A rapid method of curing chlorotic avocado trees

The iron-deficiency type of chlorosis in avocado trees may appear in different degrees of severity, in many cases due to lack of so-called "active iron " within the leaves. In light cases, chlorosis may hardly be recognized, whereas in severe cases the trees lose most of their leaves and may degenerate completely. Very often chlorotic trees can be cured by a sufficient amount of certain iron compounds, applied to the trees by the right method. In previous experiments (3), application of iron chelates through the soil was successful in curing chlorotic avocado trees. In some cases, however, it took quite a long time before the trees recovered. Furthermore, soil application usually requires the use of large amounts of compounds, some of which are very expensive. In some experiments (4) various iron compounds were applied by foliar spray, but in most cases the results were poor. Preliminary experiments to apply the iron compounds directly into the trunk or branches showed some promising results. Of the various methods developed for the injection of materials into trees (2), a modification of the method developed by Cohen (6) seemed to be the most suitable for our purpose. In the present paper the efficiency of this method is compared with that of other treatments