Chemical changes in lemons infected by Phytophthora citrophthora include a noticeable reduction in the reducing and nonreducing sugar content, an increase of organic acids in the peel and a decrease in the juice, and a considerable decrease in ascorbic acid in the infected fruit as a whole. The total amount of free amino acids remains unchanged. Ethanol and methanol are present in markedly increased amounts. No change in the amount of essential oil present in the peel is found in infected fruit.