56 HATCH EXPERIMENT STATION. [Jan. 



ence with it, although, as with every other disease, some 

 have been much more affected than others. We have 

 known several instances during the season where extensive 

 growers have lost practically their whole crop, and, as a 

 consequence, have become much discouraged with lettuce 

 growing. Inasmuch as the general characteristics of this 

 disease were given in the ninth annual report, it is not nec- 

 essary to enter upon any minute description here. Suffice 

 it to say that the disease makes its appearance in the stem, 

 close to the surface of the ground, where the tissue becomes 

 slimy and soft, and eventually the whole stem at this point 

 disintegrates and collapses. This occurs most frequently 

 just as the plants reach maturity. 



The fungus causing this disease is well known to all o-reen- 

 house men. The "damping fungus" (Botrytis), which 

 causes the drop, often gives rise to disastrous effects on 

 begonia and other cuttings in the propagating pit. The 

 fungus, however, as it appears upon the lettuce, presents 

 some aspects which are different from its appearance upon 

 cuttings, and reaches a more advanced stage of develop- 

 ment. Our present knowledge in this direction possesses 

 more of a technical than practical interest, although an un- 

 derstanding of the complete life history of the fungus will, 

 no doubt, lend much aid to its rational treatment. 



The natural conditions governing the development of the 

 organism appear to be similar to those of most organisms, 

 — that is, it requires the presence of oxygen. It is well 

 known that almost any object when driven into the ground 

 will undergo disintegration much more rapidly at the sur- 

 face of the soil, for here the conditions of moisture, etc., 

 are most favorable for the organisms producing disintegra- 

 tion. And so it is with the "drop" fungus; it finds just 

 the conditions at the surface of the soil, under the moist, 

 shady leaves of the mature lettuce plants, for its destructive 

 work. 



Our experiments upon the control of this fungus are by 

 no means complete, but it will not be out of place here to 

 offer some suggestions in regard to its general habits and 

 the methods of treatment which may be tried. Probably 



