Summary of the Express Pest Risk Analysis for Scirrhia acicola (Dearness) Siggers
Mycosphaerella dearnessii (Scirrhia acicola), causes brown-spot needle blight (EPPO/CABI 1997) of many pine species. The brown-spot fungus mainly attacks trees from Central to North America but also in Europe (Pehl 1995). Pathogen was detected in both urban and forest areas. In Central Europe fungus infects mainly pinus mugo uncinata (mug species) but also P. sylvestris, P. nigra and P. mugo. Currently used pesticites are unsufficient despite funguj spreads slowly and occurs only in few localizations. Scirrhia acicola was occasionally detected in PRA area and infested low numbers of its host plants (Pusz et. al. 2013). All Pinus species are potential hosts, but the most important in PRA area are: P. strobus, P. sylvestris, P. nigra. Some of species (like P. banksiana) have proven to be high resistant (Skilling & Nicholls, 1974).
Rating of the likelihood of entry: low/ moderate (There is possibility of spread and access to the host plants in case of fungus entry).
Rating of the likelihood of establishment outdoors and in protected conditions: low/ moderate (because of occasionally fungus occurrence in PRA area)
Rating of the likelihood of spread: low (because of low number of fungus reports)
Rating of the likelihood of impact without phytosanitary measures: low (because of other ratings)
Long-needle varieties are resistant to infection and should be preferred species in Christmas tree plantations (Phelps et.al., 1978).
Phytosanitariaty measures based on applications of Bordeaux mixture, chlorothalonil, benomyl and copper hydroxide in nurseries, seed orchards, and plantations of longleaf pine and Scots pine.
Seedlings should be sprayed at 10- to 30-day intervals from beginning of spring to the end of the summer.
Level of uncertainty of assessment depends on all previous reports of pest occurence in PRA area.
|Pest Risk Analysis