CHAPTER VIII 
DISEASES AND THEIR CONTROL 
An important factor—Anyone who engages in vege- 
table forcing will be compelled to give consideration to 
the disease factor. Ifa new house is constructed and the 
utmost care exercised in the selection of soil and in the 
management of the crops, diseases may not appear for 
several years. But they will ultimately be found and if 
not checked they will soon cause serious losses. . 
If the grower is to cope with the disease factor in a 
satisfactory manner, he should be familiar with the para- 
sites which are most likely to appear. He should know 
their life histories and how the crops become infected. 
A knowledge of the conditions, which are most favorable 
to the development and dissemination of the diseases is 
highly important. The several means of prevention and 
control should be studied and the utmost care exercised 
in the selection and execution of the plans which are 
most promising. In many instances stccess depends 
more upon timeliness and thoroughness than upon any 
particular plan. 
Sanitation —All that has been said in Chapter VII per- 
taining to greenhouse sanitation, and its importance in 
avoiding insect depredations, applies even more directly 
to the disease problem. The utmost cleanliness at all 
times in and about the greenhouses and service rooms 
will be valuable as a preventive measure. The use of dis- 
infectants during the summer or at other times when 
there are no crops in the beds will prove effective in 
guarding against possible attacks. There are times when 
it pays to disinfect pots, flats, dibbers and all soil tillage 
tools used in the beds. Refuse and all old plants should 
be promptly removed after the harvesting of every crop, 
127 
