Hort Update for the week of 10/29/07
| Current Problems: | Major Symptom: |
Lawns |
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| 1. Fall mowing heights | Kentucky bluegrass- 2.5 to 3.0” and Tall Fescue- 3.0 to 3.5” |
| 2. Winterizer fertilization | Time this important application with the last mowing of the season. |
| 3. Fall irrigation | Keep soils moist, not saturated. Protect irrigation systems from freezing. |
| 4. Skunk damage | Cone-shaped holes dug into lawns as skunks forage for insects. |
| 5. Moles | Raised tunnels across lawns. Volcano shaped dirt mounds. |
| 6. Stem rust | Yellowing in lawns. Orange powder may appear on shoes, mowers. |
| Trees & Shrubs | |
| 7. Winter wildlife damage prevention | Protect trees from rabbit, vole and deer feeding during winter. |
| 8. Sunscald prevention with tree wrap | Use carefully on young, tender barked trees for a short time only. |
| 9. Anti-transpirants | On windy, exposed sites, apply to evergreens three times during winter. |
| 10. Cottonwood defoliation | Early and fairly severe leaf defoliation due to fungal leaf spots |
| 11. Pruning | Delay most pruning until after plants are fully dormant. |
| Ornamentals | |
| 12. Rose winter protection | Wait until mid November to apply winter protection. |
| 13. Cutting back herbaceous perennials | After a hard freeze kills the tops, cut them close to the ground |
| Miscellaneous | |
| 14. Controlling fruit flies | A yeast-based trap very attractive to fruit flies. |
| 15. Fall sanitation and composting | Clean up plant debris to reduce overwintering pathogens and insects. |
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""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 1. Fall mowing height recommendations have changed. It has often been recommended to mow turfgrass fairly low in late October. The alternative, and preferred, recommendation is to now maintain the same height all season and through winter. This promotes rooting and stress tolerance. Mow Kentucky Bluegrass at 2.5 to 3.0 inches and tall fescue at 3.0 to 3.5 inches all season and leave it at that height for winter. Continue to mow as long as turfgrass is growing. Do not allow it to go into winter too tall or matting and suffocation may occur; as well as an increased incidence of snow mold disease. Kentucky Bluegrass Lawn Calendar Nebguide, http://www.ianrpubs.unl.edu/sendIt/g517.pdf Tall Fescue Lawn Calendar Nebguide, http://www.ianrpubs.unl.edu/sendIt/g558.html """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 2. Winterizer fertilizer should be applied to cool season turfgrasses, Kentucky bluegrass and tall fescue, at the time of the last mowing, usually in late October or early November. Fall fertilization is important for root and rhizome growth, and carbohydrate storage within the plant. Apply fertilizer at a rate of 1 to 1.5 pounds of nitrogen per 1000 square feet. Kentucky Bluegrass Lawn Calendar, http://www.ianrpubs.unl.edu/sendIt/g517.pdf Fall Lawn Fertilization, http://www.ext.colostate.edu/ptlk/1523.html """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 3. Fall irrigation of turf, in the absence of rainfall, is important to maintain moist soil that supports root and rhizome growth, which increases during fall. Turfgrass soils should remain moist, not saturated, well into fall. Irrigation systems must also be protected from freeze damage by draining them. Information on proper drainage procedures for home lawn irrigation systems with back flow preventers can be found on page 23 of the Integrated Turfgrass Management for the Northern Great Plains E.C.97-1557. A copy of this Extension circular is available at most UNL Extension offices. """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 4. Skunk damage to lawns appears as cone-shaped holes caused when skunks dig for grubs and other insects. Damage to turf caused by raccoons is typically more extensive with large chunks of sod being rolled and torn. Habitat modification to decrease the attractiveness of a property to skunks is the most effective means of control. Dealing With Skunks Nebguide, http://www.ianrpubs.unl.edu/sendIt/g1769.pdf eXtension Skunk Damage Management, http://www.extension.org/pages/Skunk_Damage_Management """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 5. Moles cause damage to lawns when burrowing for insects. They create raised surface tunnels and one foot diameter conical shaped mounds. Trapping and the use of repellants containing caster oil are recommended controls. Applying insecticides to reduce their food source is not recommended. A newer product called Talpirid or Tomcat is showing promise in controlling moles when used according to label directions. Moles and Their Control Nebguide, http://www.ianrpubs.unl.edu/sendIt/g1538.pdf """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 6. Stem rust of Kentucky Bluegrass is being seen, mainly in western Nebraska. A few cases are reported in central and eastern Nebraska. In late summer, lawns may develop a yellow appearance and an orangish powder (spores) appear on grass blades, which often appear on shoes and mowers. Rust typically develops on lawns with slow growth. Fall lawn care, including fertilization and correct irrigation, along with cooler fall weather promotes turfgrass growth and rust disappears. Stem rust is often a problem on compacted soils; hence core aerification is effective in reducing rust in lawns. Fungicide controls are rarely suggested for home lawns. Note for Sports Turf : If stem rust occurs on sports fields, the fungal spores can cause problems for allergy/asthma sufferers. Control of stem rust is recommended on sports turfs using a combination of turf management and timely fungicide applications. Rust Turns Lawns Orange, http://www.urbanext.uiuc.edu/turf/rustlawn.html Rust on Sports Turf, http://hcs.osu.edu/sportsturf/notes/detail.lasso?id=1094 """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 7. Winter wildlife damage protection. Barriers of hardware cloth placed around young trees and shrubs is the best means of protection from rabbit and vole damage. Make sure the barriers extend well above the usual snow line. Various taste repellants, such as Thiram or Miller's Hot Sauce, can be effective in reducing deer and rabbit damage as long as animals have other food sources to turn to. Scent repellants, such as bags of human hair or bar soaps on a rope, have been shown to be effective in some situations. eXtension Deer Damage Management, http://www.extension.org/pages/Deer_Damage_Management eXtension Vole Damage Management, http://www.extension.org/pages/Vole_Damage_Management eXtension Rabbit Damage Management, http://www.extension.org/pages/Cottontail_Rabbit_Damage_Management """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 8. Sunscald prevention with tree wraps. Sunscald commonly occurs on young, tender barked trees, such as Maples, during winter. It may be due to uneven heating of the trunk, however, there appears to be a correlation to root damage caused during transplanting. Proper planting and post planting care may be more important to protecting trees from sunscald than tree wrap. If used incorrectly, or left on too long, tree wraps can cause more harm than good. If used, tree wraps should be attached in November at the soil line and the tree wrapped upward with the wrap overlapping up to the first set of branches. Remove wrap in spring, since leaving it on too long may girdle or compress the trunk, reduce photosynthesis, and increase insect (borer) damage. Avoid the use of paint as these may cause chemical damage to the trunk. """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 9. Anti-transpirants can help plants endure stressful periods. The most common types are an emulsion of wax, latex, or plastic that forms a thin film on foliage, which minimizes water loss. We recommend their use during winter only on broadleaf (holly, Mahonia) or coniferous (yew, Arborvitae) evergreens growing in stressful sites, although they can also benefit newly transplanted trees in some situations. Apply them once every six weeks in mid- to late-November, early January, and mid- to late-February. Avoid coating plants so heavily that their needles become sticky and glued together. Read and follow label directions. Select the right product for the plant species as there are toxicity issues. Clean sprayers thoroughly after each application to prevent clogging. Have warm, soapy water nearby and clean out the sprayer immediately or the sprayer may be ruined by the product. """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 10. Cottonwood defoliation may be caused by a number of fungal leaf spot diseases which infect the leaves and cause early leaf drop. The severity of leaf drop this year was likely due to an increase in leaf spot diseases due to the frequents rains occurring in central and eastern Nebraska. Poplar Leaf Spots, http://www.ext.colostate.edu/pubs/garden/02920.html """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 11. Pruning of deciduous trees and shrubs is best done when the plant is dormant during winter. It is best to wait until after plants lose their leaves to prune them. Make correct pruning cuts and do not use a wound dressing or tree paint on the pruning wounds. Pruning Mature Trees, http://www.treesaregood.com/treecare/pruning_mature.aspx """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 12. Rose winter protection should not be put in place until roses are fully dormant, usually after the soil begins to freeze or night time temperatures are consistently dropping into the 20 degree F. range, sometime in November. Winter protection protects plants against wide soil temperature fluctuations and temperature extremes . On hybrid tea, floribunda and other tender roses, about 8 inches of soil can be mounded around the base in early November to protect the graft. About mid-November, put your cover in place. Encircling the plant with chicken wire and filling the chicken wire with a coarse mulch, such as wood chips, works well. """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 13. Cutting back herbaceous perennials is best done after the foliage naturally dies or is killed by frost. As long as the foliage is green and healthy, photosynthesis is taking place and the carbohydrates and sugars being produced are moved into roots for storage. If a plant has diseased foliage, remove and destroy the diseased portions as soon as possible for good sanitation. If plants are attractive, the tops can be left over winter and cut back just before new growth begins. """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 14. Controlling fruit flies. Once you remove breeding and food sources for fruit flies, adults die in a couple of weeks. To speed this up, use simple traps to collect fruit fly adults. Barb Ogg, UNL Extension Educator, suggests a new method to attract adult fruit flies to traps.
Managing Fruit Flies: Make Your Own Trap, http://lancaster.unl.edu/pest/resources/FruitFlyTrap.shtml """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 15. Fall Sanitation and compost piles. Fall sanitation is the removal and disposal of dead or dying plant material from gardens and from beneath fruit trees to reduce overwintering pathogens and insects. Many diseases and insects also overwinter on weeds so don’t overlook cleaning up weeds as well. Plant debris can be tilled under or removed and destroyed. It can be added to compost piles. However, if the material comes from a plant which had a disease or insect problem or is a weed that has gone to seed; it is best not to add this material to compost piles. While a properly managed pile may reach temperatures hot enough to kill most pathogens and weed seeds, many piles are not managed to reach this temperature. Garden Compost, http://www.ianrpubs.unl.edu/sendIt/g810.pdf |
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