Hort Update for the week of 8/21/06
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
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
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. Lawn Yellowing can be due to a number of factors. In many cases, lawn yellowing we are seeing now is due to iron or nitrogen chlorosis brought on by a combination of high soil moisture, low soil oxygen, high pH soils, soil compaction, and high temperatures. With iron chlorosis, yellowing is random and patchy. Grass blades will show interveinal yellowing where the veins remain green while the tissue between the veins is yellow. With a nitrogen deficiency, lawn yellowing will be more uniform and veins will not remain green. On regularly fertilized lawns, a nitrogen deficiency can be due to denitrification; a process where nitrate nitrogen is converted to gaseous elemental nitrogen which is then lost to the atmosphere. While an application of ferrous sulfate or chelated iron may green up turfgrass; avoid overwatering, relieve soil compaction with core aeration, and use management practices that promote a healthy soil/rooting environment to reduce turf yellowing.
Internet Resource: http://www.ext.vt.edu/pubs/turf/430-400/430-400.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
5. White Grubs hatch has occurred and damage may be seen into September. Clients should monitor their lawn by rolling back sod in open areas. If 8 or more grubs can be found per square foot, insecticide treatment is justified. The only rescue treatment that works well is Dylox. Sevin is labeled for white grubs, but does not work well. Dylox is short lived and white grubs need to be present for it to be effective. Homeowners may have to re-apply. If clients apply imidacloprid (Merit, Scotts GrubX) and water it in now, it will take about two weeks for it to begin to work. Correct irrigation through summer is important for control and turf recovery.
Internet Resource: http://entomology.unl.edu/turfent/documnts/wgbmgmt.htm or
http://ohioline.osu.edu/hyg-fact/2000/2500.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
6. Turf Diagnostic Resources
Identifying turf and landscape weeds can be difficult. Below are some resources that Roch Gaussion, UNL Turfgrass Specialist uses regularly and would recommend.
Turfgrass For The Midwest- http://www.turf.uiuc.edu/NCR-192/turf_midwest/
This web site contains general information about midwestern adapted turf species, including turf recommendations for specific landscape conditions.
MSU Turf Weeds.net- http://www.msuturfweeds.net/
A great reference for weeds of the Midwest and also has links to other great turf web sites.
Midwestern Turfgrass Weed Identification & Control- http://www.turf.uiuc.edu/weed_web/index.htm
Another good site for identification for weeds of the midwest.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
7. Scotch Pine Needlecast Yellowing and browning of one year and older needles on Scots pine trees. Brown needles develop brown bands across the needle. Some infected needles will cling to the tree while others will drop off. For some control, registered fungicides need to be applied in spring and throughout the growing season.
Internet Resource: http://ohioline.osu.edu/hyg-fact/3000/3071.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
8. 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
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
9. Bagworms on Evergreens: Defoliation of 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/
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
10. Leaf Scorch on trees and other ornamentals results in leaf tips and/or margins turning brown to tan. May look like a fungal leaf disease. Leaf scorch is due to leaves losing water faster than roots can replace it, especially on hot, windy days. Check for unhealthy growing conditions, such as poorly drained soils or overwatering that leads to unhealthy roots unable to efficiently supply water. Recently transplanted trees or those with trunk or root damage may show leaf scorch.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
11. Pine Wilt Report: Pine wilt was recently confirmed in Wayne, NE and has been confirmed in the Chadron area. It is now considered to be present throughout the state. Greyhound by Arbor Systems is available for injection to prevent Pine wilt but the approximate cost is $300.00 per tree with a 10” diameter trunk. Scotch pine trees that die need to be removed and chipped or destroyed ASAP.
Internet Resource: http://www.extension.iastate.edu/Publications/SUL9.pdf
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
12. 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
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
13. Zimmerman Pine Moth larvae tunnel beneath the bark of pine trees and girdle branches which die or break off readily in wind and snow storms. A pinkish pink mass is often found at the base of infested branches. Insecticides applied during the second week of April and the second week of August are required for control.
Internet Resource: http://www.coopext.colostate.edu/4DMG/Pests/pinemoth.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
14. Brown Rot of Peach Fruit: Affected fruit develops light brown spots that enlarge rapidly. The fruit may be completely rotted within a day or two. Peaches develop a dusty brown appearance and rotting fruit shrivels to form a structure called a mummy, which is colonized by the brown rot fungus. These mummies may remain attached to the tree or drop to the ground. Sanitation, or removing and destroying infected fruit now, is important for reducing the disease next year. Labeled fungicides need to be applied during blossoming and fruit development.
Internet Resource: http://www.oznet.ksu.edu/dp_hfrr/extensn/problems/pchbrnrt.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
15. Grasshoppers: Large numbers of grasshoppers can severely defoliate garden and landscape plants. Effective control includes treating egg hatching areas (roadsides and weedy areas) at egg hatch when the grasshoppers are young. Adult grasshoppers are difficult to control.
Internet Resource: http://acreage.unl.edu/News/News/grasshopper06.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
16. Emerald Ash Borer Alert: While Emerald Ash Borer has not 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. Lawn yellowing | Turf a uniform or patchy pale green to yellow color |
| 5. White Grubs | Turf browning. C-shaped, cream colored grubs can be found. |
| 6. Turf diagnostic resources | Weed and turfgrass identification resources |
| Trees & Shrubs | |
| 7. Scotch pine needle cast | Browning of one year old and older needles |
| 8. Fall webworm | Fairly large, unsightly webs filled with worms in deciduous trees |
| 9. Bagworm | Defoliation of evergreens and small brown bags attached to stems |
| 10. Leaf scorch | Browning of leaf edges |
| 11. Pine wilt | Scotch pine turn an off-color and die fairly quick |
| 12. Lacebugs | Discoloration of the leaves of hackberry, sycamore, oak, etc. |
| 13. Zimmerman pine moth | Pine tree branches begin to die or break off. |
| Vegetables/Fruits/Ornamentals | |
| 14. Peach fruit rot | Peaches rot quickly on the tree |
| 15. Grasshoppers | Chewing damage to plant parts |
| Potential Problem To Watch For: | |
| 16. 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. Lawn Yellowing can be due to a number of factors. In many cases, lawn yellowing we are seeing now is due to iron or nitrogen chlorosis brought on by a combination of high soil moisture, low soil oxygen, high pH soils, soil compaction, and high temperatures. With iron chlorosis, yellowing is random and patchy. Grass blades will show interveinal yellowing where the veins remain green while the tissue between the veins is yellow. With a nitrogen deficiency, lawn yellowing will be more uniform and veins will not remain green. On regularly fertilized lawns, a nitrogen deficiency can be due to denitrification; a process where nitrate nitrogen is converted to gaseous elemental nitrogen which is then lost to the atmosphere. While an application of ferrous sulfate or chelated iron may green up turfgrass; avoid overwatering, relieve soil compaction with core aeration, and use management practices that promote a healthy soil/rooting environment to reduce turf yellowing.
Internet Resource: http://www.ext.vt.edu/pubs/turf/430-400/430-400.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
5. White Grubs hatch has occurred and damage may be seen into September. Clients should monitor their lawn by rolling back sod in open areas. If 8 or more grubs can be found per square foot, insecticide treatment is justified. The only rescue treatment that works well is Dylox. Sevin is labeled for white grubs, but does not work well. Dylox is short lived and white grubs need to be present for it to be effective. Homeowners may have to re-apply. If clients apply imidacloprid (Merit, Scotts GrubX) and water it in now, it will take about two weeks for it to begin to work. Correct irrigation through summer is important for control and turf recovery.
Internet Resource: http://entomology.unl.edu/turfent/documnts/wgbmgmt.htm or
http://ohioline.osu.edu/hyg-fact/2000/2500.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
6. Turf Diagnostic Resources
Identifying turf and landscape weeds can be difficult. Below are some resources that Roch Gaussion, UNL Turfgrass Specialist uses regularly and would recommend.
Turfgrass For The Midwest- http://www.turf.uiuc.edu/NCR-192/turf_midwest/
This web site contains general information about midwestern adapted turf species, including turf recommendations for specific landscape conditions.
MSU Turf Weeds.net- http://www.msuturfweeds.net/
A great reference for weeds of the Midwest and also has links to other great turf web sites.
Midwestern Turfgrass Weed Identification & Control- http://www.turf.uiuc.edu/weed_web/index.htm
Another good site for identification for weeds of the midwest.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
7. Scotch Pine Needlecast Yellowing and browning of one year and older needles on Scots pine trees. Brown needles develop brown bands across the needle. Some infected needles will cling to the tree while others will drop off. For some control, registered fungicides need to be applied in spring and throughout the growing season.
Internet Resource: http://ohioline.osu.edu/hyg-fact/3000/3071.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
8. 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
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
9. Bagworms on Evergreens: Defoliation of 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/
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
10. Leaf Scorch on trees and other ornamentals results in leaf tips and/or margins turning brown to tan. May look like a fungal leaf disease. Leaf scorch is due to leaves losing water faster than roots can replace it, especially on hot, windy days. Check for unhealthy growing conditions, such as poorly drained soils or overwatering that leads to unhealthy roots unable to efficiently supply water. Recently transplanted trees or those with trunk or root damage may show leaf scorch.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
11. Pine Wilt Report: Pine wilt was recently confirmed in Wayne, NE and has been confirmed in the Chadron area. It is now considered to be present throughout the state. Greyhound by Arbor Systems is available for injection to prevent Pine wilt but the approximate cost is $300.00 per tree with a 10” diameter trunk. Scotch pine trees that die need to be removed and chipped or destroyed ASAP.
Internet Resource: http://www.extension.iastate.edu/Publications/SUL9.pdf
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
12. 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
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
13. Zimmerman Pine Moth larvae tunnel beneath the bark of pine trees and girdle branches which die or break off readily in wind and snow storms. A pinkish pink mass is often found at the base of infested branches. Insecticides applied during the second week of April and the second week of August are required for control.
Internet Resource: http://www.coopext.colostate.edu/4DMG/Pests/pinemoth.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
14. Brown Rot of Peach Fruit: Affected fruit develops light brown spots that enlarge rapidly. The fruit may be completely rotted within a day or two. Peaches develop a dusty brown appearance and rotting fruit shrivels to form a structure called a mummy, which is colonized by the brown rot fungus. These mummies may remain attached to the tree or drop to the ground. Sanitation, or removing and destroying infected fruit now, is important for reducing the disease next year. Labeled fungicides need to be applied during blossoming and fruit development.
Internet Resource: http://www.oznet.ksu.edu/dp_hfrr/extensn/problems/pchbrnrt.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
15. Grasshoppers: Large numbers of grasshoppers can severely defoliate garden and landscape plants. Effective control includes treating egg hatching areas (roadsides and weedy areas) at egg hatch when the grasshoppers are young. Adult grasshoppers are difficult to control.
Internet Resource: http://acreage.unl.edu/News/News/grasshopper06.htm
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
16. Emerald Ash Borer Alert: While Emerald Ash Borer has not 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/
