34 BOARD OF AGRICULTURE. [Pub. Doc. 



necessary for their continued protection. Every leaf that 

 is lost during the later growth of the plant means a propor- 

 tional reduction of the starch-making capacit}^ of the plant, 

 and thus a direct reduction of the crop. If we realize this, 

 and recall the consequence of the attacks of insects and 

 blights upon the foliage of the average potato field immedi- 

 atel}^ following the blossoming period, we can readily under- 

 stand why the average yields of potatoes in Massachusetts 

 and Vermont fall below 100 bushels per acre. From one- 

 half to two-thirds of the possible crop is sacrificed, and 

 chiefly because the leaves are not protected against these 

 enemies. 



Moreover, this loss is entirely unnecessary to-day. A 

 decade or so ago it was excusable, for Paris green and plas- 

 ter, which w^ere the only remedies intelligently used then, 

 do not suflSce to furnish such protection in the later life of 

 the plant. But repeated trials, extending now at the Ver- 

 mont station through some fifteen successive years, have 

 shown that practically j^erfect protection against all these 

 maladies, insects and blights alike, is secured by the proper 

 use of Bordeaux mixture, either alone or combined with 

 arsenites. 



As practical evidence of this, your attention is invited to 

 the following tabular summar}^ of the results obtained from 

 spraying the later main crop potatoes at the Vermont Exper- 

 iment Station during this period. Of course climatic and 

 varietal conditions influence the matter of total gain, and 

 these results might not be duplicated in Massachusetts. But 

 the conclusion must remain the same, — that you cannot 

 secure a perfect development of the potato plant unless you 

 conserve the water and preserve the leaf unmutilated to ma- 

 turity ; and this latter result can only be secured by proper 

 spraying in the later stages of the life of the plant. 



