19 



is about the same size as the striped cucumber beetle, and attacks the 

 same plant. 



Remedies : Same as for Striped Cucumber Beetle. 



(Fungi). 



Downy Mildew (Plasmopara cubensis) : This disease is also com- 

 mon on musk melons. Large yellow spots appear on the leaves, and 

 cause them to shrivel up. The disease is most serious during muggy 

 weather. The spores are borne on peculiar stalks on the under side of 

 the leaf, and are borne to unaffected leaves by wind. As the body of the 

 fungus lives within the tissues of the leaf, it is impossible to effect a cure 

 after the leaf is inoculated. 



Treatment : Spray with Bordeaux every ten days after the middle 

 of July, giving attention to the under sides of the leaves. This treatment 

 will at least keep the fungus in check. 



Wilt (Bacillus tracheiphilus) : is a bacterial disease of cucumber, 

 squash, and pumpkin. The leaves of affected vines suddenly wilt, and in 

 a few days shrivel and turn brown. The disease progresses in the vine 

 in the direction of growth, and kills the leaves in succession. 



Lettuce. 



(Fungi). 



Downy Mildew (Bremia lactucce) : Greyish, mouldy areas occur on 

 the under side of the diseased leaves, which show yellowish-brown patches. 

 This fungus thrives well in moist situations. The spores are borne on 

 peculiar branching stalks, constituting the mould. 



Treatment: Care in draining, watering, and ventilating will do 



much to control this disease. 



The Grey Mould (Botrytis vulgaris) : This is very common in green- 

 houses. It causes a rotting of the leaves, upon which it appears as a 

 greyish mould. In rotting leaves are found also minute black bodies 

 (sclerotia), which carry a leaf-rot disease, (Sclerotinia libertiana) called 

 the Drop,over from one crop to another. It may be that the Gray Mould 

 is the summer stage of the Drop disease. 



Treatment : Care in draining and ventilation ; sterilize the soil with 

 hot water, or add a coating of sterilized sand or earth ; apply coatings of 

 coal ashes, or sulphur and charcoal. 



Onion. 



(Insects). 



Onion-Maggot (Phorbia ceparum) : The adult is a small fly, about 



half the size of the common house fly. The eggs are laid on the young 



plants in early spring, and hatch in a few days, when the larvae burrow 



into the bulbs. When full-grown, they pass into the soil and become 



