WILLOWS 59 



of grouse, feed extensively on the bark, twigs, and buds. In re- 

 gions of the West where cover is scarce, willows sometimes provide 

 useful protective or nesting cover for game birds. Locally, wil- 

 lows have been used for controlling soil erosion on stream banks. 

 Their light, pliable wood has some value for cooperage and other 

 purposes. On the other hand, besides crowding out duck-food 

 plants in waterfowl areas and necessitating the spraying of sev- 

 eral hundred acres of willows on Federal refuges each year, wil- 

 lows cause serious water losses on margins of western reservoirs 

 and irrigation canals. 



CONTROL 



Herbicides, particularly 2,4-D formulations, are the most prac- 

 tical means of destroying willows. On black willow {S. nigra), 

 control ranging from 95% to 100% may result from a late-summer 

 foliage spraying with dosages of 4 pounds 2,4-D to 100 gallons 

 of water. Effectiveness of treatment varies with the species, and 

 in time it may be possible to give specific recommendations for 

 each of the more important kinds of willows. Glossy-leaved spe- 

 cies are likely to require a "sticker" in the spray. Injection treat- 

 ments (into cuts on trunks) and basal spraying are generally not 

 recommended for willows except for larger species such as the 

 black willow or in instances where specimens are too tall or too 

 few to justify foliage spraying. 



Control recommendations based on studies by various organiza- 

 tions in western States have been summarized in the 13th Western 

 Weed Conference Research Progress Report (Butler, 1952). Some 

 of the principal findings reported are as follows: 



2,4-D is more effective on willows than the more expensive 2,4,5-T. 



Both the amines and the esters of 2,4-D are satisfactory at comparatively low rates. 



Aerial spraj'ing using large droplets has been effective in applications as low as 3 

 pounds of acid equivalent in one gallon of oil per acre. 



Early summer applications seem best for foliage sprays. 



Old willows are likely to require treatment for 2 or 3 successive years. The dead 

 tops can be felled and burned more readily during or following the second winter after 

 the original treatment. Such removal is desirable for efficient treatment of sprouts 

 and for final eradication. 



For land spraying of foliage, 100 to 400 gallons of solution per acre may be required 

 to wet foliage effectively. In contrast to this, airplane spraying of willows in the 

 Strawberry Valley in Utah was effective with 3 pounds of acid equivalent in one gallon 

 of solution per acre. 



A hehcopter proved very satisfactory for spraying willows along canals near Malta, 

 Mont. 



REFERENCE 



1952. Undesirable Woody Plants on Irrigation Systems and Irrigation Lands. C. C. 

 Butler. Res. Prog. Report, 13th Western Weed Conf. 



