Professor Wallace, Director of Britain's Long Ashton Research Station[6], has laid the foundation for diagnosing mineral deficiencies by leaf symptoms. These are reliable indicators of what nutrients to furnish plants when they are distinct and easily recognized. But for subacute deficiencies, plant analysis and injections are resorted to. Injections of manganese sulphate as pellets into holes drilled in trunks of cherry trees caused orchards that had been barren, to bear heavy crops a few months later. Manganese, boron, zinc, copper, iron, magnesium also lend themselves quite readily for applications as nutritional sprays, when applied as suitable compounds such as the sulphates. Both spray applications and tree injections have great diagnostic values, because a response to them, if needed is relatively quick. When trees are deficient their foliage will show marked improvement from a spray application within a few days, so that a test can be made on a few trees before an entire orchard is treated. Trunk injections should of course be made during the dormant season for results to show the following summer. 5) Nutritional Sprays Florida and California lead in the application of nutritional sprays on citrus and other fruit[7]. Vegetables, too, respond remarkably thereto[8]. I see no reason why nut trees likewise should not benefit from them, especially when other spray materials are used. Copper sulphate, zinc sulphate, manganese sulphate, magnesium sulphate, iron sulphate, cobalt sulphate and borax are all compatible with each other and with most other spray materials. Combination sprays seem to perform better, anyway, than single sprays, and the only objection would seem to be that some element is applied that is not deficient. It can be taken for granted, however, that nothing is wasted, even though the benefits may be invisible. Soils benefit in the long run from sprays. One element, even though not noticeably needed, may make another available or it may antidote toxicity of some element present to excess. Indirect results in all likelihood are always obtained. In Florida, recommendations for spray applications to citrus are made annually[9]. They can be obtained from the Florida Citrus Commission, Lakeland, Fla. A typical formulae is as follows: _ 3-5 lbs. zinc sulphate | 3-5 lbs. manganese sulphate | per 100 gallons of water or 2-5 lbs. copper sulphate with | other spray material equal amounts of lime. _| 1 gallon of lime sulphur or 1-1/2 lbs. of lime is used for every 3 lbs. of sulphate of manganese or zinc. Cherries, apples, plums are quite responsive to such applications, and I have seen the defoliation of prune trees in New York State corrected with a mixture containing: