196 OHIO EXPERIMENT STATION: BULLETIN 194 



The newly hatched larva bores through the outer layer of bark 

 and rests in the white layer next the wood through the winter. With 

 the advent of spring feeding is resumed, and the larva eats its way 

 well into the body of the tree. If the tree is small the trunk may be 

 almost severed and a slight wind may blow it over. See Plate 17, 

 Fig. 2. 



The full grown larva is a creamy, club-shaped, footless grub, 

 about Y\ inch in length. See Plate 16, Fig. 2. 



The pupal stage is passed within the burrow, the adult emerg- 

 ing at the time previously stated. There remains to be found a 

 practicable, effective, combative measure for this pest. Spraying the 

 trunks of the trees with a repellant just previous to the time the 

 females deposit their eggs is of some value, though not wholly effec- 

 tive. Whale oil soap and white-wash were applied to adjoining rows 

 of trees in the Station planting, resulting in a slightly lessened injury 

 during the season following. Injecting carbon bisulphide into the 

 tunnels, by the use of an engineer's oil can, previous to the appearance 

 of the adults and closing the tunnels with grafting wax was also par- 

 tially successful in controlling the pest. 



_ 7 T . ^ & The presence of this insect in yellow 



The Locust Twig Borer, 1 . . ... 



Ecdytolotha imiticiana Zell. locust groves is quite easily detected 



by its work upon the twigs of the tree. 



The smaller twigs become swollen and after a time white, sawdust- 

 like material commences to drop from an opening in the enlarged 

 section (Plate 16, Fig. 1.) The injury is the work of a lepidopterous 

 larva, which, upon the completion of growth, drops to the ground and 

 pupates among the dried leaves. In this position the winter is passed. 

 Although not exceptionally injurious it harms the tree to a certain 

 extent. It is a question, however, whether combative measures are 

 worth while. Should action be considered necessary, the affected 

 twigs may be cut and burned while the larvae are still present in 

 them, or the leaves containing the hibernating pupae may be collected 

 and destroyed during the winter. 



SPRAYING APPARATUS. 



Power sprayers connected with large mixture tanks are the 

 most practicable for general operations against shade tree pests, as 

 only a strong pump is able to elevate the mixture to the top of tall 

 trees, and the work in doing so is enormous if it is attempted by 

 hand. The city of Cleveland has two of these sprayers, driven by 

 small gasoline engines, which are giving very good satisfaction. See 

 Plate 20, Figs. 1 and 2. One of these sprayers has a platform built 

 above the pump and engine upon which the men stand when spray- 

 ing the tops of large trees. The sides of the platform are closed, 

 thus protecting the machinery from the spraying mixtures. 



