News from the Diagnostic Centre of the Dutch Plant Protection Service
The EPPO Secretariat has extracted the following items from the 1996 Annual Report of the Diagnostic Centre of the Dutch Plant Protection Service.
1) Ralstonia solanacearum race 1, biovar 4 was found in a glasshouse in 1993 in Curcuma longa originating in Thailand. Imports of such material were visually inspected but the bacterium was not found. However, a survey of imported lots planted in glasshouses for flower production found several cases of infection. Due to these findings, all imports will be tested for the presence of latent infections of R. solanacearum.
It can be noted that in this Annual Report, many details are given on the testing methods used and studied for the detection of R. solanacearum race3 biovar 2 on potatoes.
2) After a century of absence, the oak processionary caterpillar Thaumetopoea processionea has been found again in the Netherlands. It was rediscovered in the vicinity of Reusel (Noord-Brabant) in 1987, and was later found in many other places in the province of Noord-Brabant, Limburg, Zeeuwsch-Vlaanderen and Zeeland. It is also noted that recent outbreaks of this pest have been noted in Belgium (particularly in Antwerp province), Germany (in the south-west), in Austria (near Vienna), and in parts of Hungary. This pest is a defoliator of common oak (Quercus robur), but also causes serious problems on human health (allergic reactions due to urticating hairs of the caterpillars).
3) A root disease of alder (Alnus glutinosa) caused by an unusual form of Phytophthora cambivora is reported from the Netherlands in a few locations. Diseased trees are declining, and the stem base show distinct tarry spots. A similar disease was reported from United Kingdom (EPPO RS 96/041). Further studies are being carried out on this fungus.
4) In the search of plants which could be used in rotation to reduce populations of Meloidogyne chitwoodi (EPPO A2 quarantine pest), preliminary studies carried out on various cultivars of the following species showed that:
-Agrostis tenuis, Phleum pratense are poor hosts
-Cichorium intybus, Festuca rubra are poor or very poor hosts
-Dactylis glomerata, Festuca arundinacea, Lolium perenne, Poa pratensis are very poor hosts
-Medicago sativa is recorded from non-host to poor host.
5) A petunia plant (Petunia hybrida, Surfinia ‘purple’) has been found infected by a variant of chrysanthemum stunt viroid (EPPO A2 quarantine pest). In addition, details are given on an RT-PCR method which has been developed for routine testing of chrysanthemum for the presence of chrysanthemum stunt viroid.
Sources
Annual Report 1996, Diagnostic Centre, Plant Protection Service, Wageningen, Netherlands, 114 pp.