Hort Update for the week of 5/9/08
1. Bluegrass Billbug adults are one-fourth inch long black weevils with a distinct snout. During April, May and June they can be observed walking on sidewalks and driveways. On lawns with a history of billbug damage, an application of Merit (imidacloprid) applied during the second week of May provides effective control of larvae. Adult weevils do not damage turfgrass. They deposit eggs in bluegrass stems near plant crowns. Newly-hatched larvae tunnel in grass stems causing discoloration and dieback. Subsurface feeding by older larvae through July can damage roots, causing turf to appear drought stressed. Under heavy billbug pressure, areas of lawn may turn brown and die during summer.
How to Sample for Insects in Turfgrass, http://extensionhorticulture.unl.edu/Articles/SJB/Sampling.shtml
Bluegrass Billbug Guide, http://lancaster.unl.edu/hort/factsheets/085.shtml
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
2. White grubs overwinter as larvae. In spring, they move closer to the soil surface to pupate. White grubs found during spring are not a concern and applying insecticides to kill the grubs - larvae - of masked chafers, Japanese beetles, or even May/June bugs is not justified. For insecticide applications targeting only white grubs, the ideal window for applying products such as Merit, Arena or Meridian is between the 3rd week of June and mid-July.
If insecticides are applied earlier in the season, such as in mid-May for bluegrass billbugs; some of these products can provide effective control of white grubs. However, this does not always work well. Lawn care services and homeowners need to closely monitor lawns in August for white grubs when insecticides are applied earlier than mid-June.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
3. Sod webworm damage in western Nebraska- Sod Webworms overwinter as partially grown larvae. Following drought years, activity and damage by sod webworm may increase. If overwintering larvae have a high survival rate, spring damage can occur. From North Platte west, overwintering larvae are often the main problem with damage occurring in spring. From North Platte east, the next generation of webworms are the main problem with damage occurring in June and July. When 15 or more larvae per square yard can be found, an application of bifenthrin, carbaryl (Sevin), etc. should be effective.
How to Sample for Insects in Turfgrass: http://extensionhorticulture.unl.edu/Articles/SJB/Sampling.shtml
Sod Webworms and Cutworms: http://www.ext.colostate.edu/PUBS/insect/05509.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
4. Nimblewill & Tenacity herbicide- The University of Nebraska has been testing the herbicide Tenacity (mesotrione) for control of numerous weeds. Tenacity has excellent activity on many broadleaf weeds as well as nimblewill and windmillgrass. It is currently registered in Nebraska for sod farms and golf courses only. Syngenta, the company who developed Tenacity, anticipates a label for residential applications by commercial applicators late this year or early next year and possibly a consumer label in 2010.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
5. Rough bluegrass, Poa trivialis, is a stoloniferous bluegrass that is light green in color and often a contaminant in low quality seed mixes. Once it becomes established it can overtake a Kentucky bluegrass lawn especially in shaded and wet sites. Commercial applicators can use Certainty (sulfosulfuron) to selectively remove rough bluegrass from Kentucky bluegrass. Certainty is also labeled for selective removal of tall fescue from bluegrass and yellow nutsedge control.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
6. Goosegrass, Elusine indica, is a warm season annual that germinates in the spring after crabgrass. It is much more difficult to control than crabgrass. Products containing prodiamine (Barricade) are the most effective. Post emergence control is more difficult with MSMA products working the most effectively but still only delivering 50-60% control.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
7. Cold temperature injury did occur during the recent snow storm in western Nebraska. The flowers of flowering trees were most likely affected and this can lead to a decrease in fruiting on fruit bearing trees. Effects of last years April freeze are still appearing. In the Omaha area, there are reports of redbud trees dieing.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
8. Winter Desiccation on evergreens appears to be fairly severe this year with eastern white pine, Arborvitae, Japanese Yew and broadleaf evergreens like Holly most affected. 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. This year, soils were frozen for most of the winter and roots were unable to replace lost moisture. Some winter dessication may also be due to damage from de-icing salts. To avoid winter desiccation, provide adequate moisture to plants throughout the year. During winter, protect plants from salt spray or avoid shoveling snow with de-icing salts onto plants or the soil of plants. The damaged growth can be pruned or homeowners can wait until June 1 st to see if new growth occurs.
Winter Dessication Injury, http://extensionhorticulture.unl.edu/Current/WinterInjury.shtml
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
9. Dothistroma needle blight causes browning of needles on the lower half of Austrian, Scotch and ponderosa pine trees. On close inspection, needles will have turned brown from the tip back to a reddish-purple lesion or band on the needle. Lesions or bands may be found on green needles as well. If no lesions are found, the evergreen may have winter burn or dessication. If lesions are found, fungicides applications of Bordeaux mixture or liquid copper fungicides applied about mid-May and mid to late June effectively control needle blight.
Dothistroma Needle Blight, http://extensionhorticulture.unl.edu/Current/Dothistroma.shtml
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
10. Bagworms increasing- damage to evergreens, and some broadleaf trees, has been rapidly increasing with trees being severely defoliated and killed. Now is the time to monitor trees for bagworms. Insecticides (Permethrins, Carbaryl, Bacillus thuringiensis) applied in late May to early June, when young bagworms are about one-fourth inch long, are highly effective. Bagworms overwinter as eggs inside one to two inch long, tan to brown bags attached to twigs. The bags appear cocoon-like and are covered with needles to help camouflage them. Each bag contains 300 to 1000 eggs.
Controlling Bagworms, http://extensionhorticulture.unl.edu/Current/Bagworm.shtml
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
11. Pine sawfly numbers appear to be reduced, most likely from last years April freeze which occurred when sawflies were young larvae on pine trees. Very few to no sawflies are being observed on pines in areas that typically have large numbers.
Pine Sawfly, http://extensionhorticulture.unl.edu/Current/Sawfly.shtml
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
12. Emerald ash borer (EAB) is not yet known to be present in Nebraska; hence, commercial applicators and homeowners should not be applying insecticides to ash trees for control of Emerald Ash Borer. The insecticide, Imidacloprid, does state on the label that it controls EAB. If applied correctly, this is true. However, there is currently no reason to make recommendations for control of EAB, since there is no current threat from this pest in Nebraska.
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
13. Winter kill and dieback of some herbaceous perennials and woody plants is being observed. For example, Butterfly Bush (Buddleia ssp.) and Blue Mist Spirea (Caryopteris ssp.), which typically die-back some each winter, have more severe dieback this year and in some cases these plants may have been killed and will need replacement.
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
14. Prune roses in May- Each spring, winter killed wood is pruned from roses. It is best to wait until May to do this. On roses pruned in April, additional dieback can be observed. When pruning is delayed, and roses are pruned in May, additional injury rarely occurs.
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
15. Echelon & Urea Damage- From Roch Gaussion, UNL Turfgrass Specialist- A colleague at North Carolina State University (Dr. Fred Yelverton) shared the following information. Echelon herbicide, while not being used extensively in Nebraska, might have potential in the future. At this point only the following is known. We will be cooperating with turf specialists at North Carolina and Indiana to determine the extent of the problem.
There appears to be a negative interaction of Echelon herbicide and urea (46-0-0) on tall fescue. This interaction is showing up as injury on tall fescue. Echelon is a pre-package mix of prodiamine and sulfentrazone. Echelon has been tested in many university trials in recent years and, at the proper rate, turfgrass tolerance has not been an issue. However, when mixed with 46-0-0, several lawn care operators have called to say they have observed injury on tall fescue. Researchers at North Carolina State University followed these complaints up with a research trial at the Lake Wheeler Turfgrass Field Laboratory and we have confirmed that there is significant injury on tall fescue.
It is important to point out there have been no reports of fescue death from this combination. It is also important to point out that, at this time, we have only had reports of this injury on tall fescue. It may or may not occur with other turf species.
For more information, including pictures of typical damage, visit, http://www.turffiles.ncsu.edu/Alerts.aspx#004552
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
16. Spanish/English guides available- University of Nebraska-Lincoln Extension is offering three guides to help improve communication between Spanish and English speaking individuals. Titled, español a ingles, English to Spanish, these communication guides are laminated and easy to keep with you, folding into a convenient quarter-fold size of 4.5” by 11”.
The guides feature phrases and key words in both Spanish and English, including pronunciation guides for both languages. Each of the three guides has a unique focus area including a guide for the Green Industry, one for Landscaping and Grounds Keeping, and one for Golf and Pond Maintenance. They are currently available for by calling or e-mailing John Fech at jfech@unlnotes.unl.edu or 402-444-7804.
They can also be ordered on-line at Garden Center Update, http://extensionhorticulture.unl.edu/Update.shtml.
The cost is $8.99, not including shipping and handling; there are bulk discount rates available if you order more than 10.
John Fech, University of Nebraska-Lincoln Horticulturist coordinated the making of the Spanish guides. Fech’s goal is to help native English speakers communicate with native Spanish speakers, and vice-versa. This guide is unique because it facilitates the two-way communication.
| Current Problems: | Major Symptom: |
| Lawns | |
| 1. Bluegrass billbug | One-fourth inch, black weevils found on sidewalks/driveways now |
| 2. Spring grubs | Insecticide applications are not justified for white grubs found in spring |
| 3. Sod webworm damage in western Nebraska | Damage has been occurring to lawns in western Nebraska |
| 4. Nimblewill & Tenacity herbicide | Update on the herbicide |
| 5. Rough bluegrass | Patches of a light green weedy grass, often in shady areas |
| 6. Goosegrass | Light green warm season annual weedy grass in lawns |
| Trees & Shrubs | |
| 7. Cold temperature injury | Damage from last springs freeze & recent May snow storm |
| 8. Winter desiccation on evergreens | Uniform browning of foliage; often on south or west side of tree |
| 9. Dothistroma needle blight of pine | Needle browning in lower half of trees. Fungicides applied in May |
| 10. Bagworms increasing | Monitor for bagworms now. Apply insecticides from late May into June |
| 11. Pine sawfly numbers reduced | Sawfly populations appear to be greatly reduced by last years freeze |
| 12. Emerald ash borer | Recommendations for EAB control is not yet justified in Nebraska |
| Gardens/Ornamentals | |
| 13. Winter dieback | More dieback than usually on some herbacous perennials and woody plants such as Butterfly Bush, Buddleia ssp. & Blue Mist Spirea, Caryopteris ssp. |
| 14. Pruning roses | Waiting until May to prune pays off |
| Miscellaneous | |
| 15. Echelon & Urea Damage | Combination of Echelon herbicide and urea may be damaging to tall fescue |
| 16. Spanish/English guides available | Spanish/English language guides available for the green industry |
1. Bluegrass Billbug adults are one-fourth inch long black weevils with a distinct snout. During April, May and June they can be observed walking on sidewalks and driveways. On lawns with a history of billbug damage, an application of Merit (imidacloprid) applied during the second week of May provides effective control of larvae. Adult weevils do not damage turfgrass. They deposit eggs in bluegrass stems near plant crowns. Newly-hatched larvae tunnel in grass stems causing discoloration and dieback. Subsurface feeding by older larvae through July can damage roots, causing turf to appear drought stressed. Under heavy billbug pressure, areas of lawn may turn brown and die during summer.
How to Sample for Insects in Turfgrass, http://extensionhorticulture.unl.edu/Articles/SJB/Sampling.shtml
Bluegrass Billbug Guide, http://lancaster.unl.edu/hort/factsheets/085.shtml
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
2. White grubs overwinter as larvae. In spring, they move closer to the soil surface to pupate. White grubs found during spring are not a concern and applying insecticides to kill the grubs - larvae - of masked chafers, Japanese beetles, or even May/June bugs is not justified. For insecticide applications targeting only white grubs, the ideal window for applying products such as Merit, Arena or Meridian is between the 3rd week of June and mid-July.
If insecticides are applied earlier in the season, such as in mid-May for bluegrass billbugs; some of these products can provide effective control of white grubs. However, this does not always work well. Lawn care services and homeowners need to closely monitor lawns in August for white grubs when insecticides are applied earlier than mid-June.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
3. Sod webworm damage in western Nebraska- Sod Webworms overwinter as partially grown larvae. Following drought years, activity and damage by sod webworm may increase. If overwintering larvae have a high survival rate, spring damage can occur. From North Platte west, overwintering larvae are often the main problem with damage occurring in spring. From North Platte east, the next generation of webworms are the main problem with damage occurring in June and July. When 15 or more larvae per square yard can be found, an application of bifenthrin, carbaryl (Sevin), etc. should be effective.
How to Sample for Insects in Turfgrass: http://extensionhorticulture.unl.edu/Articles/SJB/Sampling.shtml
Sod Webworms and Cutworms: http://www.ext.colostate.edu/PUBS/insect/05509.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
4. Nimblewill & Tenacity herbicide- The University of Nebraska has been testing the herbicide Tenacity (mesotrione) for control of numerous weeds. Tenacity has excellent activity on many broadleaf weeds as well as nimblewill and windmillgrass. It is currently registered in Nebraska for sod farms and golf courses only. Syngenta, the company who developed Tenacity, anticipates a label for residential applications by commercial applicators late this year or early next year and possibly a consumer label in 2010.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
5. Rough bluegrass, Poa trivialis, is a stoloniferous bluegrass that is light green in color and often a contaminant in low quality seed mixes. Once it becomes established it can overtake a Kentucky bluegrass lawn especially in shaded and wet sites. Commercial applicators can use Certainty (sulfosulfuron) to selectively remove rough bluegrass from Kentucky bluegrass. Certainty is also labeled for selective removal of tall fescue from bluegrass and yellow nutsedge control.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
6. Goosegrass, Elusine indica, is a warm season annual that germinates in the spring after crabgrass. It is much more difficult to control than crabgrass. Products containing prodiamine (Barricade) are the most effective. Post emergence control is more difficult with MSMA products working the most effectively but still only delivering 50-60% control.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
7. Cold temperature injury did occur during the recent snow storm in western Nebraska. The flowers of flowering trees were most likely affected and this can lead to a decrease in fruiting on fruit bearing trees. Effects of last years April freeze are still appearing. In the Omaha area, there are reports of redbud trees dieing.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
8. Winter Desiccation on evergreens appears to be fairly severe this year with eastern white pine, Arborvitae, Japanese Yew and broadleaf evergreens like Holly most affected. 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. This year, soils were frozen for most of the winter and roots were unable to replace lost moisture. Some winter dessication may also be due to damage from de-icing salts. To avoid winter desiccation, provide adequate moisture to plants throughout the year. During winter, protect plants from salt spray or avoid shoveling snow with de-icing salts onto plants or the soil of plants. The damaged growth can be pruned or homeowners can wait until June 1 st to see if new growth occurs.
Winter Dessication Injury, http://extensionhorticulture.unl.edu/Current/WinterInjury.shtml
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
9. Dothistroma needle blight causes browning of needles on the lower half of Austrian, Scotch and ponderosa pine trees. On close inspection, needles will have turned brown from the tip back to a reddish-purple lesion or band on the needle. Lesions or bands may be found on green needles as well. If no lesions are found, the evergreen may have winter burn or dessication. If lesions are found, fungicides applications of Bordeaux mixture or liquid copper fungicides applied about mid-May and mid to late June effectively control needle blight.
Dothistroma Needle Blight, http://extensionhorticulture.unl.edu/Current/Dothistroma.shtml
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
10. Bagworms increasing- damage to evergreens, and some broadleaf trees, has been rapidly increasing with trees being severely defoliated and killed. Now is the time to monitor trees for bagworms. Insecticides (Permethrins, Carbaryl, Bacillus thuringiensis) applied in late May to early June, when young bagworms are about one-fourth inch long, are highly effective. Bagworms overwinter as eggs inside one to two inch long, tan to brown bags attached to twigs. The bags appear cocoon-like and are covered with needles to help camouflage them. Each bag contains 300 to 1000 eggs.
Controlling Bagworms, http://extensionhorticulture.unl.edu/Current/Bagworm.shtml
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
11. Pine sawfly numbers appear to be reduced, most likely from last years April freeze which occurred when sawflies were young larvae on pine trees. Very few to no sawflies are being observed on pines in areas that typically have large numbers.
Pine Sawfly, http://extensionhorticulture.unl.edu/Current/Sawfly.shtml
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
12. Emerald ash borer (EAB) is not yet known to be present in Nebraska; hence, commercial applicators and homeowners should not be applying insecticides to ash trees for control of Emerald Ash Borer. The insecticide, Imidacloprid, does state on the label that it controls EAB. If applied correctly, this is true. However, there is currently no reason to make recommendations for control of EAB, since there is no current threat from this pest in Nebraska.
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
13. Winter kill and dieback of some herbaceous perennials and woody plants is being observed. For example, Butterfly Bush (Buddleia ssp.) and Blue Mist Spirea (Caryopteris ssp.), which typically die-back some each winter, have more severe dieback this year and in some cases these plants may have been killed and will need replacement.
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
14. Prune roses in May- Each spring, winter killed wood is pruned from roses. It is best to wait until May to do this. On roses pruned in April, additional dieback can be observed. When pruning is delayed, and roses are pruned in May, additional injury rarely occurs.
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
15. Echelon & Urea Damage- From Roch Gaussion, UNL Turfgrass Specialist- A colleague at North Carolina State University (Dr. Fred Yelverton) shared the following information. Echelon herbicide, while not being used extensively in Nebraska, might have potential in the future. At this point only the following is known. We will be cooperating with turf specialists at North Carolina and Indiana to determine the extent of the problem.
There appears to be a negative interaction of Echelon herbicide and urea (46-0-0) on tall fescue. This interaction is showing up as injury on tall fescue. Echelon is a pre-package mix of prodiamine and sulfentrazone. Echelon has been tested in many university trials in recent years and, at the proper rate, turfgrass tolerance has not been an issue. However, when mixed with 46-0-0, several lawn care operators have called to say they have observed injury on tall fescue. Researchers at North Carolina State University followed these complaints up with a research trial at the Lake Wheeler Turfgrass Field Laboratory and we have confirmed that there is significant injury on tall fescue.
It is important to point out there have been no reports of fescue death from this combination. It is also important to point out that, at this time, we have only had reports of this injury on tall fescue. It may or may not occur with other turf species.
For more information, including pictures of typical damage, visit, http://www.turffiles.ncsu.edu/Alerts.aspx#004552
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
16. Spanish/English guides available- University of Nebraska-Lincoln Extension is offering three guides to help improve communication between Spanish and English speaking individuals. Titled, español a ingles, English to Spanish, these communication guides are laminated and easy to keep with you, folding into a convenient quarter-fold size of 4.5” by 11”.
The guides feature phrases and key words in both Spanish and English, including pronunciation guides for both languages. Each of the three guides has a unique focus area including a guide for the Green Industry, one for Landscaping and Grounds Keeping, and one for Golf and Pond Maintenance. They are currently available for by calling or e-mailing John Fech at jfech@unlnotes.unl.edu or 402-444-7804.
They can also be ordered on-line at Garden Center Update, http://extensionhorticulture.unl.edu/Update.shtml.
The cost is $8.99, not including shipping and handling; there are bulk discount rates available if you order more than 10.
John Fech, University of Nebraska-Lincoln Horticulturist coordinated the making of the Spanish guides. Fech’s goal is to help native English speakers communicate with native Spanish speakers, and vice-versa. This guide is unique because it facilitates the two-way communication.
