Causes of early fall color in trees Early fall color in trees this year is due partly to cool temperatures this summer, a South Dakota State University specialist said.
SDSU Extension Forestry Specialist John Ball said that's one among several factors causing the early color change, very visible on some maples and ash
"With the decreasing daylengths and the cooler temperatures, some trees are beginning to reduce their production of chlorophyll, which is what causes the leaves to be green, and in turn increasing their production of some of the other pigments," Ball said. "But we're also seeing experiencing some color change due to stress, particularly West River, that continuing drought has stressed the trees. Some of the trees are continuing through fall color changes, not because they're preparing for fall, but just because the summer was so stressful they're beginning to drop their leaves now."
Homeowners can do something about drought stress.
"We certainly encourage people West River who are experiencing drought, whenever possible, do water those trees, even if they drop their leaves now," Ball said. "Try to get water to them for about the next two months before winter sets in. That will be a big help in making sure the trees leaf out next year."
Ball added that sap-feeding insects called aphids and scales also are playing a role in the color change.
"These are both small insects that are kind of the mosquitoes of the plant world. They suck the sap from the plants and as they're doing it, that sap
drainage is stressing the trees and causing some color change as well," Ball said.
"People can check very easily to see if aphids and scales are responsible for the color change by merely noticing the leaves. If the leaves are sticky, that's honeydew, a substance secreted by the aphids and scales as they feed. So if you notice your deck is sticky or the leaves are sticky, the problem is aphids. At this time of year we certainly don't recommend any control, but that's the reason for the color change."
Ball added that squirrels seem to be a bigger factor than usual across the region this year in bringing about some color change by gnawing the bark of branches.
"Squirrels are out there girdling the branches of trees, and they're doing this to hackberries, maples and cottonwoods," Ball said. "While we typically see this every year, where a squirrel goes up and chews around a branch and that girdles it so the leaves on it turn yellow, this year they're just going crazy. If you look up in your tree and you notice that individual branches have yellowed, rather than the entire tree, particularly if you see a little rodent up there, more than likely the problem this year is squirrels."
Ball said the squirrels won't harm the trees and said he has no explanation for why squirrels seem to be unusually active this year.
"If you're having aphids or squirrels, or if your trees are turning a little early because of the cooler weather, just enjoy the fall colors and leave it at that," Ball said.
Anglers are reminded that the 15-inch minimum length limit for walleye on Lakes Sharpe, Francis Case and the Missouri River below Fort Randall Dam downstream to the South Dakota/Nebraska border became effective again on Sept. 1. The year-round regulation of one walleye 18 inches or longer per angler per day remains in effect on these waters.
On upper Lake Oahe near Mobridge, walleye fishing is good. Live bait or plugs work best in 10-to-25 feet. Walleye, white bass and catfish are being caught from shore. At Akaska, the walleye bite has been slow but some fish are being caught.
Near Gettysburg, walleye fishing is slow. Live bait with a bare hook or a bottom bouncer with spinner work best in 30-to-35 feet. Smallmouth bass, white bass and catfish are still being caught in the major creeks.
On lower Lake Oahe, the bite has slowed due to weather but some limits are being taken. Walleye are averaging 14-to-22 inches. A bottom bouncer with 4-to-6 foot snell moving slow in 15-to-30 feet with half a crawler works best. Catfish are being caught in the creeks. The salmon bite is slow at the face of the dam.
On Lake Sharpe, the walleye bite is good in the Pierre area from the bridges down to Antelope Creek. Most fish are running 14 1?2-to-16 inches. Smallmouth bass and walleye are being taken near West Bend.
Near Chamberlain, walleye fishing is fair to good in the fast water at Big Bend Dam and above the dam near the grain bins and pump house to West Bend. In the Crow Creek area the fishing is fair. Most fish are being caught using a spinner and bottom bouncer with live bait in 20-to-25 feet.
On Lake Francis Case near Platte, walleye fishing is fair. Anglers are having the best luck pulling plugs in 20-to-30 feet they are also using a lindy rig or spinner and live bait. In the Pickstown area, walleye are biting in the fast water below the dam in the morning and evening.
Catfish and smallmouth bass are also being caught below the dam. On the lake, walleye are biting from South Shore and north using anything from a spinner and crawler to long lining plugs.
Near Yankton, anglers are catching a lot of catfish above and below the dam using stink bait or night crawlers.
Largemouth and smallmouth bass along with crappie are also biting there. Nice size walleye are being caught using a jig and live bait below the dam.
On Lewis and Clark Lake, anglers are catching walleye pulling plugs or on a spinner and live bait in 8-to-10 feet. On Lake Yankton anglers are catching catfish and largemouth bass.
For more information on fishing: Pollock � West Pollock at 605-889-2448; Mobridge � Bridge City Bait at 605-845-3132; Akaska � Akaska Bait Shop at 605-649-7847; Gettysburg � Bob's Resort at 605-765-2500 or South Whitlock at 605-765-9762; Pierre/Ft. Pierre � Carl's Bait Shop at 605-223-9453; Chamberlain � Allen's at 605-734-5591; Platte � Kuip's Hardware at 605-337-3346; Pickstown � Ft. Randall Bait at 605-487-7760; Yankton � Captain Norm's at 605-665-4271.
For up-to-date information on Lake Oahe boat ramp conditions, visit our Web site at: www.sdgreatlakes.org.