34 



A little later in the spring both of the sprayed plats were plainly 

 distinguishable by the darker green color of the grass, and, in certain 

 areas, by its much larger size. This condition was quote noticeable 

 in the case of Plat 1. The lawns adjoining Plat 2 were badly infested 

 with dandelions. The previous season's experience with this par- 

 ticular plat plainly indicated that on a poor soil with a thin stand 

 of grass and many old, vigorous dandelion plants, attempts to 

 completely eradicate the pest by spraying alone might not be entirely 

 successful. It was apparent that some additional treatment, such 

 as fertilizing and reseeding, should be given the sprayed areas. It 

 was, therefore, deemed advisable to spray this plat for another 

 season and supplement spraying with the above-mentioned after- 

 treatment measures. Accordingly, the dandelions were " sprayed 

 off " at the same time that Plat 3, immediately adjoining, was 

 sprayed. By the term " sprayed oft' " it is meant that the area 

 was gone over and sprayed with iron sulfate solution only where 

 there were dandelion plants. 



PLAT 3. 



Plat 3, size 15 x 100 feet, was located so that it immediately 

 adjoined Plat 2 on the north. This plat was badly infested with 

 dandelions, and contained other weeds such as narrow-leaved plan- 

 tain, mallow, knot grass, and a small patch of wild geranium or 

 cranesbill. By combining Plats 2 and 3, an area 30 x 100 feet 

 was made available for spraying. Beginning May 7, these combined 

 plats were sprayed six times during the season with a solution con- 

 taining one and one-half pounds of iron sulfate to each gallon. Four 

 gallons of the iron sulfate solution were used at each application. 

 Shortly following the first spraying it was very noticeable that all of 

 the dandelion foliage was killed. However, there were a few plants 

 which were blossoming. The sprayed plats, with these few blossoms, 

 presented a marked contrast to the adjoining unsprayed lawns 

 which were yellow with blossoms (Plate V). An observation made 

 during the previous two seasons was again substantiated; namely, 

 that a thoro application of iron sulfate solution early in the spring, 

 when the first central buds are forming and about ready to open, 

 will entirely prevent blossoming and seed formation. 



Blackening of the grass followed every application, and the dande- 

 lion foliage was killed down. By the end of the season the plats 



