Technical Abstract: The identification of effective adjuvants for field application of the codling moth, Cydia pomonella L., granulovirus (CpGV) is of interest to improve the commercial viability and utility of this biological pesticide. We evaluated several materials as potential adjuvants to protect CpGV from ultra-violet degradation. In laboratory tests with a solar simulator (9.36 × 106 joules/m2), the addition of kaolin clay (Surround® WP at 3 and 6% w/v), a paraffin wax-based emulsion (SPLAT¿ at 5% v/v), and a bark extract trans-cinnamaldehyde combined with a film agent (both at 1% v/v) did not significantly reduce larval entries or increase larval mortality in irradiated apples that were treated with a commercial CpGV product (Cyd-X). In semi-field tests in an apple orchard, a spray-dried lignin formulation containing CpGV (6.57 × 1012 OBs/ha) and a lignin-based adjuvant used with Cyd-X (both applied at 4.7 - 5.6 kg lignin/ha) significantly improved residual activity of CpGV compared with Cyd-X alone applied at the same rate. However, the benefits were short lived and could not be detected after 7 days. In orchard tests, we evaluated two additional refined lignin-products (Lignosulfonate and Vanisperse CB at 5.61 kg/ha) and two particle film materials (kaolin clay, `Cocoon¿, and calcium with boron `Eclipse¿) as adjuvants for UV protection of Cyd-X (6.57 × 1012 OBs/ha) in tests against a dense codling moth infestation. Although all virus treatments were highly effective (causing = 90% larval mortality), no significant effects of the adjuvant treatments could be detected. In these latter tests, the use of a silicone based wetting agent at 0.025% v/v may have been beneficial at increasing mortality among older larvae inside the fruit.