Search results for " NEZARA VIRIDULA"

Effetto della localizzazione dello stress biotico sulle difese indotte in Vicia faba

2016

Le diverse fasi che caratterizzano l’attacco della pianta da parte del fitofago (contatto, alimentazione ed ovideposizione) inducono l’attivazione di meccanismi di difesa nell’ospite. E’ noto che le piante emettono composti volatili indotti in seguito all’attacco del fitofago e che questi volatili sono in grado di richiamare i parassitoidi. Nel caso specifico degli ooparassitoidi, tali difese indirette si esplicitano mediante rilascio di HIPV (herbivore-induced plant volatiles) ed in particolare di OIPV (oviposition-induced plant volatiles). Ad oggi non ci sono studi inerenti il ruolo giocato dalle tracce rilasciate dal fitofago sulla superficie vegetale nell’induzione di volatili utilizzat…

Impact of an invasive pest in local semiochemical networks

During the host location process, egg parasitoids rely on a series of chemical stimuli from the host/plant complex. In particular, in tritrophic systems consisting of plants, herbivorous stink bugs and their egg parasitoids, previous studies demonstrated that wasps are attracted by oviposition-induced plant volatiles (OIPVs). These compounds act as indirect plant defence mechanism allowing plants to recruit egg parasitoids, which are in general the most important natural enemies of stink bugs. Moreover, when wasps land on a plant, they can exploit chemical footprints left by male and female stink bugs walking on the leaves as indirect host-related cues, since chemicals lead them in an area …

Intraguild interactions between two egg parasitoids of a true bug: from laboratory to field investigations

2011

Intraguild interactions can play a role in species coexistence and in sizing and shaping community structures. In addition, understanding how competitive interactions between parasitoid guilds can affect pest suppression may improve biological control. Interspecific competitive effects can be divided in “extrinsic competition”, the indirect interactions between adult females searching for or exploiting hosts, and “intrinsic competition”, the competition that occurs between larvae developing in the same host. In this work we performed both laboratory and field investigations to address on intraguild interactions occurring between Trissolcus basalis (Hymenoptera: Scelionidae) and Ooencyrtus t…

Outcomes of intraguild interactions between two egg parasitoids in field and semi-field conditions

2012

Intraguild interactions between two egg parasitoids, Trissolcus basalis (Wollaston) and Ooencyrtus telenomicida (Vassiliev) exploring egg masses of the Southern Green Stink Bug Nezara viridula (L.) were investigated in field and semi-field conditions. Field trials were conducted in tomato fields by using sentinel and naturally laid egg masses in 2010 and 2011. Egg parasitoids monitoring, by sentinel egg masses placed weekly on plants during the tomato growing season and recollected one week later, showed that T. basalis occurs from June to October, whereas O. telenomicida occurs mainly in July and August. In the same fields, collections of naturally laid egg masses display different types o…

Endogenous and exogenous factors affecting host chemical footprint exploitation by a hymenopterous egg parasitoid

2014

During the host location process, parasitoids encounter and explore a great variety of volatile and contact semiochemicals from the host-plant complex. In the system Nezara viridula and its egg parasitoid Trissolcus basalis, when wasps land on a plant, they can taste chemical footprints left by walking adult hosts. These cues represent a set of indirect host-related contact kairomones that induce arrestment and motivated searching behavior, as they drive wasps in an area where there is a high probability of finding hosts but are not able to “promise” the presence of the suitable host stage. Patch time allocation is strongly modified by experience gained during foraging on host traces. In fa…

Risonanza stocastica nel riconoscimento e nel corteggiamento di specie di Nezara viridula

2011

Intraguild interactions between two egg parasitoids exploring host patches

2010

Intraguild interactions between two egg parasitoids, Trissolcus basalis (Hymenoptera: Scelionidae) and Ooencyrtus telenomicida (Hymenoptera: Encyrtidae), exploring egg masses of the Southern Green Stink Bug (SGSB) Nezara viridula (Heteroptera: Pentatomidae), were investigated in laboratory conditions by single, simultaneous and sequential host attack experiments. Mortality of N. viridula eggs was higher in simultaneous and sequential releases compared to single species releases. In simultaneous host exploitations, T. basalis females displayed an aggressive behavior against O. telenomicida females. The outcome of multiparasitism showed that interspecific larval competition was dominated by O…

Behavioral response of the egg parasitoid Ooencyrtus telenomicida to host-related chemical cues in a tritrophic perspective

2010

The response of the generalist egg parasitoid Ooencyrtus telenomicida (Vassiliev) (Hymenoptera: Encyrtidae) to host-related chemical cues from tomato plants, Solanum lycopersicum L., and adults of Nezara viridula (L.) (Heteroptera: Pentatomidae) was investigated in laboratory-based no-choice and paired-choice tests. In Y-tube olfactometer experiments, when female wasps were exposed to volatiles from plants in different conditions, they were attracted only to volatiles produced by N. viridula adult-infested tomato plants. When female wasps were exposed to adults of N. viridula, they were attracted to volatiles from virgin males, and, at a lower level, to volatiles from mated females in preov…

Insect oviposition induces volatile emission in herbaceous plants that attracts egg parasitoid

2003

SUMMARYThe egg parasitoid Trissolcus basalis (Wollaston) (Hymenoptera:Scelionidae) responded to synomones emitted by leguminous plants induced by feeding and oviposition activity of the bug Nezara viridula (L.)(Heteroptera: Pentatomidae). This was shown by laboratory bioassays using a Y-tube olfactometer. Broad bean leaves (Vicia faba L.) damaged by feeding activity of N. viridula and on which host egg mass had been laid produced synomones that attracted T. basalis. By contrast,undamaged leaves or feeding-damaged leaves without eggs did not attract wasp females. French bean plants (Phaseolus vulgaris L.) also emitted attractive synomones when they were damaged by host feeding and carrying e…

Egg parasitoid attraction toward induced plant volatiles is disrupted by a non-host herbivore attacking above or belowground plant organs.

2014

Plants respond to insect oviposition by emission of oviposition-induced plant volatiles (OIPVs) which can recruit egg parasitoids of the attacking herbivore. To date, studies demonstrating egg parasitoid attraction to OIPVs have been carried out in tritrophic systems consisting of one species each of plant, herbivore host, and the associated egg parasitoid. Less attention has been given to plants experiencing multiple attacks by host and non-host herbivores that potentially could interfere with the recruitment of egg parasitoids as a result of modifications to the OIPV blend. Egg parasitoid attraction could also be influenced by the temporal dynamics of multiple infestations, when the same …