INSECT PESTS OF OHIO SHADE AND FOREST TREES 229 



Careful observations have not been made in Ohio for egg para- 

 sites, but Tachinid flies attacking the larvae have on many occasions 

 been noted as abundant. It seems that larval parasitism takes 

 place most frequently when the larvae are crawling through the 

 grass, seeking a favorable place to enter the ground. At that time 

 the flies may be observed hovering over the larvae, seeking an 

 opportune instant to swoop down and deposit their glistening white 

 eggs on the back of the host. The eggs are secured by an adhesive, 

 mucilaginous secretion, and are very plain to the unaided eye. 

 Sometimes a considerable number will be found on the body of a 

 single larva. The larvae resent the process and attempt to prevent 

 it by squirming about and swinging the head from side to side in 

 a rapid jerky movement. Unquestionably the Tachinids play an 

 important role in the natural suppression of this species. The 

 yellow-billed cuckoo, Coccyzus americana, is reported (14) as one 

 of the more active bird enemies of the species. 



Methods of control. — Unfortunately under present Ohio condi- 

 tions it is rarely practicable to attempt the application of artificial 

 control measures except in the case of trees prized for their shade 

 or ornamental purposes, nor is the timber or nut crop of sufficient 

 value to warrant the expense of the treatment. Several methods 

 are available to combat the species. If the trees are small and 

 readily sprayed, an application of arsenate of lead at the usual 

 strength at the time the caterpillars begin feeding is adequate, 

 iTuning otf the infested branch and destroying its burden of clus- 

 tered caterpillars is resorted to by some. The caterpillar may be 

 destroyed also when they collect for molting on the trunk or larger 

 branches of the trees. Crushing and scalding with hot water are 

 the means most commonly adopted for this purpose. 



THE YELLOW-NECKED APPLE DATANA 



(Datana ministra Walker) 



The yellow-necked apple datana, while primarily an orchard 

 pest, sometimes does considerable harm to ornamentals and has 

 been noted as becoming increasingly abundant in woodlands during 

 the last two seasons. 



Description. — The full-grown larva measures about 2 inches in 

 length, has yellow and black stripes extending lengthwise and is 

 sparsely covered with whitish hairs. The upper part of the neck, 

 or thoracic shield, is yellow, and on this account the insect is given 

 its name. As is characteristic of the Datana group, it elevates the 

 ends of the body when disturbed. (See Plate XXXI, Fig. 3.) 



