214 HORTICULTURE FOR SCHOOLS 



321. Insect pests and diseases. The currant-worm, 

 currant-aphis, and currant-borer are common pests. The 

 first may be destroyed by arsenical sprays (one pound pow- 

 der, or two pounds paste of lead arsenate to fifty gallons of 

 water) applied at the proper times to kill the larvae. Nicotine- 

 sulfate spray is used to kill the currant-aphis. Borers are 

 difficult to reach. The only practical way is to cut out and 

 burn the infected canes. The San Jose scale sometimes is 

 troublesome on both currants and gooseberries. The remedy 

 is lime-sulfur spray of winter strength, or oil emulsions ap- 

 plied while the plants are dormant. 



Anthracnose is a common disease of the currant and goose- 

 berry, as well as of other bush-fruits. It is a fungus, which 

 first appears as brown spots on the upper surface of the leaves, 

 and later makes the leaves turn yellow and drop. The disease 

 attacks the canes and fruits. A spray of lime-sulfur applied 

 while the plant is dormant is helpful. Applications of bor- 

 deaux mixture are made during the growing season. The 

 application of lime-sulfur or bordeaux is useful in controlling 

 other leaf-spot diseases. 



Mildew, another common disease, can be controlled by 

 application of sulfur. 



Cane-wilt in the currant is rather serious as it is difficult 

 to control. The disease enters at the buds and works down 

 the stem, causing the fruit and leaves to die. The best 

 treatment is to cut out and burn diseased canes. Bordeaux 

 mixture applied in the growing season is recommended. 



In white pine blister-rust the fungus first starts on currant 

 or gooseberry leaves, and then attacks pines. It finally kills 

 the trees. The disease cannot be spread among the pines 

 without the aid of currant or gooseberry bushes as a 

 host plant. In localities where the disease is present, no 

 attempt should be made to grow currants or gooseberries 

 within a considerable distance of white pine trees, and all 

 wild gooseberry or currant bushes should be destroyed. 



