APPLE INSECTS — BORERS AND MISCELLANEOUS 197 



flat-hea(l(Ml borer 

 •headed species, 



Fig. 188. — Pupa of 

 the flat-headed apple- 

 tree borer. 



out through an elliptical hole. Thus this 

 has a much shorter life-cycle than th(^ round 

 from which: it also differs much in all its 

 stages and in its habits. 



Although snugly hidden in its bur- 

 row beneath the bark, this flat-headed 

 borer does not escape from natural ene- 

 mies. Woodpeckers and ants devour 

 many of the grubs and pupae and the fol- 

 lowing parasites prey upon it : the Braco- 

 nids, Bracon charus and pedinator, Spa- 

 thius pallidus ; the Ichneumonids, Labena 

 apicalis and grallator; and one or more 

 species of Chalcids. 



Remedial suggestions. 



As healthy, well-established trees are rarely attacked by this 

 borer, its ravages can be largely prevented by keeping young 

 trees in a thrifty, growing condition. Many of the suggestions 

 for controlling the round-headed borer are also applicable to 

 this species. The deterrent soap and emulsion washes and pro- 

 tective coverings have been found effective, but must be applied 

 farther up the trunk and on to the larger branches. Two or 

 more applications of the washes should be made, beginning in 

 May and continuing into July. As the location of the larval 

 channels are often revealed by slight discolorations or diseased 

 conditions of the bark or by sawdust-like castings thrown out 

 of the burrows, the culprit can often be easily reached with a 

 sharp tool. Several of the grubs often infest a young tree, 

 completely undermining the bark over considerable areas ; 

 we once found on a small apricot tree three pupae in an area not 

 larger than a penny. In cases of such severe infestation the 

 trees should be removed and burned in autumn or before May. 



A closely related Buprestid beetle, Chrysobothris mali Horn, 

 which has been given the common name of ''California big- 



