Hort Update for the week of 9/1/06
1. Mushrooms growing in lawns or mulched beds are fruiting bodies of fungi growing on decomposing organic matter in soil, such as an old tree root; or on wood chip mulch. Most mushrooms are harmless to the turf; unless they are one of the fairy ring mushrooms. They will disappear when the organic matter decomposes or conditions are less conducive to fruiting. Advise homeowners to remove mushrooms to reduce the risk of children eating them. Some types are poisonous.
Internet Resource: http://www.oznet.ksu.edu/dp_hfrr/extensn/problems/mushrooms.htm
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2. Billbug damage is more prevalent this year than in recent years. In May and June, newly-hatched billbug larvae tunnel in grass stems which discolor and when pulled, readily break away at or near the crown. Subsurface feeding by older larvae through July can damage roots, causing turf to appear drought stressed. Under heavy billbug pressure, areas of lawn turn brown and die. The greatest billbug injury usually occurs from mid-June through late July. Billbug injury is easily mistaken for white grub or sod webworm damage, disease, or plant stress. Damaged turf should be carefully examined to confirm the presence of billbugs before making a management decision. Insecticide controls are best applied in May and targeted at the adult weevil.
Internet Resources: http://entomology.unl.edu/turfent/documnts/billbugs.htm or
http://lancaster.unl.edu/hort/factshes/085.shtml
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3. Crabgrass is an annual, warm season grass. Its appearance in lawns is often a sign of a thin, weak turf unable to compete with annual weeds or lawns mowed too low. To help control crabgrass, use lawn care practices that promote healthy rooting and a dense lawn. The most effective herbicide control is the use of pre-emergent herbicides applied from late April to mid May in Nebraska. Post-emergent herbicides, such as Drive or Acclaim Extra, are best applied when crabgrass is young.
Internet Resource: http://www.urbanext.uiuc.edu/lawntalk/lawntalk20.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
4. Nimblewill is a warm season perennial grass often found in older lawns. As with other warm season grasses, nimblewill is dormant from mid autumn through mid to late spring. In lawns, nimblewill forms dense patches, often a foot or more in diameter. When it goes dormant, the brownish patches may be confused for disease or insect damage. It has fibrous roots, making the plants easy to pull, and wiry stems that root at the nodes. When actively growing, nimblewill has blue-green, short, flat bladed leaves up to 2 inches long. When dormant, nimblewill is a faded dull brown. Maintaining a dense, healthy lawn through proper turf selection, establishment, and maintenance is the recommended non-chemical control. Presently, there are no selective herbicides for nimblewill. Glyphosate, a nonselective herbicide, can be applied to green, actively growing weeds from late spring through early autumn. Applications of glyphosate to nimblewill when dormant will not provide control. A new product that selectively controls nimblewill is set to be released in 2008.
Internet Resource: http://www.purdue.edu/dp/envirosoft/lawn/src/pest/perennial.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
5. Yellow Nutsedge is distinctive in lawns right now with its wide bladed, yellow green leaves with a thick mid-vein and very waxy covering. It’s shallow, fibrous root system produces many nut-like tubers, which are underground food storage organs. Each of these tubers can germinate and produce new plants. Although present in lawns now, control should not be attempted this late in the season. Handpulling or the application of herbicides needs to be done by the third week of June to be effective. Wait until next season. Certainty (sulfosulfuron) or Sedgehammer/Manage (halosulfuron) are the products of choice.
Internet Resource: http://ohioline.osu.edu/hyg-fact/4000/4010.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
6. Summer Patch symptoms are one to two foot, tan colored, circular, crescent, or serpentine shaped patches. Tufts of healthy green grass may remain in the center and is known as frog-eye. Numerous patches may cause large blighted areas of turf. This is a root disease. No leaf lesions or leaf spots will occur. Infected plants have a dark brown to black crown and root rot. Control includes using proper lawn care practices, overseeding with resistant cultivars, and fungicide applications made in April and May when the fungus is infecting the roots. Factors which favor disease development are a thick thatch layer, poorly drained and compacted soil, frequent light irrigation, low mowing height, sloped sites exposed to heat, and the use of poorly adapted grass cultivars.
Internet Resource: http://nu-distance.unl.edu/homer/disease/Hort/Turf/TuSumPtch.html
Information on resistant cultivars may be found at: http://www.ntep.org/reports/kb00/kb00_06-10/kb00_06-10.htm
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7. Fall webworms appear as large, unsightly webbed nests in fruit, ornamental and shade trees from Iate summer through fall. The nests are filled with caterpillars, dead leaves, frass and worm excrement. While unsightly, they are fairly harmless to trees at this time of year. Mechanical removal of the nests or the application of insecticides when the nests are small will reduce their numbers.
Internet Resources: http://countywebapp.unl.edu/counties/dodge/newsitems/Hort%20News%202005/hort%20news%20050804 or
http://www.oznet.ksu.edu/hfrr/extensn/problems/fallwebw.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
8. Bagworms cause defoliation of evergreen plants like spruce and juniper. Small, brown bags made of webbed together needles are found on stems. It is important to cut open the bags now. If the larvae have pupated, it is too late to apply an insecticide this season. Bacillus thuriengiensis or most general use insecticides with carbaryl or permethrins work if applied at hatching (late May into June) or prior to larvae pupating. Pick off and destroy bags at this time of year.
Internet Resource: http://ianrnews.unl.edu/static/0607200.shtml or http://ohioline.osu.edu/hyg-fact/2000/
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
9. Iron chlorosis of trees, especially pin oak, silver maple and Autumn Blaze maple, causes leaves to turn pale green to yellow, but the veins remain green. The problem is a lack of iron in the tree, rarely a lack of iron in the soil. Iron is not readily available to plants in the high pH soils found in Nebraska. Tree species susceptible to iron chlorosis should not be sold or planted. Treatments can work for a short period and include application of ferrous sulfate or chelated iron to to the soil, the foliage or as a trunk injection.
Internet Resource: http://lancaster.unl.edu/hort/articles/2005/Chlorosis.shtml
http://www.oznet.k-state.edu/hfrr/extensn/problems/irnchlor.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
10. Lacebugs cause shade tree leaves to discolor and turn yellowish or whitish. On close inspection, the leaves appear stippled and tiny lacebugs or specks of their shiny black excrement may be found on leaf undersides. Lacebugs are sap feeders. Damage this late in the season is more unsightly than harmful to trees.
Internet Resource: http://www.dakota.unl.edu/newsitems/news040805153332 or
http://www.extension.umn.edu/yardandgarden/ygbriefs/e452lacebug.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
11. Fireblight is a bacterial disease that is most destructive to apple, pear and crabapple. It can also affect hawthorne, cotoneaster and serviceberry. Symptoms include water-soaked blossoms, light brown to blackened leaves, discolored bark, and black "shepherd's crook" twigs. Fire blight bacteria can be spread by insects, rain splash or pruning tools. Controls include planting resistant varieties, cultural practices, pruning and preventive sprays.
Internet Resource: http://www.ext.colostate.edu/pubs/Garden/02907.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
12. Soldier beetles are ½ inch long, elongate, yellowish orange beetles, usually with two black spots near the base of the wing covers. They can become abundant at this time of year and create unnecessary concern. They are predators and feed on other insects such as caterpillars, aphids, and soft-bodied insects. As they lie in wait for prey on flowers they may feed on nectar and pollen but they do not damage plants. Since soldier beetles are beneficial and harmless it is unnecessary to control them.
Internet Resource: http://www.ipm.iastate.edu/ipm/iiin/soldier.html
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13. Tomato fruit disorders - Catfacing appears as deep indentations in the blossom end of the fruit. In some cases, the entire fruit becomes distorted. This damage occurs when temperatures drop below 50 E F during flowering and fruit set, resulting in poor pollination. In some cases, excess heat, 2,4-D injury, erratic soil moisture, and high nitrogen fertilization can lead to catfacing. Catfacing is often cultivar specific so keep records of cultivars grown and switch if the problem persists.
Growth cracks affect the stem end of tomatoes and typically appear as the fruit matures. Concentric cracking produces circular cracks around the stem end of the fruit. Radial cracks spread outward from the stem scar. Growth cracks often appear when conditions drastically change the rate of growth, such as wide fluctuations in temperature and moisture. Cultivars vary in their ability to withstand cracking. High nitrogen and low potassium may lead to fruit cracking. Proper fertilization and adequate, regular irrigation will reduce the likelihood of growth cracks.
Internet Resource: http://ipcm.wisc.edu/news/misc/tomfrtdis.htm
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14. Emerald Ash Borer Alert- While Emerald Ash Borer HAS NOT YET been found in Nebraska, it has been found west of Chicago. We need to be on the watch for the movement of this pest into Nebraska, especially via firewood brought in by campers. Ash tree symptoms include trees dieing from the top back, suckering at the base and 1/8” diameter, D-shaped emergence holes in the tree trunk and larger branches. Familiarize yourself with emerald ash borer and watch for them.
Internet Resource: http://www.emeraldashborer.info/
| Current Problems: | Major Symptom: |
Lawns |
|
| 1. Mushrooms | Mushrooms growing in lawns and mulched beds |
| 2. Billbug damage | Turf appears drought stressed; turns brown and dies |
| 3. Crabgrass | Apple green colored grass with ¼” wide blades |
| 4. Dormant nimblewill | Circular, matted, brown patches in otherwise healthy turf |
| 5. Yellow nutsedge | Yellow-green, 3-ranked, grass-like weed with waxy leaves |
| 6. Summer Patch | Circular, tan-colored patches; may have a tuft of green in the centers |
| Trees & Shrubs | |
| 7. Fall webworm | Fairly large, unsightly webs filled with worms in deciduous trees |
| 8. Bagworm | Defoliation of evergreens and small brown bags attached to stems |
| 9. Iron chlorosis | Pale green or yellow leaves with darker green veins |
| 10. Lacebugs | Discoloration of the leaves of hackberry, sycamore, oak, etc. |
| 11. Fireblight | Light brown to blacking of leaves, often near branch ends |
| Vegetables/Fruits/Ornamentals | |
| 12. Soldier beetles | Orangish beetles with two black spots; often found on flowers |
| 13. Tomato fruit cracking/catfacing | Fruit cracks near stem or distorted fruit |
| Potential Problem To Watch For: | |
| 14. Emerald ash borer | Ash trees die from the top down and sucker at the base |
1. Mushrooms growing in lawns or mulched beds are fruiting bodies of fungi growing on decomposing organic matter in soil, such as an old tree root; or on wood chip mulch. Most mushrooms are harmless to the turf; unless they are one of the fairy ring mushrooms. They will disappear when the organic matter decomposes or conditions are less conducive to fruiting. Advise homeowners to remove mushrooms to reduce the risk of children eating them. Some types are poisonous.
Internet Resource: http://www.oznet.ksu.edu/dp_hfrr/extensn/problems/mushrooms.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
2. Billbug damage is more prevalent this year than in recent years. In May and June, newly-hatched billbug larvae tunnel in grass stems which discolor and when pulled, readily break away at or near the crown. Subsurface feeding by older larvae through July can damage roots, causing turf to appear drought stressed. Under heavy billbug pressure, areas of lawn turn brown and die. The greatest billbug injury usually occurs from mid-June through late July. Billbug injury is easily mistaken for white grub or sod webworm damage, disease, or plant stress. Damaged turf should be carefully examined to confirm the presence of billbugs before making a management decision. Insecticide controls are best applied in May and targeted at the adult weevil.
Internet Resources: http://entomology.unl.edu/turfent/documnts/billbugs.htm or
http://lancaster.unl.edu/hort/factshes/085.shtml
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
3. Crabgrass is an annual, warm season grass. Its appearance in lawns is often a sign of a thin, weak turf unable to compete with annual weeds or lawns mowed too low. To help control crabgrass, use lawn care practices that promote healthy rooting and a dense lawn. The most effective herbicide control is the use of pre-emergent herbicides applied from late April to mid May in Nebraska. Post-emergent herbicides, such as Drive or Acclaim Extra, are best applied when crabgrass is young.
Internet Resource: http://www.urbanext.uiuc.edu/lawntalk/lawntalk20.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
4. Nimblewill is a warm season perennial grass often found in older lawns. As with other warm season grasses, nimblewill is dormant from mid autumn through mid to late spring. In lawns, nimblewill forms dense patches, often a foot or more in diameter. When it goes dormant, the brownish patches may be confused for disease or insect damage. It has fibrous roots, making the plants easy to pull, and wiry stems that root at the nodes. When actively growing, nimblewill has blue-green, short, flat bladed leaves up to 2 inches long. When dormant, nimblewill is a faded dull brown. Maintaining a dense, healthy lawn through proper turf selection, establishment, and maintenance is the recommended non-chemical control. Presently, there are no selective herbicides for nimblewill. Glyphosate, a nonselective herbicide, can be applied to green, actively growing weeds from late spring through early autumn. Applications of glyphosate to nimblewill when dormant will not provide control. A new product that selectively controls nimblewill is set to be released in 2008.
Internet Resource: http://www.purdue.edu/dp/envirosoft/lawn/src/pest/perennial.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
5. Yellow Nutsedge is distinctive in lawns right now with its wide bladed, yellow green leaves with a thick mid-vein and very waxy covering. It’s shallow, fibrous root system produces many nut-like tubers, which are underground food storage organs. Each of these tubers can germinate and produce new plants. Although present in lawns now, control should not be attempted this late in the season. Handpulling or the application of herbicides needs to be done by the third week of June to be effective. Wait until next season. Certainty (sulfosulfuron) or Sedgehammer/Manage (halosulfuron) are the products of choice.
Internet Resource: http://ohioline.osu.edu/hyg-fact/4000/4010.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
6. Summer Patch symptoms are one to two foot, tan colored, circular, crescent, or serpentine shaped patches. Tufts of healthy green grass may remain in the center and is known as frog-eye. Numerous patches may cause large blighted areas of turf. This is a root disease. No leaf lesions or leaf spots will occur. Infected plants have a dark brown to black crown and root rot. Control includes using proper lawn care practices, overseeding with resistant cultivars, and fungicide applications made in April and May when the fungus is infecting the roots. Factors which favor disease development are a thick thatch layer, poorly drained and compacted soil, frequent light irrigation, low mowing height, sloped sites exposed to heat, and the use of poorly adapted grass cultivars.
Internet Resource: http://nu-distance.unl.edu/homer/disease/Hort/Turf/TuSumPtch.html
Information on resistant cultivars may be found at: http://www.ntep.org/reports/kb00/kb00_06-10/kb00_06-10.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
7. Fall webworms appear as large, unsightly webbed nests in fruit, ornamental and shade trees from Iate summer through fall. The nests are filled with caterpillars, dead leaves, frass and worm excrement. While unsightly, they are fairly harmless to trees at this time of year. Mechanical removal of the nests or the application of insecticides when the nests are small will reduce their numbers.
Internet Resources: http://countywebapp.unl.edu/counties/dodge/newsitems/Hort%20News%202005/hort%20news%20050804 or
http://www.oznet.ksu.edu/hfrr/extensn/problems/fallwebw.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
8. Bagworms cause defoliation of evergreen plants like spruce and juniper. Small, brown bags made of webbed together needles are found on stems. It is important to cut open the bags now. If the larvae have pupated, it is too late to apply an insecticide this season. Bacillus thuriengiensis or most general use insecticides with carbaryl or permethrins work if applied at hatching (late May into June) or prior to larvae pupating. Pick off and destroy bags at this time of year.
Internet Resource: http://ianrnews.unl.edu/static/0607200.shtml or http://ohioline.osu.edu/hyg-fact/2000/
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
9. Iron chlorosis of trees, especially pin oak, silver maple and Autumn Blaze maple, causes leaves to turn pale green to yellow, but the veins remain green. The problem is a lack of iron in the tree, rarely a lack of iron in the soil. Iron is not readily available to plants in the high pH soils found in Nebraska. Tree species susceptible to iron chlorosis should not be sold or planted. Treatments can work for a short period and include application of ferrous sulfate or chelated iron to to the soil, the foliage or as a trunk injection.
Internet Resource: http://lancaster.unl.edu/hort/articles/2005/Chlorosis.shtml
http://www.oznet.k-state.edu/hfrr/extensn/problems/irnchlor.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
10. Lacebugs cause shade tree leaves to discolor and turn yellowish or whitish. On close inspection, the leaves appear stippled and tiny lacebugs or specks of their shiny black excrement may be found on leaf undersides. Lacebugs are sap feeders. Damage this late in the season is more unsightly than harmful to trees.
Internet Resource: http://www.dakota.unl.edu/newsitems/news040805153332 or
http://www.extension.umn.edu/yardandgarden/ygbriefs/e452lacebug.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
11. Fireblight is a bacterial disease that is most destructive to apple, pear and crabapple. It can also affect hawthorne, cotoneaster and serviceberry. Symptoms include water-soaked blossoms, light brown to blackened leaves, discolored bark, and black "shepherd's crook" twigs. Fire blight bacteria can be spread by insects, rain splash or pruning tools. Controls include planting resistant varieties, cultural practices, pruning and preventive sprays.
Internet Resource: http://www.ext.colostate.edu/pubs/Garden/02907.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
12. Soldier beetles are ½ inch long, elongate, yellowish orange beetles, usually with two black spots near the base of the wing covers. They can become abundant at this time of year and create unnecessary concern. They are predators and feed on other insects such as caterpillars, aphids, and soft-bodied insects. As they lie in wait for prey on flowers they may feed on nectar and pollen but they do not damage plants. Since soldier beetles are beneficial and harmless it is unnecessary to control them.
Internet Resource: http://www.ipm.iastate.edu/ipm/iiin/soldier.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
13. Tomato fruit disorders - Catfacing appears as deep indentations in the blossom end of the fruit. In some cases, the entire fruit becomes distorted. This damage occurs when temperatures drop below 50 E F during flowering and fruit set, resulting in poor pollination. In some cases, excess heat, 2,4-D injury, erratic soil moisture, and high nitrogen fertilization can lead to catfacing. Catfacing is often cultivar specific so keep records of cultivars grown and switch if the problem persists.
Growth cracks affect the stem end of tomatoes and typically appear as the fruit matures. Concentric cracking produces circular cracks around the stem end of the fruit. Radial cracks spread outward from the stem scar. Growth cracks often appear when conditions drastically change the rate of growth, such as wide fluctuations in temperature and moisture. Cultivars vary in their ability to withstand cracking. High nitrogen and low potassium may lead to fruit cracking. Proper fertilization and adequate, regular irrigation will reduce the likelihood of growth cracks.
Internet Resource: http://ipcm.wisc.edu/news/misc/tomfrtdis.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
14. Emerald Ash Borer Alert- While Emerald Ash Borer HAS NOT YET been found in Nebraska, it has been found west of Chicago. We need to be on the watch for the movement of this pest into Nebraska, especially via firewood brought in by campers. Ash tree symptoms include trees dieing from the top back, suckering at the base and 1/8” diameter, D-shaped emergence holes in the tree trunk and larger branches. Familiarize yourself with emerald ash borer and watch for them.
Internet Resource: http://www.emeraldashborer.info/
