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An experiment to determine tbe sbort-term cbaracteristics of root colonization by two vesicular-arbuscular (VA) mycorrhizal fungi witb apple (Mains x dotnestica Borkh.) was initiated concurrently witb an experiment to determine longer-term effects of colonization by tbese fungi on tbe growtb of apple seedlings. Sbort-term cbaracteristics of colonization were determined by sequential barvesting of a cuvette system wbicb also allowed monitoring of bypbal spread from inoculated 'spreader' plants, tbrougb a root-free soil region, to non-inoculated 'receiver' plants. Glomus mosseae (Nicol. & Gerd.) Gerd. & Trappe exceeded Glomus macrocarpttm Tul. & Tul. in rate of initial colonization, amount of maximum colonization, and persistence of arbuscules and external hypbae. Colonization by eitber fungus reduced sboot fresb weigbt 11 days after inoculation but increased sboot and total fresb weigbt by day 38. Hypbae of G. mosseae bad traversed tbrougb 2 and 3 cm of root-free soil to colonize non-inoculated 'receiver' roots by 29 days, and bypbae of G. macrocarpum by 38 days. G. mosseae colonized ' receiver' roots more intensely tban did G. macrocarpum at 2 and 3 cm, and 3 and 4 cm distance, at subsequent harvests. Tbe fungi were effective, singly and in combination, in increasing apple plant biomass, as compared to non-mycorrbizal controls. Relative beigbt growth rate, and colonization at barvest, of G. macrocarpum-'n\Qcw\&t

A recording volumetric spore trap was operated continuously amidst overwintered grape leaves in a vineyard at Walenstadt, Switzerland from early May to mid‐July 1988. Ascospores of Pseudopezicula tracheiphila were captured in the air beginning 11 May and 96 % of the total seasonal release occurred between 16 May and 2 June. Rain always preceded ascospore release. However, trap catches were associated with the simulataneous cessation of rainfall, decreased relative humidity (RH), increased temperature, and drying of foliage. Maximum ascospore release occurred in the second hour, following commencement of drying. Ascospores discharged dry onto glass coverslips survived with greater than 60 % viability after 1, 3, and 6 days exposure to 10, 15, 20, and 25°C at 70 % RH. Only at 30°C was viability reduced to slightly less than 50 % after 6 days.

Botryotinia fuckeliana, the causal agent of grey mould, was biolistically transformed to hygromycin B resistance using a plasmid (pOHT) containing a bacterial hygromycin phosphotransferase gene fused to regulatory sequences from Aspergillus nidulans. Multiple copies of the plasmid, precipitated onto tungsten particles, were delivered into the conidia by a helium-driven gene gun. Southern analysis showed that the plasmid was integrated into the fungal genome at one single locus. After five subsequent transfers on selective medium, all transformants were mitotically stable. When propagated on non-selective medium, four out of eight transformants retained their resistance to hygromycin B. Southern analysis of the fifth generation of transformants showed that no genetic rearrangements occurred during vegetative growth of stable transformants.