10 MISSOURI AGRICULTURAL EXPERIMENT STATION BULLETIN 176 



if orchards and nurseries are near tim- 

 ber land. In this case again the dam- 

 age done is entirely due to injury caused 

 by the splitting of the twigs for placing 

 the eggs. No injury is done by the in- 

 sect feeding on the trees. 



Newly planted orchards and nursery 

 stock suffer most. On bearing trees it 

 simply serves as extra twig prunning and 

 no serious damage results. 



CONTROL. There is no very effective 

 treatment to check injury once the adult 

 insects arrive in the orchard or nursery. 

 Systematic driving will help to some ex- 

 tent. As a precaution one can deter- 

 mine in advance when the next brood will 

 appear and if a young orchard is to be 

 started select land that has been in culti- 

 vation for more than seventeen years if 

 possible and select an orchard site as far 

 as possible from timber. This will insure 

 the least possible number of Cicadas in 

 the orchard later when the pest appears. 



Insect Pests of Apple Foliage 



This includes a very large group of 

 caterpillars, grasshoppers, plant lice, leaf- 

 hoppers, plant bugs and other more or 

 less destructive foliage pests. Where ap- 

 lications of sprays are recommended they 

 are included in the regular spray sche- 

 dule gi\e in connection with the control of 

 the codling moth on page 22. 



Canker Worms (Alsophila pometaria and Paleacrita vernata). There 

 are two species of canker worms, the fall and spring canker worms. The first 

 appears as the adult in the fall and lays eggs while the latter appears in the 

 spring. The female moth is wingless. The caterpillars are common dark- 

 colored, span worms and do their destructive work just before, during and 

 following apple blooming time. They often completely destroy the foliage and 

 crop of fruit. There is one generation of the pest a year. The caterpillars 

 when full fed leave the trees and pupate in the soil or rubbish. Here they 

 remain until late fall or early spring, depending on the species. 



CONTROL. The pest is controlled effectively by spraying with an arsenical 

 just before the blossoms open, or on isolated trees banding with tangle foot, or 

 screen-wire cones is effective since the females are wingless and must climb up 

 the trees to deposit eggs. Occasionally these caterpillars may do some damage 

 to nursery stock and when they do apply arsenical sprays promptly. 



Bagworms (Thrldopteryx ephermeraeformis}. This peculiar cater- 



FIG. 9. Periodical Cicada; limbs 

 split by female Cicada for placing 

 eggs (After Riley) 



