The sexual generation of Dryocosmus destefanii Cerasa Melika, 2018 that emerges from galls on Q. suber L. in Italy is described for the first time, establishing its heterogonic life cycle. We provide ...observations on its distribution, illustration of adults and galls and information on its biology as supported by morphological and molecular data. An illustrated identification key to Western Palaearctic Dryocosmus species is also given.
Accurate identification of parasitoids is crucial for biological control of the invasive brown marmorated stink bug,
Halyomrpha halys
(Stål). A recent work by Talamas et al. (2017) revised the ...Palearctic fauna of
Trissolcus
Ashmead, egg-parasitoids of stink bugs, and treated numerous species as junior synonyms of
T. semistriatus
(Nees von Esenbeck). In the present paper, we provide a detailed taxonomic history and treatment of
T. semistriatus
and the species treated as its synonyms by Talamas et al. (2017) based on examination of primary types, molecular analyses and mating experiments.
Trissolcus semistriatus
,
T. belenus
(Walker),
T. colemani
(Crawford), and
T. manteroi
(Kieffer) are here recognized as valid and a key to species is provided. The identification tools provided here will facilitate the use of
Trissolcus
wasps as biological control agents and as the subject of ecological studies.
Anchonocranus oleae Marshall (Coleoptera: Curculionidae) is a seed-feeding weevil native to southern Africa; its larvae are known to develop in the fruits of the African Wild Olive and, more rarely, ...cultivated olives. The species has been mainly found in the Western Cape province of South Africa, but it has remained in relative obscurity because it does not seem to represent a current threat to commercial olive production. As part of an ongoing effort to produce baseline genetic data for olive-associated entomofauna in South Africa, we generated reference DNA barcodes for A. oleae collected from wild and cultivated olives and sequenced its mitogenome for assessment of the phylogenetic position of the species in the family Curculionidae. The mitochondrial phylogeny estimate indicated that A. oleae shares a common ancestor with Elaidobius (tribe Derelomini), but a definite and close relationship to this tribe and the precise tribal placement of A. oleae in the subfamily Curculioninae could not be inferred due to the lack of representative mitogenomes of other relevant curculionine tribes and genera. This study will assist future work on the DNA-based species identification, genetic diversity, and phylogenetic position of the genus Anchonocranus and related taxa.
The Mediterranean fruit fly
Ceratitis capitata
is a major pest of fruit orchards worldwide. In order to develop control methods based on natural products, particularly required in organic farming, a ...laboratory study was carried out to evaluate the response of adults to leaf extracts from four plant species:
Ruta graveolens
,
Eriobotrya japonica
,
Rubus ulmifolius,
and
Ficus carica
. Air-dried leaf powders were subjected to an ethanolic cold extraction. Chemical composition was assessed by GC/MS analysis. Extracts were tested in laboratory bioassays to assess the electroantennographic (EAG) response, attraction/repellence toward ovipositing females, and induced mortality toward adults. Among the extracts tested, only
R. graveolens
elicited significant differences compared to the control in all the bioassays. This extract, whose main volatile compounds were 2-nonanone and 2-undecanone (45% of the total), recorded the greatest EAG response, and stimulated a positive oviposition response compared to the control.
Ruta graveolens
extract elicited a significant insecticidal activity, confirmed to be dose-dependent. LD50 and LD90 concentrations were 3.64 and 6.01% (v/v), respectively. To our knowledge, this is the first study reporting a single plant extract, from
R. graveolens
, acting as attractant and oviposition stimulant, and at the same time having insecticidal properties toward
C. capitata
adults. The incorporation of such extract or its components into food bait could be useful in medfly “attract and kill” control strategies.
The hymenopteran family Platygastridae is a large group of parasitic wasps. A survey was carried out on the subfamily Sceliotrachelinae (Hym.: Platygastridae) in East Azerbaijan and Fars provinces of ...Iran. The genus Fidobia Ashmead and three species, Allotropa conventus Maneval, Fidiobia hofferi Kozlov and Isolia mongolica (Kozlov) are newly recorded from Iran. Illustrations of the morphological characteristics and their geographical distribution are presented.
The family Braconidae consists mostly of specialized parasitoids, some of which hold potential in biocontrol of agricultural pests.
and
are parasitoids associated with
, a major pest of cultivated ...olives. The native range of
is the Mediterranean, and
and
are native to sub-Saharan Africa. This study reports the mitochondrial genomes of the three species, thus laying the foundation for mitogenomic analyses in the genus
. Comparative mitogenomics within Braconidae showed a novel gene arrangement in
in involving translocation and inversion of transfer RNA genes. The placement of
in the subfamily Opiinae was well-supported, and the divergence between
and its closest relative (
) was at ~55 MYA 95% highest posterior density (HPD): 34-83 MYA.
occupied the most basal position among the three
, having diverged from the other two species ~11 MYA (95% HPD: 6-17 MYA).
and
were recovered as sister species diverged at ~2 MYA (95% HPD: 1.1-3.6 MYA). This phylogeny combining new sequences and a set of 31 other cyclostomes and non-cyclostomes highlights the importance of a comprehensive taxonomic coverage of Braconidae mitogenomes to overcome the lack of robustness in the placement of several subfamilies.
The olive fruit fly, Bactrocera oleae, is considered the main olive pest worldwide, and has been the target of biological control programmes through the release of the braconid parasitoid Psyttalia ...concolor. Laboratory tests were performed to evaluate the influence of distance from the host on parasitisation, placing larvae of the substitute host Ceratitis capitata at seven distances (0, 0.5, 1, 1.5, 2, 2.5, 3 mm) and four different time periods (7, 15, 30, 60 min). Moreover, field collected olives of Ogliarola Barese cultivar infested by B. oleae were exposed to P. concolor females to confirm its ability to parasitise B. oleae in small olives. Psyttalia concolor oviposition was inhibited at 2.5 and 3 mm due to the ovipositor length of the parasitoid females (2.7 mm). Hosts were easily parasitised at distances between 0 and 1.5 mm. The thin fruit pulp (up to 3.5 mm) of field collected olives allowed the parasitisation to occur also in mature fruits. At the best combination distance/time (0 mm, 30 min), tests performed with different larvae/parasitoid female ratio showed an increasing emergence of P. concolor (from 20% to 57%) with larvae/parasitoid ratio increasing from 0.11 to 0.74. The results of the present study might optimise the mass rearing of P. concolor, through a proper setting of its parameters, such as the host/parasitoid ratio, exposure distances, and interaction time.
The susceptibility of olive cultivars to the olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), has seldom been studied. This article examines factors associated with olive fruit fly ...infestation of 16 commonly planted Sicilian olive cultivars. Total infestation data were simultaneously correlated with categorical and quantitative factors using ordinal logistic regression. When all factors were included in the analysis, year, sampling date, cultivar, and fruit color were highly significant, but the quantitative factors fruit volume, fruit elongation, and fruit hardness were not. When the analysis was repeated excluding cultivar, all quantitative factors were significant, and elongation and volume were highly significant. Spherical, large, and hard fruit seemed to be preferred by B. oleae over fruit that are elongate, small, and soft. Therefore, fruit color, elongation, volume, and hardness provide useful information regarding the susceptibility of cultivars. In both organic and conventional olive cultivation, information about olive cultivar susceptibility to olive fruit fly will help orchard managers to produce quality oil and table olives while reducing treatments for olive fruit fly control.
Wild olive seed weevil, Anchonocranus oleae Marshall, larvae as well as oviposition and feeding damage were recorded in cultivated olives during a recent study on olive seed wasps. Prematurely ...dropped fruit and fruit picked at harvest in two orchards near Stellenbosch and Agter-Paarl were examined regularly for olive seed wasp infestation over three seasons. In addition, olives were collected in the olive growing regions of the Western Cape province for a survey to determine olive seed wasp distribution. DNA barcoding was used to confirm the identity of weevil larvae in kernels. The number of A. oleae larvae found in olive seeds and the number of olives with weevil oviposition or feeding damage in this study were low. The presence of larvae and weevil damage in two orchards in the survey with no wild olive trees in close proximity suggest that the weevil could breed and persist in cultivated olive orchards. Currently A. oleae is not of economic concern, but if infested olives are discarded at harvest and left in orchards, the weevils could complete their development in the kernels and numbers could eventually increase to damaging levels.
A new species, Dryocosmus destefanii Cerasa Melika n. sp. associated with a Cerris section oak, Quercus suber L., is described from Italy. Description, diagnosis, host associations and biology for ...the new species and an illustrated identification key to the Western Palaearctic Dryocosmus species are given. The description is supported by morphological and molecular data.
PDF
