PHRAGMITES 37 



late summer. The soil sterilant, erbon, was successful at 40 

 pounds active per acre, and monuron at the rate of 40 pounds 

 active per acre was fairly effective if disked into the ground. 

 Operational programs using dalapon or mixtures of dalapon and 

 ATA applied in approximately 400 gallons of water per acre by 

 power sprayers are now being conducted in New York, New Jer- 

 sey, and Delaware. 



HERBICIDES ON FLOODED OR CONTINUOUSLY WET SITES 



Dalapon alone has proved unsatisfactory in flooded habitat, 

 regardless of poundage used or stage of plant growth. However, 

 treatment with dalapon at 25 to 35 pounds combined with ATA 

 at 8 to 10 pounds gave good results when done during the vulner- 

 able stage. ATA alone was sometimes successful when used at 

 20 to 24 pounds in the vulnerable period. A recent airplane treat- 

 ment with a mixture of dalapon and ATA in 15 to 20 gallons of 

 water and using triethanolamine as dispersion agent has given 

 encouraging indications. This method of control can have special 

 importance as a means of reducing or eliminating phragmites in 

 comparatively inaccessible flooded areas. 



MECHANICAL METHODS 



A mowing of phragmites in August 1951, followed by burning 

 and two diskings that fall, resulted in limited spring survival rang- 

 ing from 5% to 20% at the Fish and Wildlife Service Killcohook 

 Refuge near Salem, N. J. The plants were growing on a fill depos- 

 ited from dredgings of the Delaware River. After a third disking, 

 cultivated crops were planted. In New Jersey mosquito-control 

 programs it has been found that crushing and crimping by tractor 

 wheels equipped with angle-iron cleats is more destructive to 

 phragmites and other marsh plants than mowing. 



At the Delta Duck Station in Manitoba, 3 years of summer mow- 

 ing have been reported as effective in transforming phragmites 

 beds into meadows on peaty soil which becomes dry in late summer. 

 However, mowing on wet, nonpeaty soils elsewhere has given little 

 or no control. Underwater cutting on small plots during the flow- 

 ering season in Delaware and Maryland studies was effective, but 

 the method has limited practicability. 



BURNING 



Burning appears to injure phragmites to only a minor extent 

 except in localities where the plants are growing on peat. At the 

 Delta Duck Station in Manitoba, late-summer burning not only 



