CORK SPOT OF D’ANJOU PEAR FRUIT RELATIVE TO CRITICAL CALCIUM CONCENTRATION AND OTHER MINERALS

Fruit mineral analyses from nine orchards showed that fruit Ca was negatively correlated with incidence and severity of cork spot (CS) both at harvest (r = -.75) and after storage (r = -.76) in both years.
The N:Ca ratio was similarly correlated to CS at harvest and after storage (r = .74 and .75) although N alone was weakly correlated.
Significant correlations between CS incidence and fruit Ca or N:Ca could be found as early as 120 days before harvest.
Critical minimum D’Anjou fruit Ca is about 7 mg Ca per 100g fresh weight for incipient cork spot.
If the N:Ca ratio exceeds 10, CS can be expected to exceed 30% unless fruit Ca is greater than 8 mg per 100g fresh weight.
Correlations between CS severity and fruit Ca were highly significant (r = -.86) and water soluble Ca was more correlated with CS than was total Ca.
Ranges of fruit Ca from non-lesioned, light, medium, and severely lesioned CS fruit were 8.1, 5.7, 4.8, and 3.8 mg Ca per 100g fresh weight, respectively.
Severity of CS was not correlated with B, N, K, P, Mg or any other minor elements.

III International Symposium on Pear Growing

D.G. Richardson, A.M. Al-Ani

https://doi.org/10.17660/ActaHortic.1982.124.15