444 BOARD OF AGRK ULTURE. [Pub. Doc. 



from spraying cx})eriiiients are not, however, entirely satis- 

 factory in all cases, })artly, no doubt, from the fact that a 

 number of diU'erent organisms have been involved in fruit 

 rots, some of which would appear to be more difficult to 

 control than others. For jjreenhouse culture we recom- 

 mend, as a partial means of prevention, the keeping of mois- 

 ture from the fruit or foliage as much as })ossible ; for in 

 our experiments we have found 83 per cent less fruit rot 

 Avhere we did not practise syringing the plants than where 

 we did sj'ringe. 



There are other troublesome diseases of the tomato, 

 apparently more common in the south than in the north. 

 Among these may be mentioned leaf blights {8ep(oria, Al- 

 ternaria), tomato wilts {^Fusarium, Bacillus)^ etc. There 

 is also a functional disorder occasionally met with in green- 

 house tomatoes, known as (Edema, or dropsy. This gives 

 rise to a curling and ru})turing of the cells of the leaf. 

 (EdeyrM is caused by excessive absorption of water from the 

 soil, brought about by too high soil temperatures. The 

 jjeculiar crinkling, curling and high coloration of tomato 

 leaves, connnon to greenhouse culture, especially when 

 grown in a rich soil and when severe pruning has been prac- 

 tised, must not be confounded with the dropsy. The latter 

 peculiarity is a form of indigestion, and the same peculiar 

 curling of leaves may be obserA ed on young stump shoots 

 of forest trees which have been cut. Unpruned tomato 

 plants, grown under exactly similar conditions, seldom, if 

 ever, exhibit these peculiar symptoms. 



Cucumbers. 

 The diseases affectino- oreenhousc cucumbers arc referred 

 to more extensively in Bulletin No. 87, issued by the Hatch 

 Experiment Station. 



Downy Mildew (Plasviopara Cuhensis, (B. tSc C.) Hum- 

 phrey). 



This mildew can be readily distinguished hy the typical 

 yellowish, angular spots on the leaves (see Fig. o). It is 

 likely to occur on greenhouse crops from August to Novem- 



