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. If a 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 success 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, 



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