Differences in leaf litter, ascospore production and infection of pear scab (Venturia pirina) in Dutch organic orchards

B.G.H. Timmermans, P.J. Jansonius

Research output: Chapter in Book/Report/Conference proceedingConference paperProfessional


In 2010 and 2011 the amounts of leaf litter and ascospore production per unit of leaf litter area in 7 organic pear orchards throughout the Netherlands were measured. In one of the orchards, adapted managements strategies were implemented, being grass/clover that is grown as ground cover on the tree-strip, and organic cattle-manure that replaces chicken manure pellets, in order to stimulate the earthworm population and change the palatability of the leaf litter. First results indicate large differences between orchards in percentage of ground covered by dead leaves at the time of major ascospore infections, but also in number of ascospores per cm2 leaf litter and in resulting potential ascospore dose. These data, together with weather data (temperature, rainfall), were used in a simple multivariate analysis to gain insight in the dynamics of the system. The first results show that, to a limited degree, leaf litter was indeed important for the scab epidemic in 2011, whereas in 2010 the high amount of rainfall in the second part of the growing season must have led to a high conidial infection pressure. Surprisingly, in both years ascospore number per unit leaf area was of more importance than leaf litter area or potential ascospore dose.
Original languageEnglish
Title of host publicationEco-fruit : 15th international conference on cultivation technique and phytopathological problems in organic fruit-growing and viticulture, 20-22 February 2012, Hohenheim
Place of PublicationWeinsberg
PublisherFoerdergemeinschaft Oekologischer Obstbau e.V.
Publication statusPublished - 2012
Externally publishedYes
Event15th International Conference on Organic Fruit-Growing: -
Duration: 20 Feb 201222 Feb 2012


Conference15th International Conference on Organic Fruit-Growing:


  • venturia pyrina
  • pears
  • fruit growing
  • epidemiology
  • plant pathogenic fungi
  • fungal diseases
  • plant diseases
  • organic farming
  • analysis
  • cultural control
  • rain
  • ascospores


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