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Complete nucleotide (nt) and deduced amino acid sequences of two onion yellow dwarf virus (OYDV) isolates showing mild and severe symptoms in onion but being unable to infect garlic were determined. The genomes consisted of 10,459 and 10,461 nt (without the 3' poly(A) tail) and were 92.2 % identical. Comparison of their whole genomes, polyproteins and P1, HC-Pro, P3, CI, VPg and NIa-Pro regions with those of garlic isolates previously identified as OYDV gave percentage values below that proposed as the molecular threshold for potyvirus species demarcation. This and the striking differences in host range between onion and garlic isolates suggest that they represent different virus species.

Moth plant Araujia sericifera is an environmental weed in northern regions of New Zealand Due to its rapid spread its ability to cause substantial damage to natural ecosystems and the increasing cost of conventional control methods a biological control programme was initiated A survey of the plant in New Zealand found that damage attributed to either disease or insect herbivory was minimal with little biocontrol potential Botanical pathogen and insect surveys were subsequently initiated in the native South American range to locate and identify potential agents for classical biocontrol Potential agents associated with plant damage were collected Damage was mostly due to pathogenic attack with 90 of moth plant populations showing disease symptoms To date eight fungal pathogens have been associated with plant die back leaf necroses and a severe fruit rot At least two mosaic (virus) diseases were also found frequently associated with colonies of the aphid Aphis nerii

Lippia, Phyla canescens (Kunth) Greene (Verbenaceae) is a fast-growing, mat-forming plant native to South America. It is a weed in Australia, where it was introduced as an ornamental during the nineteenth century. The knowledge about the biology of lippia is currently limited to unconcluded taxonomical studies; there is scarce information about the ecology and natural enemies in the native range. Surveys for the plant and its natural enemies were initiated in Argentina in 2005 to determine its distribution and to search for possible biological control agents, both insects and phytopathogens. We have found Phyla sp. in 54 out of 102 sites sampled, mostly east of 66°W, circumscribing the weed to the Chaco Domain. In places where the plant was present, at least 20 arthropods and 16 fungi were found. Among insects, the most promising candidates are three flea beetles (Chrysomelidae): two species of Longitarsus and Kuschelina bergi Harold. Pathogens include the rust Puccinia cf. lantanae Farl., Cercospora cf. lippiae Ellis and Everh. and three Colletotrichum spp., associated with leaf spots and stem cankers. Additional information on their biology and host specificity is required to propose any of these as biological control candidates.

Symptoms of general wilting and yellowing were found affecting Beta vulgaris L. (sugar beet, fodder beet and chard) in the Argentinean region of Bahía Blanca (Buenos Aires province), Valle Medio, and Valle Inferior de Rio Negro (Patagonia region). PCR amplification of the 16S rRNA region showed presence of phytoplasma in approximately 80% of the samples from symptomatic plants. Phylogenetic analyses revealed the presence of phytoplasmas of the 16SrIII-J subgroup. This is the first molecular evidence of phytoplasmas associated with yellow wilt disease in B. vulgaris in Argentina.