WEED POISONS 



225 



If salt is used, it should be scattered freely in the dry form. Caution is 

 necessary where it is liable to be washed on to lawns, lest it damage 

 the grass borders. Carbolic acid or arsenical poisons are preferable, 

 being both less liable to wash and more enduring in their action. One 

 quart of crude carbolic acid in eight gallons of water, or one pound of 

 either arsenical compound mentioned above in a like amount of water, 

 will suffice to cover a square rod or more of surface; and one or at 

 most two applications per year will be sufficient, 



Walks should be so made that weeds cannot grow in them. This 

 can be done by making a deep stone foundation and filling between the 

 stones with cinders, coal ashes, or other similar material. 



List of weeds that may be controlled by means of chemical sprays. 



The following named weeds may be eradicated or largely subdued in 

 cereal grain fields through the use of chemical sprays: False-flax, 

 worm-seed mustard, tumbling mustard, common wild mustard, 

 Shepherd's purse, pepper-grass, ball-mustard, corn cockle, chickweed, 

 dandelion, Canada thistle, bindweed, plantain, rough pigweed, king- 

 head, Red River weed, ragweed, cocklebur. 



Weeds on which field spraying methods as- now in use are not effective. 



The following weeds are not effectively controlled by chemical sprays 

 as now used : Hare's ear mustard, French weed, pink cockle, perennial 

 sow-thistle, lamb's-quarters, pigeon-grass, wild oats, chess, quack- 

 grass, sweet-grass, or holy-grass, and wild barley. 



Results of spraying with iron sulfatefor the control of weeds (Rhode Island Sta.) 



