APS Conference: new data
By browsing through the abstracts of papers presented at the APS/ESA Joint Annual Meeting (Las Vegas, US, 1998-11-08/12), the EPPO Secretariat has extracted the following data concerning quarantine pests or pests of potential quarantine interest.
Citrus mosaic disease. It has previously been reported that citrus mosaic disease (EU Annex II/A1) is associated with a badnavirus (EPPO RS 96/137). This disease is widely distributed in India, especially on sweet orange (Citrus sinensis) and pummelo (C. grandis). Studies made in quarantine conditions in Florida (US) showed that an Indian isolate of citrus mosaic badnavirus could be experimentally transmitted with Planococcus citri to sweet orange seedlings (S31).
Claviceps africana. Details are given on the spread of Claviceps africana in Mexico. In addition to Guanajuato, Jalisco, Michoacan and Tamaulipas, the fungus also occurs in San Luis Potosi, Sinaloa and Veracruz states (S.123).
Ditylenchus dipsaci. Ditylenchus dipsaci (EPPO A2 quarantine pest) occurs in lucerne crops in Colorado, US (S107).
Peach X-disease phytoplasma. A new outbreak of western-X disease (caused by peach X-disease phytoplasma - EPPO A1 quarantine pest) is reported in cherry orchards near Placerville, in California (US). In June 1997, symptoms were observed and the presence of the phytoplasma was confirmed by PCR (using specific primers). Disease incidence was 4% in one orchard, 13-17% in several orchards and up to 50% in two others. Control measures including timely insecticide applications against leafhopper vectors and sanitation were applied (S91).
Xanthomonas axonopodis pv. dieffenbachiae. Field studies have shown that Xanthomonas axonopodis pv. dieffenbachiae (EPPO A1 quarantine pest) can survive over a period of 6 months in leaf and petiole tissues left on the surface or buried in the field. The pathogen remained viable and infectious even after decomposition of tissues. The bacterium could also
be isolated from root tissues, which identifies roots of systemically-infected anthurium as a potential inoculum source after that diseased plants have been removed from the field (S23
de Tomasel, C.M.; McIntyre, G.A. (1998) Distribution and biology of Ditylenchus dipsaci and Aphelenchoides ritzema-bosi in Colorado (S107).
Duffy, B.K. (1998) Field survival of the anthurium blight pathogen, Xanthomonas campestris pv. dieffenbachiae, in crop debris (S23).
Garnsey, S.; Behe, C.G.; Lockhart, B.E. (1998) Transmission of citrus yellow mosaic badnavirus by the citrus mealybug (S43).
Uyemoto, J.K.; Moratorio, M.S. (1998) A new outbreak of western-X disease in cherry orchards in California (S91).
Velasquez-Valle, R.; Odvody, G.; Isakeit, T.; Williams, H. (1998) Spread of sorghum ergot in the USA and Mexico (S123).
Abstracts of papers presented at the APS/ESA Joint Annual Meeting, Las Vegas, US, 1998-11-08/12. Phytopathology, 88(9), Supplement, 144 pp.