The gypsy moth Slow the Spread Program is a joint U.S. Forest Service and state effort aimed at reducing the rate of gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), spread into new areas in the United States. Between 2000 and 2007, federal funding for this program has ranged from $8 million to $10 million, with an additional 25 percent of funds contributed by participating states. Changes in funding levels can have important ramifications on the implementation of this Program, consequently affecting the rate of gypsy moth spread. This report presents a cost analysis for implementing the Slow the Spread Program across a range of funding levels, and predicts the consequent changes in gypsy moth spread rates. This work should be useful to program managers in implementing the Slow the Spread Program given yearly financial constraints and fluctuations, and also potentially serve as a template in the design of barrier zone management programs against other nonindigenous species.