Abstract

Bagworms (Thyridopteryx ephemeraeformis) are a common pest of landscape plants. The efficacy and costs were determined for the manual removal (handpicking) of bagworms from a single Leyland cypress (X Cupressocyparis leylandii) and estimated for a planting of 40 trees. Manual removal costs were compared to the estimated costs of spraying trees with the insect growth regulator tebufenozide. Handpicking the bags provided 92% control and required 160 minutes for one tree and an estimated 6,400 minutes for 40 trees. Labor costs for manual removal were estimated at $44 for one tree and $1764 for 40 trees. Estimated time required to spray a single tree was 71 minutes while 40 trees required an estimated 251 minutes. Estimated cost to spray one tree was about $28 and the cost for 40 trees was estimated to be $105. The time spent and costs of control are similar for handpicking and spraying single trees. Handpicking may be acceptable on single or small numbers of short trees that may be safely handpicked. However, as the number of trees increases, time and costs associated with handpicking increase dramatically, while costs to spray increase only slightly.