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With the invasion or local occurrence of Bemisia tabaci and Tuta absoluta in recent decades, they both have become two major insect pests of tomato crops in many countries. The biological control of these two pests through heteropteran predators, e.g., Nesidiocoris tenuis or Macrolophus pygmaeus, is a key pest management strategy. However, by contrast to M. pygmaeus, N. tenuis could usually cause plant damage and yield loss. The joint use of these two mirids for pest management has not been described yet, although it may be helpful in reducing the side effects of N. tenuis on crop (owing to competitive and/or agonistic interactions between the two species). In this study, we compared the abundance of predators and pests in treatments with N. tenuis and M. pygmaeus together versus N. tenuis alone and in the presence of B. tabaci only or B. tabaci and T. absoluta. We also measured necrotic rings and tomato flower production in these four treatments. We found that the joint use of both mirid predators together led to (1) a reduced overall mirid density and (2) a sustained biocontrol efficiency, when compared to the use of N. tenuis alone. In addition, plant feeding activities of mirids were significantly reduced when predators were used jointly (vs. N. tenuis alone). The applicability of zoophytophagous predators as biocontrol agents could be facilitated by simultaneously releasing two (or more) heteropteran predator species instead of a single one. [ABSTRACT FROM AUTHOR]

Ecologists study how populations are regulated, while scientists studying biological pest control apply population regulation processes to reduce numbers of harmful organisms: an organism (a natural enemy) is used to reduce the population density of another organism (a pest). Finding an effective biological control agent among the tens to hundreds of natural enemies of a pest is a daunting task. Evaluation criteria help in a first selection to remove clearly ineffective or risky species from the list of candidates. Next, we propose to use an aggregate evaluation criterion, the pest kill rate, to compare the pest population reduction capacity of species not eliminated during the first selection. The pest kill rate is the average daily lifetime killing of the pest by the natural enemy under consideration. Pest kill rates of six species of predators and seven species of parasitoids of Tuta absoluta were calculated and compared. Several natural enemies had pest kill rates that were too low to be able to theoretically reduce the pest population below crop damaging densities. Other species showed a high pest reduction capacity and their potential for practical application can now be tested under commercial crop production conditions. [ABSTRACT FROM AUTHOR]

Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a key insect pest, seriously damaging tomato crops and inducing tremendous yield and economic losses. The area of origin of this insect is in South America, while it has recently become an invasive pest in Europe, Africa, Asia and Central America. In the Middle East and North Africa (MENA) region, there has been growing evidence that biological control through field releases of egg parasitoids and predatory mirids generally induces promising control results of T. absoluta whenever the natural enemy species as well as the timing and release rates are suitably chosen. As such, application of botanical and/or microbial pesticides represent a potential control approach to be adopted against T. absoluta. This would decrease the detrimental side effects on non-target beneficial arthropods typically exhibited by hazardous chemical insecticide applications. The scientific literature emphasizing the (i) releases of parasitoids and/or predators, (ii) applications of biopesticides, and (iii) combination « release of parasitoid and/or predator + biopesticide treatments and/or other biorational tools», as sustainable control options of T. absoluta throughout the MENA region over the last decade, is comprehensively reviewed and unraveled herein. [ABSTRACT FROM AUTHOR]

The damsel bug, Nabis pseudoferus Remane (Hemiptera: Namidae), is a generalist predator of small arthropods, including key insect pests of vegetable crops. In this study, we characterized the predation and development of various N. pseudoferus life stages when preying on the eggs and first‐ and fourth‐instar nymphs of the invasive South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). These findings were compared to those of the bug's common prey, cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae). Of the life stages tested, females showed the highest predation rate on all tested prey, due to their high longevity, large body, and great energy requirements for reproduction. The predator's oviposition rate was clearly influenced by prey type, and was highest when feeding on fourth instars of T. absoluta. Considering the zoophytophagy of most of the life stages of other mirid species of tomato, and the lower propensity of N. pseudoferus to feed on plants, these results show that this species can be considered as a key indigenous natural enemy for sustainable pest control packages against T. absoluta in newly invaded areas. [ABSTRACT FROM AUTHOR]

Drosophila suzukii has become a key invasive pest of soft- and thin-skinned fruit crops in its invaded regions in Europe and Americas, where naturally occurring natural enemies are generally not effective for the suppression of this pest or largely absent such as larval-attacking parasitoids. As a part of systematic evaluations of candidate agents for classical biological control of this invasive pest, we evaluated the functional responses of three Asian-native larval hymenopteran parasitoids, Asobara japonica (Braconidae), Ganaspis brasiliensis , and Leptopilina japonica (both Figitidae) to D. suzukii or Drosophila melanogaster (A. japonica only) larvae. Host larval densities were 5, 10, 15, 20, 25, 30, 35, or 40 larvae per test for A. japonica and 3, 6, 9, 12, 18, 24, 30, 36, or 42 larvae per test for G. brasiliensis or L. japonica. Host larvae were provided in standard artificial diet in tubes for a 24-h exposure to individual female parasitoids under the quarantine conditions (23°C). All three parasitoids showed a linear (type I) functional response to the tested host densities. Host species (for A. japonica only) did not affect the number of hosts parasitized or the functional response. Asobara japonica was more efficient than either figitid in terms of the searching efficiency while L. japonica preformed slightly better than G. brasiliensis under the tested conditions. The results are discussed with respect to the selection of parasitoid species to be released in North America and Europe to suppress D. suzukii. [ABSTRACT FROM AUTHOR]

Honeydew is a sugar-rich food source produced by sap-feeding insects, notably by major pests such as aphids and whiteflies. It is an important alternative food source for the adult stage of various key natural enemies (e.g., parasitoids), but it may be used also as food by agricultural pests. Necremnus tutae is an idiobiont parasitoid, and it is the most abundant larval parasitoid associated with the South American tomato pinworm, Tuta absoluta, in recently invaded European areas. The impact of N. tutae on T. absoluta populations was evaluated under greenhouse conditions with and without the presence of a honeydew producer, the aphid Macrosiphum euphorbiae. In addition, laboratory experiments were performed to evaluate the longevity of N. tutae and T. absoluta adults when fed with water, honey or honeydew produced by the aphid. In the greenhouse, N. tutae effectively reduced T. absoluta population by the end of the experiment, and this independently of the presence of the aphid; still the presence of M. euphorbiae led to delayed and reduced T. absoluta population peak when controlled by the parasitoid (there was a fourfold increase in parasitoid density in presence of aphid). The longevity of both N. tutae and T. absoluta females increased in the presence of honeydew (when compared to water only) under laboratory conditions; it hinted that honeydew could be used by an herbivore as T. absoluta. The interactions between the two phytophagous species showed contrasting effects, and this mostly independently of parasitoid presence. Tuta absoluta had no impact on aphid population dynamics. By contrast, the production of T. absoluta larvae was higher in the first part of the experiment as the adults lived longer (feeding on aphid honeydew) and produced more larvae. In the second part of the experiment, there were fewer T. absoluta larvae in the presence of the aphid, likely owing to resource competition and/or negative plant-mediated indirect interactions. We demonstrated that honeydew producers could impact parasitoid-host population dynamics both through direct and indirect interactions and that potential positive effects of a sugar food source toward a pest can be nullified in the long term by other negative effects occurring simultaneously. [ABSTRACT FROM AUTHOR]

We conducted a review of published information on Tuta absoluta parasitoids for the Neotropical region to (1) corroborate species records, (2) analyze associations including the T. absoluta, other insect and plant hosts and (3) identify research directions for enhancing their use as biological control agents. The literature review shows more than 50 species or morphospecies of Hymenoptera associated with T. absoluta, but less than a half (23) could be confirmed as parasitizing T. absoluta. Erroneous reports or invalid names of species, two new species records were found. Over a 100 pests and non-economically important insect and cultivated and non-cultivated plants directly or indirectly interact with T. absoluta in the region. Four T. absoluta parasitoid species include in their host range predatory insects or act as hyperparasitoids, a negative feature considered for a biological control agent. Five larval parasitoids have a narrow host range and could be considered for classical biological control programs in the areas of new invasion. Six Trichogrammatidae species are commercially used in various countries; of those, T. minutum and T. pretiosum are considered to be moderately generalist, being able to exploit several insect hosts. Apart from Apanteles gelechiidivoris and Pseudapanteles dignus, other native species have been the subject of field studies as biological control agents. The review presented here provides useful insights for identifying species that deserve further evaluation as T. absoluta biological control agents through augmentative or conservation strategies in South America, as well as for potential classical biological control programs in other continents. [ABSTRACT FROM AUTHOR]

Seldom have natural enemies been quantified in their ability to control fungivorous arthropods, despite the severe losses they can cause in production of edible fungus. Here, we evaluated the omnivorous predator Orius sauteri (Poppius) when preying on eggs and larvae of the fungivorous sciarid fly Lycoriella pleuroti (Yang et Zhang) and compared against a microencapsulated artificial diet. We also estimated the predation ability of O. sauteri feeding on different densities of L. pleuroti larvae and eggs. The results indicated that O. sauteri successfully oviposit on a mushroom substrate. Moreover, both L. pleuroti eggs and larvae were capable of supporting O. sauteri populations. A type II functional response was observed for both males and females of the predator. Further, moderate values for parameter a′ (instantaneous attack rate) and greatly reduced Th (handling time) revealed a high potential for O. sauteri in suppressing outbreaks of L. pleuroti. This is the first report of a generalist predator feeding and developing within an edible mushroom-pest system. O. sauteri is a prime candidate for testing as a biological control agent, either in inoculative or in inundative release, for targeted suppression of the fungivorous sciarid L. pleuroti. [ABSTRACT FROM AUTHOR]

The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a devastating invasive pest of tomato crops in several areas around the world including Africa. Here, we comprehensively review and discuss the relevant scientific knowledge on its occurrence, biological and ecological aspects, fortuitous insect natural enemies, and potential advantages and constraints of pest management scenarios adopted against this pest in tomato crops in both Northern and Sub-Saharan Africa. We conclude the manuscript with a comprehensive research agenda providing future priorities towards sustainable control of this important tomato pest. [ABSTRACT FROM AUTHOR]

Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) is an effective predator of multiple pests of vegetable crops, such as thrips, mites, aphids, whiteflies, leafminers. It is mass-reared and released for augmentative biocontrol programs mainly aimed at controlling whiteflies and Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in greenhouses and open field. We evaluated the lethal and sublethal toxicity upon N. tenuis adults of label doses of three insecticides (pyriproxyfen, spirotetramat, cypermethrin) and seven fungicides (benomyl, chlorothalonil, copper oxychloride, cyazofamid, fluopicolide + propamocarb hydrochloride (FPH), penconazol, trifloxystrobin) commonly used in various crops. Two exposure routes were tested: (i) contact with dry residues of insecticides or fungicides on tomato sprouts and (ii) multiple exposure to these chemicals via topical sprays on adults which foraged on treated sprouts; and fed on treated eggs of Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) simultaneously. Mortality and reproductive capacity were investigated as indicators of lethal and sublethal effects on N. tenius. The tested insecticides and fungicides were all classified as harmless when predator was exposed only to the dry residues of each. However, the multiple exposure to either cypermethrin, benomyl, chlorothalonil, copper oxychloride or trifloxystrobin caused significant mortality of N. tenuis adults. Cypermethrin also significantly reduced its reproductive capacity. Interestingly, N. tenuis produced a higher number of progeny when exposed to fungicides penconazol and FPH in both exposure scenarios. Overall, findings suggest that the two insecticides, pyriproxyfen and spirotetramat but not cypermethrin, and all tested fungicides can be considered compatible with N. tenuis. [ABSTRACT FROM AUTHOR]

The Asian vinegar fly Drosophila suzukii (spotted wing Drosophila [SWD]) has emerged as a major invasive insect pest of small and stone fruits in both the Americas and Europe since the late 2000s. While research efforts have rapidly progressed in Asia, North America, and Europe over the past 5 years, important new insights may be gained in comparing and contrasting findings across the regions affected by SWD. In this review, we explore common themes in the invasion biology of SWD by examining (1) its biology and current pest status in endemic and recently invaded regions; (2) current efforts and future research needs for the development of predictive models for its geographic expansion; and (3) prospects for both natural and classical (=importation) biological control of SWD in invaded habitats, with emphasis on the role of hymenopteran parasitoids. We conclude that particularly fruitful areas of research should include fundamental studies of its overwintering, host-use, and dispersal capabilities; as well as applied studies of alternative, cost-effective management techniques to complement insecticide use within the integrated pest management framework. Finally, we emphasize that outreach efforts are critical to effective SWD management by highlighting successful strategies and insights gained from various geographic regions. [ABSTRACT FROM AUTHOR]

The South American tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a major threat to tomato ( Solanum lycopersicum L.) crops. After its first detection in Spain in 2006, it spread rapidly through the Western Palaearctic region, arriving in Tunisia 2 years later. The aim of this research was to assess whether generalist indigenous parasitoids are adapting to this exotic host in Tunisian tomato crops. For this, we conducted a survey in four Tunisian tomato-growing areas by sampling infested leaves of tomato and solanaceous weeds and exposing artificially infested sentinel plants. Two ectoparasitoid species were found attacking and developing on T. absoluta: Bracon sp. (Hymenoptera: Braconidae) and Necremnus sp. nr artynes (Hymenoptera: Eulophidae), whereas no egg or pupal parasitoids were found. The eulophid wasp was the most abundant with a peak of apparent parasitism rate of 25.5%. It emerged from parasitized T. absoluta young larvae in exposed sentinel plants and in sampled infested tomato leaves, both in greenhouse and open field cultivations. Bracon sp. showed a gregarious development on T. absoluta mature larvae and it was collected only on sentinel plants exposed in the Ragueda (Kiarouan) site, with 10.23% of estimated parasitism. Although further research is still needed to assess properly the ecological role of these parasitoids in the biological control of T. absoluta, this study represents the first step toward establishing the scientific basis for including these parasitoids in the Tunisian IPM and biological programs against this pest. [ABSTRACT FROM AUTHOR]

Abstract: The generalist predator Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) is a key natural enemy of various arthropods in agricultural and natural ecosystems. Releases of this predator are frequently carried out, and it is included in the Integrated Pest Management (IPM) programs of several crops. The accurate assessment of the compatibility of various pesticides with predator activity is key for the success of this strategy. We assessed acute and sublethal toxicity of 14 pesticides on O. laevigatus adults under laboratory conditions. Pesticides commonly used in either conventional or organic farming were selected for the study, including six biopesticides, three synthetic insecticides, two sulfur compounds and three adjuvants. To assess the pesticides’ residual persistence, the predator was exposed for 3d to pesticide residues on tomato sprouts that had been treated 1h, 7d or 14d prior to the assay. The percentage of mortality and the sublethal effects on predator reproductive capacity were summarized in a reduction coefficient (Ex ) and the pesticides were classified according to the IOBC (International Organization for Biological Control) toxicity categories. The results showed that the pesticides greatly differed in their toxicity, both in terms of lethal and sub lethal effects, as well as in their persistence. In particular, abamectin was the most noxious and persistent, and was classified as harmful up to 14d after the treatment, causing almost 100% mortality. Spinosad, emamectin, metaflumizone were moderately harmful until 7d after the treatment, while the other pesticides were slightly harmful or harmless. The results, based on the combination of assessment of acute mortality, predator reproductive capacity pesticides residual and pesticides residual persistence, stress the need of using complementary bioassays (e.g. assessment of lethal and sublethal effects) to carefully select the pesticides to be used in IPM programs and appropriately time the pesticides application (as function of natural enemies present in crops) and potential releases of natural enemies like O. laevigatus. [Copyright &y& Elsevier]

Biological control remains unutilized as yet in the framework of Drosophila suzukii Matsumura management. Although several parasitoid species attack the pest under laboratory conditions, information is lacking on their host-finding and dispersal capabilities in natural environments. We tested the effect of repeated parasitoid releases on D. suzukii populations in infested orchards. The pupal parasitoid Trichopria drosophilae (Perkins) was released on different crops at eight sites. Parasitism was monitored using traps placed at various distances from the parasitoid release point (RP). A second experiment was carried out under semi-field conditions to evaluate augmentation of the parasitoid. In both experiments, D. suzukii infestation was evaluated through fruit samplings, both from the plant, and from the ground. In the open field trials, T. drosophilae attacked D. suzukii in traps up to 40 m away from the RP, and pest emergence was significantly reduced within a radius of 10 m at seven out of eight sites. In the semi-field trials, parasitoid releases significantly reduced D. suzukii emergence from ground-sampled fruit, and augmentation enhanced parasitism, increasing the numbers of parasitoids emerging from host pupae. Although further field studies are required, these results suggest that T. drosophilae may be considered a potential biocontrol agent for D. suzukii . [ABSTRACT FROM AUTHOR]