RELATIONSHIP AMONG ORANGESTRIPED OAKWORM (LEPIDOPTERA, SATURNIIDAE) FRASS LENGTH, FRASS PRODUCTION, HOST-PLANT, AND DEFOLIATION

Defoliation of urban oak trees by the orangestriped oakworm, Anisota s enatoria (J. E. Smith), and associated frass has become a significant problem in southeastern Virginia. Measurements of frass length and pro duction provided a decision-making guideline for A. senatoria manageme nt. Frass length was used to differentiate A. senatoria instars reared on Q. palustris (Muenchhausen), pin oak. Host plants significantly af fected A. senatoria frass length and production per larva and host pla nts should be considered when determining instars. Frass length was lo nger and frass production higher when larvae were reared on Q. nigra ( water oak), Q. phellos (willow oak), Q. coccinea (scarlet oak), and Q. palustris compared with six other species. Frass length was shorter i n second, fourth, and fifth instars when larvae were reared on Q. alba (white oak) compared with six, eight, and five other species, respect ively. Landscape fabrics were used to collect frass and recovered 90% of all frass deposited. Frass production on small pin oaks (mean ht = 2.1 m, mean diameter at breast ht = 6.3 cm) was significantly correlat ed with defoliation. An aesthetic injury level of 25% defoliation resu lted in frass collections of 2.2 g per tree.