DISEASES OF HOUSE TOMATOES. 



177 



it is almost impossible to thoroughly eradicate them. 



The root-gall, caused by a nematode worm (Hetero 

 dera radicico/a), often does great damage in tomato 

 houses (Fig. 29, page 87). The treatment is to use only 

 soil which has been thoroughly frozen, as explained on 

 page 85. After cleaning the benches of infected soil, it is 

 well to wash them in strong lye.* 



Diseases. We have had serious difficulty with dis- 

 eases. The rot of the fruit has been one of the worst, 

 and this has appeared chiefly upon the first fruits. This 

 disease appears to originate as a physiological trouble (not 

 from the attacks of fungi, as commonly supposed), and the 

 proper treatment is to keep the house dry and sweet. 



The t o- 

 mato blight 

 or rust ( Cla- 

 dosporium 

 fulvuni) i s 

 frequent i n 

 tomato 

 houses, par- 

 ticularly to- 

 wards 

 spring. Fig. 

 60 shows the 

 patches o f 



Tomato blight (Cladosporiumfulvum). 



the fungus at the points marked a. It causes rusty patches 

 upon the leaf, and the foliage soon shrivels and dies. It 

 is very likely that the disease may be brought into the 

 house in soil upon which diseased plants have been 

 grown. If it appears, the plants should be thoroughly 

 sprayed at once with Bordeaux mixture. 



The dropsy or oedema of the tomato is a physiologi- 

 cal disease produced in house tomatoes by a too succu- 



* For a fuller account of the root-gall on house tomatoes, see Bulle- 

 tin 43, Cornell Exp. Sta. (Sept. 1892). 



