. Insect and disease conditions in the United States, 1979-83 : what else is growing in our forests?. Forest insects United States; Trees Diseases and pests United States; Plants Disease and pest resistance. Figure 3. Uredia on the underside of an oak leaf. F-705655 Since 1930, however, more than 20 million acres ( million ha) have been planted with even- aged stands of primarily slash and loblollyâpines that are the most susceptible to fusiform rust infec- tion. Both species were moved outside their natural ranges. At the same time, the number of oaks increased as fire control pro- grams w
. Insect and disease conditions in the United States, 1979-83 : what else is growing in our forests?. Forest insects United States; Trees Diseases and pests United States; Plants Disease and pest resistance. Figure 3. Uredia on the underside of an oak leaf. F-705655 Since 1930, however, more than 20 million acres ( million ha) have been planted with even- aged stands of primarily slash and loblollyâpines that are the most susceptible to fusiform rust infec- tion. Both species were moved outside their natural ranges. At the same time, the number of oaks increased as fire control pro- grams were established. Under these conditions, fusi- form rust has flourished across the Southeast. Despite occasional years of low infection, the annual rates of infection have escalated. Both the intensity of infection and the acres affected have increased about 2 to 3 percent per year over much of the southern pine type. New plantations of susceptible slash or loblolly pine may become 100 percent infected (Dinus and Schmidt 1977). Resources Affected Tree mortality caused by fusi- form rust may increase runoff; create or increase wildlife habitat; pose a safety hazard in recreation areas; and increase forage. But these relationships have not been documented. What have been documented are the effects of fusiform rust on the timber resource: losses occur primarily as mortality in young stands and quality loss in older stands. Also, the disease is more severe in plantations than in naturally regenerated stands, and Figure 4. Zones of fusiform rust by infection level for loblolly â¡ 10 to 30 percent â¡ 30 to 50 percent â¡ 50 to 70 percent â 70 to 100 percent ] Not surveyed. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Loomis, Robert C; Tucker, Susan; Hofacker, Thomas H; United States. State and Pri
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