228 WEEDS 



nozzles. The treatment is most effectively made when the grain is 

 3 to 6 inches tall, since at this stage the large charlock leaves spreading 

 above the grain are easily covered by the spray. About one barrel of 

 the solution (30 to 50 gallons) suffices to cover an acre and destroy the 

 charlock, and this amount causes little or no damage to the grain. 

 This same treatment is reported to be more or less effective against a 

 variety of other common grain-field weeds. The wild turnip (Brassica 

 campestris) and some allied cruciferous weeds are less easily killed 

 because the spray does not adhere to their smooth leaves. 



When to apply weed sprays (Ohio Station). 



In practice, the time of applying sprays needs to be adjusted to the 

 condition of the growing crop, and the relative development of the weeds 

 to be killed. It seems probable that very early spraying will be less 

 effective than spraying after the weeds have developed a fair supply of 

 leaves. The first spraying should be made not later than the beginning 

 of bloom. Repeated applications need to be made as often as a new 

 supply of leaves is developed, provided the condition of t}ie host crop 

 permits this. In grain-fields, the best results will be obtained on prac- 

 tically all weeds, when only a single spraying is to be made, to apply 

 the spray just as the crop is ready to occupy the land. With mustards, 

 this will find some already in bloom. With ragweed, it is best to spray 

 before the stems of the plants become hardened. With other weeds, of 

 which these two are the type, as well as with these, it is often profitable 

 to make an extra earlier spraying than that designated. For perennial 

 sow-thistle, wild lettuce, and orange hawkweed, the spraying in grain- 

 fields should precede the blooming of the plants, and in cases of bad 

 infestation with perennial sow-thistle or the golden hawkweed, two 

 sprayings should be made before the grain occupies the land. It is 

 not clear just what can be done in the handling of bindweeds in grain- 

 fields, but similar principles will apply. For spraying in timothy or 

 other grass meadows to kill white-top, yarrow, self-heal, ox-eye daisy, 

 and a number of meadow weeds, the principle is similar to that stated 

 for grain-fields, namely, to spray thoroughly just before the grass begins 

 heading out. This will be during late May and early June for Ohio. 



In spraying pastures to check weeds, the maximum returns will 

 usually come from a beginning application in late June or early July 

 before many weeds are coming to bloom. After the initial application, 



