STUDIES ON OSCINELLA FRIT LINN: OBSERVATIONS ON INFESTATION AND YIELD, SUSCEPTIBILITY TO INFESTATION, RECOVERY POWER, THE INFLUENCE OF VARIETY ON THE RATE OF GROWTH OF THE PRIMARY SHOOT OF THE OAT AND THE REACTION TO MANURIAL TREATMENT

Abstract

Summary.The notes collected in the present publication are each concerned with some aspect of the problem of production of varieties of oat plants resistant to the attack of the frit fly.The quality of a variety may compensate for comparatively heavy infestation.Data are recorded confirming previous experimentation relating to the susceptibility of the oat shoot to infestation, emphasising its limitation to the early leaf stages.Experimentation concerned with recovery power after injury showed that different varieties of oats react very differently and indicated the importance of the primary shoot in relation to yield. A few field data are recorded to support this inference.With common English varieties of oats the influence of variety on the rate of growth of the primary shoot was practically negligible, and therefore observed differences between varieties in extents of infestation of primary shoots cannot be ascribed to variations in rates of growth of primary shoots. The time of tillering did not depart markedly from the mean, but it was not correlated with time of shoot production, so that correlation between extent of infestation of shoot and of grain cannot be expected.Excess of nitrogenous manure failed to influence the extent of shoot infestation but effected a reduction in the extent of grain infestation during a season when the extent of the attack of the fly was below normal.