Hort Update for the week of 3/6/2009
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1. Prairie and Meadow Voles scar lawns by constructing surface runways (one to two inches wide) and clipping grass very close to the roots. Runways are most visible after snow melts. Small holes lead to underground runways or nesting areas. Vole damage to lawns usually repairs itself during spring growth and is not permanent. Voles are small, mouse-like rodents that exist throughout Nebraska. Their short tails (about 1 inch long) stocky build and small eyes distinguish them from true mice.
Controlling Vole Damage, http://www.ianrpubs.unl.edu/sendIt/g887.pdf
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2. Prostate Knotweed is an annual weed that thrives from early spring to late autumn in thinned areas of turfgrass. It grows flat (prostate) from a long white taproot. Stems and individual plants may spread up to two feet across. Germination occurs in very early spring. Where control is needed and preemergence herbicides are used, these products need to be applied late winter to early spring as weather allows. The earlier preeemergence herbicides are applied for knotweed, the better as this weed can begin to germinate as snow melts. After germination knotweed is easily controlled with most broadleaf herbicides as a seedling. As it matures, however, control becomes increasingly difficult, Control preemergence or as a seedling for best results.
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3. Economics of Tree Fertilization: In difficult economic times, every dollar needs to be spent wisely. Some tree and lawn care services offer the added service, for an extra fee, of fertilizing landscape trees. As a general rule, Nebraska soils provide adequate fertility for tree growth; and in landscape situations where the lawn is fertilized, trees are receiving adequate, if not excessive, fertilization already. The need for- and economics of fertilizing landscape trees growing in or near fertilized lawns is quite questionable. Unless a soil test determines the need for fertilization, or a tree is showing signs of poor fertility (pale green foliage, below average growth, dieback of small twigs) and other causes have been overruled; it is best not to spend money to fertilize landscape trees in addition to lawn fertilization. Excess fertilization can lead to other tree issues such as increased susceptibility to insects.
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4. Bagworms: Tightly woven brown “bags”, 1.5 to 2.5 inches long, covered with brown needles and tightly attached to twigs. Most often found on evergreens, but also on deciduous trees such as crabapple. Damage caused to deciduous plants is not as great of a concern as damage caused to evergreen plants due to the ability of deciduous trees to recover. These bags contain overwintering eggs. Removing and destroying the bags between now and late May will help reduce bagworm populations. The effective time to apply insecticides is just after eggs hatch in early June. Insecticides applied now will not provide any control.
Insects on Evergreen Trees in Nebraska, http://www.nfs.unl.edu/ForestHealth/fh-insect-evergreen.asp
Seasonal Problems- Bagworm, http://extensionhorticulture.unl.edu/Current/Bagworm.shtml
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5. Winter Dessication has started to show up in eastern Nebraska. Japanese Yew, Arborvitae, and broadleaf evergreens like Holly are most commonly affected; especially those growing on the south side of homes or other reflective areas. Dessication causes a fairly uniform browning, often on the south or west facing side of plants and on exterior plant parts. Evergreens lose moisture from green foliage during winter and the lost moisture cannot be replaced from frozen or cold soil. Some winter dessication is caused by salt spray. To avoid winter desiccation, provide adequate moisture to plants throughout the growing season. During winter, protect plants from salt spray and avoid shoveling snow with de-icing salts onto plants or the soil around plants. Winter damaged growth can be pruned or homeowners can wait until June 1st to see if new growth occurs.
Winter Dessication Injury, http://extensionhorticulture.unl.edu/Current/WinterInjury.shtml
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6. Pine Wilt continues to kill Scotch pine trees across Nebraska, and some Austrian pine. Scotch pines that die fairly rapidly likely have pine wilt. When wilt is suspected, these trees should be removed by April 30 to slow the spread of the disease. Pine wilt is caused by a microscopic organism called the pinewood nematode. Nematodes are spread by pine sawyer beetles which carry thousands of nematodes on their bodies when they fly to other pines to feed. Trees infected with pine wilt cannot be saved and should be cut down and burned, buried or chipped for mulch before beetles emerge in May. Do not save wood from these trees for firewood. Scotch pine should no longer be planted in Nebraska for windbreak or landscape situations. Some Austrian pines have also been killed by pine wilt. New NebGuide now available.
Pine Wilt in Nebraska, http://www.ianrpubs.unl.edu/sendIt/g1899.pdf
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7. Emerald Ash Borer is the borer killing thousands of green and white ash, mainly in eastern states. In late summer of 2008, it was confirmed in southeast Missouri and southeast Wisconsin. It is not yet known to be in Nebraska, but is expected to reach our state in the near or distant future. For this reason, UNL Extension and the Nebraska Forest Service have stopped recommending the planting of green or white ash trees in Nebraska. A common way for this borer to move into a state is through transportation of firewood across state lines. It is important for people to know this and to not transport ash firewood across state lines. To remain up to date on Emerald Ash Borer, refer to www.emeraldashborer.info
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8. Liming Soils: The addition of lime to soils is a recommendation that is seen in garden magazines, books or on-line newsletters; or one that may be given to a Nebraska farmer. Lime is added to soil to raise the pH of the soil. In the Great Plains, most soils have a high (alkaline) pH. Most plants prefer a slightly acid pH of about 6.5 to 6.8. For these reasons, it is uncommon for soils in Nebraska to need lime. In Nebraska, the addition of lime could raise pH to the point where it causes problems with plant growth. Some Nebraska farmers lime soils because fertilizers such as anhydrous ammonia lower soil pH and there is sometimes a need to lime cropland soils. For home gardens and landscapes, the need to lime soil would be unusual. When it comes to soil amendments, save money by having a soil test taken before an amendment, such as lime or gypsum, is incorporated.
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9. Fruit Tree Pruning Tips: March is the best time to prune fruit trees. A small amount of annual pruning encourages production of fruiting wood and opens trees to increased light penetration which increases fruit production and quality. When pruning fruit trees, understand what age wood the different types of trees bear fruit on. Make proper pruning cuts and use sharp pruning tools. Do not use pruning paints or wound dressings on pruning wounds.
Pruning Fruit Trees, http://www.oznet.ksu.edu/library/hort2/C631.PDF
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10. Delay Mulch Removal on plants such as strawberries, roses, Chrysanthemums and other tender perennials that are now protected by winter mulch. Early removal may cause new growth to begin too early and be susceptible to cold temperature damage. Ideally, delay mulch removal as long as possible but remove it before new growth begins beneath the mulch. If warm temperatures cause new growth to begin early, rake the mulch to the side of the plant so it can be raked back over plants if freezing temperatures are forecast.
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11. Mealybugs are soft-bodied, white, usually flat and oval-shaped, 1/8” long insects that attack many greenhouse plants, especially houseplants. Mealybugs have a white powdery substance over their bodies and white, waxy filaments projecting from the rear of their bodies. Mealybugs injure plants by sucking juices from tender leaves and roots. When populations are high, feeding causes stunted and distorted new growth. Mealybugs also excrete honeydew which causes leaves to feel sticky and a black sooty mold may form on the honeydew. Females lay 300 to 600 eggs in compact waxy sacs attached to axils of stems or leaves. Small populations of mealybugs can be removed from plants by wiping foliage with a warm, soft cloth or by treating plants with insecticidal soaps. Systemic insecticides labeled for indoor use are most effective for heavier infestations.
Mealybugs on Houseplants, http://www.ento.okstate.edu/ddd/insects/mealybugs.htm
| Current Problems: | Major Symptom: |
| Lawns | |
| 1. Voles | Runways of clipped grass on lawn surfaces |
| 2. Knotweed | Apply pre-emergence herbicide now or broadleaf killers in seedling stage |
| Trees & Shrubs | |
| 3. Economics of Tree Fertilization | Confirm applications are needed before spending the money |
| 4. Bagworms | 1.5 to 2.5” long brown bags attached to trees, mainly evergreens |
| 5. Winter Dessication | Uniform browning of foliage; often on south or west side of a plant |
| 6. Pine Wilt | Dead Scotch pine trees or rapid crown dieback - remove by April 30 |
| 7. Emerald Ash Borer | NOT yet known to be in Nebraska. Informational website |
| Ornamentals, Vegetables & Fruits | |
| 8. Liming Soils Rarely Needed | Do not use on soil unless a soil test indicates the need for |
| 9. Fruit Tree Pruning | March is the ideal time to prune fruit trees |
| 10. Delay Mulch Removal | i.e. on roses, strawberries, Chrysanthemums, other tender perennials |
| 11. Mealybugs on Houseplants | Soft-bodied, white, oval-shaped, 1/8” long insects on houseplants |
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1. Prairie and Meadow Voles scar lawns by constructing surface runways (one to two inches wide) and clipping grass very close to the roots. Runways are most visible after snow melts. Small holes lead to underground runways or nesting areas. Vole damage to lawns usually repairs itself during spring growth and is not permanent. Voles are small, mouse-like rodents that exist throughout Nebraska. Their short tails (about 1 inch long) stocky build and small eyes distinguish them from true mice.
Controlling Vole Damage, http://www.ianrpubs.unl.edu/sendIt/g887.pdf
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2. Prostate Knotweed is an annual weed that thrives from early spring to late autumn in thinned areas of turfgrass. It grows flat (prostate) from a long white taproot. Stems and individual plants may spread up to two feet across. Germination occurs in very early spring. Where control is needed and preemergence herbicides are used, these products need to be applied late winter to early spring as weather allows. The earlier preeemergence herbicides are applied for knotweed, the better as this weed can begin to germinate as snow melts. After germination knotweed is easily controlled with most broadleaf herbicides as a seedling. As it matures, however, control becomes increasingly difficult, Control preemergence or as a seedling for best results.
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3. Economics of Tree Fertilization: In difficult economic times, every dollar needs to be spent wisely. Some tree and lawn care services offer the added service, for an extra fee, of fertilizing landscape trees. As a general rule, Nebraska soils provide adequate fertility for tree growth; and in landscape situations where the lawn is fertilized, trees are receiving adequate, if not excessive, fertilization already. The need for- and economics of fertilizing landscape trees growing in or near fertilized lawns is quite questionable. Unless a soil test determines the need for fertilization, or a tree is showing signs of poor fertility (pale green foliage, below average growth, dieback of small twigs) and other causes have been overruled; it is best not to spend money to fertilize landscape trees in addition to lawn fertilization. Excess fertilization can lead to other tree issues such as increased susceptibility to insects.
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4. Bagworms: Tightly woven brown “bags”, 1.5 to 2.5 inches long, covered with brown needles and tightly attached to twigs. Most often found on evergreens, but also on deciduous trees such as crabapple. Damage caused to deciduous plants is not as great of a concern as damage caused to evergreen plants due to the ability of deciduous trees to recover. These bags contain overwintering eggs. Removing and destroying the bags between now and late May will help reduce bagworm populations. The effective time to apply insecticides is just after eggs hatch in early June. Insecticides applied now will not provide any control.
Insects on Evergreen Trees in Nebraska, http://www.nfs.unl.edu/ForestHealth/fh-insect-evergreen.asp
Seasonal Problems- Bagworm, http://extensionhorticulture.unl.edu/Current/Bagworm.shtml
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5. Winter Dessication has started to show up in eastern Nebraska. Japanese Yew, Arborvitae, and broadleaf evergreens like Holly are most commonly affected; especially those growing on the south side of homes or other reflective areas. Dessication causes a fairly uniform browning, often on the south or west facing side of plants and on exterior plant parts. Evergreens lose moisture from green foliage during winter and the lost moisture cannot be replaced from frozen or cold soil. Some winter dessication is caused by salt spray. To avoid winter desiccation, provide adequate moisture to plants throughout the growing season. During winter, protect plants from salt spray and avoid shoveling snow with de-icing salts onto plants or the soil around plants. Winter damaged growth can be pruned or homeowners can wait until June 1st to see if new growth occurs.
Winter Dessication Injury, http://extensionhorticulture.unl.edu/Current/WinterInjury.shtml
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6. Pine Wilt continues to kill Scotch pine trees across Nebraska, and some Austrian pine. Scotch pines that die fairly rapidly likely have pine wilt. When wilt is suspected, these trees should be removed by April 30 to slow the spread of the disease. Pine wilt is caused by a microscopic organism called the pinewood nematode. Nematodes are spread by pine sawyer beetles which carry thousands of nematodes on their bodies when they fly to other pines to feed. Trees infected with pine wilt cannot be saved and should be cut down and burned, buried or chipped for mulch before beetles emerge in May. Do not save wood from these trees for firewood. Scotch pine should no longer be planted in Nebraska for windbreak or landscape situations. Some Austrian pines have also been killed by pine wilt. New NebGuide now available.
Pine Wilt in Nebraska, http://www.ianrpubs.unl.edu/sendIt/g1899.pdf
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7. Emerald Ash Borer is the borer killing thousands of green and white ash, mainly in eastern states. In late summer of 2008, it was confirmed in southeast Missouri and southeast Wisconsin. It is not yet known to be in Nebraska, but is expected to reach our state in the near or distant future. For this reason, UNL Extension and the Nebraska Forest Service have stopped recommending the planting of green or white ash trees in Nebraska. A common way for this borer to move into a state is through transportation of firewood across state lines. It is important for people to know this and to not transport ash firewood across state lines. To remain up to date on Emerald Ash Borer, refer to www.emeraldashborer.info
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8. Liming Soils: The addition of lime to soils is a recommendation that is seen in garden magazines, books or on-line newsletters; or one that may be given to a Nebraska farmer. Lime is added to soil to raise the pH of the soil. In the Great Plains, most soils have a high (alkaline) pH. Most plants prefer a slightly acid pH of about 6.5 to 6.8. For these reasons, it is uncommon for soils in Nebraska to need lime. In Nebraska, the addition of lime could raise pH to the point where it causes problems with plant growth. Some Nebraska farmers lime soils because fertilizers such as anhydrous ammonia lower soil pH and there is sometimes a need to lime cropland soils. For home gardens and landscapes, the need to lime soil would be unusual. When it comes to soil amendments, save money by having a soil test taken before an amendment, such as lime or gypsum, is incorporated.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
9. Fruit Tree Pruning Tips: March is the best time to prune fruit trees. A small amount of annual pruning encourages production of fruiting wood and opens trees to increased light penetration which increases fruit production and quality. When pruning fruit trees, understand what age wood the different types of trees bear fruit on. Make proper pruning cuts and use sharp pruning tools. Do not use pruning paints or wound dressings on pruning wounds.
Pruning Fruit Trees, http://www.oznet.ksu.edu/library/hort2/C631.PDF
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10. Delay Mulch Removal on plants such as strawberries, roses, Chrysanthemums and other tender perennials that are now protected by winter mulch. Early removal may cause new growth to begin too early and be susceptible to cold temperature damage. Ideally, delay mulch removal as long as possible but remove it before new growth begins beneath the mulch. If warm temperatures cause new growth to begin early, rake the mulch to the side of the plant so it can be raked back over plants if freezing temperatures are forecast.
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11. Mealybugs are soft-bodied, white, usually flat and oval-shaped, 1/8” long insects that attack many greenhouse plants, especially houseplants. Mealybugs have a white powdery substance over their bodies and white, waxy filaments projecting from the rear of their bodies. Mealybugs injure plants by sucking juices from tender leaves and roots. When populations are high, feeding causes stunted and distorted new growth. Mealybugs also excrete honeydew which causes leaves to feel sticky and a black sooty mold may form on the honeydew. Females lay 300 to 600 eggs in compact waxy sacs attached to axils of stems or leaves. Small populations of mealybugs can be removed from plants by wiping foliage with a warm, soft cloth or by treating plants with insecticidal soaps. Systemic insecticides labeled for indoor use are most effective for heavier infestations.
Mealybugs on Houseplants, http://www.ento.okstate.edu/ddd/insects/mealybugs.htm
