74 REPORT OF OFFICE OF EXPERIMENT STATIONS. 



notably tlie relation of marl}' soils and of lime to chlorosis of citrus 

 fruits, the specific iniiuence of the dirt'erent factors Avhicli go to make 

 up climate upon the health of plants and their susceptihilitj^ to dis- 

 ease, and the relation of nutrition to the latter. Naturally a quite 

 large number of plant diseases are to be made the subject of s^'ste- 

 matic study. In some cases these are new or little-understood dis- 

 eases, and in others the object is to clear up doubtful points as to the 

 organisms inducing them, their life CA^cle, relationships, susceptibility 

 to various influences, means of dissemination, etc., as a more intelli- 

 gent basis for combating them. There is opportunity for much prof- 

 itable work of this kind, for in the jjressure for results Avhich should 

 indicate remedies to be applied, it has often been impossible to go as 

 deeply into the nattire and cause of the disease and the influences 

 affecting it as is clearly desirable. 



The same is true to a considerable extent in the case of economic 

 insects and the use of sprays and other treatment. Xow that the 

 opportunity is offered, it is found desirable to go back to some of our 

 most common insect pests and study more thoroughly certain points 

 in their habits and life histories, ('n\ironmental conditions which 

 affect them, and similar matters, as bearing ultimately on methods 

 of control. The entomological work proposed is, as a whole, of high 

 order, indicating for the most part a clear conception of the features 

 of research and an appreciation of its importance as applied to that 

 branch of science. The list of i:)rojects is also relatively large and 

 varied. Several investigations have to do with the toxicity of various 

 insecticides, the manner in which they act, and similar points, as well 

 as of their physiological effects on the trees and plants receiving the 

 treatment. 



In horticulture there are seyeral physiological studies Avhich are 

 of special interest and importance, such as the causes and means of 

 control of fruit-bud formation on the apple and peach ; the pyhsiology 

 and i:)hilosophy of pruning and of grafting, both of which as planned 

 involve extensive systematic studies; the elimination of the color of 

 peach twigs by breeding to make them less susceptible to early frost; 

 the factors affecting the setting of fruit on the tomato, to determine 

 the cause of failure to set in dry localities where the i)lants bloom 

 freely, and other studies of the effect of environmental conditions. 



The subject of dry farming, in which there is such active interest 

 of late, naturally suggested a considerable number of projects. A 

 mnnber of special investigations have been undertaken, such as the 

 absolute water reciuirements of plants, the periodicity of this require- 

 ment, the water-holding capacity of the soil and factors Avhich affect 

 it, the conservation of the soil moisture, the breedina" of drouirht- 

 I'esislanl crops, and Ihc like. 



