14 



gram according to how tight the house is. Use the corresponding 

 proportions of sulfuric acid and water, fumigate at night for three 

 hours, and then ventilate. Repeat the fumigation two weeks later 

 and a third time two weeks later. This treatment must be used with 

 caution, as tender plants may under exceptional conditions be some- 

 what injured. 



Eel Worms, 



For eel worms on cucumbers, melons, violets, tomatoes, roses, etc. 

 change the soil, or freeze or sterilize it. Excess of water in soil or 

 drenching it for a few days has a marked repressive effect on eel- 

 worms. Avoid manure containing greenhouse refuse or that con- 

 taminated with eel worms. 



Mildews and Leaf Spots. 



Mildews and leaf spots can be controlled by paying careful atten- 

 tion to details of heat, light, ventilation and moisture. Powdery 

 mildew of cucumbers is brought on by lack of light and too much 

 moisture in the atmosphere during the short days in winter. Downy 

 mildew of cucumbers is a summer trouble and does not survive the 

 winter in the greenhouse. It affects both out-door and indoor crops 

 about the middle of x\ugust in this State. In order to avoid downy 

 mildew in the greenhouse, crops should not be planted until Septem- 

 ber or October, and what holds true of downy mildew on cucumbers 

 is also applicable to outbreaks of bacterial wilt on greenhouse 

 cucumbers. Anthracnose occurs usually about the middle of March 

 on greenhouse cucumbers and is induced by too much moisture in the 

 atmosphere and lack of light and ventilation. If cucumbers are 

 affected with anthracnose, apply sulfur and oil to the pipes. 



Leaf blight of tomatoes (scab) is caused by a too moist atmosphere 

 and lack of light. The leaf spot of the tomato (Cylindrosporium) 

 results from crowding and shading. To prevent the leaf blight, 

 avoid excessive moisture, and give sufficient light and ventilation. 

 If present, paint the pipes with sulfur. For the leaf spot, (Cylin- 

 drosporium), prevent crowding of the plants and allow access of air 

 and sunshine. For chrysanthemum leaf spots, (Cylindrosporium), 

 give the same treatment as for tomato leaf spot. For rose mildew 

 evaporate sulfur or paint the pipes occasionally with a mixture of 

 sulfur and oil. 



