REPORT OF THE COMMISSIONER OF AGRICULTURE. 29 



These have all received as mnch. attention as the time and means 

 at command would allow. Concerning all the diseases here named 

 there remains more to be learned than is now known. The life his- 

 tory of these disease-producing pests has for the greater part yet to 

 be traced. Careful and long-continued observations, both in the field 

 and laboratory, will be required to accomplish this, but such work is 

 necessary if we wish to make intelligent application of remedies to 

 combat these evils. We have to learn how these fungi are distrib- 

 uted, how they come upon or enter the i^lants they infest, what phases 

 of development they pass through — phases often more complicated 

 than the transformation of insects and far more difficult to trace; 

 and, finally, how they maintain their existence during the season of 

 winter. This work has been accomplished in only a very few cases. 



From results obtained, however, and from other sources of informa- 

 tion received during the administration of this branch of the Depart- 

 ment, we may safely assume that the value of the corn and wheat 

 annually destroyed in this country by diseases induced by fungi is not 

 less than $200,000,000. The potato rot, so destructive in wet seasons, 

 caused a loss in 1885, in the chief potato-growing States, of from 10 

 to 40 per cent, of the entire crop. The grape vine is particularly sub- 

 ject to the attacks of fungi. Scientists have described over 200 spe- 

 cies found upon this plant alone. Some of these, as the mildew and 

 black rot, are particularly destructive, so much so that grape-grow- 

 ing has ceased to be profitable in many localities once noted for their 

 production of this fruit, and hundreds of acres of vineyards have 

 been rooted out simply because of a lack of information respecting 

 the nature and habits of these parasites and the means to be employed 

 in preventing their ravages. The rust of the cotton plant is another 

 fungous disease that causes incalculable loss to planters of the cot- 

 ton-growing States. The orange interests in Florida are seriously 

 threatened by the fungi that attack this tree, over 100 species of 

 which have been figured and described by European mycologists. 

 The apple tree has its peculiar and destructive parasites, and so have 

 the pear, the peach, the plum, the quince ; and so also have the small 

 fruits, as the raspberry, blackberry, currant, and strawberry ; nor 

 are our garden vegetables, nor the plants we cultivate for ornament 

 or shade, more exempt than others from the ravages of these diseases. 



While this branch of investigation could not be prosecuted more 

 than superficially, owing to the want of funds, yet it is gratifying to 

 note that an encouraging result has followed. 



During the early part of the present season circulars were distrib- 

 uted to all parts of the country, for the purpose of gaining a more 

 exact knowledge of the range and extent of injury occasioned by the 

 fungous diseases of the grape, and material was collected and plates 

 of illustrations prepared for a special report on this interesting and 

 important subject. Circulars were also sent out proposing for trial 



