ISHS Acta Horticulturae 492: I International Symposium on Cucurbits
EFFECT OF BIOLOGICAL CONTROL AND FRUIT PRUNING ON PLANT DECAY OF CUCUMBER (CUCUMIS SATIVUS L.) GROWN IN PLASTIC GREENHOUSES |
| Author: | P. BLEYAERT |
| Keywords: | Fusarium oxysporum, Trichoderma harzianum, Streptomyces griseoviridis, hymexazol, leaf necrosis, water relations, soil mulch |
| Abstract:
Cucumbers seem to offer good possibilities for growing in cold, non-heated, plastic greenhouses during the relatively hot summerperiods in Belgium. Plants grow well and fruit quality equals that of cucumbers grown in glasshouses. However two problems remain: leaf necrosis in the heads of young plants, due to high light intensities, and fallout of adult plants by wilting and necrosis of the elder leaves, starting from August on. Plant analysis showed the presence of Fusarium oxysporum. It is questioned however, if the primary nature of the disorder was not rather physiological, giving rise to a secondary attack of plant parasites. In 1989 and 1990, three preparations of Trichoderma spp., one preparation of Streptomyces griseoviridis and the chemical fungicide hymexazol with or without soil disinfection using dazomet, could not affect yield or plant decay. In 1991 until 1994, removing the flowers from the first 7, 9, 12, 14 or 17 leaf axils, in various combinations with alternate removal of the flowers of the higher axils either did not diminish plant decay or improve fruit yield. On the contrary, significant higher yields were obtained from plants with little fruit removal, being those with a heavy fruit load. As the same plants also suffered significantly less from head leaf necrosis, a relation with plant water status is suggested, the fruits serving as a water resource. | |
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