ISHS Acta Horticulturae 525: International Conference on Integrated Fruit Production
GROWTH REGULATION IN IFP PRODUCTION SYSTEMS. |
| Authors: | T. Deckers, E. Daemen |
| Abstract:
Growth regulation in fruit growing can be devided into different fields of application: they can be applied to improve fruit set, to reduce vegetative shoot growth in the post floral period or they can be applied before harvest to reduce fruitfall and improve fruit quality. Some growth regulators can be applied during season to improve the fruit skin quality on apple or pear cultivars that are susceptible to fruit russeting. The improvement of fruit set can be a direct influence by a stimulation of the parthenocarpic fruit set (e.g. use of gibberellines on pear cv. Conference) or can be an indirect effect due to a change in the balance vegetative growth - generative growth during the periods of flower drop and/or June drop. Under these restrictions the growth regulator CCC was accepted in the belgian guidelines for integrated fruit production; when a growth retardant is applied during season, it can stop vegetative shoot growth earlier and increase flower bud formation on the one year old shoots; this is a very important factor for productivity in difficult years with night frost damage on the flowers. The later phenological evolution of the flowers on the 1 year old wood allow them often to escape to frost damage. The use of growth retardants can also reduce the risk of fungal diseases like apple scab (Venturia ineaqualis) and mildew (Podosphaera luecotricha) on apple and of insect damage on pear trees (Psylla sp.) This can result in a reduction of input of chemicals in orchards where growth is stopped artificially. It is estimated that it is possible to save four anti scab treatments and two anti mildew treatments when growth is stopped 6 weeks earlier then normal. This means that one treatment with a growth regulator could replace 6 fungicide treatments. Some growth regulators seem to have an influence on bacterial diseases like fire blight (Erwinia amylovora) and can in this way reduce the necessity of the use of antibiotics in the orchard. This may also retard the development of streptomycine resistant fire blight strains. The areas where growth regulation should be allowed within IFP production systems is discussed in this paper. | |
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