INSECT ENEMIES OF WESTERN FORESTS 



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Figure 9. — Ponderosa pine seed chalcid Megastigmus albifrons: A and B, 

 Adults laying eggs through small green cones into seeds (drawings by 

 Edmonston), enlarged; C, larvae, pupae, and adults, X 3; females above, 

 males below. 



cium cyanide, or 3 gallons of carbon disulfide, or 6 gallons of a 

 3-to-l mixture of ethylene dichloride and carbon tetrachloride. 

 Methyl bromide also has been successfully used as a fumigant. 

 Recommended dosages per 1,000 cubic feet are 2.5 pounds for 

 16-hour exposure or more, at temperatures of 60°-75° F. ; 4 

 pounds for 4 hours at 50°-70° or for 2 hours at 70° or above. 

 Insects in seed may also be destroyed by fumigation at 140° for 

 10 minutes without injuring germination unless the seed is of low 

 vigor or its moisture content is high. 



The different species of the genus Megastigmus and the hosts 

 from the seeds of which they have been reared are as follows : 



