160 HATCH EXPERIMENT STATION. [Jan. 



We visited several cucumber houses this last spring in 

 which the plants were subject to wilt, and observed a num- 

 ber of houses which contained badly affected plants. In those 

 houses running north and south, the vines in the morning 

 on the east side, which are subject to the sun's rays, would 

 be entirely wilted ; while those on the west side, and away 

 from the sun's rays, were not in the least affected. In the 

 afternoon, when the sun had reached the west side of the 

 house, the vines would then become badly wilted, and those 

 on the east side, when no longer exposed to the direct rays 

 of the sun, would commence slowly to recover. The cause 

 of the wilt in every instance was not difficult to understand ; 

 but, as a necessary precaution against drawing deductions 

 too hastily, we examined every portion of a number of plants 

 very carefully, to convince ourselves that there was no other 

 cause than that which we had in mind; It is well known 

 that there is a bacterial disease of cucumbers that gives 

 rise to a wilting of the leaves, but careful examination of 

 the tissues shows nothing in the nature of bacteria to be 

 present. 



At about the same time we visited several other cucumber 

 growers in other sections of the State, and had an oppor- 

 tunity of examining many vines in about the same stage of 

 development. In some instances the identical varieties of 

 cucumbers were grown, but in the majority of cases another 

 variety was used, namely, the White Spine, and in all cases 

 the methods of cultivation were radically different, and the 

 wilting of the vines was something unknown to them. Long 

 before we visited the region of wilt a number of letters of 

 inquiry had shown us that the disease in question was local, 

 and the majority of growers had never had trouble with it. 



The cause is not due to any organism, whether insect or 

 fungous, but to extremely abnormal conditions of the plants, 

 brought about by irrational methods of cultivation that give 

 rise to defective transpiration, or, in other words, to the 

 giving off of water from the leaves. The activity of tran- 

 spiration is affected by various causes. It is well known that 

 the stomata or breathing pores of the leaf are open during 

 sunshine and closed during darkness, and that the greatest 



