Denis I. Castillo B.1 y Juan Acevedo A.2

The protection of winter wheat Triticum aestivum L. Melifén with aphicides during several phenological stages was studied in an experiment conducted during 1975-76 at the Experiment Station Carillanca, in Temuco - Chile. Results were evaluated in terms of grain yield, deterirated spikes, weight of hectoliter, number of spikes per meter, weight per thousand grains and aphid population.
Best yields were obtained for protection during the following phenological stages: planting - physiological ripening; planting - anthesis; jointing - physiological ripening; planting - milky stage; planting - flay stage and jointing - flag stage. Yields obtained in these treatments ranged between 7.51 and 6.96 ton/ha and represented increases in yield of 44.7 and 34.3% in relation to the unprotected control treatment (5.12 ton/ha). The most critical phenological stage in this trial was that between jointing and flag stage.
It is concluded that protection with aphicides during the critical phenological periods resulted in substantial increases in yield. The best treatments markedly reduced deterirated spikes.

1Ing. Agr. Programa Entomología, Estación Experimental Carillanca (INIA), Casilla 58-D, Temuco, Chile.
2Ing. Agr. M.S. Programa Cereales, Estación Experimental Carillanca (INIA), Temuco, Chile.