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AFLP analysis was used to examine the genetic structure of the mycoparasite Sphaerellopsis filum on willow rust Melampsora larici-epitea using two sets of samples of a willow clone in a short-rotation coppice planting. The first set was collected from a plot (short strip) in 1998, 1999 and 2000 and the second from another plot (long strip) in 2000. In all, 228 S. filum isolates were typed, 139 AFLP loci scored and 54 AFLP genotypes identified. In the short strip, genotypes sampled in 1998 were no longer detected in subsequent years and genotype diversity fluctuated (0·25–0·68) over the years, indicating that migration had a major impact on the genotype structure. Two distinct groups (average Nei and Li's similarity coefficient between the groups = 0·047) were identified. The group B genotypes were sampled only in 2000. Within the groups, the average similarities were > 0·96. Both the index of association test and the parsimony tree length permutation test suggest that there was a significant clonality in group A while recombination cannot be ruled out in group B. Localized clusters of AFLP genotypes were detected using the software SaTScan that is based on the spatial scan statistic. Possible mechanisms involved in the spread of S. filum in willow coppice plantations are discussed. [ABSTRACT FROM AUTHOR]

In order to detect the presence of Melampsora pinitorqua in some Italian provenances of Melampsora populnea on Populus tremula from mountain zones of probable pine twist rust outbreak, the rust provenances from six areas typical of Melampsora larici-tremulae distribution but suitable for the survival of M. pinitorqua, were considered. Teliospore germinability tests and subsequent basidiospore inoculations on Pinus sylvestris and Larix deciduas with these six provenances of M. populnea were carried out. The results indicated that in the provenance of M. populnea from Camigliatello M. pinitorqua is present; therefore this area is at the greatest risk of twist rust epidemics which are, as yet, unrecorded on new plantations of Pinus nigra subsp. laricio. [ABSTRACT FROM AUTHOR]

This article focuses on a study conducted as of February 1976, regarding the germination ability of teleutospores of melampsora pinitorqua, a fungus, overwintered in different situations and under different types of soil cover. The germination period is affected by local environmental conditions. The intensity of germination of teleutospores overwintered in the underbrush is much lower than that of teleutospores overwintered on uncovered soil. The findings may be very useful for understanding variability of disease incidence in different stations, years and types of soil coverings, besides, for obtaining the best germination ability of teleutospores in susceptibility trials of pine.

Present knowledge of host range and distribution of Melampsora pinitorqua Rostr. in Italy is reported. Melampsora larici-tremulae, which occurs at high altitude in the Apennines and the Alps and infects only larch, can infect pine also in artificial conditions. [ABSTRACT FROM AUTHOR]