332 JOURNAL OF ECONO^IIC ENTOMOLOGY [Vol. 5 



The injury as observed on May 21st, was so clearly caused by Lygus 

 pratensis that cages made of cheese cloth stretched over wooden frames 

 were placed over the trees in the nursery rows and the following obser- 

 vations made: 



Cage No. 1. May 23, 3 p. m. Cage placed over three plants apparently free 

 from injury. Nine specimens of L. pratensis were placed in cage. 



May 24, 4 p. m. Terminal buds on all three plants wilted and show same injmy 

 as newly affected plants on outside. 



May 25. Terminal buds of five lateral branches on tree No. 1; four on tree No. 

 2, and five on tree No. 3, affected. 



May 26. Terminal buds of both main and lateral shoot.s have turned black. 



May 27. All terminals affected. Injury identical with that of plants throughout 

 nursery. 



Cage No. 2. May 23, 3.15 p. m. cage placed over six plants which showed no 

 injury. All L. pratensis excluded. 



May 24. No injury apparent. 



May 25. " " 



May 27. " " 



Cage No. 3. May 23, cage placed over nine plants; five of the nine plants plainly 

 affected; four not affected. Dead terminal buds of affected plants carefully cut 

 away. All insects excluded. 



May 24. No new development of Stop-back. 



May 25. No change. 



May 27. Non-affected plants still unaffected and affected plants from which injured 

 terminals were cut, show no further injury. 



Cage No. 4- May 23, cage placed over seven plants; four affected, three not 

 affected, all insects excluded and affected terminals not removed. 



May 24. No change. 



May 25. " " 



May 27. No further spread of injury on affected plants, and non-affected plants still 

 uninjured. 



Cage No. 5. May 25. Two very healthy non-affected plants caged and six bugs 

 placed in cage. Tree No. 1 has main and 7 lateral shoots. Tree No. 2 has main and 

 16 lateral shoots. 



May 27. On tree No. 1, terminal buds of main and six lateral shoots affected. 

 On tree No. 2, terminal buds of main and twelve lateral shoots affected. 



May 28. On both trees terminal buds of all shoots affected, and turning black. 



Cage No. 7. May 28, cage placed over six plants, three affected, three not affected. 

 Insects excluded. 



June 1st. No further spread of injury, non-affected trees growing rapidly, with 

 terminal shoots crowding against top of cage. 



Cage No. 8. May 28. Cage placed over six non-affected trees and nine bugs added. 



June 1st. AU terminal and many lateral buds of both main and lateral shoots in- 

 jured, showing characteristic appearance of Stop-back. 



Although Lygus pratensis was disappearing from peach trees in 

 Eastern Virginia by June 1st, it was found to be increasing in abundance 

 on peach nursery stock at Blacksburg, where the season, due to an 

 elevation of 2200 feet, is fully three weeks later. But few specimens 

 of pratensis could be found at Blacksburg on May 24th. To produce 



