Summary1Manurial treatment exercises a strong influence on the growth of apple trees, their time of blossoming, the amount of bloom, the foliage colour and the fruit colour. The effect is mainly due to nitrogen which induces increased growth, earlier flowering, more bloom, greener foliage and softer and greener fruit. Potash and phosphate have little effect on the growth of the trees, or on blossoming or foliage, but favour the production of more highly colonred fruit.2Nitrogenous manuring increases the nitrogen content of the fruit. Thus in 1930 the mean nitrogen content for the samples from plots receiving and not receiving nitrogen, was 0.0229 and 0.0550 respectively. In the following year the results for similarly treated pots were 0.0430 and 0.0745 respectively. Considering the results obtained in the years in question the mean nitrogen content for 1930 when there was a good yield was 0.0372 in contrast with 0.0587 for 1931 when the yield was poor. The control plot alone gave values of 0.0218 and 0.0343.3In 1930 the rates of radial advance (in mm. per day) ofCytosporina ludibundafor samples from plots receiving different treatments were K, 0.082; K+P, 0.118; X, 0.130; P, 0.150; C, 0.259; N+K+P, 0.456; N+P, 0.678; N, 1.213; and N+K, 1.249. The rate for the ample from the plot treated with N+K is fifteen times that calculated for the apples from the plot treated with K. The effect of nitrogenous as compared with non‐nitrogenous or no manuring has been studied in each of three years. The mean values for radial advance obtained for samples from plots receiving no nitrogen were 1930, 0.153; 1931, 0.33; 1932, 0.54, while for samples from plots receiving nitrogenous manuring the values were 1930, 0.889; 1931, 1.08; and 1932, 0.89. The values obtained in 1930 receive confirmation from observations on the radial spread of the fungus on the sterilized tissue from apples produced on trees in the various plots. The value γrm=+0.9112 was obtained for the correlation between radial advance (R) and radial spread (M). In 1930 the rate of growth of the fungus in the sample from the plot treated with K was one‐third of that in the sample from the control plot.4Radial advance is correlated with nitrogen content (N) of the fruit and this relationship is shown by the following values for the correlation coefficient: 1930, γRN+=0.8571; 1931, γrm=+0.7277.5Nitrogenous manuring increases the intensity of the attack ofVenturia inaequalison the fruit in the orchard. Evidence is produced in support of the suggestion that fruit resistant to attack byV. inaequalismay also be resistant to invasion by a rot producing fungus in storage. The value of the correlation between radial advance (R) and the percentage weight of scabbed fruit (S) was γRS+=0.6395. The percentage weight of scabbed fruit was shown to be correlated with the nitrogen content of the fruit and the value of the coefficient obtained was γSN;