Computer model reveals gypsy moth controls

A team from Penn State and University of Cambridge in the United Kingdom developed a computer model that provides land managers with a more efficient and cost-effective approach for controlling gypsy moths and other invasive pests.

The team’s results indicate the best strategies for managing the pests include eradicating medium-density infestations and reducing high-density infestations, rather than reducing spreading from the main infestation.

“Our model is state dependent, which means that it recommends different management strategies depending on the situation,” said Katriona Shea, Penn State associate professor of biology and the team’s leader. “Most managers currently use the same strategy in all situations, but our model suggests that by tailoring their approach to a particular situation, managers can be more effective in slowing the spread of invasive species.”

Although the model has little to offer those states that already have succumbed to infestation, it does have the potential to slow or halt the moths’ spread into new areas. States that stand to benefit the most include North Carolina, Virginia, West Virginia, Ohio, Indiana, Illinois and Wisconsin.

The model’s results allow managers in those states where the moths are actively spreading to select a management strategy based on the number of medium-density and high-density infestation patches in their jurisdictions. The model ignores smaller patches because they often go extinct by themselves and, if they escape extinction as small patches, they will be detected in the model as medium patches.

For example, if an area contains 20 medium patches and 20 large patches, the model suggests that managers should focus energy and money on reducing some of those large to medium patches. This strategy, ultimately, would be the most effective means of controlling gypsy moths in that particular circumstance.

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For more: Katriona Shea, Penn State, (814) 865-7910; k-shea@psu.edu.

August 2008