ISHS Acta Horticulturae 525: International Conference on Integrated Fruit Production
A FOUR YEAR EXPERIMENT ON THE DEVELOPMENT OF MITE POPULATIONS ON SCAB RESISTANT APPLES |
| Authors: | V. Mercier, F. Combe, G. Fauvel, G. Marboutie, Y. Lespinasse |
| Keywords: | Scab resistant apple, Acari, Panonychus ulmi, Typhlodromus pyri, Chemical control, Integrated control |
| DOI: | 10.17660/ActaHortic.2000.525.37 |
| Abstract:
Varieties displaying resistance against pathogens or noxious insects are of great interest for Integrated Pest Management. INRA has selected scab resistant apple varieties and a 4-year study (1990–1993) was conducted on the evolution of mite fauna on them in comparison with susceptible ones under selective spray programs.
If necessary acephate and pirimicarb were used to control aphids and granulosis virus against codling moth with the exception of the 1st year. On scab resistant apple selections the number of fungicide sprays was reduced by 85% over the 4 years. The percentage of leaf infestation by Panonychus ulmi always remained low (<22%) and no miticide treatment was necessary. On conventional cultivars receiving a usual fungicidal cover, one acaricide spray was applied every year, because the populations of P. ulmi were very high (up to 90% leaves occupied). Finally, the diversity of the beneficial species was greater on scab resistant varieties and their populations were larger. One important result of this study was the natural regulation of P. ulmi populations by predarory mites especially Typhlodromus pyri on scab resistant selections. Repeated fungicide applications seem to induce an important imbalance in the apple's mite fauna and favour the development of P. ulmi. | |
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