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Monitoring Change in Rust Incidence Over Time |
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| Data for the most recent survey in each State was compared to data from
the next-to-last survey (tables 1-8) to examine changes in host
acreage and rust infection over time. Changes in acreage on a percentage basis are
presented in tables 9-14. Host acreage southwide had increased by
about 4.3 million acres from the previous survey--a 10-percent increase (table 1). The proportions by ownership categories changed little. Overall, for both natural and planted stands, slash pine acreage had decreased slightly (-6 percent) while loblolly pine acreage had increased (+16 percent) between the 2 most recent surveys (tables 9, 12). For both species, planted acreage increased (+7 percent for slash pine, +44 percent for loblolly pine; tables 10 and 13) while natural acreage decreased (-24 percent for slash, -14 percent for loblolly; tables 11 and 14) over the period between surveys. The number of acres with >10-percent infection did not follow these trends (tables 9-14). For planted slash pine, infected acreage decreased 3 percent while infected acreage of natural slash pine increased 1 percent. Similarly, planted loblolly acreage with >10-percent infection decreased 7 percent while infected acreage in natural stands decreased 3 percent. Changes in acreages at the >30-percent and > 50-percent infection levels followed somewhat similar patterns regionwide. Changes at all levels varied from State to State (tables 9-14). |
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