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In view of the ongoing revival of the chestnut orchards in southern Switzerland, evaluation of chestnut quality represents an important issue. Chestnuts are mainly consumed roasted. Three native varieties and a French one were roasted and submitted to sensory and chemical analysis in comparison to a commercial marrone variety imported from Italy. Weight loss due to roasting ranged from 23 to 30%. Roasted chestnuts contained 260±350 g kg À1 starch, 50±102 g kg À1 sucrose, 0.5±4.4 g kg À1 fructose, trace amounts of glucose and 9±15 g kg À1 total fatty acids. The main fatty acid in chestnuts was linoleic acid, amounting to 49% of total fatty acids. Sensory analysis showed that acceptance of chestnuts was highly dependent on sweetness, which was related to sucrose content. It should be at least 90 g kg À1 .Varietal differences were observed in this study and it was shown that roasting caused little change in composition. Thus chestnut varieties used for roasting have to be selected accordingly. The commercial variety Marrone di Cuneo con®rmed its superiority with regard to suitability for roasting. Among the Swiss varieties, only Lu È ina exhibited satisfactory quality.

With a view to enhancing the quality of local chestnut in southern Switzerland, the impact of three treatments ['soaking', 'cold bath' (hydrotherapy) and 'warm bath' (thermo-hydrotherapy)] on the qualitative, chemical and sensory characteristics of the nuts during 90 days of cold storage was evaluated. Weight and water content decreased significantly with increasing duration of storage. Starch content decreased following a negative logistic trend. Sucrose, however, increased steeply according to a monomolecular trend and was significantly higher between 0 and 60 days of storage in the soaked chestnuts than in the cold-bath treated nuts. The mean proportion of mouldy fruit remained constant at 27% for the warm-bath treated nuts and increased from 16 to 30% for the cold-bath treated fruit and from 28 to 63% for the soaked nuts during the 90 days of cold storage. The most frequently isolated moulds were Ciboria batschiana, Penicillium spp. and Mucor hiemalis. Warm and cold baths were successful in eliminating the larvae of Cydia splendana but the cold bath was inadequate to control Curculio elephas. Cold bath significantly reduced the sensory qualities (sweetness, aroma, texture) of the nuts, but made them easier to peel, as did the warm bath.

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Fire blight, caused by Erwinia amylovora, is a major disease threat to apple, pear and other pome fruit worldwide. The disease is widespread in Europe and has recently become established in Switzerland. Antibiotics are the most effective controls used in North America but these are not permitted for agricultural use in most European countries. A newly registered biological control product Biopro Ò , based on the antagonist Bacillus subtilis strain BD170, is being used as an alternative strategy for fire blight management. A specific molecular marker was developed for monitoring the spread of this agent on blossoms after Biopro Ò spray application in a Swiss apple orchard throughout the bloom period for 2 years. Direct spraying resulted in efficient primary colonisation of pistils in flowers that were open at the time of treatment. Subsequent bacterial dissemination (secondary colonisation) of flowers that were closed or at bud stage at the time of treatment was observed but was found to be dependent on the timing of treatments relative to bloom stage in the orchard. Foraging honeybees were shown to be disseminators of Biopro Ò . We also report detection of the biocontrol agent in honey collected from hives where bees were exposed by placing Biopro Ò at the entrance or in the hatching nest and from hives that were simply placed in sprayed orchards.

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