Influence of ground beetles (Carabidae) as biological agent to control of the Mediterranean fruit fly pupae,Ceratitis capitata,in Iranian citrus orchards

Damage by Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in the northern Iranian citrus orchards has been led to spray by different chemical pesticides. The present study was conducted in the citrus orchard in Mazandaran province of Iran where with the exception of mineral oil treatments for scale insects, had not been sprayed with synthetic insecticides for six years. The purpose of this study was initially to investigate faun and seasonal activity of predaceous ground carabid beetles in the citrus orchards. Additionally, their role as predators of Ceratitis capitata (Wiedemann) pupae was evaluated under laboratory and field conditions. Predation in laboratory was evaluated by no choice feeding experiments while predation under field conditions was evaluated by molecular detection of the pest DNA in the gut contents of field-collected Carabids. A total of 3437 beetles of ten carabid species were collected from a non-chemical treatment citrus orchard. The results of the seasonal density fluctuation indicated increasing population in spring reaching the highest in September, simultaneously with the peak of fruit fly damage, and thereafter decreasing during winter when the pest was overwintering. However, three species, Harpalus rufipes, Broscus karelinii and Brachinus brevicollis were most abundant in the field collection but the results of no-choice experiments in the laboratory indicated H. rufipes, B. karelinii and Pterostichus macer were the most voracious predators on pupae. Results of gut content analysis of the voracious species indicated the positive testing for pest DNA in 79.16 % of H. rufipes, 76.92 % of B. karelinii and 75 % of P. macer of analyzed beetles. The results of the study strongly indicated that in citrus orchards where intensive spraying is eliminated, natural enemies such as Carabid beetles could play an important role in reducing pests such as medfly.     

Influence of Ground Predators on the Survival of the Mediterranean Fruit Fly Pupae, Ceratitis capitata, in Spanish Citrus Orchards

A survey of predaceous ground arthropods was conducted in two citrus orchards in Valencia, Spain, and their role as predators of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) pupae was evaluated under field and laboratory conditions. A total of 2959 predaceous arthropods were collected in pitfall traps in the two orchards from July 2003 to September 2004. Ants (Hymenoptera) were the most abundant group (83.61%), followed by Staphylinidae (7.77%), Araneae (5.24%), Dermaptera (2.13%), Carabidae (0.64%) and Cicindelidae (0.61). Pupae disappearance rates were higher during the warmer months of the year, from May to October, and in the orchard with the largest ant population. In the warm season, the mean survival of C. capitata pupae was 35.7±6.2% and 14.3±6.7%, respectively, in both orchards. Patterns of predation, inferred from broken or abnormal pupae, were more frequently observed in the colder months, from November to April, when spiders, Staphylinidae and other predators were present. In the cold season, the combined effect of predation and low temperature led to an adult emergence rate of 26.7±9.9% and 13.0±7.5% in both orchards. In no-choice laboratory trials, all predator species tested fed at significantly different rates on C. capitata pupae. Preliminary data show that the Carabids, Pseudophonus rufipes (Duftschmid) and Harpalus distinguendus (Degeer), were the most voracious species, consuming more than one pupa per day.     

Intraguild interactions between two biological control agents in citrus fruit: implications for biological control of medfly

The parasitoid wasp Spalangia cameroni and the predatory beetle Pseudoophonus rufipes have long been studied for use as biological control agents against the Mediterranean fruit fly Ceratitis capitata, particularly in citrus fruit orchards. Nevertheless, these two species of natural enemies, when competing for a common resource, may experience intraguild predation (IGP) interactions. These possible interactions, affecting parasitism and predation, have been evaluated in the present work, under laboratory conditions, through potential changes in functional response. Regarding host/prey density, both natural enemies, when acting alone, showed a type II functional response. Nevertheless, due to IGP, S. cameroni, in the presence of P. rufipes, showed a higher fertility rate and a type III functional response. The parasitism behaviour of S. cameroni was affected by the presence of the predator, reducing the host handling time. Conversely, the parasitism rate of S. cameroni did not vary in the presence of P. rufipes but the degree of superparasitism decreased and led to an increased fertility rate and an increasingly female‐biased sex ratio. Meanwhile, the predatory efficiency of P. rufipes was not affected by the presence of S. cameroni but discrimination between parasitised and unparasitised pupae of C. capitata, with a preference for the latter, was reported for this predator species. Our results suggest that in biological control programmes, the use of only one of these species is recommended at low infestation levels, whilst at high densities of the pest, the combination of both natural enemies seems to be the most appropriate strategy.     

Activity-density of <Emphasis Type="Italic">Pardosa cribata</Emphasis> in Spanish citrus orchards and its predatory capacity on <Emphasis Type="Italic">Ceratitis capitata</Emphasis> and <Emphasis Type="Italic">Myzus persicae</Emphasis>

The wolf spider Pardosa cribata Simon is the most abundant ground-dwelling spider inhabiting citrus orchards in eastern Spain. However, little is known about its activity-density and its predatory role in the citrus agrosystem. Here we report on the activity-density of P. cribata monitored by pitfall traps, and on its capacity to prey on two citrus pests that appear both in the citrus canopy and the ground cover, Ceratitis capitata (Wiedemman) and Myzus persicae (Sulzer), respectively. Pardosa cribata was present in citrus orchards throughout the year, with a peak in spring and a higher peak in summer. Pardosa cribata preyed on adults and third-instar larvae but not on pupae of C. capitata. A type II functional response was obtained for teneral-like adults, with an estimated attack rate (a′) of 0.771 ± 0.213 days⁻¹ and a handling time (T _h) of 0.051 ± 0.013 days. Pardosa cribata also preyed efficiently on M. persicae, giving a type II functional response with an estimated attack rate and handling time of 2.833 ± 0.578 days⁻¹ and 0.031 ± 0.001 days, respectively. The data reported here indicate that this wolf spider could play an important role in regulating both these pests, and therefore might contribute to developing conservation biological control strategies for citrus pests. Handling Editor: Arne Jenssen.     

Seasonal monitoring of Drosophila suzukii (Diptera: Drosophilidae) in a mixed fruit production system

Drosophila suzukii Matsumura (Diptera: Drosophilidae), an invasive pest native to Southeast Asia, is now reported throughout North America and Europe. We used traps baited with apple cider vinegar to monitor D. suzukii adult presence in multiple crops and associated fruiting plants at the Wolfskill USDA Germplasm Repository in Winters, CA, USA from 2011 to 2013. Traps were placed in small (~ 160 m × 40 m on average) almond, apricot, cherry, fig, grape, mulberry, peach, persimmon, plum, and pomegranate deciduous fruit orchard blocks as well as a citrus block and evergreen trees located near a house at the repository. D. suzukii was present in all blocks with the greatest monthly deciduous fruit captures in the cherry and fig blocks. Few D. suzukii were captured in almond, apricot, pomegranate and grape blocks. Deciduous fruit blocks had two distinct periods of trap capture: spring through midsummer and again in fall. Most deciduous fruit blocks had low trap captures during the hottest summer months (August to September) and the coldest winter months (December to April). However, from late December through mid-January, high trap captures were associated with the citrus and house sites. This study provides seasonal trapping data of D. suzukii adults in an unsprayed multi-crop mosaic, and may serve as a model of adult capture patterns across smaller mixed-crop commercial orchards and associated urban landscapes.     

Temperature and rate of seed consumption by ground beetles (Carabidae)

Predation is a key source of seed mortality in many weed species and thus is a part of natural control. In the field, the intensity of seed predation by invertebrates varies during the course of a year. One source of this variation is fluctuations in ambient temperature. Here, the effect of temperature on seed consumption is investigated for the first time, using two abundant carabid seed predators, Pseudoophonus rufipes and Harpalus affinis (Coleoptera: Carabidae), and dandelion (Taraxacum officinale) as a model system. Field collected individuals were sexed, kept at one of six constant temperatures between 10 and 28 °C and provided with a surplus of seed. Seed consumption was recorded over a period of 4 days. Averaged over all the temperatures, the smaller H. affinis consumed 12.2 seeds day^?1 and larger P. rufipes 29 seeds day^?1. On average, females consumed more seeds than males. Seed consumption by both species increased with temperature. In H. affinis the increase was linear and different for males and females. In P. rufipes the consumption was similar in both sexes but curvilinear because there was no further increase in consumption above 20 °C. Assuming a linear relationship between temperature and consumption at up to 20 °C we calculated the temperature at which seed consumption ceased (?0.1 to 0.3 °C in H. affinis and 6.3–6.9 °C in P. rufipes) and the increment in seed consumption per 1 °C increase in temperature above this threshold (0.4–1.0 and 1.5–4.2 seeds individual^?1 day^?1, respectively) for the two species. Thus, it is possible to calculate the average daily consumption of each species over a range of temperatures up to 20 °C.     

Distance-dependent capture probability of male Mediterranean fruit flies in trimedlure-baited traps in Hawaii

Many countries operate regional trapping programs for the detection of exotic tephritid fruit flies, which because of their polyphagous habits pose a serious threat to fruit and vegetable crops. Detection of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), relies primarily on trimedlure (TML), a synthetic male-specific lure, yet few studies have measured the relationship between distance from TML-baited traps and the probability of male capture, and consequently the detection sensitivity of medfly trapping programs is largely unknown. The present study measured distance-dependent capture probabilities for male C. capitata in TML-baited traps using mark–release–recapture procedures. Releases were performed at distances of 25, 50, 100, and 200 m at 4 sites in Hawaii, and the resulting capture rates were used to estimate the minimum detectable population size (detection probability > 99.9%) for a trapping density of 5 TML traps per 2.59 km² (= 1 mi², the density used in California, USA). Capture rates were similar for 3 of the sites (6.5%, 3.8%, 1.1%, and 0.1% for the 4 distances, respectively) and yielded an estimated minimum detectable population of ≈ 2300 males, a value similar to that obtained in a comparable study conducted in California. For unknown reasons, capture rates were significantly lower at the remaining site (1.8%, 0.6%, 0.1%, 0.04%) and the estimated minimum detectable population was correspondingly much larger (≈ 10,000 males). Implications of these results for medfly detection programs are discussed.     

Mediterranean fruit fly subplot hot spots prediction by experts' experience

The Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), is a major pest, infesting hundreds of crop types. Since current field monitoring is mostly manual, understanding the spatiotemporal patterns of pest emergence at the fine scale can optimize precise trap placement and site‐specific treatment activities, also within area wide integrated pest management projects. We carried out a three‐year study in deciduous orchards in Israel, testing for the existence of subplot hot spots in which medfly populations display small‐scale aggregations over consecutive seasons, beyond the expected spatial variability resulting from host type and ripening sequence. medfly population increase in these locations often preceded or was parallel to infestations in surrounding orchards, suggesting that hot spots can provide an important tool for effective prediction and control of pest emergence. We also examined the use of expert knowledge to predict hot spot locations and suggest a methodology for verifying them.     

Carabid patterns in olive orchards and woody semi-natural habitats: first implications for conservation biological control against <Emphasis Type="Italic">Bactrocera oleae</Emphasis>

The role of carabids (Coleoptera: Carabidae) for pest control service in perennial crop systems has been scarcely investigated. We addressed this knowledge gap exploring activity patterns and traits of adult carabids dwelling olive orchard agroecosystems as potential natural enemies of third instar larvae and pupae of Bactrocera oleae (Diptera: Tephritidae). Olive orchard supported a well-structured carabid assemblage, whose species phenologies revealed a temporal overlapping within the pest cycle. The assemblage of adjacent woody semi-natural habitats is more of conservation interest, but may play a weaker role in B. oleae control provisioning. We suggest the identification of carabids main traits for B. oleae conservation biological control as a cost-effective strategy for addressing future attention and resources only to those predators that satisfy basic requirements. This research may open new scenarios on management interventions to both conserve predators and encourage alternative approaches against olive orchards pest.     

Medfly Ceratitis capitata as Potential Vector for Fire Blight Pathogen Erwinia amylovora: Survival and Transmission

Monitoring the ability of bacterial plant pathogens to survive in insects is required for elucidating unknown aspects of their epidemiology and for designing appropriate control strategies. Erwinia amylovora is a plant pathogenic bacterium that causes fire blight, a devastating disease in apple and pear commercial orchards. Studies on fire blight spread by insects have mainly focused on pollinating agents, such as honeybees. However, the Mediterranean fruit fly (medfly) Ceratitis capitata (Diptera: Tephritidae), one of the most damaging fruit pests worldwide, is also common in pome fruit orchards. The main objective of the study was to investigate whether E. amylovora can survive and be transmitted by the medfly. Our experimental results show: i) E. amylovora can survive for at least 8 days inside the digestive tract of the medfly and until 28 days on its external surface, and ii) medflies are able to transmit the bacteria from inoculated apples to both detached shoots and pear plants, being the pathogen recovered from lesions in both cases. This is the first report on E. amylovora internalization and survival in/on C. capitata, as well as the experimental transmission of the fire blight pathogen by this insect. Our results suggest that medfly can act as a potential vector for E. amylovora, and expand our knowledge on the possible role of these and other insects in its life cycle.     

Assessment of Ceratitis capitata (Diptera,Tephritidae) pupae killed by heat or cold as hosts for rearing Spalangia cameroni (Hymenoptera: Pteromalidae)

In this work, we study the suitability of using dead medfly Ceratitis capitata pupae, killed by heat- or cold-shock, for the mass rearing of Spalangia cameroni, a pupal parasitoid of key pests. 100% mortality of medfly pupae could be accomplished with cold-shock at –20°C for 60 min or with heat-shock at 55°C for 30 min. Neither parasitism percentage nor sex ratio of the offspring differed significantly among heat-shocked, cold-shocked and untreated pupae. In addition, there was no significant difference in the percentage of parasitoids that aborted (♂♂ or ♀♀) among pupal treatments. Some of the pupae were covered with peat because the third larval instar of the medfly buries itself before pupation. However, the buried pupae were not parasitised at a greater or lesser rate than those not covered with peat. The percentage of parasitism was also unaffected by whether the pupae had been killed recently or had been stored at between 4°C and 6°C over 15 or 30 days. The use of dead hosts and later storage permitted the following: (a) the use of hosts over long periods of time; (b) a rapid increase in parasitoid numbers and (c) the availability of pupae killed at the most suitable postpupation times for the production of parasitoids. Furthermore, in biological control projects, the use of dead parasitised pupae in the field avoids the risk of enhancing the pest and allows an increase in parasitism in the field through the use of pupae treated with cold- or heat-shock.     

Attraction of female Chiracanthium mildei(Araneae: Clubionidae) to olfactory cues from maleMediterranean fruit flies Ceratitis capitata(Diptera: Tephritidae)

Chiracanthium mildei, a common sac spider (Clubionidae) in Israel, is an important predator of pest insects in citrus and apple orchards. Field observations indicate that the females of this hunting spider are attracted to traps containing the parapheromone trimedlure and males of the Mediterranean fruit fly (Ceratitis capitata),which were caught in these traps. Laboratory testsshow that C. mildei females are attractedto olfactory cues from male C. capitata, but notto trimedlure. This suggests that C. mildeimay be an important nocturnal predator of C.capitata.     

Parasitism of Aganaspis daci against Ceratitis capitata under Mediterranean climate conditions

The effect of environmental factors is essential to the success of parasitoids as biological control agents, as it determines their foraging activity, development, and survival. The larval‐pupal parasitoid wasp Aganaspis daci (Weld) (Hymenoptera: Figitidae) is known to have a very low fertility (i.e., offspring production) in the field in certain Mediterranean areas, probably due to its inability to efficiently oviposit under such climatic conditions. In this study, the percentage of parasitism and induced mortality (mortality of host pupae attributed to parasitoids, from which adults do not emerge) caused by this wasp to the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), was assessed under field conditions across 1 year, using medfly‐infested apples and parasitoid‐confined release in a lemon orchard of southeastern Spain. As A. daci is known to have very few emergences in the field, fertility was assessed in the laboratory from parasitized pupae recovered from the field. We found average parasitism rates of 27% and high induced mortality rates of 66% under field conditions. Consequently, medfly population reduction (total mortality of C. capitata caused by A. daci, i.e., induced mortality + % parasitism) was, on average, 87%. Parasitism and induced mortality varied throughout the year, depending on the average temperature and relative humidity. The interaction of these factors resulted in the highest parasitism rates at low mean temperature and humidity values; likewise, the highest percentages of induced mortality were obtained with a combination of high mean temperature and low mean humidity values. In conclusion, A. daci may exert a strong impact on medfly populations, being a good candidate for inundative field releases for the management of C. capitata in the Mediterranean Basin.     

Pseudomonas caspiana sp. nov., a citrus pathogen in the Pseudomonas syringae phylogenetic group

In a screening by multilocus sequence analysis of Pseudomonas strains isolated from diverse origins, 4 phylogenetically closely related strains (FBF58, FBF102^T, FBF103, and FBF122) formed a well-defined cluster in the Pseudomonas syringae phylogenetic group. The strains were isolated from citrus orchards in northern Iran with disease symptoms in the leaves and stems and its pathogenicity against citrus plants was demonstrated. The whole genome of the type strain of the proposed new species (FBF102^T = CECT 9164^T = CCUG 69273^T) was sequenced and characterized. Comparative genomics with the 14 known Pseudomonas species type strains of the P. syringae phylogenetic group demonstrated that this strain belonged to a new genomic species, different from the species described thus far. Genome analysis detected genes predicted to be involved in pathogenesis, such as an atypical type 3 secretion system and two type 6 secretion systems, together with effectors and virulence factors. A polyphasic taxonomic characterization demonstrated that the 4 plant pathogenic strains represented a new species, for which the name Pseudomonas caspiana sp. nov. is proposed.     

Transgenic sexing system for Ceratitis capitata (Diptera: Tephritidae) based on female-specific embryonic lethality

Fruit fly pest species have been successfully controlled and managed via the Sterile Insect Technique (SIT), a control strategy that uses infertile matings of sterile males to wild females to reduce pest populations. Biological efficiency in the field is higher if only sterile males are released in SIT programs and production costs are also reduced. Sexing strains developed in the Mediterranean fruit fly Ceratitis capitata (medfly) through classical genetics are immensely beneficial to medfly SIT programs but exhibit reduced fertility and fitness. Moreover, transfer of such classical genetic systems to other tephritid species is difficult. Transgenic approaches can overcome this limitation of classical genetic sexing strains (GSSs), but had resulted so far in transgenic sexing strains (TSSs) with dominant lethality at late larval and pupal stages. Here we present a transgene-based female-specific lethality system for early embryonic sexing in medfly. The system utilizes the sex-specifically spliced transformer intron to restrict ectopic mRNA translation of the pro-apoptotic gene hid^Ala5 to females only. The expression of this lethal effector gene is driven by a tetracycline-repressible transactivator gene tTA that is under the control of promoters/enhancers of early-acting cellularization genes. Despite observed position effects on the sex-specific splicing, we could effectively establish this early-acting transgenic sexing system in the medfly C. capitata. After satisfactory performance in large scale tests, TSSs based on this system will offer cost-effective sexing once introduced into SIT programs. Moreover, this approach is straight forward to be developed also for other insect pest and vector species.     

Odour-mediated foraging by yellowjacket wasps (Hymenoptera: Vespidae): predation on leks of pheromone-calling Mediterranean fruit fly males (Diptera: Tephritidae)

Predation is probably the most important male mortality factor in insect species with courtship displays that render males performing them conspicuous targets of predators. Sexually active Mediterranean fruit fly males, Ceratitis capitata (Wied.), aggregate in leks, where they participate in agonistic encounters and engage in visual, acoustic and pheromone-calling displays to attract receptive females. The objective of this study was to assess: a) whether sexually displaying C. capitata males in leks inside host and non-host foliage are subject to predation by the most prominent predators yellow-jacket wasps, Vespula germanica (F.), and if so, b) whether olfactory, visual or auditive stimuli are used by foraging wasps in locating male C. capitata prey. Studies were carried out in a citrus orchard and surroundings on the island of Chios, Greece. Observations were conducted using perforated containers hung within mulberry, fig or citrus foliage. Living C. capitata flies of different sex and either mature or immature were placed inside. Our results show that the yellowjacket wasps have learned to associate the presence of sexually active medfly males aggregated in leks with their prey's pheromone (kairomone). Foraging wasps, flying through the crowns of host trees, responded to the odour source of C. capitata male pheromone by approaching from downwind. Even inside dense citrus tree foliage, wasps keyed in on aggregations of pheromone-calling males using olfactory stimuli. Stimuli of visual and acoustic male signalling were only used at close range, after having followed the pheromone plume close to its source. Visual cues played a greater role in directing wasp foraging under more open and exposed host foliage conditions. Odour-based foraging of wasps inside host foliage in the mid-morning hours, when medfly male lekking activities peak, shifted gradually to a more visual-based host fruit patrolling in the afternoons to capture ovipositing and feeding medfly females. On ripe fruit, particularly fig, V. germanica visual prey hunting also included the capture of feeding medfly males, other feeding Diptera, as well as medfly larvae extracted from wasp-made perforations in the fruit.     

Habitat effects on second-order predation of the seed predator Harpalus rufipes and implications for weed seedbank management

Seed predators provide a valuable ecosystem service to farmers by reducing densities of weed seeds, and, in turn, densities of weed seedlings they must manage. The predominant invertebrate weed seed predator in Maine, USA, agroecosystems is the carabid beetle Harpalus rufipes DeGeer. Pitfall trapping has shown that H. rufipes prefers sites with vegetative cover to fallow sites, preference speculated to be driven by predator avoidance behavior. To test this hypothesis, ‘second-order predation assays’ were developed, in which live H. rufipes prey were presented to second-order predators. Field experiments were conducted to determine foremost if H. rufipes was subject to second-order predation, and secondly, whether (a) vegetative cover affords H. rufipes protection from second-order predators, and (b) high rates of second-order predation correspond with decreased invertebrate seed predation rates. Two 72-h experiments were conducted (mid August and September 2012) at crop and non-crop sites across a 28 ha diversified farm in Stillwater, ME, USA.Second-order predation was 2.8% per day. Based on images from motion-sensing cameras, H. rufipes’ predators included birds and small mammals. Neither a relationship between second-order predation and vegetative treatment, nor an empirical relationship between second-order predation and invertebrate seed predation were detected. However, a simulation model predicted that 2.8% per day second-order predation could increase the number of seeds entering the seedbank by more than 17% annually. Additionally, complex habitats supported higher rates of second-order predation than did simple habitats.     

Guiding Classical Biological Control of an Invasive Mealybug Using Integrative Taxonomy

Delottococcus aberiae De Lotto (Hemiptera: Pseudococcidae) is a mealybug of Southern African origin that has recently been introduced into Eastern Spain. It causes severe distortions on young citrus fruits and represents a growing threat to Mediterranean citrus production. So far, biological control has proven unsatisfactory due to the absence of efficient natural enemies in Spain. Hence, the management of this pest currently relies only on chemical control. The introduction of natural enemies of D. aberiae from the native area of the pest represents a sustainable and economically viable alternative to reduce the risks linked to pesticide applications. Since biological control of mealybugs has been traditionally challenged by taxonomic misidentification, an intensive survey of Delottococcus spp. and their associated parasitoids in South Africa was required as a first step towards a classical biological control programme. Combining morphological and molecular characterization (integrative taxonomy) a total of nine mealybug species were identified in this study, including three species of Delottococcus. Different populations of D. aberiae were found on wild olive trees, in citrus orchards and on plants of Chrysanthemoides monilifera, showing intra-specific divergences according to their host plants. Interestingly, the invasive mealybug populations from Spanish orchards clustered together with the population on citrus from Limpopo Province (South Africa), sharing COI haplotypes. This result pointed to an optimum location to collect natural enemies against the invasive mealybug. A total of 14 parasitoid species were recovered from Delottococcus spp. and identified to genus and species level, by integrating morphological and molecular data. A parasitoid belonging to the genus Anagyrus, collected from D. aberiae in citrus orchards in Limpopo, is proposed here as a good biological control agent to be introduced into Spain.     

How glyphosate altered the behaviour of agrobiont spiders (Araneae: Lycosidae) and beetles (Coleoptera: Carabidae)

Cultivation of herbicide-tolerant strain of GM corn involves applications of a non-selective herbicide. Mortality of arthropod natural enemies resulting from the application of herbicides is negligible. But nothing is known how herbicides affect the behaviour of natural enemies and thus alter their pest control efficacy. Aim of the study was to assess the effect of the Roundup residues on the predatory, defensive, locomotory and reproductive behaviour of epigeic spiders and carabid beetles. Specimens of Pardosa agricola (Araneae: Lycosidae) and Poecilus cupreus (Coleoptera: Carabidae) were exposed for 2 h to the fresh and 1-day old residues of Roundup Biaktiv (Monsanto, IPA 480 g/l). Predation rate was similar for all treatments in both spiders and beetles. Spiders did not avoid surface treated with herbicide residues more than the control surface, but beetles slightly avoided surface with fresh residues. The speed of locomotion of spiders was not altered by herbicide residues, but beetles exposed to residues crawled at significantly lower speed than the control group. Herbicide residues did not affect the escape efficacy of spiders from a predator. Residues had no detrimental effect on the courtship, mating frequency and duration in spiders. Roundup Bioaktiv thus appears to be harmless to lycosid spiders and only slightly harmful to carabid beetles. The biological control potential of both predators should not be reduced by the application of Roundup Bioaktiv.     

Biology of Apanteles myeloenta (Hymenoptera: Braconidae), a larval parasitoid of carob moth Ectomyelais ceratoniae (Lepidoptera: Pyralidae)

The carob moth, Ectomyelois ceratoniae (Lepidoptera: Pyralidae), is the most important pest of pomegranate orchards (in terms of economic damage) within Iran, and hence, several control procedures, including biological methods of control, have been attempted as a means of controlling populations of this insect. This research was carried out in order to study the biology of Apanteles myeloenta (Hymenoptera: Braconidae), a larval parasitoid of the carob moth. Laboratory studies were conducted to determine larval developmental time, adult longevity, sex ratio, parasite progeny production, and host stage preference of A. myeloenta. At 25 ± 1 °C, immature developmental time (egg to pupa; mean ± SE) was 28.33 ± 0.85 days and 27.46 ± 0.37 days for male and females, respectively. Adult females survived on average 17.5 ± 0.14, 11.7 ± 0.22, 3.4 ± 0.18, and 2.8 ± 0.12 days at 25 C when provided with honey and water, honey only, water only or no food source, respectively. The sex ratio (females to males) of A. myeloenta was 1:3.5 from hosts parasitized in the first instar, 1:3 for second instars and 1:2 for third instar carob moth larvae. Female A. myeloenta typically preferred to parasitize second instar over third or first instar. The oviposition activity peaked on the 7th and 8th days following emergence, when provided with honey, and 10% sucrose solution, respectively.