MICHIGAN EXPERIMENT STATION BULLKTINS 337 



"gum disease" of the peach. 



After lains in tlu' early siiiinj^', patches of giini are noticed upon the 

 twigs and smaller brandies of peach trees, and examination shows the 

 bark beneath to be ruptured. Sometimes the injury is near the buds, in 

 which case it will generally be found that growth has started jjrema- 

 turely, or that it w^as not ])erfectly ripened in the fall, and has been 

 injured by frost; the baric being ruptured the sap exudes. When away 

 from the buds, the injury may be due to the same cause, but small spots 

 are often found on the bark, that have been caused by fungi of various 

 kinds, fi'om which the sap. has come. As preventives, spraj' the trees 

 with fungicides, and use cover crops and mineral fertilizers, avoiding 

 southern exposures where there is not free circulation of the air. If the 

 branches are much injured they should be cut back below where the 

 worst of the spots are found. 



CURL LEAF. 



Although not coming under the operation of the spraying and orchard 

 inspection laws, yet the severe loss suffered last year, in all parts of the 

 state, from this disease, makes it worthv of mention here. The effect of 

 the disease upon the foliage of the tree is know-n by all jieach growers. 

 The tissues become thickened and the leaves become wrinkled and often 

 more or less marked with yellow and red, and finally a w'hitish pow'der 

 is seen upon the infected portions. In severe cases, all of the leaves, 

 except those that have recently developed, drop from the branches of the 

 trees, thus subjecting them to a severe check, and as a result some or 

 all of the fruit drops from the tree — the amount varying wath the severity 

 of the attack. The disease is most troublesome in seasons w^hen the 

 weather has been wet and cold. These conditions cause a check to the 

 development of the leaves and in that condition the spores of the fungus, 

 which is the cause of the disease, readily gain access to the interior of the 

 leaves. It is known that the spores and mycelium of the fungus winter 

 upon the twigs, and if they can be destroyed the danger of the attack to 

 the foliage will be greatly lessened. While the ordinar}- solution of cop- 

 per sulphate, (one pound in fifteen gallons of w-ater) is effectual in de- 

 stroying these spores, better results are obtained with Bordeaux Mixture 

 that contains a large excess of lime (five pounds of copper sulphate, ten 

 pounds of lime and fifty gallons of water). If this is thoroughly sprayed 

 over the trees, before the buds open, covering every portion of the trunk 

 and brandies, it will greatly lessen the danger of an attack to the foliage. 

 As soon as the blossoms have fallen, a second application with the same 

 mixture should be made and, if the weather is favorable to the disease, 

 this should be repeated at the end of ten days or tw^o weeks. Experiments 

 for the last four years have shown that if the trees are sprayed as above 

 recommended, Uwve will be but little trouble from the disease. To be 

 effectual, however, the spraying must be very thorough and must be 

 done at the right time. Certain varieties, like Elberta, are much more 

 injured than others, owing to the peculiarities in the growth and texture 

 of the foliage, and when we have a variety that is little, if any, injured 

 by the disease, it should be preferred in planting to others that are sub- 

 ject to the disease, providing they are of an equally valuable variety. As 

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