ANNUAL REPORT 1995 •••• Research Station for Fruit Growing Brugstraat 51 4475 AN Wilhelminadorp The Netherlands Phone+31-113-242500 Fax+31-113-242650 Postgironr 495017 Information contained in this report may not be reproduced in total or in part without permission. Neither the authors nor the Research Station can accept any liability of loss, damage or injury resulting from the application of any concept or procedure in or derived from any part of this report. ISSN 1381-6594 Price Dfl 25.00 A.R. 1995 Research Station for Fruit Growing The research on fruit growing is funded by the Ministry of Agriculture, Nature Conser­ vancy and Fishery, Landbouwschap and Produktschap voor Siergewassen (PVS). landbouw, natuurbeheer en visserij Postbus 20401, 2500 EK Den Haag Tel. 070 3793911 Landbouwschap Prinsenvinkenpark 19, 2585 Den Haag Tel. 070 3526666 OOP OGV Postbus 93099, 2509 AB Den Haag Tel. 070 3041234 CONTENTS PAGE Remarks on the brands of pesticides and herbicides 1 Donor Members 1 Board 2 Staff 3 The Experimental Garden Weather and full bloom data 6 Department of Pomology and Economics Top Fruit and Nursery Rootstocks and interstems for pome and stone fruit 8 (apple rootstock trial - cherry rootstock trial) Unusual fruit crops 14 (Hazelnut - walnut - quince) Fruit-tree nursery 19 (effect of benzyladenine on feathering of trees in the nursery) Planting systems and light utilisation 21 (planting systems with Jonagold, Fiesta and Elstar) Evaluation growth regulators 25 (Pre-harvest drop control Conference pear - evaluation of GA4-rich mixture for russeting control - evaluation of auxin-protein conjugates for rooting of cuttings - growth control with a retardant) Pruning and tree shapes 28 (Growth control Conference) Fruit quality, orchard and climate 30 (Influence of light on fruit quality for four rootstocks - pruning and thinning with Elstar - simulation of fruit growth during the season) Black skin discoloration in pear 34 Chemical thinning 36 (Evaluation of new thinning compounds on apple - early thinning of Elstar a necessity - olanting trees on or in the ground) Evaluation of Top Fruit Cultivars pultivar testing with apple 44 (cultivar testing in Wilhelminadorp - clone trials in Wilhelminadorp - clone trials in regional experimental gardens) Cultivar testing with pear 49 (cultivar testing in Wilhelminadorp) Cultivar testing with stone fruit 51 (cultivar testing with plum in Wilhelminadorp - cultivar testing with sweet cherry in Ahrweiler (Germany) - cultivar testing with sweet cherry in Rillaar (Belgium)) The pollination of pome and stone fruit 53 (crossings) Small Fruit Strawberry cultivar trials 54 (cultivars in the open - everbearing cultivars - other strawberry trials) Cultivar trials of bush and cane fruits 56 (red and white currant - black currant - gooseberry - blackberry - raspberry - blueberry) Development of methods for an early and late harvest of currants, raspberries, blackber­ ries and blueberries 70 (early and late harvest with blueberries in a mobile tunnel - late harvest of blueberry by means of rain covers - late harvest and the effect of soil treatment with Elliott) Economics and Farm Management Analysis Intergrated fruit growing ' 73 Decision support systems in fruit growing 75 (a decision support system for economic and ecological calculations - price and quality) Plant Nutrition and Fruit Quality Physiology Fruit ripening as affected by environmental factors during the growing season .... 79 (the effect of temperature at early and late stages in the season on some of the riping and quality criteria in apple) Storage and Quality Prediction of optimum harvest date for long-term storage in apple and pear 82 (first picking date for direct consumption) Optimum harvest date of apples for direct consumptium and for prolonged storage . 84 (aim - materials and methods - results) Distribution of fruit quality in the tree at harvest and post-harvest behaviour in relation to the effect of fruit position in Elstar 89 (aim - methods - results - nutrient relations - correlations between fruit characteristics - simulated picking) Optimum storage conditions and the suitability of storage techniques for fruit 95 (aim - new cultivars - Jonagold mutants - results) Prediction of risk on superficial scald in Jonagold 99 Fungicide reduction in spray scheme for controlling storage rot 102 Pre- and postharvest fruit quality in relation to nutrition and other orchard factors . 104 Reduction of internal disorders during storage of Conference pear 106 (aim - method - results) Skin spots on Elstar 108 (aim - the effect of calcium spraying - results - effect of pull-down and speed warming- up) Soil Science and Plant Nutrition Control of growth and production of pit and stone fruit by water and nutrient supply110 (advisory system for the water supply - water project Zeeland) Improvement of the quality of pit and stone fruits through the water and nutrient supply 102 (calcium fertigation) Water and nutrient requirements of strawberries and berry fruit 116 (water requirement of blueberry) Optimization fertilization - recommendation basis for strawberry and bush and cane fruit 117 (optimization fertilization blueberry) Crop Protection Phytopathology and Weed Control Biology and control of secondary or sporadic disease in fruit crops 118 (European canker - root rot in pear - fruit rot on blueberry) Biology and control of apple scab 119 (development in spring - testing fungicides - resistance to DMI fungicides - leaf drop accelaration) Biological control of diseases in fruit crops 120 (powdery mildew on gooseberry) Population dynamics of Pratylenchus penetrans in fruit crops 121 (comparison of various preceding crops for the control of replant disease caused by the nematode Pratylenchus penetrans - optimization of alternatives for chemical soil disinfection - control of nematodes with bacteria - alternatives for chemical soil disinfection - origin of planting material and soil treatment - testing of various root- stocks for their susceptibility to nematodes - ridge culture with potting soil against nematodes - strip disinfection compared to overall disinfection) Entomology and Biological Control Testing of insecticides, fungicides and bactericides in fruit growing 129 (tests of three potential aphicides - tests of insecticides against the mullein bug) Integrated control of pests on top fruit 130 (Integrated control of pests on apple - carnation leaf-roller - damage by bugs) Biological control of pests on strawberry and soft fruits 132 Development of farming systems for integrated fruit growing 132 (aim - materials and methods - results in 1995 - farming systems research for scabresis- tant apple cultivars - results - conclusion) List of Chemicals 145 Publications 147 List of Entries 152 Publications of the Research Station for fruit growing 161 Remarks on the brands of pesticides and herbicides The dosages mentioned for pesticides and herbicides in this report refer to the commer­ cial products. Trade names of products have been used for the sake of convenience, but this makes it unavoidable that in some cases similar endorsement of named products is intended. Some of the experiments described in this report are carried out with chemicals and/or concentrations not yet legally improved. Donor members Those who are interested in the work of Research Staion and wish to keep an active touch with and support its research, are invited to become donor member. Donor members will receive the Annual Report and other publications of the Research Station without charge. The minimum subscription for donor membership is 35 guilders for private individulas in The Netherlands, 60 guilders for institutions in The Nether- ands, and 50 guilders for foreign private individuals and foreign institutions, annually. 3aymant by transfer to an account of the Proefstation voor de Fruitteelt (post office giro account nr. 49 50 17, account ABN/AMRO-bank Goes nr. 47.21.74.878) or by nternational postal money order in Dutch currency, payable to the Proefstation voor de zruitteelt at Wilhelminadorp, with the indication "Donorship Subscription". Jaarverslag FPO 1995 Board (31 December 1995) Board of the foundation research station for fruit growing Executive committee Other members J.A.M. Musters, Dinteloord, chairman F.J. van Beerendonk, Best H.W.M. Kurver, vice-chairman C.J.M. Geraeds, Den Haag A.H. Tap Dodewaard, secretary Ir. J.L. Grève, Den Haag G.A. van Haarlem, Buurmalsen Advisors Ing. C.G.M, van Leeuwen, Den Haag Ir. J.M. Gerritsen H.E.P. Reinders, Helden-Panningen J. Zevenbergen H.F.M. Schrama, Biddinghuizen Ir. R.J.M. Meijer G. de Weert, Rossum J. van Woudenberg, Niehove vacancy vacancy Jaarverslag FPO 1995 Staff (31 December 1995) Research Station for Fruit Growing Directeur: Ir. R.J.M. Meijer omology and Economics Dr.Ir. S.J. Wertheim (head, deputy director) Top Fruit and Nursery Dr. Ir. S.J. Wertheim vlrs. Ing. J.M.T. Balkhoven-Baart vlrs. Dr. P.S. Wagenmakers J.M. de Groene vi. Tazelaar Evaluation Top fruit Cultivars ng. H. Kemp Small Fruit äi.J.P. van de Waart Economics and farm Management Analysis J. Goedegebure vlrs. Ir. M.J. Groot ibrary and Editorial staff vlrs. M.M. Cremers-van Scherpenzeel 'lant Nutrition and Fruit Quality Dr.lr. A. de Jager (head) »oil Science and Plant Nutrition r. M.P. van der Maas "hysiology rof. Dr. J. Tromp :h.A.R. Römer Storage and Quality Dr.lr. A. de Jager ng. F.P.M.M. Roelofs ng. H. de Putter aboratory ulrs. Ing. L.M. van Westing (head) k/lrs. M.T.T. de Leeuw-Vereecken »/Irs. A.M. Meerman-van de Repe yirs. P.C. Rijk Jaarverslag FPO 1995 Mrs. D.T. Slazak Mathematics and Statistics E.M.A. van Remortel Crop Protection Dr.ir. B. Heijne (head) Spraying Techniques Dr.ir. B. Heijne R.H.N. Anbergen Entomology and Biological Control Ir. J. Woets Integrated Fruit Control Mrs. Ir. A.M.E. Schenk H. Veijer Data Management W. Beeke Coordination and Public Relation Ir. J.A. Jobsen Administration and Support Services J.A.M. Kouwenberg (head) Administration Mrs. A.M.Th. Mateijsen Mrs. T.L. Buizer-Schuit Mrs. M.C. Schrier-Nijssen Mrs. J.G. Snaterse-van Loo Mrs. P.E. van Vossen-Hopmans Mrs. M.S. Westerweele-Korsuize Housekeepers Mrs. D.N. Nijsse-Hoogesteger Mrs. M.M.