Enrico de Lillo

What’s “cool” on eriophyoid mites?

Fundamental knowledge on the morphology, biology, ecology, and economic importance of Eriophyoidea has been exhaustively compiled by Lindquist et al. (Eriophyoid mites—their biology, natural enemies and control; Elsevier, 1996). Since that time, the number of recognized species and the economic importance of the taxon have increased substantially. The aim of this paper is to analyze and briefly review new findings from eriophyoid mites’ literature after Lindquist et al. book, stressing persistent gaps and needs. Much recent attention has been given to sampling and detection, taxonomy and systematics, faunistic surveys, internal morphology, rearing techniques, biological and ecological aspects, biomolecular studies, and virus vectoring. Recommendations are made for integrating research and promoting broader dissemination of data among specialists and non-specialists.

A modified method for Eriophyoid mite extraction (Acari: Eriophyoidea)

Abstract An extraction method for sampling grapevine mites, especially Eriophyoidea, is described. The protocol modifies previous extraction methods requiring commonly used household chemicals, which are used easily and safely. The plant material is washed in tap water with 2% sodium hypochlorite and 0.2% dish detergent. After thorough mixing, the suspension is filtered by means of stacked sieves for mite extraction and observed in an open, Petri dish with grid. Advantages, applications and a few tips for better utilization of the new method are discussed.Abstract An extraction method for sampling grapevine mites, especially Eriophyoidea, is described. The protocol modifies previous extraction methods requiring commonly used household chemicals, which are used easily and safely. The plant material is washed in tap water with 2% sodium hypochlorite and 0.2% dish detergent. After thorough mixing, the suspension is filtered by means of stacked sieves for mite extraction and observed in an open, Petri dish with grid. Advantages, applications and a few tips for better utilization of the new method are discussed.

‘Salivary secretions’ of eriophyoids (Acari: Eriophyoidea): first results of an experimental model

This paper concerns an approach to direct collection of eriophyoid ‘salivary secretions’, and reports preliminary results on biological assays providing evidence for the presence of plant growth promoting substances in these secretions. Eleven species belonging to the Phytoptidae, Eriophyidae and Diptilomiopidae, characterized by different host–plant interactions, were studied by immersing mites into the following oils: condensate of cedar oil, oil for immersion lenses, two kinds of olive oil, α-terpineol, hystolemon, vaseline oil, and soybean oil. Some species secreted small droplets of lipophobic substances at the tip of their mouthparts when they were immersed in objective lens oil. Mite mortality and percentage of secreting specimens depended on the species and the medium used. Aceria caulobia (Nalepa) was selected as the candidate for subsequent study, because this species displayed a higher percentage of secreting mites than the other species and numerous specimens were easily collected by means of an airflow and filtering device. The induced secretions were studied from January to June of 2000, 2001 and 2002. Rapid salivary bioassays were performed during the period of maximum induced secretion in 2001. They were evaluated using a wheat-coleoptile and an excised-radish-cotyledon growth test, respectively, for indole-3-acetic acid-like and cytokinin-like activity. The bioassays suggested the presence of chemicals with plant growth regulatory effects. A brief account of eriophyoid mortality in the oils was also given.

Bioaccessibility, bioavailability and ecotoxicity of pentachlorophenol in compost amended soils

The influence of compost on the bioaccessibility, bioavailability and ecotoxicity of pentachlorophenol (PCP) as a function of time was studied by means of different chemical and ecotoxicological methods. Experiments were conducted in both sterile and non-sterile microcosms and samplings carried out at 20, 60 and 120d from initial contamination. PCP bioaccessibility, assessed by means of Porapak resin extraction, was around 75% of the applied dose with no aging or compost effects. Two different methods were applied to assess the bioavailability of PCP, respectively, to bacteria and earthworms and linked to ecotoxicological assays (biosensor and earthworm coelomocytes assays). Water extraction was applied to assess the bioavailability to bacteria: results showed that this fraction was always below 50%, with significant decreases as a result of aging processes and compost addition. In non-sterile microcosms, compost amendment increased the amount of PCP biodegraded, while the ecotoxicological assay with the biosensor Pseudomonas fluorescens pUCD607 indicated a higher toxicity in the most degraded samples, thus suggesting the formation of more toxic metabolites. Earthworm body accumulation results were rather in accordance with water extractions data, with decreasing bioavailable amounts as a result of time and compost addition. No compost or aging effects were instead detected by coelomocytes assay. Results indicate how different methods must be applied altogether to assess the bioavailability and ecotoxicity of xenobiotics such as PCP in soil. The addition of compost was also proven as an effective strategy for the remediation of PCP contaminated soils, although issues related to the possible formation of toxic metabolites must be taken into account.

Transmission of grapevine Pinot gris virus by Colomerus vitis (Acari: Eriophyidae) to grapevine

Grapevine Pinot gris virus (GPGV) is a new virus reported in Europe and several other grape-growing countries. In an attempt to identify a vector for GPGV, samples of the eriophyid mite Colomerus vitis collected from buds and erinea in GPGV-infected vines were analysed by RT-PCR, using specific primers. Molecular analysis revealed the presence of GPGV in C. vitis. Transmission trials were conducted using C. vitis collected from GPGV-infected vines. Mites were able to transmit GPGV to healthy grapevines, suggesting that C. vitis is a potential vector of this virus.

Resistance of grapevine to the erineum strain of Colomerus vitis (Acari: Eriophyidae) in western Iran and its correlation with plant features

The interaction of grape erineum mite (GEM), Colomerus vitis Pagenstecher (Acari: Eriophyidae), with grape was investigated in the laboratory. We studied some plant morphological biochemical features potentially related to vine resistance/tolerance of eight native grapevine cultivars, extensively cultivated in western Iran, and two non-native cultivars. Free-choice experiments indicated that the cultivars Shahani, Flame seedless and Yaghuti were colonized by lower levels of GEM, whereas Muscat Gordo, Gazne and White Thompson seedless hosted denser populations. These differences between cultivars may be due to differential attractiveness to GEM, possibly associated with plant biochemical and morphological traits. In no-choice assays with six grapevine cultivars, mite population development and some cultivar features were assessed. Mite populations grew fastest on Gazne and Muscat Gordo, and slowest on Yaghuti and Shahani. The degree of mite infestation was associated with reduction of leaf area, increase of leaf weight, shortening of shoots and more numerous erinea: these features were larger on the most infested Gazne, whereas morphological features of Shahani and Yaghuti were scarcely affected by GEM infestation. Also trichome type and density of the assayed cultivars appeared to be related to mite density: the most infested cultivars (Gazne and Muscat Gordo) displayed higher ranks of blade and vein hairs and lower ranks of blade and vein bristles and domatia. No correlation was found between mite density and leaf thickness of mature leaves. The amount of leaf waxes was highest in Shahani and Yaghuti, which displayed the lowest mite density, the fewest erinea and the largest leaves. Carbohydrate amount of uninfested leaves was lowest on the least infested Shahani and highest on the most infested Gazne; phenols increased in leaves of Shahani and decreased in those of Gazne after mite infestation. Finally, cultivars also appeared to influence some morphological traits of the mites: larger specimens were detected on White Thompson seedless, Flame seedless and Gazne, whereas smaller mites were found on leaves of the less infested Yaghuti and Shahani. These results indicate that leaf hairiness, leaf wax and carbohydrate contents may be useful tools for a preliminary screening among vine cultivars and help predict resistance/tolerance to GEM. Shahani and Yaghuti seem quite promising for developing grape resistance programs against GEM in western Iran.

Capnodis tenebrionis (L. 1758) (Coleoptera: Buprestidae): Morphology and Behaviour of the Neonate Larvae, and Soil Humidity Effects on the Egg Eclosion

Abstract Capnodis tenebrionis (L. 1758) is reported for several countries of the Mediterranean subregion as a common phytophagous insect of many cultivated and wild species of trees and shrubs belonging to the family Rosaceae. Infestations on stone-fruit orchards have economic effects and can often cause the death of the plants in consequence of larval tunnelling into the roots. Egg laying occurs in late spring and summer on the trunk base or nearby in the soil. The importance of the neonate larval skills in relation to the biological success of this pest has stimulated its morphological, ecological and ethological studies to better understand the hatching mechanisms and the mortality effects of humidity on the eggs. In the present contribution, the morphology of the first larval instar is described throughout and illustrated, and the morphological details are compared with those of the mature larva. A survey on the hatching mode points out that neonate larvae, wherever eggs are laid, always come into contact with the soil. Finally, hatching rates were determined under laboratory conditions at four soil moisture levels, expressed as percentage of the Field Water Holding Capacity. A comparison was made with respect to a control of dry soil. The results prove that soil humidity significantly affects the egg eclosion, especially at the higher values.

Three new Aceria species (Acari: Eriophyoidea) from Turkey

Abstract Turkish populations of eriophyid mites infesting Malvaceae, Asteraceae and Caryophyllaceae were examined. Analyses of morphometric data, induced symptoms, and comparisons to the morphology and descriptions of known species indicated presence of three new species which are described and illustrated. These are: Aceria egmirae n. sp. from Althaea rosae (L.) Cavan, A. tinctoriae n. sp. from Anthemis tinctoria L. and A. ankarensis n. sp. from Dianthus chinensis L. No injuries were detected on the host plants.

Morphological adaptations of mite chelicerae to different trophic activities (Acari)

The authors briefly review the current knowledge on the structural organization and functional significance of the chelicerae and their sensory structures among mites of economical interest in agriculture that have been recently investigated for their gnathosoma. The chelicerae of the polyphagous predatory mite Typhlodromus exhilaratus Ragusa (Gamasida, Phytoseiidae) have a rather unspecialized organization and are of chelate type. They function mainly in grasping the prey and other food, while the other mouthparts are adapted to prey wounding, salivary injection and juice suction. In the Honey Bee parasite, Varroa destructor Anderson & Trueman (Gamasida, Varroidae), the chelicerae have almost completely lost the fixed digit while the movable digit is thinner and elongated. The chelicerae participate directly, along with the other mouthparts, only in the perforation of the Honey Bee integument. In the plant-feeder, Penthaleus major (Duges) (Actinedida, Penthaleidae), the movable digit is composed of a long and stout stylet-like structure, and a peculiar basal sclerite which activates the digit movements. During cheliceral protrusion, the stylets may work jointly or independently from each other in piercing the plant surface and causing deep and large wounds. The protruded stylets may justapose each other; they may delimit an intercheliceral channel and may be involved in salivary injection. The fixed digit is a large somewhat soft structure which covers dorsally the pre-oral and supralabral chamber, and is passively involved in juice sieving and sucking. The movable digit of the fungivorous Tarsonemus nodosus Schaarschmidt (Actinedida, Tarsonemidae) is needle-like and articulated with a transverse lever to the second cheliceral article. The basal cheliceral articles are fused together forming a stylophore. The fixed digits partly envelop the movable digits and they are consolidated with the subcapitulum. The stylar morphology suggests an independent piercing action of the movable digits. The phytophagous Two-Spotted Spider mite, Tetranychus urticae Koch (Actinedida, Tetranychidae), and False Red Spider mite, Cenopalpus pulcher (Canestrini & Fanzago) (Actinedida, Tenuipalpidae), have extensively protractable styliform chelicerae. The movable digits are very elongated and stylet-like, originating proximally from the stylophore (fused first cheliceral articles); the fixed digits are partially fused to each other. During cheliceral protrusion, the stylets are forced to be interlocked to each other to delimit an intercheliceral canal which is directly connected to the salivary duct. At the same time, the fused fixed digits are involved in salivary pump functioning. So, the chelicerae play a double role in piercing the plant surface and discharging saliva into the host tissue. In the tiny phytophagous mites of the superfamily Eriophyoidea (Actinedida), the gnathosoma has a strongly derived organization. Fixed and movable digits are both styliform, laminar shaped, and included in a strict frame of nine stylets of different origin which function together in host piercing, salivary injection and juice suction. The short sliding movements of the cheliceral shafts are activated by the unpaired motivator. The chelicerae seem to be mainly involved in deeping the mouthparts into the wounds and partially in salivary injection. In each of the investigated species, chelicerae are provided with putative chemoreceptive sensilla, in addition to other mechanoreceptors, which seem to be strictly involved in food perception and acceptance. As yet, however, an alternative perceptive function cannot be excluded. Key words: Acari, gnathosoma, mouthparts, feeding mechanisms, sensory structures, digitus mobilis, digitus fixus, morphological adaptations, host piercing, salivary injection, basal sclerite, lever, motivator, stylophore.

Three new Aceria species (Acari: Eriophyoidea) on Centaurea spp. (Asteraceae) from Turkey

During 2001 and 2002, we examined Turkish populations of eriophyid mites infesting Centaurea solstitialis L. and C. squarrosa Willd. (Asteraceae). The analyses of the morphometric data, induced symptoms, and the morphological comparison with the descriptions of known species allowed us to identify three new Aceria species, here described and illustrated. Aceria solcentaureae and A. solstitialis were collected on C. solstitialis, and A. squarrosae was associated with C. squarrosa in Cappadocia. Infested plants were stunted, showing reduced growth, a heavy broom-like appearance being bushy, with the apical parts of the stems and flowerheads still green and fresh during the hot and dry season, less spiny than usual, and producing smaller seedheads. Additional information is given about the ecology of these associations and on the potential role of these eriophyids as control agents. Key words: mites, Eriophyidae, weeds, knapweeds, biological control. TRE SPECIE NUOVE DI AceriA (ACARI: ERIOPHYOIDEA) SU centAureA SPP. (ASTERACEAE) DALLA TURCHIA Durante il biennio 2001-2002, campioni di Centaurea solstitialis L. e C. squarrosa Willd. (Asteraceae) a sviluppo alterato sono stati raccolti in Turchia ed esaminati per individuarne le cause. L’analisi dei dati morfometrici della popolazione di eriofidi rinvenuta e la comparazione di questi e della sintomatologia con le altre specie note sul gruppo delle Centaurea hanno consentito di individuare 3 nuove specie di Eriophyidae appartenenti al genere Aceria. Sono state, quindi, descritte e illustrate A. solcentaureae e A. solstitialis, raccolte su Centaurea solstitialis, e A. squarrosae rinvenuta su C. squarrosa. Le piante infestate mostravano una crescita stentata e ridotta in altezza, ad aspetto cespitoso e affastellato, con le parti apicali dei fusti e delle infiorescenze ancora verdi e fresche nel periodo caldo e secco, con capsule provviste di “spine” morbide ed elastiche, e con una minore produzione di semi. Informazioni aggiuntive vengono riportate circa gli aspetti ecologici di questa associazione e il potenziale impiego delle specie come agenti di controllo biologico. Key words: acari, Eriophyidae, erbe infestanti, controllo biologico.