76 FRUIT INSECTS 



have occurred at Washington, in Connecticut and in Michigan 

 on apple, quince and wild cherry, sometimes 25 or 30 mines 

 occurring in a single leaf. The bark of the trunk and larger 

 branches were fairly covered with the hibernating cases, 47 

 having been counted on a spot not larger than a dime. 



Reference 

 Comstock, Rept. U. S. Ent. for 1879, pp. 210-213. 



Natural enemies of the lesser leaf-miners of the apple. 



All of these little leaf-miners have enemies which are more 

 or less effective aids in preventing their occurrence in injurious 

 numbers. At least two tiny Chalcid parasites, Sympiesis 

 nigrifemora and Astichus tischeriae attack both the spotted 

 and unspotted tentiform-miners. Ants often tear open the 

 cases of the resplendent shield-bearer and devour the inclosed 

 caterpillar or pupa ; two minute hymenopterous parasites also 

 attack this miner. We have bred a tiny parasite from the 

 serpentine miner, and many of the scale-like hibernating 

 cocoons have been found in the stomachs of chickadees. 



Remedial treatments. 



In well cultivated and thoroughly si)rayed orchards, leaf- 

 miners rarely l)ecome abundant enough to cause appreciable 

 loss, and special treatment is therefore rarely m^cessary. As all 

 of these lesser leaf-miners feed insid(^ th(^ leaves they cannot be 

 effectively reached with poison sprays. For the tentiform- 

 miners, resort to the treatments recommended for the trumpet 

 leaf-miner. Possibly a spray of " Black Leaf 40 " tobacco ex- 

 tract, 1 pint in 100 gallons of water, to which 4 or 5 pounds of 

 soap have been added would penetrate mines and kill the cater- 

 pillars of the shield-bearer and serpentine-miner. When very 

 numerous many of the cases of the shield-miner could be scraped 

 from the trees and destroyed. 



