First Report in Argentina of Apple stem pitting virus Causing Pear Vein Yellows Disease in Pear.

Apple stem pitting virus (ASPV) is an important latent virus of apple trees transmitted by grafting. In pear trees, ASPV is associated with pear vein yellows and pear necrotic spot diseases. Symptoms consist of chlorotic leaf banding and red mottling and flecking along the veins and necrotic spotting in some cultivars may also occur (4). During the spring of 2007, chlorotic leaf banding was observed in Bartlett pear (Pyrus communis L.) trees from one orchard in Bahía Blanca (Buenos Aires Province) and in Anjou, Packham, Abate Fetel, and Bartlett pears in another orchard in General Roca (Río Negro Province). The percentage of symptomatic plants was 10% in both cases. Pooled samples consisting of eight leaves per tree, 25 samples from Bahía Blanca and 25 samples from General Roca, were tested by double-antibody sandwich (DAS)-ELISA with a polyclonal antiserum from BIOREBA AG (Reinach, Switzerland). Five samples from Bahía Blanca and ten from General Roca were positive by DAS-ELISA. Only four positive samples by DAS-ELISA were also positive by immunocapture-reverse transcription (RT)-PCR using virions trapped in a microcentrifuge tube (3). A fragment of 370 bp was amplified with specific primers from each of these four samples. Amplicons were cloned and the nucleotide sequences were determined for one clone of each sample (GenBank Accession Nos. GQ356781, GQ356782, GQ356783, and GQ356784). All sequences had the highest identities with coat protein genes of ASPV. One of them was 94% identical with the coat protein gene of isolate PA66 isolate from Germany (GenBank Accession No. D21829.1) (1). Losses in pear by ASPV have not been demonstrated yet in Argentina. However, when the virus is present with other virus or virus-like diseases, a synergistic effect may occur and growth reduction may exceed 50% (2). Because of the mild symptoms in pear plants, nurserymen or growers must take care when they select material for propagation, in part because laws requiring virus-free propagation material do not exist in Argentina. To our knowledge, this is the first report of ASPV in pears in Argentina. References: (1) W. Jelkmann. J. Gen. Virol. 75:1535, 1994. (2) A. L. Jones and H. S. Aldwinckle. Compendium of Apple and Pear Diseases. The American Phytopathological Society, St. Paul, MN, 1990. (3) W. Menzel et al. J. Virol. Methods 99:81, 2002. (4) M. Németh. Virus, Mycoplasma and Rickettsia Disease of Fruit Trees. Martinus Nijhoff Publishers, Dordrecht, the Netherlands, 1986.

Intestinal parasites and the environment: frequency of intestinal parasites in children of Neuquén, Patagonia, Argentina.

The frequency of intestinal parasites (IP) in 69 children between 2 and 14 years of age was studied within the city of Neuquén, Patagonia, Argentina in relation to socioeconomic, cultural and environmental conditions. Soil type was determined and contamination with IP was investigated in 75 soil samples. Frequency of IP in children was 50.7%. Blastocystis hominis was the most frequent species (24.6%). Simultaneous infection with 2 to 4 species was found in 47,5% of the infected children. Statistical association was found between parasitic infection and family hygienic level (p < 0.001). Socioeconomic level was defined as lower middle class, however, infrastructure and public services were adequate. The climate is continental semiarid and the soil is sandy with a low organic matter level. Intestinal protozoan organisms were found in 33.3% of soil samples and Sarcocystis sp. was the most frequent species (14.6%). The parasites present in soil are related to the environmental conditions that allow their viability and development. Socioeconomic and cultural factors are important for the appearance and spread of IP in communities where sanitary conditions and infrastructure are adequate.

Host range, specificity, and virulence of Steinernema feltiae, Steinernema rarum, and Heterorhabditis bacteriophora (Steinernematidae and Heterorhabditidae) from Argentina.

Infections were carried out in the laboratory to determine the host range, specificity, and virulence of Steinernema rarum, S. feltiae, and Heterorhabditis bacteriophora that were isolated from different regions of Argentina. All insect orders showed a remarkable susceptibility to the three nematode species, showing mortality values higher than 66%, except for Anoplura. The mortality of the insects of agronomic interest was more than 90%. As for insects of sanitary importance, S. feltiae and S. rarum caused 60% of mortality, whereas H. bacteriophora caused 80%. The results fluctuated when considering the buccal apparatus function of the insects. Nematodes completed their cycle in anoplurans, orthopterans, lepidopterans, and hymenopterans, while the development varied in coleopterans, homopterans, hemipterans, and dipterans. S. rarum developed completely both in immature and adult, while S. feltiae and H. bacteriophora developed preferably in immature. The three isolates are capable of parasitizing a wide host range under laboratory conditions; H. bacteriophora is more virulent than the evaluated Steinernema spp. against Galleria mellonella larvae; the pathogenicity and specificity depend on the bioecological characteristics of nematodes and hosts.