June, '15] 



LEONARD: CONTROL OF TARNISHED PLANT-BUG 



361 



FURTHER EXPERIMENTS IN THE CONTROL OF THE TAR- 

 NISHED PLANT-BUG 



Lygus pratensis Linn. 

 By M. D. Leonard, Ithaca, N. Y J 



In June, 1914, Professor C. R. Crosby^ and the writer published a 

 bulletin on the tarnished plant-bug, in which were recorded the results, 

 all negative in character, of experiments performed in a nursery near 

 Rochester, N. Y., where the insect has been very destructive to peach 

 stock. The conclusion was reached b}^ the writers that: 



''The foregoing experiments show that it is doubtful whether the 

 injuries to peach nursery stock by the tarnished plant-bug can ever be 

 prevented b}^ the use of deterrents, or whether the adult bugs can be 

 killed under actual field conditions by any contact insecticide now at 

 our disposal. Catching the bugs by mechanical means has thus far 

 been unsuccessful. Furthermore, either catching or killing the bugs 

 in the nurserv would be of very little value in protecting the trees, 

 because of the invasion of the blocks by swarms of bugs from adjoining 

 fields. It would seem that the only feasible means of preventing 

 the injury to the trees would be either by excluding the adults 

 from the nursery blocks by a wire screen fence, or by enclosing the tips 

 of the terminals in bags during the period in which most of the injury 

 is inflicted. It might also be possible to prevent some of the loss from 

 this cause by assisting the trees to outgrow the injury by proper 

 pruning and cultural methods." (Crosby & Leonard, 1914:497.) 



The suggestions for future experimental work contained in the above 

 statement were folloAved out in the same nursery during the past sum- 

 mer and it is the results of these experiments which are presented in 

 the present paper. 



Fencing 



In order to thoroughly test the efficiency of excluding tarnished 

 plant-bugs from the nursery blocks by means of a fence, an experiment 

 was carried out using wire screen cloth on a much larger scale than that 

 of the previous summer. It had been our experience during the 

 seasons of 1912 and 1913 that the insects did not appear on the peach 

 stock in any considerable numbers till about June 23, and that then, 



> I wish to express my thanks to Professor Crosby, under whose direction the work 

 outUned on this paper was done, for assistance in planning and carrying out the ex- 

 periments. 



