Possibilities and problems in the integrated plant protection of apples
1991
Jenser, G. | Balazs, K. (Magyar Tud. Akademia (Hungary) Novenyved. Kut. Int.)
In apple orchards regularly sprayed for 4 and 3 years, resp., with the active agent diflubenzuron, the number of miners (Leucoptera malifoliella) dropped to a minimum, that of the tortricid moth (particularly Adoxophyes orana) rose, and there was a reappearance of Anthonomus porum, Aphis pomi, Dysaphis devecta and D. plantagines. Parallel to the decrease in the number of miners, their parasitoids also disappeared from orchards, while the number of predatory mites (Zetzellia mali) rose within 1-2 years. When integrated plant protection is introduced the balanced application of several specific insecticides with different effects is required, while fungicides and acaricides dangerous to predatory mites must be avoided. The date treatments must be chosen to give adequate control of the dominant species. Within the framework of integrated plant protection, the N fertilizer rates must be reduced to the level which is really needed. A high N content in the leaves of apple trees favours the multiplication of spider mites and continuous summer multiplication of the aphid Aphis pomi.
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