Pathogenicity tests performed on male adults of Drosophila melanogaster through a bodily contact bioassay showed that all analyzed airborne Aspergillus species were pathogenic to fruit flies, with high insect mortality rates and shortened lifespan. All the studied fungi induced 100% mortality of fruit flies within 30 culture days, with one exception constituted by A. creber (39 days), while the shortest lifespan (17 days) was observed in fruit flies treated with A. tubingensis. Our results allow us to hypothesize that the studied airborne fungal species may have a pathogenic effect on humans, given the affinity between fruit flies and the human immune system, and may help to explain the health risk linked with Aspergillus fungi exposure in densely populated environments.

Potensi Oleoresin Gulma Daun Siam (Chromolaena odorata) pada Mortalitas Hama Lalat Buah (Bactrocera cucurbitae) pada Uji in-vitro

Fruit flies are the main pests that attack various types of fruit vegetables and fruits that can caused a damage in the quality and quantity of production. Fruit flies controlling by chemical insecticides is common to use nowadays, but excessive use of chemical insecticides has a negative impact on the health and environment. One alternative to control the fruit flies is using oleoresins of Chromolaena odorata leaf. This study aims to determine the effect of C. Odorata leaf oleoresin on increasing the mortality of fruit fly pests (Bactrocera cucurbitae). This research used an experimental method with Completely Randomized Design (CRD) which had 6 treatment levels, namely: N0 (Aquadest), N1 (Oleoresins 2%), N2 (Oleoresins 4%), N3 (Oleoresins 6%), N4 (Oleoresins 8%), N5 (Oleoresins 10%), was replicated 4 times so there were 24 experimental units. The results showed that the application of C. Odorata leaf oleoresin had no sigificant effect on mortality percentage and mortality rates, but oleoresin had the potential to increasing fruit fly mortality as concentrations increased. It is necessary to test the increasing concentration of oleoresin > 10% to control fruit fly pests.

Resveratrol protects against copper and iron toxicity in Drosophila melanogaster

BackgroundCopper (Cu) and iron (Fe) are essential trace elements that when in excess are capable of causing cytotoxic effects leading to lipid peroxidation and promoting oxidative stress. Resveratrol (RES) is a natural polyphenol with antioxidant and anti-inflammatory properties. This study was carried out to evaluate the protective role of RES in Fe and Cu sulphate-induced oxidative stress in Drosophila melanogaster. MethodsAdult wild type flies were fed Cu2+ and Fe2+ (1 mM each) and/or RES (30 and 60 mg/kg diet) for 7 days. Survival, negative geotaxis and emergence rate were evaluated by daily recording of fruit fly mortality and final analysis. Fruit flies were anaesthetized using CO2 gas, homogenized and centrifuged at 4,000 rpm for 10 minutes at 4 °C. Aliquots of the supernatants were used for the estimation of biochemical markers using spectrophotometry. ResultsFruit flies co-treated with FeSO4 + CuSO4 (1 mM each) + RES (30 and 60 mg/Kg) significantly elevated H2O2, NO, lipid peroxidation, acetylcholinesterase as well as GSH, GST, catalase and total thiols (p<0.05) compared with the Cu2+ + Fe2+ (1mM each) treated group. Flies co-treated with FeSO4 + CuSO4 (1mM each) + RES (30 and 60mg/Kg) also had significantly improved (p< 0.05) eclosion and climbing rates compared with the Cu2+ + Fe2+ (1mM each) treated group. ConclusionThis study demonstrated that RES reduced Cu2+ and Fe2+-induced radical generation in D. melanogaster and improved the antioxidant buffering capability of the flies. Therefore, RES could be used in management of disorders involving oxidative stress.

Entomopathogenic nematodes for the control of oriental fruit fly Bacterocera dorsalis (Diptera: Tephritidae)

BackgroundFruit fly species are most damaging pests around the globe which reduced the commercial value of fruits at maturity. Entomopathogenic nematodes (EPNs) from genera Heterorhabditis and Steinernema cause death by inducing septicimia in insect pests in the soil, moreover, endemic nearly all soils. Current study was planned to manage the oriental fruit fly, Bacterocera dorsalis (Hendel.) (Diptera: Tephritidae) hazards by using indigenous EPNs (Heterorhabditis bacteriophora, H. indica, Steinernema asiticum, S. corpocapsae and S. glasseri) as they have host finding ability and recognise as potential eco-friendly biocontrol agent over synthetic chemicals. MethodsStudy for the assessment of EPNs concentrations, various temperatures, soil type and soil moisture levels against mortality (%) of fruit fly (B. dorsalis) larvae was conducted in completely randomized design (CRD) under factorial arrangements. ResultsEPNs concentrations (70 IJs/ml, 110 IJs/ml, 150 IJs/ml) showed that S. asiaticum (150 IJs/ml) showed maximum mortality (94.97 %) of B. dorsalis as compared to other used EPNs along with their respective concentrations. Impact of various temperatures (20 °C, 24 °C, 28 °C, 32 °C, 36 °C) with respect to used EPNs exhibited that H. indica (36 °C) showed maximum mortality (94.33 %) of B. dorsalis as compared to all other treatment. Various soil types (Sandy, Sandy loam, Loam, Clay) impacted the infectivity of EPNs against fruit fly, In case of sandy loam soil, S. asiaticum showed maximum mortality (98.05 %) of B. dorsalis followed by all used treatments. Soil moisture level (12 %, 18 %, 24 %, 30 %) also significantly influenced the infectivity of EPNs against mortality of fruit fly. In case of 12% moisture level, S. asiaticum showed maximum mortality (99.06 %) of B. dorsalis over all the applied treatments along with respective moisture levels. ConclusionIn crux, Steinernema asiaticum higher concentration exhibited efficient control of fruit fly larvae in sandy loam soil with 12 % moisture level at 36 °C over the used EPN species. While application of EPNs against fruit fly is most suitable strategy to manage the fruit fly hazards and it should be included as a part of integrated pest management control programme.

Application of Biopesticide from Eucalyptus grandis on Mortality of Fruit Flies (Bactrocera sp.) on Sweet Citrus (Citrus X Sinensis) Plants

The application of biopesticides is one of the safest alternatives to realize organic agriculture that does not cause harmful impacts to both consumers and the environment. This activity aims to apply biopesticides in eradicating fruit flies (Bactrocera sp.) on Sweet Orange (Citrus X Sinensis) plants. The partner location is the Bukit Rumah Sendi Farmers Group in Karo Regency. Eucalyptus grandis leaves were extracted using steam distillation then the concentration of 1,8 Sineol was determined using GCMS and the concentration was 52%. Eucalyptus oil was mixed with kerosene and detergent then determined the LC50 value in fruit flies and observed for 24, 48, 72, and 96 hours and produced an LC50 value of 35%. This shows that biopesticides are quite effective in eradicating fruit flies.

Mortality of Fruit Flies (Diptera: Tephritidae) Exposed to Spinetoram Toxic Bait in the Laboratory

Fruit flies (Diptera: Tephritidae) cause significant losses during the production and marketing of horticultural products. Brazilian growers usually adopt full-coverage insecticide spraying to control fruit flies, but toxic bait is a more strategic technique, because reach efficacy and the target surface is the foliage and branches. We provide information regarding the toxicity of spinetoram bait to two fruit fly species in the laboratory as an alternative to organophosphates and the specific spinosad formulation. We tested toxic baits in the laboratory, using commercial hydrolysed corn protein (10% v/v) plus 90 g, 120 g, 150 g and 180 g dilutions of spinetoram 250 WG (commercial product/1,000 litres of water). All toxic baits were compared with an untreated control (only protein) for the adults of females and males of Anastrepha obliqua (Macquart, 1835) and Ceratitis capitata (Wiedemann, 1824) up to 30 hours of exposure. Dry food for adults was included in all dilutions (5% w/v). In addition, we tested the residual effect of toxic baits applied to the leaves of mandarin seedlings. We used the same treatments of the earlier bioassay without dry food, collecting treated leaves and exposing them to C. capitata (medfly) females for 24 hours in the laboratory. Leaves were collected 1, 3, 7, 15 and 30 days after application. Overall, medfly adults were more susceptible to spinetoram baits than A. obliqua. All toxic baits resulted in 100% C. capitata mortality 24 hours after initial exposure, and the toxic bait at 150 g/1,000 L of water resulted in the maximum mortality (96%) in A. obliqua. Except for 90 g of spinetoram bait at 30 days after application, all spinetoram bait concentrations resulted in significantly, more dead C. capitata females than the control over all tested periods in the residual bioassay. At 30 days after application, spinetoram baits at 120 g, 150 g and 180 g resulted in 85%, 87% and 86% mortality in C. capitata, respectively. Spinetoram toxic baits have proven promising for long-term fruit fly management.

Fruit fly parasitoids (Hymenoptera: Braconidae) in south‐east Queensland, Australia

AbstractOpiine braconids include natural enemies of tephritid fruit flies, and interest in their greater utilisation for fruit fly control is growing. However, there is a lack of basic data on the prevalence and impact of these wasps for most regions of Australia. We sampled fruit fly host fruits from urbanised and peri‐urban locations of south‐east Queensland and reared out parasitoids and their host flies to determine the regional parasitoid community and how parasitism varied across time and habitat type. A total of 4969 fruits were collected from which 21 277 tephritid puparia were obtained. Of 12 601 fruit flies that emerged, the Queensland fruit fly, Bactrocera tryoni, was the dominant species. A total of 5736 parasitoids, representing four species, were recovered from both suburban and peri‐urban sites. For all samples combined, the average parasitism rate was 30%. The exotic, egg–larval–pupal parasitoid Fopius arisanus represented 81% of the parasitoids collected and was recovered from all of the 13 host fruit species sampled. The second most common species, the native larval–pupal parasitoid, Diachasmimorpha kraussii, represented 15% of recovered parasitoids and was collected from a smaller range of host fruit species. The remaining two parasitoids, Diachasmimorpha tryoni and Psyttalia fijiensis, were rare in samples. Parasitoid infestation was highly variable across samples, with higher rates of parasitism observed from October to May. A targeted field experiment to measure differences in parasitism by D. kraussii between urban and peri‐urban habitats detected no variation in the abundance of D. kraussii across habitats, a result consistent with the general survey. The data show that for south‐east Queensland, parasitoids are a significant fruit fly mortality factor in both peri‐urban and urban landscapes. Any manipulation of parasitoids for regional pest management should focus on conservation of F. arisanus.

Toxicity of flavor enhancers to the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae).

The objective of this study was to evaluate the toxicity of flavor enhancers to the oriental fruit fly Bactrocera dorsalis (Hendel). The flavor enhancers glycine, disodium guanylate, succinic acid disodium salt, monosodium glutamate (MSG), disodium inosinate, and L-alanine significantly increased the mortality of B. dorsalis flies. The mortality of flies that fed on glycine, disodium guanylate, succinic acid disodium salt, and MSG was greater than 90%. Additionally, fruit fly mortality increased with increases in both time and concentration. Glycine not only reduced the climbing ability of B. dorsalis but also affected the duration and frequency of its behavioral patterns (flight, walking, grooming and inactivity). Compared with adult flies in the control group, adult B. dorsalis flies that fed on glycine exhibited a significantly increased duration and frequency of inactivity and a decreased duration and frequency of both flight and walking. However, the effect of glycine on grooming activity was not significant. These findings demonstrate the toxic effects of flavor enhancers on B. dorsalis. Glycine also affected the behavior of adult flies at a low dose. Therefore, glycine has potentially toxic to insects and also likely to have a negative impact at sublethal concentrations.

Purple sweet potato anthocyanin attenuates fat-induced mortality in Drosophila melanogaster

A high fat diet induces the accumulation of lipid hydroperoxides (LPO), accelerates the ageing process and causes a greater mortality in Drosophila melanogaster. Purple sweet potato is rich in antioxidant anthocyanin. The purpose of the present study was to examine if supplementation of purple sweet potato anthocyanin (PSPA) could reduce the mortality of fruit flies fed a high-fat diet. Results showed that the mean lifespan of fruit flies was shortened from 56 to 35days in a dose-dependent manner when lard in the diet increased from 0% to 20%. PSPA supplementation partially attenuated the lard-induced mortality. The maximum lifespan and 50% survival time were 49 and 27days, respectively, for the 10% lard control flies, in contrast, these parameters increased to 57 and 30days in the PSPA-supplemented fruit flies. Similarly, addition of lard into diet increased the total body LPO, while addition of PSPA partially attenuated its increase. Real-time PCR analysis indicated that PSPA-supplemented diet significantly up-regulated the mRNA of superoxide dismutase (SOD), catalase (CAT) and Rpn11, compared with the control lard diet. The western blot analysis also demonstrated that PSPA supplementation was associated with up-regulation protein mass of SOD1, SOD2, and CAT. In addition, PSPA supplementation could restore the climbing ability of fruit flies fed a 10% lard diet. We could conclude that the lifespan-prolonging activity of PSPA was potentially mediated by modulating the genes of SOD, CAT and Rpn11.

PENGARUH IRADIASI SINAR GAMMA [60Co] TERHADAP BACTROCERA CARAMBOLAE DREW & HANCOCK IN VITRO DAN IN VIVO

Effect of gamma irradiation [60Co] against Bactrocera carambolae Drew & Hancock in vitro and in vivo. Bactrocera carambolae Drew & Hancock is one of the most important pests on guava fruit. According to a quarantine regulation in export-import commodities, irradiation treatment is a suitable methods for eradicating infested organism, which is relatively safe for the environment. The aim of this research was to determine mortality doses and an effective dose of [60Co] gamma ray irradiation for the eradication purpose, and its implication on the survival of fruit fly B. carambolae. Two irradiation methods of in vitro dan in vivo were carried out, by exposing egg and 3rd instar larvae of B. carambolae obtained from the laboratory reared insect. Eleven doses of gamma ray irradiation of 0, 30, 50, 75, 100, 125, 150, 175, 200, 300, 450, and 600 Gy were applied, respectively. The level of 99% fruit fly mortality was estimated by the value of LD99 using probit analysis and the number of larvae, pupae and adult survival were evaluated by analysis of variance (ANOVA), and the means compared by Tukey’s test, at 5% of significance level. These result showed that the effective lethal dose (LD99) of irradiation that could be successful to eradicate eggs and 3rd instar larvae in vitro were 2225 and 2343 Gy and in vivo were 3165 dan 3177 Gy, respectively. Almost all of the treated larvae survived and developed to pupae, therefore only the minimum irradiation dose of 30 Gy allowed the pupae to develop into adults.

Regressograms and Mean-Covariance Models for Incomplete Longitudinal Data

Longitudinal studies are prevalent in biological and social sciences where subjects are measured repeatedly over time. Modeling the correlations and handling missing data are among the most challenging problems in analyzing such data. There are various methods for handling missing data, but data-based and graphical methods for modeling the covariance matrix of longitudinal data are relatively new. We adopt an approach based on the modified Cholesky decomposition of the covariance matrix which handles both challenges. It amounts to formulating parametric models for the regression coefficients of the conditional mean and variance of each measurement given its predecessors. We demonstrate the roles of profile plots and regressograms in formulating joint mean-covariance models for incomplete longitudinal data. Applying these graphical tools to the Fruit Fly Mortality (FFM) data, which has 22% missing values, reveals a logistic curve for the mean function and two different models for the two factors of the modified Cholesky decomposition of the sample covariance matrix. An expectation-maximization algorithm is proposed for estimating the parameters of the mean-covariance models; it performs well for the FFM data and in a simulation study of incomplete longitudinal data.

Honeydew and insecticide bait as competing food resources for a fruit fly and common natural enemies in the olive agroecosystem

Honeydew from phloem-feeding insects and fruit fly insecticidal baits may serve as adult food resources for some insect species. In California (USA) olive orchards, the black scale [Saissetia oleae (Olivier) (Hemiptera: Coccidae)] is a common honeydew producer, and spinosad-based fruit fly bait (GF-120) is used to control the olive fruit fly [Bactrocera oleae (Rossi) (Diptera: Tephritidae)]. We investigated the effects of black scale honeydew and GF-120, as food resources, on adult foraging behaviour and survival of the olive fruit fly and two parasitoids in the olive agroecosystem: Scutellista caerulea (Fonscolombe) (Hymenoptera: Pteromalidae), a natural enemy of black scale, and Psyttalia humilis (Silvestri) (Hymenoptera: Braconidae), a parasitoid of the fruit fly. In food choice tests, female flies did not show a preference between GF-120 bait and honeydew, whereas male flies and the parasitoids we tested preferred honeydew. Adults of the three insect species readily fed on honeydew, but the natural enemies never (P. humilis) or rarely (S. caerulea) fed on GF-120 bait. Olfactometer tests further confirmed that the tested natural enemies were not attracted to GF-120 bait. The presence of honeydew significantly reduced fruit fly mortality when both honeydew and GF-120 were provided, compared with GF-120 given alone. A single meal of honeydew increased longevity in all insect species tested. The mean longevities of honeydew-fed insects were not significantly different from those feeding on clover honey. Our results suggest that the presence of honeydew would benefit the three insect species and may reduce the efficacy of GF-120 for fruit fly control because of preference of honeydew rather than fruit fly bait as a food resource.

Perlakuan Uap Panas (Vapor Heat Treatmant) untuk Disinfestasi Lalat Buah dan Memperthankan Mutu Buah Belimbing (Averrhoa Carambola L.)

The objectives of this research were to study mortality of carambola fruit fly (B. carambolae D & H) and to study responses of VHT on quality of carambola (A. carambola L). Fruit fly mortality due to heat has been investigated by immersing fruit fly eggs into hot water at temperatures of 40, 43, 46 dan 49oC for 30 minutes and then at temperature of 46.5oC for 0, 5, 10, 15, 20, 25, 30 minutes. Star fruit were treated at temperature of 46.5oC for 5, 15, 30 minutes and then stored in temperatures of 5, 15oC and room temperature (28-30 oC). The result show that mortality has been achieved 100% at temperature more than 43.0oC for 30 minutes and at temperature 46.0oC for more than 15 minutes. VHT had significant influences to decrease the fruit respiration rates, chilling injury, antraknose, to increase the weight loss, color, and soluble solid content. However, there were no significant change in the hardness, water content, vitamin C and organoleptic test. VHT at temperature 46.5oC for 20 up to 30 minutes were effective to kill fruit flies inside carambola and VHT combined by storing in temperature of 15oC were able to maintain carambola quality during storage.Keywords: vapor heat treatment, fruit fly, B. carambolae, carambola, disinfestationDiterima: 1 Februari 2010; Disetujui: 19 April 2010

Effects of Bait Age and Prior Protein Feeding on Cumulative Time-Dependent Mortality of <I>Anastrepha ludens</I> (Diptera: Tephritidae) Exposed to GF-120 Spinosad Baits

A fruit fly bait to attract and kill adult fruit flies, GF-120, was tested in cages to determine effects of pretreatment diet and bait aging before use on cumulative mortality rates of Mexican fruit fly, Anastrepha ludens (Loew) (Diptera: Tephritidae). Protein-starved and protein-fed, 9-d-old flies both experienced varying overall cumulative mortality at 4, 8, 24, and 48 h. Pretreatment diet had no significant effect on mortality. Overall mortality rates were below 10% for 4 h, 39-43% at 8 h, but mortality in all treatments increased to 89-93% by 24 h, and 99% by 48 h. In a second experiment, GF-120 baits were either freshly prepared or aged for 24 h. Subtreatments consisted of protein-fed and protein-starved flies. The 24-h-aged bait killed significantly more flies at 4 and 8 h than the freshly prepared bait. Protein-starved flies had significantly higher mortality at 4 h and marginally higher mortality at 8 h than protein-fed flies. At 24 and 48 h, there were no significant differences among treatments, and overall morality rose to 99-100% by 48 h. These results may explain differences noted in previous publications in which fruit fly mortality to GF-120 was reported as unusually low as well as reports of bait ineffectiveness for protein-fed flies. The overall impact of any initial repellency of GF-120 seems negligible as judged by overall cumulative mortality at later evaluation times.

Kajian Disinfestasi Lalat Buah (Bactrocera dorsalis) dengan Perlakuan Uap Panas (Vapor Heat Treatment) pada Mangga Gedong Gincu

Since the prohibition of chemical method for insect disinfestations processes such as ethylene dibromide in 1984, heat treatment method was developed as quarantine technology. One of the heat treatment methods is vapor heat treatment (VHT). The objectives of this research were to study mortality of fruit fly (Bactrocera dorsalis) and to study the responses of VHT on quality of gedong gincu mango. Fruit fly mortality due to heat has been investigated by immersing fruit fly eggs into heated water at temperatures of 40, 43, 46 and 49OC for 30 minutes immersed, also at temperature of 46OC for 5, 10, 15, 20, 25 and 30 minutes. Gedong gincu mangoes were treated at temperature 46.5OC for 0, 10, 20, and 30 minutes. The results showed that mortality has been achieved 100% at temperature more than and equal to 43OC for 30 minutes and attemperature 46OC for more than and equal to 10 minutes. The VHT has significantly and fungi population although without adversely affecting to the fruit quality and there were no significant change in the fruit weight loss, hardness, color, soluble solid content, water content, vitamin C and organoleptic test. VHT at temperature 46.5OC for 20 up to 30 minutes were effective to kill fruit flies inside mangoes and were able tomaintaining mango quality during storage.Keywords : mango, fruit fly, disinfestations, vapor heat treatmentDiterima: 24 Maret 2008; Disetujui: 22 Oktober 2008

Chemical Alternatives to Malathion for Controlling <I>Ceratitis capitata</I> (Diptera: Tephritidae), and Their Side Effects on Natural Enemies in Spanish Citrus Orchards

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), is one of the most important fruit pests worldwide. Mediterranean fruit fly control in Spain has been based on organophosphate sprays, especially malathion, mixed with protein baits. However, this insecticide has recently been excluded from annex 1 of the Directive 91/414 CEE, which lists authorized active ingredients for pest control in the European Union. This article reports on the efficacy of four alternative baited insecticides on Mediterranean fruit fly and their side effects on three natural enemies [Cryptolaemus montrouzieri (Mulsant), Neoseiulus californicus (McGregor), and Aphidius colemani (Viereck)] relevant for pest control in citrus agroecosystems. A high Mediterranean fruit fly mortality was obtained for all baited insecticides (phosmet and spinosad) except lambdacyhalothrin, which caused the lowest mortality and showed a novel disabling effect on surviving Mediterranean fruit fly adults. Spinosad proved to be the most selective bait treatment for C. montrouzieri and N. californicus, whereas for A. colemani the most selective bait was phosmet and lambda-cyhalothrin. These findings would contribute to a sustainable chemical control of C. capitata populations under an integrated pest management system in Spanish citrus orchards.

The fruit fly PUB: a phagostimulation unit bioassay system to quantitatively measure ingestion of baits by individual flies

Abstract: A bioassay to investigate quantitative phagostimulation and ingestion physiology of baits on individual fruit flies is presented. The study was undertaken using two fruit fly species: the Mediterranean fruit fly (Ceratitis capitata), a cosmopolitan insect pest, and the Ethiopian fruit fly (Dacus ciliatus), a quarantine insect in Israel. Our model bait suspension included spinosad as the toxic agent, and 1% yeast hydrolysate with 10% sucrose as phagostimulant. A preliminary toxicology study showed that the two fruit flies are highly sensitive to low concentrations of spinosad baited with this phagostimulant. The maximum concentration needed to kill 90% of the female flies was 4.2 and 8.5 p.p.m. for C. capitata and D. ciliatus, respectively. The bioassay was able to detect the ingestion of low volumes (e.g. 1 μl) of tested solutions. The bioassay was also able to detect differences in intake of different concentrations of spinosad solutions and relate ingestion to fruit fly mortality. Additionally, the bioassay was sensitive enough to highlight differences in intake related to the physiological status of the fruit fly and fly species. The bioassay can also be used to follow ingestion kinetics of baits. We expect that this bioassay will contribute in the exploration of more efficient bait systems for fruit flies.

Commodity Heating Medium and Mexican Fruit Fly Mortality

The objective of this research was to investigate whether the medium used to transfer heat to a commodity influenced the mortality of Mexican fruit fly larvae. A similar 2-h heat dose was delivered to grapefruit via immersion in a variable temperature water bath or via exposure to a rapidly circulating gas. The concentration of oxygen and carbon dioxide inside the grapefruit was analyzed at 30-min intervals and grapefruit center temperatures recorded every 60 s during heating. The mortality of larvae located inside grapefruit during heating in a controlled atmosphere or in hot water was significantly higher than that of larvae located inside grapefruit heated in air. The internal atmosphere of grapefruit heated in a controlled atmosphere or in hot water contained significantly higher levels of carbon dioxide and lower levels of oxygen than grapefruit heated in air. Larval mortality was compared after larvae were heated in media by rapidly circulating air or by an atmosphere containing 4 kPa of oxygen and 18 kPa of carbon dioxide to evaluate whether the altered atmosphere or a heat-induced fruit metabolite was responsible for enhanced mortality. The significantly higher mortality of larvae heated in media in the presence of an altered atmosphere suggested that the altered atmosphere enhanced larval mortality. Results from this research suggest that reducing oxygen and or increasing the level of carbon dioxide during heating can enhance mortality of the Mexican fruit fly and potentially reduce the heat dose required for quarantine security.