318 OHIO EXPERIMENT STATION: BULLETIN 332 



swelling. The larvae become mature by mid-autumn, drop to the 

 ground and pupate among the leaves. Occasionally a large percent- 

 age of the twigs of a grove is affected by this insect and under 

 such conditions tree growth is checked perceptibly. 



Food plant. The black or yellow locust (Robinia Pseudacacia) 

 is the only host recorded. 



Distribution. This insect has been reported from the District 

 of Columbia, Massachusetts, Indiana, West Virginia, New York and 

 New Jersey. It is found in all parts of Ohio. 



Control. Cutting and destroying the infested twigs during the 

 summer before the larvae escape is of some value, but is practicable 

 only upon a very limited scale. 



THE POPLAR BORER 

 (Saperda calcarata Say) 



Description. In the adult stage the poplar borer is a long- 

 horned beetle. It measures about one and one-fourth inches in 

 length, is of a mouse-gray color, irregularly marked with yellow, 

 elongate spots, and the whole is thickly sprinkled with minute black 

 dots. One variety of the species is brown. The larva is yellowish- 

 white and is nearly 2 inches in length. (See Plate LXIV, Fig. 2.) 



Life history and habits. The eggs are deposited beneath the 

 bark through slits made in the surface. The first eggs of the seasoi 

 probably are deposited in July and the process may extend over the 

 two months following. The resulting larvae feed upon the wood: 

 tissues of the host, meanwhile discharging through their tunnel 

 entrances large quantities of sawdust-like castings, and when nearl: 

 mature are found in large, deep galleries in the tree trunk. In thes< 

 secure retreats, they transform to the pupal stage, the adull 

 emerging and remaining abroad during July, August and into Se] 

 tember. The winter is passed in the larval stage. 



Nature of work. The boring of the trunk of the host not 01 

 ruins the wood for lumber purposes, but also so weakens it that the 

 trees frequently break during storms. In addition, the mutilation oJ 

 the tree tissues invites the entrance of destructive bacteria and fun- 

 gus spores and these secondary invaders frequently are quite as I 

 ruinous as the borer itself. Death of the host is very common. 

 Plate LXIV, Fig. 3, conveys some idea of the character of the injury 

 and a glance at Plate II shows the extended destruction possible by 

 this insect. 



Food plants. Carolina poplar, cotton wood, Populus tremul-* 

 oides, lombardy poplar and willows are the food plants. 



Distribution. This insect is distributed over practically the 

 entire United States and is also reported from Canada. 



