294 STATE BOARD OF AGRICULTURE. 



and there should be one or two Vermorel nozzles so arranged as to spray 

 each of four rows. 



If this outfit is used the driver will have to operate the pump and 

 when large areas are to be sprayed it will be advisable to use a traction 

 outfit, of which several forms are manufactured. They are made espec- 

 ially for spraying potatoes and similar crops and are so arranged that 

 the power for operating the pump is taken from the wheel of the cart 

 by means of a chain and sprocket wheels. 



GRAPE DISEASES AND THEIR TREATMENT. 



The weather for the last two or three years has been very favorable 

 for the development of the mildew and rot of the grape. Like the potato 

 diseases, these are not generally prevalent unless climatic conditions 

 are favorable for them. The so-called black rot of the grape is espe- 

 cially troublesome in years when the weather is wet and muggy and 

 it also is most likely to occur during the months of July and August 

 and the first half of September. 



Like other fungous diseases the spores do not germinate unless the 

 fruit and leaves are covered with moisture from rain or dew, and this 

 condition is more likely to be met with in low lands and on north slopes 

 where the circulation of air is restricted and where the drying etfect 

 of the sun is less than upon hillsides, and especially if they slope to the 

 south. 



The rot of the grape shows in numerous brown circular spots upon 

 the foliage, in the middle of which there are minute black dots. Upon 

 the fruit, it first appears as circular olive green spots a little larger 

 than the head of a pin. These soon turn brown and enlarge until the 

 entire grape is in'fected. At this stage it is of a brown color and, hence, 

 the disease is often confused with the brown rot which is a name prop- 

 erly given to the rot caused by downy mildew. The diseased grapes soon 

 begin to shrivel and in a few weeks the skin is drawn closely down 

 around the seeds. By that time it has become of a dark brown, almost 

 black color, from which appearance the correct name of the disease, 

 black rot, is taken. About the time the shriveling begins, numerous 

 black dots can be found upon the grape at the point where the rot started 

 and these gradually spread over the entire surface. As indicated above, 

 although the disease is of a fungous nature it is not troublesome except 

 when the weather conditions are favorable. During the ten years pre- 

 vious to 1004 the months of August and September were comparatively 

 dry and little harm was done. In that year the disease did consider- 

 able harm in Berrien and Van Buren counties and in 1005 and 1006 it 

 spread to other vinevards and in most cases was even more severe than 

 in 1904. 



This disease has practically put an end to grape growing in many 

 portions of Missouri, Illinois, Indiana and Ohio, where the soil and 

 climate seem even more favorable than that of ]\Ii(>higan for the devel- 

 opment of the black rot. It was found, however, that by the early and 

 frequent use of Bordeaux mixture the disease could, for the most part, 

 be held in check. In a general way, the treatment is the same as is 

 recommended for the rot and blight of the potato. It is advisable, how- 

 ever, to make one application of Bordeaux mixture, or of copper sul- 



