Hort Update for September 15, 2014

Hort Update for September 15, 2014

Wolf Spider
Wolf Spider
In This Issue: Major Symptom:
1. Late for seeding No for tall fescue; okay for Kentucky bluegrass & perennial ryegrass
2. Raccoon damage Damage turf by turning sod over to forage for insects/earthworms
3. Armadillos in Nebraska Reported in Lincoln, Ord and Norfolk
4. Broadleaf weed control Fall is ideal time to spot treat broadleaf weeds with herbicides
5. Core aeration Soil should not be too wet; flag irrigation lines
6. Bagworm Too late for insecticide control; hand-pull and destroy
7. Cottonwood leaf rust Yellowish-orange colored leaves; leaf drop; minor issue
8. Ash fungal leaf spot Common in wet years; leaf drop; not harmful now
9. Twig girdlers Branch terminals turn brown; variety of trees affected
10. Fall tree planting Check roots in containers before planting
11. Emerald Ash borer updates Homeowner guide available from Nebraska Forest Service
12. Impatiens downy mildew Severe plant defoliation and flower drop
13. Cutting back perennials Delay until after a freeze for most healthy perennials
14. Bumble bee beetles on tomatoes Brown beetles feed on overripe or damaged tomatoes
15. Garden sanitation Remove and discard old or damaged fruits and plant material to reduce disease and insect overwintering sites
16. Squash bugs on squash & pumpkins Yellowing of foliage, vine wilting and death
17. Harvesting and curing pumpkins Harvest pumpkins at best stage for good storage
18. Fall planting of garlic Great crop for Nebraska gardeners, plant in October
19. Albino cucumbers Completely white cucumbers, a couple possible causes
20. Dividing/transplanting rhubarb Maintain rhubarb vigor through periodic division
21. Fruit bud development in tree and small fruit crops Fall watering important if rains stop
22. Thin strawberry beds Renovate and thin plantings to maximize production
23. Nuisance insects and mice Boxelder bugs, Asian lady beetles, millipedes, mice.....
24. Wolf spiders Large, brown, somewhat hairy beneficial spider.
25. Cattail control Mechanical control effective in fall
Articles
1. Late for seeding cool-season turfgrass - Ideally, seeding should best be done by September 15. Though seeding of these grasses can still be done, it is possible that depodning on the fall weather they will not get established by winter and/or be affected by winterkill. The sooner these grasses are seeded, the better. Any practice that will improve seed to soil contact will greatly increase success, such as power raking or core aerating. Post seeding care with frequent irrigation, mowing, and fertilization are critical to maximize establishment in the shortened time period before winter..

Establishing Lawns From Seed, University of Nebraska-Lincoln
Improving Turf in Fall, University of Nebraska-Lincoln

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2. Raccoons, skunks, opossum, maybe armadillo damaging turf - Wildlife such as raccoons, skunks, and opossums can damage lawns by peeling back turf or uprooting turfgrass to forage for soil insects and earthworms. Now that armadillos have been found in Nebraska, be aware these too can cause turf damage when foraging. The best way to reduce damage to turf is to deter wildlife from the area. Trapping is also an option. The following NebGuides provide guidelines on habitat management as well as trapping. Controlling white grubs can still be done with Dylox, but it may take 7-10 days before grubs die and animals will continue to feed.

Controlling Raccoon and Opossum Damage, UNL Extension
Dealing with Skunks, UNL Extension

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3. Armadillo in Nebraska - According to Dennis Ferraro, the nine-banded armadillo, Dasypus novemcinctus, is the most wide spread of all armadillos and is moving northward into Nebraska. In the summer of 2014, at least eight armadillos were recorded in Nebraska. One was found near Lincoln in Lancaster County, and two were found as far north as Ord and Norfolk, Nebraska. For additional information see Dennis' article in Acreage Insights:
September Animal - Armadillo

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4. Broadleaf weed control - Now is the most effective time to control perennial broadleaf weeds with spot treatments of herbicides. Use a combination of fall care practices that improve the turfs ability to compete with weeds and fall applied herbicides to effectively control perennial broadleaf weeds. See link for useful tips.

Lawn Pro Series: Broadleaf Weed Control, UNL Turf iNfo

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5. Time to core aerate - Fall is a good time to aerify lawns. While the soil should be moist when aeration is done, it should not be too wet. Remember to flag irrigation lines before aerating to avoid damage to irrigation systems. Core aeration removes plugs from soil to relieve soil compaction. This is a good cultural practice for lawns growing on urban soils that tend to be compacted. It could be done annually and should be done at least once every few years, depending on soil type, traffic, etc.

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6. Evergreen bagworm have completed feeding and larvae are pupating. Therefore insecticide applications will no longer be effective. Bags can be hand-picked and destroyed to help reduce this insect. They overwinter in the egg stage inside of female bags. To check for bagworms, look closely at evergreens. At this time, bagworms are about two inch long, tan bags made of needles and webbing and attached to twigs. Insecticide control for bagworms is best done in June after eggs hatch.

Bagworms, University of Nebraska-Lincoln

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7. Cottonwood leaf rust causes the leaves of cottonwood and other Poplars to appear yellowish-orange. The disease is easily identified by small, yellow-orange pustules found on leaf undersides in late summer and early fall. It is caused by the fungus Melampsora. This disease rarely causes serious damage to trees since it develops in late summer and usually results in minor defoliation. Like most rust diseases, two plant host are required for the fungus to complete its life cycle. The fungus overwinters on fallen cottonwood or poplar leaves. During wet spring weather, spores are released and infect evergreen needles, such as pine, fir or spruce, where they cause little damage. After two to three weeks, spores are produced on these evergreen hosts and blown to cottonwood leaves. If conditions are wet, leaf infections occur resulting in yellowish-orange leaves and some defoliation by fall. Fungicide control is not recommended. Sanitation is helpful. Rake and destroy infected leaves this fall.

Aspen and Poplar Leaf Spots, Colorado State University 

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8. Ash leaf spot can lead to browning of leaves and leaf drop. One leaf spot fungus that infects ash trees is Mycosphaerella. In wet years it can cause early defoliation.  In drier years, it mostly just results in minor leaf spotting and only minor defoliation. Like many fungal leaf spots that do not result in defoliation until late in the season, after the leaves have done their job of photosynthesis for food storage, fungicide controls are not recommended. Use good sanitation by raking and removing fallen leaves.

Mycosphaerella Leaf Spot, Kansas State University Extension

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9. Twig girdler causes terminal leaves to turn brown; a symptom called'flagging'. It also causes twig dieback and the girdler can attack oak, elm, linden, hackberry, honeylocust, poplars, hickory, pecan, persimmons and some fruit trees like apple. The girdler is a long-horned beetle that emerges in late summer. As part of egg laying, the female girdles the twig to kill it because the larvae cannot develop in healthy wood. The dead tip may fall to the ground or hang in the tree until wind knocks it out. While damage is obvious, it is rarely severe, and there is usually no need for control. Larvae overwinter inside twigs. Pick up and discard dead twig sections that fall to the ground to reduce this insect. Squirrels clipping tree twigs can be confused with girdler damage.

Twig Girdler, Kansas State University
Twig Girdler and Twig Pruner, University of Missouri

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10. Tree planting - Fall is tree planting time. Some trees have been growing in containers since last spring; and it is a good idea to inspect the root ball of container grown trees before buying or planting them. If the plant is in a container, remove it and examine the root system. Is it root bound? Are there an excessive number of spiraling roots? These will both cause major tree health issues. If the tree contains just a few spiraling roots, you can score the bottom and sides of the root ball to prevent them from causing long-term damage to the tree's health. Always look for girdling roots that are wrapped around the trunk. Even if they are on just one side of the trunk, they must be removed. Girdling roots will eventually choke off the tissue responsible for the uptake of water and nutrients, and the tree will not survive.

Avoiding the Top 10 Mistakes of Tree Planting, Nebraska Forest Service

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11. Emerald ash borer (EAB) Homeowners Guide available. While EAB has not yet been found in Nebraska, it is in Iowa, Missouri and Colorado. To aid homeowners and others with decision-making about their ash trees now and when EAB is found in Nebraska, the Nebraska Forest Service has developed the following guide.

Emerald Ash Borer: Guidelines for Nebraska Homeowners, Nebraska Forest Service

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12. Impatiens downy mildew is an emerging disease that has now been confirmed in Nebraska with reports from Lincoln, Omaha and Grand Island, and confirmation from the UNL Plant and Pest Diagnostic clinic.   It infects common impatiens, Impatiens walleriana, hybrids with I. walleriana parentage and several wild species of impatiens like touch-me-not, I. balsamina.  New Guinea impatiens, I. hawkerii, is highly resistant. Initial infections in Nebraska began with infected bedding plants, but the disease lives for several years in infected beds so can be expected to reoccur once plants have been infected.

Leaves of infected plants appear light yellow, or stippled yellow and green.  Then leaf edges curl downward and leaves appear wilted.  Fluffy white growth appears on the undersides of infected leaves.  Blossoms are shed first, followed by infected foliage, leaving plants with nothing but bare stems.  Finally stems collapse and lay flat on the ground. Recent rain will hasten the spread and advancement of the disease.  Several fungicides can provide protection to healthy plants, but no curative fungicides are available. Replanted infected sites with resistant plants, such as coleus, caladium, begonia or New Guinea impatiens.

Managing Impatiens Downy Mildew in the Landscape, University of Minnesota Extension

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13. Cutting back the foliage of healthy perennials, such as iris, peony, daylily or Asiatic lilies, can wait until the foliage is killed by frost. If foliage has been severely damaged by disease and or insects, remove and discard it as soon as possible for sanitation purposes. Peonies can be cut back any time after early September. Even if they are still green, peonies are dormant.

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14. Bumble bee beetles, also known as bumble flower beetles or brown fruit chafer, is a mottled yellow/brown beetle, with a thick layer of fine hairs on its thorax. Adults emerge in later summer and feed on rotting fruit, corn, sap, and other plant juices.  They sometimes cause damage to flowers and have been found feeding on overripe or damaged tomatoes in Platte County. Remove old damaged or rotting fruits to reduce population.  Handpick adults and drop into a bucket of soapy water.  Chemical control is not necessary.

Bumble Flower Beetle,  Utah State University Cooperative Extension

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15. Garden sanitation during fall involves cleaning up or tilling under plant debris in the vegetable garden and around fruit trees to reduce overwintering pests. The sooner this can be done after a plant dies or after fruit drops to the ground, the better. Plant pathogens are less likely to survive if organic matter is quickly decomposed. Remove plant debris or infected plant parts after each growing season.

  • Turn the soil after harvest to help break down small roots that may harbor nematodes, fungi or bacteria.
  • Gardeners may compost dead plants if they have a good composting system; otherwise, these piles may serve as a source of pathogens.
  • Prune or remove twigs and branches of woody plants affected with fire blight and other bacterial or fungal canker diseases.
  • Keep gardens weed free. Weeds often are another source of pathogens. Eradicate weeds to break the life cycle of pathogens and control them. Weed removal also can increase air movement and thus decrease conditions that favor disease development.
  • So that pathogens do not spread from one area to another, always disinfest machinery and other tools with steam, hot water under pressure, or a 10 percent solution of household bleach diluted with water.
Orchard sanitation is essential for good maintenance of fruit trees and small fruit plantings. Insects and diseases can overwinter on dead or infected plant material. Dried fruits or "mummies" carry disease organisms through the winter to attack next years' crop. Remove and destroy any fruits that have fallen to the ground, or those appearing to rot on the branches.

Non-chemical Control of Disease, Colorado State University

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16. Squash bugs on squash and pumpkins - Squash bugs are one of the most damaging insect pests of pumpkins and winter squash. The adult is a brownish, shield-shaped bug about 5/8 inch long and 1/3 inch wide. Adults are very difficult to control; hence plants must be monitored closely for squash bug eggs and young nymphs to effectively control this insect. Eggs are brick red and found on leaf undersides in the V made by veins. Young nymphs are gray and tear drop shaped. Scout plants often for adults, eggs and young nymphs. When nymphs are present, carbaryl (Sevin) or permethrin can be applied for control in home gardens.

Few good options are available for late season squash bug control.  Hand-pick adults and squish egg masses. Threshold for chemical control is one egg mass per plant.  Destroy or remove plant material in fall, in and around production fields, to minimize overwintering sites. 

Squash Bug, University of Minnesota
Squash Bug Control on Melons & Cucumbers, UNL Extension

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17. Harvesting and curing pumpkins - Pumpkins will rot if harvested too young, or if allowed to stay in the field once they are mature and exposed to freezing temperatures. Mature pumpkins should be uniformly colored across the entire fruit- orange, white, gray or blue- depending on the variety you chose to grow. Look for the mature coloration of your variety indicated on the seed packet for a guide to ripeness. Mature pumpkins have hard, shiny shells that can't be easily punctured by a fingernail. Once your pumpkin reaches this stage, it's time for curing.

Curing is a process that causes the pumpkin skin to harden and promotes healing of small wounds in the skin. Most pumpkins have already been cured when you purchase them at the garden center or store, but if you are growing your own then it is important to allow time for curing. Once a pumpkin is mature, cure it by allowing it to remain in the garden during dry, sunny weather, ideally, 80-85° F, for about 7-14 days.

Pickin' Pumpkins, Backyard Farmer

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18. Fall planting of garlic - Garlic produces well in Nebraska when planted in October or very early spring, using individual bulb cloves or the small bulbils found on topsetting types.  Fall or very early spring planting is required because dormant cloves and young garlic plants must be exposed to cold temperatures of 32 to 50 degrees F. for one to two months to induce bulb formation. There are two main types of garlic - soft neck and hardneck. Each has several distinct groups and cultivars. Don't buy garlic bulbs at the grocery store to plant in your garden.  These are mainly softneck varieties, adapted to warmer climates, and usually have not been stored at temperatures conducive to good bulb formation if they are grown on in the garden. 

So when preparing the soil for planting, apply 3 to 4 pounds of 10-10-10 fertilizer per 100 square feet (or follow soil test recommendations) and spread one to three inches of organic matter such as chopped leaves, dry grass clippings, compost or sphagnum peat over the soil surface. Use a spading fork to turn over and break up the soil and begin mixing in the organic matter. A rototiller also can be used to prepare the soil, but remember that over-tilling can destroy the soil structure.

When incorporating organic matter that must be decayed, such as dry leaves and grass clippings, it is best to do it a few weeks before planting so soil microbes will have a chance to start breaking it down.

Plant the cloves 3 to 5 inches apart in an upright position (pointed end up) to ensure good emergence
and straight necks. Cover cloves to a depth of about 2 to 3 inches. Allow 12 to 24 inches between rows. Garlic also lends itself well to wide-row planting; space cloves five inches apart in all directions in foot-wide rows or raised beds. This requires considerably less garden space for the same yield, but weeding must be done by hand.

Growing Garlic in the Home Garden, Ohio State University
Growing Garlic in Minnesota, University of Minnesota Extension

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19. Albino cucumbers - Sometimes oddities occur in the vegetable garden, such as completely white cucumbers.  Gardeners find these things, and wonder what caused them.  There are white cucumber varieties, such as White Wonder.  If a stray seed from a white variety was mixed into the seed packet, this would result in white cucumber fruits in the garden.  However, if the white fruits occur on plants that also produce green fruits, shading could be the culprit.  Complete shading of fruits by heavy leaf cover could result in white fruits.

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20. Dividing and transplanting rhubarb - As rhubarb plants age their productivity diminishes. After 5 to 6 years, plants benefit from rejuvenating crown division. Early spring, before new growth begins, is the preferred time for division, but plants can also be divided in fall. In fall, dig up the entire crown going at least 6-10 inches in to the soil. Lift the entire plant.  Remove the old, large leaves and allow only the smaller young leaves to remain.  Using a sharp knife divide the crown into pieces containing 1 to 3 growing points per division.  Replant the new divisions as soon as possible.  Keep the new plants well watered through fall.  Provide additional winter protection by applying 6 inches of wood chips in mid-December.

Rhubarb in the Home Garden, Iowa State University

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21. Fruit bud development in fruit crops - Flower bud initiation and development for many tree and small fruits begins in summer, as early as late June in peach, and continues through summer and fall for pear, apple, cherry, grape, strawberry and raspberry. Flower buds develop in the axis between a leaf petiole and the stem, or on fruiting spurs, in fruit trees and shrubs.  In small fruits, like strawberries, flower buds initiate from the crown and are not visible until the following year's growth begins.  One of the major factors determining flower bud development, including the number of flowers and their size, is water availability to the plant.  Nebraska experienced a very dry period from late June through mid August, but recent rains have provided much needed moisture.  If dry conditions return this fall, it's important to keep fruit-bearing plants well watered so that flower bud development is not hindered.

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22. Thin strawberry beds - Strawberry plantings can produce for several years, but yields decrease with each year of harvest.  Diseases, weeds and weak plants limit the life span of a single planting, so a planting should not be expected to maintain its quality for more than three seasons.  Follow the recommended renovation or renewal procedures to maximize the life of a planting. Ideally strawberry beds are renovated right have harvest is done.  Rows are narrowed to a width of 10-15 inches by tilling.  Matted beds are tilled to create 10-15" wide rows with 24" wide walkways.   Plants in rows are thinned to 7-11" apart, by removing old mother plants and weak new runners.  If time and weather permits, plantings should be thinned again in September or October to leave only 5-7 plants per square foot.

Strawberries for the Home Garden, University of Minnesota Extension

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23. Nuisance insects and mice enter homes in fall as temperatures cool and they begin to look for overwintering sites. Pests like boxelder bugs, millipedes and Asian lady beetles are common. Most are harmless but a nuisance. Exclusion is the best means of reducing nuisance pests and mice indoors. Caulk cracks, crevices and conduits of the home. Repair window screens and check that doors are tight fitting. If needed, insecticides can be applied to building foundations according to label direction. Ideally, apply the insecticide from the foundation out to five to 10 feet.

Controlling House Mice, University of Nebraska-Lincoln Extension
The Mice Are Coming, UNL Extension Acreage Insights
Centipedes and Millipedes, UNL Extension in Lancaster County
Boxelder Bugs, UNL Extension in Lancaster County
Multicolored Asian Ladybird Beetles, UNL Extension in Lancaster County

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24. Wolf spiders are large, somewhat hairy spiders found indoors and outdoors. While frightening to some because of their large size, wolf spiders are not considered poisonous; although a bite may cause a reaction in sensitive individuals. They do not build webs to catch their prey, but pounce on their prey. Wolf spiders accidentally find their way indoors, most often during late summer or fall. Because only a few wolf spiders usually find their way indoors, insecticide applications are not needed. Instead, place sticky traps, such as small mouse glue boards, in the corners of rooms to trap unwanted spiders and other insects. Make sure screen doors are tight fitting and caulk or screen openings spiders and other insects may use to enter the home.

Wolf Spiders, UNL Extension in Lancaster County

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25. Cattail control can be achieved by cutting plant stems down in fall.  If possible, the plants should be cut below the water line. If they must be cut above the water line, the water level should be raised to submerge the cut stems at least eight inches. Research in Iowa (Weller, 1975) found that cutting shoots two or three times during the growing season before flower production, reduced a cattail stand by 95-99% in one year. A single cutting in August followed by submergence resulted in 80% control. It is important to remove all dead and live cattail stems to achieve this control.

Power equipment that has been used to cut cattails includes sickle mowers and hand operated power trimmers equipped with metal cutting wheels instead of strings. Hand scythes, machetes (corn knives) and long-handled shovels also have been used to manually cut cattails that are close to the shoreline.

Controlling Cattails, UNL Extension Acreage Insights

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