Development and validation of a real-time RT-PCR test for screening pepper and tomato seed lots for the presence of pospiviroids.

Potato spindle tuber viroid and other pospiviroids can cause serious diseases in potato and tomato crops. Consequently, pospiviroids are regulated in several countries. Since seed transmission is considered as a pathway for the introduction and spread of pospiviroids, some countries demand for the testing of seed lots of solanaceous crops for the presence of pospiviroids.

A pospiviroid from symptomless portulaca plants closely related to iresine viroid 1.

In symptomless plants of portulaca a potential new pospiviroid was characterized. Analysis by both double and return PAGE showed the presence of a circular RNA. RT-PCR and sequencing revealed a genome of 351 nt with properties characteristic of members of the genus Pospiviroid and with highest sequence identity (circa 80%) with iresine viroid 1 (IrVd-1).

Development and validation of a real-time RT-PCR assay for generic detection of pospiviroids.

In many countries phytosanitary regulations apply to Potato spindle tuber viroid, because it can cause serious diseases in potato and tomato crops. Other pospiviroids, some of which are distributed widely in ornamental crops, can cause similar diseases. Consequently, there is a need for a reliable and cost-effective generic testing method.

Fusarium foetens, a new species pathogenic to begonia elatior hybrids (Begonia x hiemalis) and the sister taxon of the Fusarium oxysporum species complex.

A new disease recently was discovered in begonia elatior hybrid (Begonia × hiemalis) nurseries in The Netherlands. Diseased plants showed a combination of basal rot, vein yellowing and wilting and the base of collapsing plants was covered by unusually large masses of Fusarium macroconidia. A species of Fusarium was isolated consistently from the discolored veins of leaves and stems.