Gabriella Lo Verde

Pathogenicity bioassays of isolates of Beauveria bassiana on Rhynchophorus ferrugineus

BACKGROUND The control of Rhynchophorus ferrugineus (Olivier), the main palm pest in the Mediterranean Basin, is problematic because of its biology and the current restrictions in many European countries on the use of chemical insecticides in urban areas. Entomopathogenic fungi have been studied as potential biological control agents, but information on their natural incidence is limited. Strains of Beauveria bassiana (Balsamo) Vuillemin were isolated from symptomatic insects collected on dead palms, and their pathogenicity against different instars of R. ferrugineus was evaluated in the laboratory. RESULTS The overall percentage of infected insects found in Canary palms was 7%. In laboratory bioassays, hatching of eggs treated with three different isolates of B. bassiana was 41.2, 26.8 and 29.9%, significantly lower than the control (62.4%). Larvae and adults were treated with a single isolate in two ways: spraying each insect with a conidial suspension or feeding them with fruit portions previously immersed in the same conidial suspension. At the end of the two trials, the mortality of treated larvae was 88 and 92%, and the mean survival time was 10.4 and 11.8 days, significantly different from the control, where no insect died during the trials. Mortality and survival time recorded in either trial on adults did not significantly differ between treatment and control. CONCLUSION This study shows that the pathogenicity of wild isolates of B. bassiana differs among the tested R. ferrugineus instars. The low mortality of treated adults supports their use as vectors of B. bassiana as a potential tool for reducing R. ferrugineus populations.

Risk assessment of non-target effects of Closterocerus chamaeleon (Girault) parasitoid of the eucalypt gall maker Ophelimus maskelli (Ashmead) (Hymenoptera, Eulophidae)

The pre-release risk assessment, a recommended practice in biological control programmes, was carried out before introducing Closterocerus chamaeleon (Girault), a eulophid parasitoid of the eucalypt gall maker Ophelimus maskelli (Ashmead) (Hymenoptera, Eulophidae), in Sicily, Italy. We evaluated its host specificity in laboratory small arena no-choice tests on six non-target hosts, using O. maskelli as a control species. The non-target species fit with at least one of the following criteria: a) common geographical origin; b) ecological or behavioural affinities with the target host; c) concealed habit of the preimaginal stages; d) taxonomic affinity; e) taxonomic affinity with hosts of congeneric parasitoids of the candidate agent; and f) presence in Italy/Sicily. Closterocerus chamaeleon performed an oviposition sequence of 10 recognisable behaviours, always leading to parasitization when exposed to O. maskelli. The same behaviour sequence was carried out on the gall maker Leptocybe invasa Fisher et La Salle, the only non-target species living on Eucalyptus, but just until Step 6, i.e. until ovipositor extraction and insertion, and never until egg-laying. All of the other non-target hosts were ignored. Furthermore, the adult parasitoid longevity was assessed in three rearing conditions: 1) no food/no parasitisation permitted; 2) food/no parasitisation permitted; and 3) food provided after parasitisation. Adult wasp longevity was significantly higher in treatment 2 (21.1 days ± 4.1 SE) than in treatment 1 (3.6 days ± 0.5 SE) or 3 (3.8 days ± 0.6 SE). Laboratory tests carried out in this study on C. chamaeleon indicated high host selection ability, later confirmed by our post-release field data.

Sustainable Weed, Disease and Pest Management in Medicinal and Aromatic Plants

As for all other crops, in MAPs as well, weeds, diseases and pests are important yield-reducing factors, which may severely curtain biomass production and, that is maybe more important, may affect several qualitative aspects of production. Research about this topic is generally lacking, for two main reasons: the first is that MAPs are generally grown on rather limited areas, and the incidence of specific pests and diseases rarely takes a relevance outside rather narrow boundaries. The second reason is that the economical importance of MAPs is much lower than that ascribed to the “major” crops, which the bigger efforts of research are addressed to. In the changing scenario of latter years, however, MAPs are taking an increasing relevance, and there is the necessity to draw proper guidelines for their cultivation technique, also including the advisable strategies for their sustainable protection.

Description of dryocosmus destefanii new species (Hymenoptera: Cynipidae: Cynipini) from Quercus suber L. in Italy

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.

New Mediterranean records of Trabutina mannipara (Hemprich & Ehrenberg 1829) (Hemiptera: Coccomorpha: Pseudococcidae)

The occurrence of Trabutina mannipara (Hemprich & Ehrenberg, 1829) (Hemiptera: Coccomorpha) is reported for the first time at Linosa (Pelagian Islands, Sicily Channel, Italy) and Libya. T. mannipara was approved by USA authorities for release as biocontrol agent against invasive saltcedars. The potential impact of this species, that in the Mediterranean area showed to be occasionally invasive, is discussed.

Behavior-modifying and insecticidal effects of plant extracts on adults of Ceratitis capitata (Wiedemann) (Diptera Tephritidae)

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.

Revision of the genus Prionotropis Fieber, 1853 (Orthoptera: Pamphagidae: Thrinchinae).

The genus Prionotropis Fieber, 1853 is revised. It is distributed in scattered areas of the Mediterranean region from Turkey in the East to Spain in the West. Overall, seven species are listed, namely P. maculinervis (Stål, 1878) (Turkey; P. urfensis Ramme, 1933 is here considered its synonym), P. willemsorum n. sp. (Greece, Epirus; previously considered P. appula), P. appula (O.G. Costa, 1836) (South Italy), P. hystrix (Germar, 1817) (Bosnia and Herzegovina, Slovenia, Croatia, North-East Italy; P. hystrix sontiaca is here synonymized), P. rhodanica Uvarov, 1923 resurrected status (France, Crau, Rhone delta; here considered a valid species), P. azami Uvarov, 1923 n. status (France, Var region; here considered a valid species), and P. flexuosa (Serville, 1838) (Spain; the ssp. pereezi Bolívar, 1921 and sulphurans Bolívar, 1921 are here considered its synonyms). A key to species is presented.

New records of Cynipidae (Hymenoptera) from Italy

Summary New records of Cynipid gall wasps and inquilines for the Italian peninsula and Sicily and their new host plants for the Palaearctic Region are listed and commented on. Among them we find: Cerroneuroterus cerrifloralis (Müllner 1901) as new for Italy and new for the Palaearctic region as host on Quercus suber; Andricus multiplicatus Giraud 1859 on Q. suber, as new host for the Palaearctic region; Aylax papaveris (Perris 1839), reported in Italy over a century ago, but later overlooked; Cerroneuroterus minutulus (Giraud 1859), also reported more than a century ago from Sicily, but later overlooked. Among the inquilines are here listed: Synergus variabilis Mayr 1872, emerged from Janetia cerris (Kollar 1850) galls (Diptera Cecidomyiidae), and found for the first time in the Palaearctic Region as host on Q. suber; Saphonecrus haimi (Mayr 1872) and Saphonecrus barbotini Pujade-Villar & Nieves-Aldrey 1986, are new records for Italy.