ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 43 



The female deposits eggs in the cracks and crevices of locust 

 bark. 



Control Measure 4 (end of circular) for protection of young 

 trees. Honey locust, which is not readily attacked, should be used 

 for shade in place of black locust. 



Bagworm, fig. 2. — This pest occurs on both black locust and 

 honey locust. See under Arborvitae. Control Measure 1, 3, 11, or 

 21 (end of circular) in June, while worms are small. 



Locust Mite, Eotetranychus multidigituli (Ewing). — This 

 mite, somewhat similar to other species of mites found on trees 

 and shrubs, seems to be peculiar to honey locust. Just large 

 enough to be visible to the naked eye, the mite varies in color 

 from pale yellow to green; it has irregular dark areas near the 

 edge of the body. The female deposits colorless spheroid eggs 

 along the midrib of the under side of a leaflet. The base of the 

 leaflet on the under side is the preferred feeding area. At first, 

 heavily infested foliage appears stippled from above, but later it 

 becomes blanched, and leaflets drop prematurely. 



Control Measure 9 (end of circular) when mites occur. 



Mimosa Webworm, Homadaula albizziae Clarke, fig. 31. — 

 This pest, relatively new in Illinois, has been observed in the 

 Washington, D. C, area on mimosa since 1940 and on honey locust 

 since 1943. Damage to the foliage of these trees may be extensive. 



The adults, mouse-gray moths, each with a wing expanse of 

 only about one-half inch, emerge from overwintering pupae early 

 in June. The female deposits eggs on the leaves of honey locust 

 or mimosa. The small, pale gray to brown larvae web the leaves 

 together to form a sort of nest, in which they skeletonize the 

 leaflets. Badly damaged leaflets become dry and brown. In Illi- 

 nois, such symptoms of webworm attack may appear by the 

 latter part of July. When grown, each larva drops to the ground 

 on a silken thread to pupate under ground cover. Second brood 

 larvae produce conspicuous webbing in August. In the Wash- 

 ington, D. C, area, the mimosa webworm produces a partial third 

 generation each year. 



Control Measure 1, 2, or 3 (end of circular). 



MAPLE 



Cottony Maple Scale, Pulvinaria innumerabilis (Rathv.), 

 fig. 32. — A common, conspicuous, and injurious pest of soft ma- 



