EFFECTS OF AIR POLLUTANTS ON GROWTH, LEAF DROP, FRUIT DROP, AND YIELD OF CITRUS TREES

Commercially producing lemon and navel orange trees were studied to determine the effects of the air pollutant complex, especially photochemical oxidants and fluorides, in the Los Angeles Basin on the following responses: growth; weight of prunings; leaf drop; fruit drop; arid yield of mature fruit. The results showed that overall growth was not affected significantly. Leaf drop was significantly less in lemons where carbon filtered air was supplied to the trees. A similar trend was present in oranges but was not significant statistically. Fruit drop in navel oranges was significantly less in carbon filtered air than in ambient. Yield of fruit is also reduced significantly by photochemical oxidants, sometimes by as much as 50%. © 1969, American Chemical Society. All rights reserved.