8 FARMERS' BULLETIN 826. 



a heavy storm the previous season from a larkspur-infested bench 

 located above the plot. When examined on September 27, 1916, no 

 plants could be found on Plots 1 or 2, and only three seedlings on Plot 

 3. It is believed that the eradication is now complete on these areas. 



It was much easier to grub out the plants on Plots 1 and 2, where 

 the soil was loose and sandy and contained little rock or gravel, than 

 on Plot 3, which had a moist, gravelly soil. Furthermore, the soil 

 on Plots 1 and 2 becomes dry during the latter part of the season, 

 while on Plot 3 it remains moist. This is a factor to be taken into 

 account, as the grubbed plants are more likely to survive where the 

 soil is moist than where it is dry. 



The original grubbing of Plots 1, 2, and 3 was done in August and 

 September, when the vegetation was mature, which made it difficult 

 to find all of the plants. Besides, the first regrubbing was done 

 toward the close of the season of 1914, when the skunk cabbage and 

 other thrifty, leafy species growing on the plots had fallen and cov- 

 ered a large number of the smaller larkspur plants. The large number 

 of plants still on the plots, especially Plot 3, in 1915, is attributed to 

 these unfavorable conditions under which the grubbing w T as done. 



The eradication work on the plots grubbed in 1915, except Plot 

 2A, was more effective than on those grubbed in 1913. The large 



FIG. 3. Tall larkspur growing on Stanislaus National Forest on area adjoining ex- 

 perimental Plot No. 3. Approximately 3,500 plants per acre. Cost of eradication 

 by grubbing, $12 per acre. 



