134 DISEASES OF GLASSHOUSE PLANTS 
Wilt of the Tomato 
The brown rot or wilt of the tomato is a disease 
common to many members of the important plant 
group, the Solanacee. As is the case in other wilt 
diseases, the plant may wilt suddenly while the leaves 
are still green, or the leaves may turn yellow and slowly 
wither unaccompanied by wilting. Young plants show 
the former symptoms and old woody ones the latter. 
Finally the stems droop and the softer parts of the plant 
collapse and shrivel. On cutting across a diseased 
stem the vascular system is seen to be stained brown, 
and a greyish-white or brownish-white bacterial slime 
oozes out of the bundles. Unlike the cucumber wilt, 
this slime is not sticky and cannot be drawn out in 
fine strings. The brown discoloration is not confined 
entirely to the wood, but may be seen in the pith and 
sometimes in the bark. In the young, rapidly growing 
shoots the discoloration may frequently be seen through 
the more translucent tissues. Under favourable con- 
ditions the interior of the pith is reduced to a soft, watery 
mass teeming with bacteria. Generally no lesions can 
be seen on the exterior of the plant to account for the 
wilt, and it is necessary to cut open the stem. The 
disease, due to Pseudomonas solanacearum KE. F.S8. has 
been submitted to an exhaustive investigation by 
Dr. Erwin F. Smith (44), to whom we are indebted for 
the larger portion of our knowledge of bacterial diseases 
of plants. It attacks a very large number of plants, 
among which may be mentioned the potato (Solanum 
tuberosum), tobacco (Nicotiana tobacum), egg-plant (So- 
lanum melongena), black nightshade (Solanum nigrum), 
thorn apple (Datura stramonium), D. metelloides, Physalis 
crusstfolia, P. philadelphica, Petuniasp., and Nasturiivumsp. 
While there is little doubt that this disease occurs in 
England, it is probable that the temperature conditions 
are not favourable to it, and no serious case has come 
within the author’s experience. It is a serious disease, 
