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The Hollyhock Rust. 



6H3. SiE, — I have a great collection of double hollyhocks, and some disease or insect 

 is spoiling all the leaves. They blister on the back, and the leaves spot and wither, begin- 

 ning at the bottom and upward, till near tlie flower buds. Please tell me the cause and cure. 



D. Campbell, London South, Out. 



Reply by Prof. John Craig. 



The hollyhock leaf which you forwarded me from Mr. D. Campbell, is 

 affected with a fungous disease known as " Hollyhock rust," technically called 

 Puccinia malvacearum, Mont. This rust attacks most forms of the cultivated 

 hollyhock, causing the leaves to shrivel and fall off. I do not know of any 

 effectual remedy which can be applied. The best practice would be to take off 

 and destroy, with the fallen leaves, all the affected foliage. If the plants are 

 severely attacked it would be well to root them up and destroy them entirely. 



Fruitless Cherry Trees. 



663. Sir, — I have some cherry trees eight years old which have not yet yielded a 

 good crop of fruit. Though there has been plenty of bloom, the fruit after setting dropped 

 off, when about the size of a pea. On one tree I noticed a number of insects, similar to 

 ants, but about three-eighths of an inch long, and the body partly black and partly red- 

 dish brown. Later I noticed that the leaves began to curl, and under them were many 

 small black insects. 



An Inquirer, Vancouver, B.C. 



Cherry trees seem somewhat susceptible to injury by sudden changes of 

 weather. The dropping off of the young fruit is a frequent occurrence with us 

 in Ontario, owing, no doubt, to the somewhat unfavorable conditions during the 

 time of blossoming, which prevents proper fertilization. This has be6n especially 

 noticeable during the present season. The long, cold, wet weather during 

 blossoming was succeeded by a very hot and* protracted drouth, resulting in the 

 blighting of the young fruit, which was strewed on the ground in immense 

 quantities, and left but a small crop to be harvested, even on our older and more 

 vigorous trees. 



The insects of which our correspondent speaks are probably the larva of 

 one of the lady bugs. This insect is a friend of the fruit grower and should not 

 be destroyed on any account. He visits the trees to devour those very trouble- 

 some black insects which he speaks of as being found on the under side of the 

 leaves in such large quantities, and which are known as aphides. If the 

 larvjE of the lady bug are sufficiently numerous they will entirely rid the trees of 

 the aphides, but otherwise it will be necessary to spray with kerosene emulsion 



(30I) 



