MICHIGAN EXPERIMENT STATION BULLETINS. 209 



THE SPRAYING OF FRUITS. 



The necessity for the use of insecticides and fungicides seems to increase 

 from year to year. Not only do new insects and diseases appear, to destroy 

 the crops, but the injuries caused by old and well known pests are more 

 noticeable. 



For many of them, however, we have quite effective remedies, and, as 

 much light has been given during the past year upon the best methods of 

 applying them, these brief notes are submitted. 



Most of the diseases of plants are due to the development of parasitic 

 fungi. These are for the most part microscopic plants, that feed upon the 

 tissues of their hosts, and finally develop spores that answer as seeds fo» 

 their reproduction, and as they are light and are blown about by the wind, 

 the dissemination of the disease may be very rapid. 



These fungi may feed upon the roots, stems, leaves, or fruits of plants, 

 and as they not only rob the plant of food designed for its development, 

 but, by destroying its tissues, hinder the organs of the plants in the per- 

 formance of their various functions, they exert a two-fold injury. 



It has been found that various compounds of copper, zinc, sulphur, iron, 

 etc., will destroy the spores of all fungi with which they may be brought 

 in contact, and by thoroughly spraying the plants with these materials, 

 the spread of the disease can be prevented in many cases. A large pro- 

 portion of these fungi penetrate to the interior of the plants and there are 

 safe from all applications, except when they push out the slender stalks 

 upon which the spores are borne. It will therefore be seen thAt for such 

 fungi all remedies must at best be preventive. Many fungi, ' however, are 

 quite superficial in their workings and can be readily destroyed. 



Most of the fungi pass the winter upon the £tems, or the fallen leaves 

 and fruit, and only await favorable conditions for germination. Careful 

 experiments have shown that in order to hold the diseases in check, early 

 applications of fungicides are desirable. Thoroughly spraying the trees 

 early in the spring, before the leaves start, with some approved mixture, 

 will destroy all of the spores that may have' wintered upon the stem or 

 branches, and all that may fall upon them for several weeks. For most 

 fruits it it is well to repeat the operation as soon as the blossoms have 

 fallen, and a third application at the end of four weeks will frequently be 

 desirable. 



Many plants have insects that prey upon them in the early spring, and, 

 by adding a small quantity of some poison, all that eat the foliage can be 

 destroyed, with no expense except for the material used as an insecticide. 



From the experiments of the past two years, the following are regarded 

 as among the most effective: 



FUNGICIDES. 



For all plants that are not injured by the application of lime to the 



foliage the Bordeaux mixture will be found the most reliable form. It can 



be used upon all kinds of plants without fear of burning the leaves, but, 



although the lime itself is of value in cementing the material upon the 



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