Hort Update for the week of 5/2/08
1. Crabgrass is a warm season annual grass. A minimum soil temperature of 50-55°F degrees is needed for crabgrass seed to begin to germinate, with most crabgrass seed germinating at even higher soil temperatures. Pre-emergent herbicides for control of crabgrass are best applied just prior to the active germination period to provide the longest period of effective control. In Nebraska, apply these products the first week of May in eastern Nebraska and the second week of May in western Nebraska. If they are applied much earlier, a second application may be required in mid to late June. Maintaining a dense, healthy turf that competes with crabgrass and raising the mowing height to 2.5 to 3 inches will also reduce crabgrass.
Crabgrass control tips, http://www.extension.umn.edu/info-u/plants/BG533.html
Kentucky Bluegrass Lawn Calendar, http://www.ianrpubs.unl.edu/sendIt/g517.pdf
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
2. Soil temperature- While air temperatures may be warm, it is important to monitor soil temperatures. A minimum soil temperature of about 40°F degrees is needed for plant roots to begin growth and to function. A minimum soil temperature is required for most crop and weed seeds to germinate. Many plant care practices and crop seeding should begin after soil temperatures warm to at least minimum if not optimum soil temperature for that practice or crop.
To monitor soil temperatures, use a soil temperature thermometer or see the Crop Watch soil temperature update at: http://citnews.unl.edu/cropWatch/soilTemperature.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
3. Turfgrass for shade- It is not easy to establish or maintain quality turfgrass in heavily shaded areas, less than 6 hours of full sunlight, due to a lack of sunlight and root competition from trees. Soil compaction is an additional deterant to turfgrass growth. Select shade tolerant grasses. Fine-leaf fescues such as creeping red fescue, chewings fescue, sheep fescue and hard fescue are the most shade tolerant. In moderate shade, turf type tall fescue is a good choice. If these grasses fail, even with good management practices for shade, consider the use of shade-tolerant ground covers in place of turfgrass.
Landscapes for Shade, http://www.ianrpubs.unl.edu/sendIt/g1341.pdf
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
4. Turfgrass for drought- With the growing awareness of water conservation, it is important to select turfgrass species and management practices with lower irrigation needs. Historically, consumers have over-applied water on lawns, not only in Nebraska, but nationwide.
If you have an in-ground irrigation system the first step in conserving water is to make sure your irrigation system is functioning properly and that you are adjusting the irrigation cycles as the season progresses. Consider using less nitrogen to decrease water requirement and mowing at a higher height to increase rooting and decrease the need for supplemental irrigation.
If you have a Kentucky bluegrass lawn consider letting it go dormant during the summer months if the lawn does not receive a lot of traffic (dormant bluegrass is not very traffic tolerant).The bluegrass will resume growth with timely rains.
If you have a tall fescue lawn in Eastern Nebraska, in most year supplemental irrigation is not necessary except in extreme drought. Unlike bluegrass , tall fescue does not go dormant under limited moisture conditions and may require supplemental irrigation in Central and Western Nebraska and with sustained drought in Eastern Nebraska.
The following species are rated from lowest to highest regarding their irrigation requirements, to sustain season long green color, in Eastern Nebraska - buffalograss, zoysiagrass, turf-type tall fescue, and Kentucky bluegrass. As you move to Central and Western Nebraska the differences between turf-type tall fescue and Kentucky bluegrass are less pronounced.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
5. Wild violets are perennial lawn weeds with heart shaped leaves and small purple flowers. The newer herbicide Drive has shown fairly good results on wild violet. Trimec can also be used. Repeat applications over a few years are often needed on a well established wild violet stand. September is the time to apply these herbicides for the most effective control.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
6. Tree selection for Nebraska- Due to pine wilt disease and the potential for emerald ash borer to enter our state in future years, Scotch pine, green ash and white ash trees are not recommended for planting in Nebraska at this time. Planting a variety of trees to increase diversity of tree species in landscapes is important. When selecting trees to plant, avoid Scotch pine, green and white ash, and other trees that appear to be over-planted in your area.
For a list of trees for Nebraska, visit the Nebraska Forest Service web site below, scroll down to "Community Forestry" and click on "Trees for All Nebraska".
Nebraska Forest Service publications, http://www.nfs.unl.edu/publications.asp
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
7. Winter injury on evergreens appears as a fairly uniform browning, often on the south or west facing side of the tree and on the outer parts of the plant. Evergreens lose moisture on sunny winter days. If the soil doesn't contain enough moisture to replace the loss, needles - starting from the tip - dry out and turn brown. Sometimes the soil is moist but the roots can't absorb water due to frozen soil or damaged roots. To avoid winter desiccation, provide adequate moisture to the plants throughout the year. The damaged growth can be pruned or you can wait to see if the new growth will cover up damaged needles.
Winter Dessication Injury- http://extensionhorticulture.unl.edu/Current/WinterInjury.shtml
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
8. Dothistroma Needle Blight causes browning of needles on the lower half of Austrian pine trees. On close inspection, needles will have turned brown from the tip down to a reddish-purple lesion or band on the needle. Lesions or bands may be found on other green needles as well. If no lesions are found, the evergreen may have winter burn or desiccation. This is environmental and no chemical controls are needed. Dothistroma needle blight can also be found on Ponderosa, Scotch and Mugo pine.
Dothistroma Needle Blight of Pines, http://www.urbanext.uiuc.edu/shrubselector/detail_problem.cfm?PathogenID=58
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
9. Rabbits feed on a wide variety of landscape plants. The best control is exclusion with fencing, such as a chicken wire fence placed securely around a plant or garden. Repellents can provide some short term control. Planting rabbit resistant plants may help if the rabbit has other sources of food.
Prevention and Control of Rabbit Damage, http://www.ianrpubs.unl.edu/sendIt/g1526.pdf
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
10. Safe use of manure in gardens- Due to concerns about the potential risk of human pathogens being transmitted to vegetables, herbs or fruits, it is best not to incorporate manure (fresh or decomposed) or manure-based compost into gardens in the spring. Fall incorporation is best. At least 17 weeks should elapse between incorporation of manure and harvesting a garden crop.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
11. Damping off is a fungal disease that kills young seedlings in vegetable gardens. It is most prevalent when seed is planted into cold, wet soils. Waiting to plant seeds until soil temperatures are conducive to rapid germination and active growth; or planting into raised beds, where soils warm up faster and excess water drains away more quickly, can reduce problems with damping off.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
12. Asparagus beetles overwinter as adults in plant debris near the garden and begin to feed about mid May. They are blue/black beetles with a red prothorax with yellow spots. The larvae are a soft, greenish grub. Both damage asparagus spears by chewing the tips and spear surfaces leading to scarring of the spears. Early control of beetles is important to reduce feeding damage later. Rotenone, malathion, or Sevin will provide control. Read and follow all label directions.
Asparagus Beetles, http://www.oznet.ksu.edu/dp_hfrr/extensn/problems/asparagu.htm
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
13. Wood or Oriental cockroach- It is important to distinguish between these two cockroaches. Wood roaches are a nuisance pest common during rainy weather. They rarely, if ever, establish in homes and control is not required, other than swatting. Oriental cockroaches (water bugs) can become an established pest in homes and they do require control measures.
To aid in identification, see the UNL Entomology web site cockroach identification page at: http://entomology.unl.edu/images/cockroaches/cockroaches.htm
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
14. Red clover mites-These small mites are often found on west and south facing windows and walls in the spring. These mites overwinter under siding and window frames. When temperatures warm up the mites become active. A wet washcloth or paper towel will control the pests on windows and walls. These nuisance mites do no damage to people, pets, or the house structure. Insecticides are not recommended for use indoors. An outdoor perimeter spray applied in the fall will help keep the mites from entering the home.
Clover Mite, http://ohioline.osu.edu/hyg-fact/2000/2095.html
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
15. Boxelder bugs are emerging from their overwintering sites. Adults are black and orange. Nymphs are soft bodied and bright red to orange-red. Boxelder bugs feed mainly on the samara (fruit) of maple trees, particularly boxelder maple. These insects are harmless to the trees, people, pets and buildings. If they are massing around your home, they will soon disseminate to lay eggs on or near maple trees. Spraying the homes foundation will provide little, if any control. If boxelder bugs were found inside a home, weather proof the home this summer with caulking and screening to reduce the number of insects that may enter the home next fall for overwintering.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
16. Hiring a Pest Control Company- Fred Baxendale, Extension Entomology Specialist, recommends hiring a commercial pest control operator for the following pests: cockroaches, termites, fleas and brown recluse spiders.
For information on hiring a pest control operator, refer to:
How to Select a Pest Control Company, http://www.ianrpubs.unl.edu/sendIt/g1647.pdf
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
17. 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 http://lancaster.unl.edu/hort/resources.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. Crabgrass control | Apply most pre-emergence herbicides in May. |
| 2. Soil temperatures | Use a soil thermometer or the climate web site to monitor. |
| 3. Turfgrass for shade | Select the right grass for conditions and maintenance. |
| 4. Turfgrass for dry sites | Select the right grass for conditions and maintenance. |
| 5. Wild violets | Control with Drive or Trimec. Fall applications are best |
| Trees & Shrubs | |
| 6. Tree selection | Select the right tree for the site and function. |
| 7. Winter injury on evergreens | Needle browning; often on south or west side of tree. |
| 8. Dothistroma needle blight on pine | Banding and browning of needles on lower half of tree. |
| Gardens/Ornamentals | |
| 9. Rabbit control | Use fencing or repellents. |
| Vegetables/Fruits | |
| 10. Safe use of manure in gardens | Avoid adding manure to gardens during spring. |
| 11. Damping off | Avoid too early planting into cold, wet soils. |
| 12. Asparagus beetles | Feeding on ferns usually begins in May. |
| Household Pests | |
| 13. Wood or Oriental roach | Positive identification is important to avoid confusing these two. |
| 14. Clover mite | Red specks (mites) on sunny sides of homes indoors & outdoors. |
| 15. Boxelder bugs | Bright red or orange-red insects on homes or in plant debris. |
| 16. Hiring a PCO | When to hire a commercial pest control operator |
| Miscellaneous | |
| 17. Spanish/English guides available | Spanish/English language guides available for the green industry |
1. Crabgrass is a warm season annual grass. A minimum soil temperature of 50-55°F degrees is needed for crabgrass seed to begin to germinate, with most crabgrass seed germinating at even higher soil temperatures. Pre-emergent herbicides for control of crabgrass are best applied just prior to the active germination period to provide the longest period of effective control. In Nebraska, apply these products the first week of May in eastern Nebraska and the second week of May in western Nebraska. If they are applied much earlier, a second application may be required in mid to late June. Maintaining a dense, healthy turf that competes with crabgrass and raising the mowing height to 2.5 to 3 inches will also reduce crabgrass.
Crabgrass control tips, http://www.extension.umn.edu/info-u/plants/BG533.html
Kentucky Bluegrass Lawn Calendar, http://www.ianrpubs.unl.edu/sendIt/g517.pdf
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
2. Soil temperature- While air temperatures may be warm, it is important to monitor soil temperatures. A minimum soil temperature of about 40°F degrees is needed for plant roots to begin growth and to function. A minimum soil temperature is required for most crop and weed seeds to germinate. Many plant care practices and crop seeding should begin after soil temperatures warm to at least minimum if not optimum soil temperature for that practice or crop.
To monitor soil temperatures, use a soil temperature thermometer or see the Crop Watch soil temperature update at: http://citnews.unl.edu/cropWatch/soilTemperature.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
3. Turfgrass for shade- It is not easy to establish or maintain quality turfgrass in heavily shaded areas, less than 6 hours of full sunlight, due to a lack of sunlight and root competition from trees. Soil compaction is an additional deterant to turfgrass growth. Select shade tolerant grasses. Fine-leaf fescues such as creeping red fescue, chewings fescue, sheep fescue and hard fescue are the most shade tolerant. In moderate shade, turf type tall fescue is a good choice. If these grasses fail, even with good management practices for shade, consider the use of shade-tolerant ground covers in place of turfgrass.
Landscapes for Shade, http://www.ianrpubs.unl.edu/sendIt/g1341.pdf
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
4. Turfgrass for drought- With the growing awareness of water conservation, it is important to select turfgrass species and management practices with lower irrigation needs. Historically, consumers have over-applied water on lawns, not only in Nebraska, but nationwide.
If you have an in-ground irrigation system the first step in conserving water is to make sure your irrigation system is functioning properly and that you are adjusting the irrigation cycles as the season progresses. Consider using less nitrogen to decrease water requirement and mowing at a higher height to increase rooting and decrease the need for supplemental irrigation.
If you have a Kentucky bluegrass lawn consider letting it go dormant during the summer months if the lawn does not receive a lot of traffic (dormant bluegrass is not very traffic tolerant).The bluegrass will resume growth with timely rains.
If you have a tall fescue lawn in Eastern Nebraska, in most year supplemental irrigation is not necessary except in extreme drought. Unlike bluegrass , tall fescue does not go dormant under limited moisture conditions and may require supplemental irrigation in Central and Western Nebraska and with sustained drought in Eastern Nebraska.
The following species are rated from lowest to highest regarding their irrigation requirements, to sustain season long green color, in Eastern Nebraska - buffalograss, zoysiagrass, turf-type tall fescue, and Kentucky bluegrass. As you move to Central and Western Nebraska the differences between turf-type tall fescue and Kentucky bluegrass are less pronounced.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
5. Wild violets are perennial lawn weeds with heart shaped leaves and small purple flowers. The newer herbicide Drive has shown fairly good results on wild violet. Trimec can also be used. Repeat applications over a few years are often needed on a well established wild violet stand. September is the time to apply these herbicides for the most effective control.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
6. Tree selection for Nebraska- Due to pine wilt disease and the potential for emerald ash borer to enter our state in future years, Scotch pine, green ash and white ash trees are not recommended for planting in Nebraska at this time. Planting a variety of trees to increase diversity of tree species in landscapes is important. When selecting trees to plant, avoid Scotch pine, green and white ash, and other trees that appear to be over-planted in your area.
For a list of trees for Nebraska, visit the Nebraska Forest Service web site below, scroll down to "Community Forestry" and click on "Trees for All Nebraska".
Nebraska Forest Service publications, http://www.nfs.unl.edu/publications.asp
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
7. Winter injury on evergreens appears as a fairly uniform browning, often on the south or west facing side of the tree and on the outer parts of the plant. Evergreens lose moisture on sunny winter days. If the soil doesn't contain enough moisture to replace the loss, needles - starting from the tip - dry out and turn brown. Sometimes the soil is moist but the roots can't absorb water due to frozen soil or damaged roots. To avoid winter desiccation, provide adequate moisture to the plants throughout the year. The damaged growth can be pruned or you can wait to see if the new growth will cover up damaged needles.
Winter Dessication Injury- http://extensionhorticulture.unl.edu/Current/WinterInjury.shtml
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
8. Dothistroma Needle Blight causes browning of needles on the lower half of Austrian pine trees. On close inspection, needles will have turned brown from the tip down to a reddish-purple lesion or band on the needle. Lesions or bands may be found on other green needles as well. If no lesions are found, the evergreen may have winter burn or desiccation. This is environmental and no chemical controls are needed. Dothistroma needle blight can also be found on Ponderosa, Scotch and Mugo pine.
Dothistroma Needle Blight of Pines, http://www.urbanext.uiuc.edu/shrubselector/detail_problem.cfm?PathogenID=58
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
9. Rabbits feed on a wide variety of landscape plants. The best control is exclusion with fencing, such as a chicken wire fence placed securely around a plant or garden. Repellents can provide some short term control. Planting rabbit resistant plants may help if the rabbit has other sources of food.
Prevention and Control of Rabbit Damage, http://www.ianrpubs.unl.edu/sendIt/g1526.pdf
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
10. Safe use of manure in gardens- Due to concerns about the potential risk of human pathogens being transmitted to vegetables, herbs or fruits, it is best not to incorporate manure (fresh or decomposed) or manure-based compost into gardens in the spring. Fall incorporation is best. At least 17 weeks should elapse between incorporation of manure and harvesting a garden crop.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
11. Damping off is a fungal disease that kills young seedlings in vegetable gardens. It is most prevalent when seed is planted into cold, wet soils. Waiting to plant seeds until soil temperatures are conducive to rapid germination and active growth; or planting into raised beds, where soils warm up faster and excess water drains away more quickly, can reduce problems with damping off.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
12. Asparagus beetles overwinter as adults in plant debris near the garden and begin to feed about mid May. They are blue/black beetles with a red prothorax with yellow spots. The larvae are a soft, greenish grub. Both damage asparagus spears by chewing the tips and spear surfaces leading to scarring of the spears. Early control of beetles is important to reduce feeding damage later. Rotenone, malathion, or Sevin will provide control. Read and follow all label directions.
Asparagus Beetles, http://www.oznet.ksu.edu/dp_hfrr/extensn/problems/asparagu.htm
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
13. Wood or Oriental cockroach- It is important to distinguish between these two cockroaches. Wood roaches are a nuisance pest common during rainy weather. They rarely, if ever, establish in homes and control is not required, other than swatting. Oriental cockroaches (water bugs) can become an established pest in homes and they do require control measures.
To aid in identification, see the UNL Entomology web site cockroach identification page at: http://entomology.unl.edu/images/cockroaches/cockroaches.htm
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
14. Red clover mites-These small mites are often found on west and south facing windows and walls in the spring. These mites overwinter under siding and window frames. When temperatures warm up the mites become active. A wet washcloth or paper towel will control the pests on windows and walls. These nuisance mites do no damage to people, pets, or the house structure. Insecticides are not recommended for use indoors. An outdoor perimeter spray applied in the fall will help keep the mites from entering the home.
Clover Mite, http://ohioline.osu.edu/hyg-fact/2000/2095.html
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
15. Boxelder bugs are emerging from their overwintering sites. Adults are black and orange. Nymphs are soft bodied and bright red to orange-red. Boxelder bugs feed mainly on the samara (fruit) of maple trees, particularly boxelder maple. These insects are harmless to the trees, people, pets and buildings. If they are massing around your home, they will soon disseminate to lay eggs on or near maple trees. Spraying the homes foundation will provide little, if any control. If boxelder bugs were found inside a home, weather proof the home this summer with caulking and screening to reduce the number of insects that may enter the home next fall for overwintering.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
16. Hiring a Pest Control Company- Fred Baxendale, Extension Entomology Specialist, recommends hiring a commercial pest control operator for the following pests: cockroaches, termites, fleas and brown recluse spiders.
For information on hiring a pest control operator, refer to:
How to Select a Pest Control Company, http://www.ianrpubs.unl.edu/sendIt/g1647.pdf
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
17. 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 http://lancaster.unl.edu/hort/resources.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.
