"Bubble caps" containing MCH 

 protect high-value trees from 

 Douglas-fir beetle attack. 



How to minimize Douglas-fir beetle damage. 



Losses from Douglas-fir beetle may be reduced by 

 promptly removing fresh logs from the forest. Exten- 

 sive winter windthrow must be removed before beetles 

 emerge. Any standing, live trees that were killed 

 during the initial attack on logs should be removed as 

 well. Trees that have been dead a year or more are 

 generally no longer suitable habitat and need not be 

 removed. Salvage operations need to be carefully 

 planned and executed in a timely manner. Tree tops 

 and large limbs need to be piled or scattered away 

 from standing green trees to prevent emerging beetles 

 from attacking healthy trees. The experimental phero- 

 mone MCH, a Douglas-fir beetle anti-aggregant, could 

 be used in the future in selected areas such as camp- 

 grounds to protect trees from attack. 



throughout the Coast Range and western Cas- 

 cades. In most areas, the disease is of little 

 consequence, causing premature shedding of 

 3- and 4-year-old needles. Since the early 

 1980s, however, thousands of acres of Doug- 

 las-fir plantations in western Washington have 

 shown increasingly severe damage from this 

 disease. In late winter and early spring, dis- 

 eased plantations appear noticeably yellow to 

 brownish yellow, in contrast to the adjacent. 



green and vigorous natural stands. Individual 

 tree symptoms include severe chlorosis (yel- 

 lowing), poor retention of needles, and reduced 

 height and diameter growth. With little foli- 

 age remaining for photosynthesis, tree growth 

 declines, and some trees eventually die. The 

 severity of symptoms differs considerably 

 among individuals in the Douglas-fir popula- 

 tion, indicating that tolerance to infection ex- 

 ists in the species. 



Trees with Swiss needle cast often retain only one or two year's worth of needles compared to iJie four 

 year's retained by healthy Douglas-fr (left). Diseased needles turn yellow and are easily shed (right). 



Washington — 48 



