Insect Pests and Plant Diseases. 



197 



ONION-. 



or blight as it is commonly called is a fungous disease, much 



Mildew like the blight of potatoes. Spray with Bordeaux, 5-5-50, 



beginning when the plants show three leaves. Repeat every 



ten days until crop is harvested. Add one gallon sticker (see page 202) to every 



50 gallons of the mixture. It is useless to begin spraying after the disease 



appears. See Cornell Bulletin 218. 



This can be detected by the black pustules on the leaves and 

 bulbs. It is troublesome only where onions are grown exten- 

 sively ; it may attack the seedlings killing them outright, or 

 may appear on mature bulbs in fall. Onions from sets or those 



started in clean soil and transplanted seldom suffer. Practice crop rotation. 



Drill into the rows when planting seed, 100 lbs. sulfur and 50 lbs. air-slaked lime 



mixed, to the acre. See Geneva Bulletin 182. 



Smut. 



/' .^ \ 



PEACH. 



is the most serious fungous disease of stone fruits in this state 

 Brown-rot ^iid one of the most difficult to control. Plant resistant varie- 

 ties. Prune the trees so as 



to let in sunlight and air. Thin the fruit 



well. As often as possible pick and destroy 



all rotten fruits. In the fall destroy all fruits 



remaining on the trees and on the ground. 



Spray with Bordeaux mixture before the 



buds break. Owing to danger of injuring the 



foliage later applications of copper compounds 



are not recommended. The self-boiled lime- ^ 



sulfur wash (see page 202) is now being ad- I 



vocated for the control of this and other dis- 

 eases of peach. In some experiments carried 



on by the U. S. Dept. Agr. 1907 the loss from 



this disease was reduced from j^iyo on un- 



sprayed trees to about 10% on sprayed rows. 



The new remedy is at least worth a trial. 



Spray with self-boiled lime-sulfur wash, 



10-15-50. First application when fruit is about 



the size of the end of your thumb. Repeat 



every two weeks until about two weeks be- 

 fore fruit ripens. See American Pomological 



Society Report 1907, also Report Missouri 



Horticultural Society, 1907. (Fig. 170.) 



is a fungous disease in which the leaves become swollen and 

 Leaf-curl distorted in spring and drop during June and July. Elberta is 

 an especially susceptible variety. Easily and completely con- 

 trolled by spraying the trees once, before the buds szvell with Bordeaux, 5-5-50, 



or with the lime-sulfur mixtures used for San Jose scale (see under fungicide). 



See Cornell Bulletins 164 and 180, Michigan Special Bulletins 27 and 30. Copper 



Fig. 170. Mummies on peach tree 

 the result of brown-rot. 



