1,721,209 research outputs found
Application of Chemical Cues in Arthropod Pest Management for Orchards and Vineyards
No full textThis chapter reviews the literature on semiochemical-parasitoid systems in perennial crops. The first part of the chapter analyses the possible effects of pheromone-based tactics on parasitoid efficacy. In both orchards and vineyards, the most successful application of synthetic sex pheromones has been their use as mating disruptants. It also discusses the possibility of using parasitoid pheromones to directly affect parasitoid behaviour. The second part of the chapter summarizes research in orchards and vineyards that has tested whether synthetic chemical cues such as herbivore-induced plant volatiles (HIPVs) and host-associated volatiles (HAVs) can be used to manipulate parasitoid behaviour, and specifically to enhance their searching efficacy. Finally, the chapter considers the interaction of semiochemical–parasitoid systems with habitat management as novel combined strategies that have recently been developed to improve the success of semiochemical-based integrated arthropod pest management
Introduzione di due predatori americani, Podisus maculiventris (Say) e P. connexivus Bergroth (Heteroptera: Pentatomidae), per il controllo biologico di fitofagi esotici.
No full textChemical Ecology of Floral Resources in Conservation Biological Control
Full text linkConservation biological control aims to enhance populations of natural enemies of insect pests in crop habitats, typically by intentional provision of flowering plants as food resources. Ideally, these flowering plants should be inherently attractive to natural enemies to ensure that they are frequently visited. We review the chemical ecology of floral resources in a conservation biological control context, with a focus on insect parasitoids. We highlight the role of floral volatiles as semiochemicals that attract parasitoids to the food resources. The discovery that nectar-inhabiting microbes can be hidden players in mediating parasitoid responses to flowering plants has highlighted the complexity of the interactions between plants and parasitoids. Furthermore, because food webs in agroecosystems do not generally stop at the third trophic level, we also consider responses of hyperparasitoids to floral resources. We thus provide an overview of floral compounds as semiochemicals from a multitrophic perspective, and we focus on the remaining questions that need to be addressed to move the field forward
Trichoderma harzianum Strain T22 Modulates Direct Defense of Tomato Plants in Response to Nezara viridula Feeding Activity
Full text linkPlant growth-promoting fungi belonging to genus Trichoderma are known to help plants when dealing with biotic stressors by enhancing plant defenses. While beneficial effects of Trichoderma spp. against plant pathogens have long been documented, fewer studies have investigated their effect on insect pests. Here, we studied the impact of Trichoderma root colonization on the plant defense responses against stink bug feeding attack. For this purpose, a model system consisting of tomato plant, Solanum lycopersicum cv Dwarf San Marzano, Trichoderma harzianum strain T22 and the southern green stink bug, Nezara viridula, was used. We firstly determined stink bug performance in terms of relative growth rate and survival on tomato plants inoculated by T. harzianum T22. Then, we evaluated relative expression of plant defense-related genes on inoculated plants induced by stink bug feeding. We found evidence that T. harzianum T22 affects tomato defense responses against N. viridula nymphs leading to reduction of growth rate. Our results also showed that T. harzianum T22 enhances plant direct defenses by an early increase of transcript levels of jasmonic acid marker genes. Yet this effect was time-dependent and only detected 8 h after herbivore induction. Taken together, our findings provide better understanding on the mechanisms underlying tomato induced resistance against herbivorous stink bugs
Morphology of antennal gustatory sensilla and glands in some parasitoid Hymenoptera with hypothesis on their role in sex and host recognition
No full textCompetitive interactions in insect parasitoids: effects of microbial symbionts across tritrophic levels
Full text linkCompetition for hosts is a common ecological interaction in insect parasitoids. In the recent years, it has become increasingly evident that microorganisms can act as ‘hidden players’ in parasitoid ecology. In this review, we propose that parasitoid competition should take into consideration the microbial influence. In particular, we take a tritrophic perspective and discuss how parasitoid competition can be modulated by microorganisms associated with the parasitoids, their herbivore hosts, or the plants attacked by the herbivores. Although research is still in its infancy, recent studies have shown that microbial symbionts can modulate the contest outcome. The emerging pattern is that microorganisms not only affect the competitive traits of parasitoids but also the fighting arena (i.e. the herbivore host and its food plant), in which competition takes place. We have also identified important gaps in the literature that should be addressed in future studies to advance our understanding about parasitoid competition
Genetic variation in the behavioural mechanisms involved in the response of the egg parasitoid Trissolcus brochymenae to contact chemical cues left by the pest Murgantia histrionica
No full textThe ability of parasitoid females to perceive chemical traces left by their hosts is of utmost importance in the host location process. The behaviours involved in such ability have thus most likely been promoted by natural selection in the course of the evolutionary time. For this to happen, however, there must be significant genetic variation in natural populations on which natural selection could act. Using the isofemale line method and motion analysis, we detected significant intra-population genetic variation for several walking behaviour traits of the egg parasitoidTrissolcus brochymenae(Hymenoptera: Scelionidae) females responding to chemical traces left by its hostMurgantia histrionica(Heteroptera: Pentatomidae). Besides opening new avenues of research on the reproductive strategies, behaviour, and biological control potential of parasitoid wasps, these results also have implications for understanding their life-history evolution in general
Source of the host marking pheromone in the egg parasitoid Trissolcus basalis (Hymenoptera: Scelionidae)
No full textContrasting reproductive traits of competing parasitoids facilitate coexistence on a shared host pest in a biological control perspective
Full text linkBACKGROUND: Interspecific competition in insect parasitoids is an important ecological phenomenon that has relevant implications for biological pest control. To date, interspecific intrinsic (=larval) competition has been intensively studied, while investigations on extrinsic (=adult) competition have often lagged behind. In this study we examined the role played by parasitoid reproductive traits and host clutch size on the outcome of extrinsic competition between Trissolcus basalis (Wollaston) and Ooencyrtus telenomicida (Vassiliev), two egg parasitoids of the pest Nezara viridula (L). Laboratory experiments were conducted by allowing both parasitoid species to exploit an egg mass made of 10, 20, 30, or 40 hosts through single or simultaneous releases. Furthermore, under field conditions, egg masses consisting of 10 or 40 hosts were exposed in a tomato crop in order to validate laboratory investigation. RESULTS: The results show that the egg mass size is an important predictor of extrinsic competition in our study system as a higher proportion of T. basalis emerged from large egg masses, while O. telenomicida dominated in small egg masses. Analysis of reproductive traits of parasitoid species indicates that T. basalis has superior abilities in host exploitation compared with O. telenomicida. CONCLUSIONS: We found that contrasting reproductive traits of two competing egg parasitoid species facilitate coexistence on a shared stink bug host. This work also highlights the importance to consider extrinsic competitive interactions between parasitoid species in a biological control perspective. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry
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