86 



One of the most serious outbreaks of the corn billbug, ^plienopli- 

 orus smlptilis, occurred in a field of timothy of three years' standing, 

 containing 35 acres, which was broken during March of the present 

 year, and on the 18th of May was planted with corn. June 6 the 

 owner came to me with specimens of this beetle, claiming that the 

 corn over the entire field had either been killed outright or hopelessly 

 ruined from attacks of this pest. A visit to the field a few days later 

 revealed a state of atfairs that had not been overdrawn by its owner, 

 with the exception of a few acres along one side, over which it was 

 represented the timothy had been killed out by some unknown cause 

 and redtop had taken its place. Here the injury had been very slight, 

 but through the remainder of the field the damage was almost total. 

 The owner had noticed that much timothy the year before whitened 

 and died, but had not learned the cause. On examination I was able 

 to find a considerable abundance of the timothj^ roots that had been 

 hollowed out, clearly by the larvte of this insect. While slight inju- 

 ries by this pest are not uncommon in Ohio, Indiana, and Illinois, I 

 never before saw so large a field of corn so thoroughly and effectually 

 destroyed by these insects. In this case the only thing it seemed pos- 

 sible to advise was the replanting of the field between the old rows, 

 leaving the remnant of the first planting to engage the insects dur- 

 ing the remainder of their life, and thus, as it was hoped, to keep 

 them away from the second planting. 



Onion thrips, Thrip^ tabaci^ were excessively abundant in some 

 localities last year. In order to learn something about the wmter 

 habit of this insect frequent visits were made to onion fields where 

 it occurred in greatest abundance during the fall of 1899. These vis- 

 its were made during the entire winter whenever the weather was 

 suitable, the result being that the insect was found in matted ])lue 

 grass and in the piles of refuse onions that had been left in the field, but 

 more especially in the matted grass along ditches. It was found to 

 winter over in all stages except that of the ^^g. A study of the vari- 

 ous onion fields in northern Ohio has shown that where the surround- 

 ings have been kept free of matted grass and largely cultivated there 

 has been the least injury from these insects. The fact that it winters 

 over in several stages of development fully explains the difficulty of 

 tracing out generations in the field. On one extensiA^e onion planta- 

 tion that has heretofore been intersected by open ditches, the banks of 

 which were grown up with blue grass, the experiment of destroying 

 this grass is being carried out. As the field is situated on muck land 

 it was, of course, impossible to burn these grassy banks over in the 

 ordinary wa}^, and therefore they were first sprayed with kerosene 

 while the ground was still frozen and then fired. Either by this 

 means or by plowing all of the grass along the banks of the ditches 

 has been destroyed, and will be prevented from growing the present 



