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Video of the Week: Controlling Bagworms

6/13/2017

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Pests: Still Early to Treat Bagworms

6/6/2017

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Many bagworms have hatched and have come out of the mother's bag but we are still a bit early to treat as we may miss those that are late to emerge. The latter half of June is a good target to treat for these insects. However, make sure you have living bagworms as sometimes natural predators and parasites provide good levels of control. Look for a miniature version of the mature bagworm. They are still tiny and are about the size of the lead point on a pencil.

Insecticides commonly used for controlling bagworms include spinosad (Conserve; Fertilome Borer, Bagworm, Leafminer & Tent Caterpillar Spray; Captain Jack’s Dead Bug Brew, Bonide Caterpillar Killer), Bacillus thuringiensis(Dipel, Thuricide), acephate (Acephate, Orthene, Bonide Systemic Insect Control), cyfluthrin (Tempo, Bayer Vegetable & Garden Insect Spray) and permethrin (numerous trade names). Products containing Bacillus thuringiensis (BT) are only effective when used against bagworm larvae while they are still small. Note that spinosad
and BT are both organic but spinosad is a more effective product, especially on larger larvae.

Thorough coverage is vital for good control. Most failures are due to the spray not penetrating deep enough in the tree rather than the insecticide not working. (Ward Upham)
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Horticulture Newsletter 2016, No. 34

8/23/2016

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Turfgrass:
Give Cool-Season Grasses a Boost

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​September is almost here and that means it is prime time to fertilize your tall fescue or Kentucky bluegrass lawns. If you could only fertilize your cool-season grasses once per year, this would be the best time to do it.
        
These grasses are entering their fall growth cycle as days shorten and temperatures moderate (especially at night). Cool-season grasses naturally thicken up in the fall by tillering (forming new shoots at the base of existing plants) and, for bluegrass, spreading by underground stems called rhizomes. Consequently, September is the most important time to fertilize these grasses.
        
Apply 1 to 1.5 pounds of actual nitrogen per 1,000 square feet. The settings recommended on lawn fertilizer bags usually result in about 1 pound of nitrogen per 1,000 square feet. We recommend a quick-release source of nitrogen at this time. Most fertilizers sold in garden centers and department stores contain either quick-release nitrogen or a mixture of quick- and slow-release. Usually only lawn fertilizers recommended for summer use contain slow-release nitrogen. Any of the others should be quick-release.
        
The second most important fertilization of cool-season grasses also occurs during the fall. A November fertilizer application will help the grass green up earlier next spring and provide the nutrients needed until summer. It also should be quick-release applied at the rate of 1-pound actual nitrogen per 1,000 square feet. (Ward Upham) 

Vegetables:
Common Smut on Sweet Corn

smut on sweet corn
​Smut (Ustilago maydis) is a fungal disease of corn that may infect leaves, stems, tassels or ears though infections on ears are the most obvious.  Immature galls are white and spongy but become brown with dark powdery spores with maturity.  Leaf galls remain small but those on the ears or stems can become rather large and will release large numbers of spores when they rupture. This disease is likely to be most severe on plants injured by hail, cultivation or insects and tends to be worse on soils that have had heavy applications of nitrogen fertilizer or manure. Also anything that slows growth such as hot, dry weather or cool, wet weather when the plants are young can result in more infections.
        
Immature smut galls are considered an edible delicacy known as cuitlacoche in Mexico. They are a high value crop for some growers in the northeast U.S. who sell them to Mexican restaurants.
        
There is no chemical control for this disease. Crop rotation and a balanced fertilizer program can help minimize this disease. Remove and destroy galls from infected plants before they rupture. (Ward Upham)

Flowers:
Dividing Daylilies

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Daylilies need to be divided every three to four years to maintain vigor. Though they may be divided in early spring before growth starts, it is more common to divide them at this time of year. Many gardeners cut back the tops to about half their original height to make plants easier to  handle.
        
Daylilies have a very tough root system that can make them difficult to divide while in place. Dividing in place is practical if it hasn’t been long since the last division. In such cases, a spading fork can be used to peel fans from the existing clump. If the plants have been in place longer and are well grown together, it is more practical to divide them after the entire clump has been dug.
        
Use a spade to lift the entire clump out of the ground. Although it is possible to cut the clump apart with a sharp spade, you'll save more roots by using two spading forks back-to-back to divide the clump into sections. Each section should be about the size of a head of cauliflower. An easier method involves using a stream of water from a garden hose to wash the soil from the clump, and then rolling the clump back and forth until the individual divisions separate. Space divisions 24 to 30 inches apart, and set each at its original depth. The number of flowers will be reduced the first year after division but will return to normal until the plants need to be
divided again. (Ward Upham)

Pests:
Likely Too Late to Spray for Bagworms

bagworms
Bagworms can cause a great deal of damage during the last few weeks of feeding, and gardeners may be tempted to spray for them now. But late-August sprays are often totally ineffective because the insects have usually stopped feeding.  Never spray in August unless the insects are actively feeding.  Handpicking is still possible if there are not so many bags it becomes impractical. Understanding the life cycle of this moth will explain why spraying now is not recommended and help plan effective control measures.
        
In Kansas, bagworms normally finish feeding and close their bags during mid-August. After that, insecticides are ineffective because they cannot reach the pest.
        
Bagworms are unusual because they use an uncommon form of reproduction called paedogenesis in which the female larva reproduces. The female larva never pupates, but produces mature sexual organs during the last larval instar. She releases a sex hormone that attracts the male who does pupate and emerges as a flying moth. The male flies to the female's bag and mates with her while she remains in the bag. After mating, the female's body fills with eggs. She will eventually die inside the bag, and her body will become a dried, mummified egg case that will protect the eggs during the winter. Each female case normally contains 300 to 1,000 eggs. Egg hatch does not occur until the next spring, usually around the end of May in Kansas.
        
Insecticide sprays are more likely to be effective when the bagworms are small. Even Bacillus thuringiensis (Dipel, Thuricide) can be effective on young bagworms. Another organic product, spinosad (Captain Jack’s Deadbug Brew; Fertilome Borer, Bagworm, Leafminer and Tent Caterpillar Spray; Monterey Garden Insect Spray), is very effective against both young and more mature bagworms. Other commonly used pesticides include acephate, cyfluthrin, permethrin, malathion and Sevin.
        
During most years, spraying about June 15 will provide good control. Don't forget that insecticides are not the only means of control. Hand picking and destroying the bags is effective any time when the bags are large enough to be picked. (Ward Upham)

Mycosphaerella Leaf Spot on Ash

Mycosphaerella Leaf Spot on ash
With all the concern about Emerald Ash Borer (EAB), many people may assume that any ash tree with problems is being attacked by EAB. However, EAB has only been confirmed in Douglas, Jefferson, Johnson, Leavenworth and Wyandotte counties.  One of the other problems we see with ash is Mycosphaerella Leafspot. Though this disease looks serious, it is not.
 
Mycosphaerella leaf spot causes small, brown spots that enlarge to become blotches and may result in early leaf drop. Defoliation this late in the growing season will not hurt the health of the tree. Therefore, because this disease appears sporadically and tree health is not harmed, we do not recommend treatment. Furthermore, treatment would have to be preventative and applied before the disease had infected the leaves. Applying a fungicide now would have no effect. (Ward Upham)

Miscellaneous:
Are Crabapples Safe to Eat?

crabapples
Crabapples are safe to consume as long as you don’t eat too many of them. Actually, the only difference between crabapples and apples is the size of the fruit. By definition, crabapples have fruit that are 2 inches or less in diameter, and apples are more than 2 inches in diameter. By this definition, most of the apples grown from seed will be crabapples. The fruiting apples are grafted.
        
So, did people ever plant crabapples from seed? Of course they did. Just think of Johnny Appleseed. But those apples were normally used for jelly, applesauce, and cider and not for fresh eating.
        
There is one other caveat with using crabapples from a tree in the landscape. Make sure the tree hasn't been sprayed as an ornamental with a pesticide that isn't labeled for fruit tree apples. If it has, then the fruit should not be used. (Ward Upham)
                                   
Contributors: Ward Upham, Extension Associate

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Horticulture Newsletter 2016, No. 23

6/7/2016

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Video of the Week:
Controlling Bagworms

Fruit:
Brown Rot of Stone Fruits​

brown rot on stone fruit
The wet weather we have seen in some areas has caused perfect conditions for the formation of brown rot on stone fruits such as peaches and plums. Affected fruit develop a gray to brown, fuzzy growth on the fruit, itself, which may rot in as little as a day or two. It is best to start treating fruit about a month before harvest but spraying is still helpful even if we are within that one month period. Fruit that shows symptoms cannot be saved but should be destroyed to prevent further spread.
 
Use Captan or myclobutanil (Immunox) for control. Many fruit tree sprays contain Captan but check the label to be certain. Apply Captan or Immunox every 7 to 14 days.  Both products can be applied up to the day of harvest.  Note that though Immunox is labeled for fruit but Immunox Plus is not. (Ward Upham)

Flowers:
​Sidedressing Annual Flowers

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Modern annual flowers have been bred to flower early and over a long period of time. They are not as easily thrown off flowering by high nitrogen levels as vegetables are. As a matter of fact, providing nitrogen through the growing season (sidedressing) can help maintain an effective flower display for warm-season flowers.
 
Apply a high nitrogen sidedressing four to six weeks after flowers have been set out. Additional fertilizations every three to four weeks can be helpful during a rainy summer, or if flower beds are irrigated. Common sources of nitrogen-only fertilizers include nitrate of soda, urea, and ammonium sulfate. Blood meal is an organic fertilizer that contains primarily, but not exclusively, nitrogen. Use only one of the listed fertilizers and apply at the rate given below.
 
Nitrate of soda (16-0-0): Apply 1/3 pound (.75 cup) fertilizer per 100 square feet.
Blood Meal (12-1.5-.6): Apply 7 ounces (7/8 cup) fertilizer per 100 square feet.
​Urea (46-0-0): Apply 2 ounces (1/4 cup) fertilizer per 100 square feet.
Ammonium Sulfate (21-0-0): Apply 4 ounces (½ cup) fertilizer per 100 square feet.
 
If you cannot find the above materials, you can use a lawn fertilizer that is about 30 percent nitrogen (nitrogen is the first number in the set of three) and apply it at the rate of 3 ounces (3/8 cup) per 100 square feet. Do not use a fertilizer that contains a weed killer or weed preventer.  (Ward Upham)

Spring-Flowering Bulb Foliage Can Be Removed

old foliage on spring bulbs
It is important to leave spring-flowering bulb foliage in place until it “ripens” or becomes brown.  The energy produced by the leaves after flowering is transferred to the bulb so that it can flower the following year.
 
The ripening  process should be near completion about now for tulips, daffodils and various other spring- flowering bulbs.  Use clippers, scissors or even a mower to remove dead foliage.  Also, try to map out where the bulbs are planted as there will be no foliage to make the location next fall when it is time to fertilize.  (Ward Upham)

Rose Rosette

rose rosette
Rose rosette is a serious problem in Kansas on wild roses (Rosa multiflora) in pastures and hedges. It is also found in domestic rose plantings.
 
Infection is thought to start with rapid elongation of a new shoot. The rapid shoot growth may continue for several weeks to a length of two to three feet. Following shoot elongation, a witches' broom or clustering of small branches occurs. The stems develop excessive thorniness and produce small, deformed leaves with a reddish-purple pigmentation. Stems and petioles of Rosa multiflora plants may have reddish blotches or streaks.
 
Rose plants infected with the rose rosette virus die rapidly, usually within one to two years. Rose rosette is caused by a Emaravirus species.  Transmission of the disease has been shown experimentally through grafting and is also thought to be spread by mites. Though KnockOut roses are resistant to many diseases, they are susceptible to this one.
 
There is no effective control measure for infected plants. In garden settings, infected plants should be removed and destroyed, including roots. Any roots that remain after plant removal may produce infected shoots which can harbor the disease. If possible, eliminate all multiflora rose plants from the vicinity as they are extremely susceptible and will act as a carrier. Multiflora rose is the wild rose often seen growing in ditches and pastures.
 
Since the disease can be transmitted by pruning shears, disinfect the shears when moving from one plant to another by using rubbing alcohol or a disinfectant such as Lysol. (Ward Upham)

Ornamentals:
European Fruit Lecanium Scale: Adding a "Decorative Touch" to Bald Cypress

European fruit lecanium scale
The European fruit lecanium scale (Parthenolecanium cornii) is quite noticeable on bald cypress (Taxodium distichum) twigs and branches. The damage associated with this scale, which depends on the extensiveness of the infestation, includes plant stunting and wilting. The European fruit lecanium scale is a soft scale, so honeydew (a sticky, clear liquid) will be produced during feeding. The honeydew serves as a substrate for black sooty mold and attracts ants. In addition, honeydew can drip onto vehicles parked underneath infested trees leaving unsightly residue.
 
The scales are dark brown, 1/8 to 1/4 inches in diamete. Some scales may have white markings on the body. European fruit lecanium scale overwinters as an immature on twigs and branches with maturing occurring in spring. In May and June, females lay many eggs underneath their bodies. In June eggs hatch into small tan-colored crawlers. The duration of an egg hatch can last several days depending on the temperature. Crawlers migrate to leaf undersides and subsequently feed on plant fluids until late summer. At that point, the crawlers migrate back onto twigs and branches to complete their development the following spring. There is one generation per year in Kansas.
 
Management of European fruit lecanium scale primarily involves timely applications of insecticides.  Applications should be made when crawlers are present because the crawlers are most vulnerable life stage to insecticide sprays. Mature scales possess a shell-like covering that protects them from exposure to insecticides. Repeat applications will be required as the eggs do not all hatch simultaneously but may hatch over a three to four-week period. The most appropriate time to apply insecticides is in late June to early July when the crawlers are feeding on leaves; thus enhancing their exposure to any spray residues. There are a number of insecticides, with contact activity that are effective in suppressing populations of the European fruit lecanium scale. However, many have broad-spectrum activity and will kill many natural enemies including: parasitoids and predators. In fact, most outbreaks of scale insects are caused by the indiscriminate use of pesticides (insecticides and miticides). Therefore, always read the label and exercise caution when applying any pesticide. In the winter, dormant oils can be applied to kill overwintering scales by means of suffocation.
 
I need to acknowledge Jeff Otto of Wichita, KS for bringing to my attention that European fruit lecanium scale was active. I have also observed infestations in Manhattan, KS.  (Raymond Cloyd)

Oak Vein Pocket Gall Info Available

oak vein pocket gall
As with many areas in Kansas, Sedgwick County has seen a high level of oak vein pocket gall this year. Matthew McKernan, our Sedgwick County Horticulture Agent and Dr. Raymond Cloyd, our Horticulture Extension Entomologist, have put together a two page fact sheet discussing the problem. Excellent photos and informative text make this a timely and valuable resource for those who need more information on this subject. You can find the publication at: http://www.hfrr.k-state.edu/doc/hort-tips/Oak-Vein-Pocket-Gall.pdf
(Ward Upham)

Pests:
Ticks

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Ticks are very active throughout the state, and have been for the past month. The most commonly reported
species has been the American dog tick, Dermacentor variabilis.

The cool, humid weather over the past month has provided great conditions for tick development.  These annoying, and potentially dangerous parasites have even been encountered in corn fields, which is unusual as they typically develop in more undisturbed areas of grasses, weeds, and other overgrown vegetation. But, they are very good at finding hosts and getting the blood meal they require for development and reproduction. For more information on ticks in Kansas, please visit: https://www.vet.k-state.edu/vhc/docs/ticks-in-kansas.pdf.  (Jeff Whitworth and Holly Schwarting)

Still Early to Treat Bagworms

Bagworm
Many bagworms have hatched and have come out of the mother's bag but we are still a bit early to treat as we may miss those that are late to emerge.  The latter half of June is a good target to treat for these insects. However, make sure you have living bagworms as sometimes natural predators and parasites provide good levels of control. Look for a miniature version of the mature bagworm. They are still tiny and are about the size of the lead point on a pencil.
 
Insecticides commonly used for controlling bagworms include spinosad (Conserve; Fertilome Borer, Bagworm, Leafminer & Tent Caterpillar Spray; Captain Jack’s Dead Bug Brew, Bonide Caterpillar Killer), Bacillus thuringiensis (Dipel, Thuricide), acephate (Acephate, Orthene, Bonide Systemic Insect Control), cyfluthrin (Tempo, Bayer Vegetable & Garden Insect Spray) and permethrin (numerous trade names). Products containing Bacillus thuringiensis (BT) are only effective when used against bagworm larvae while they are still small. Note that spinosad and BT are both organic but spinosad is a more effective product, especially on larger larvae.
 
Thorough coverage is vital for good control. Most failures are due to the spray not penetrating deep enough in the tree rather than the insecticide not working. (Ward Upham)

Miscellaneous:
After-Effects of Too Much Rain

water logged plants
Some areas of Kansas have had saturated or near-saturated soils for several weeks now. Gardeners are likely to assume that watering won’t be needed for quite some time now as soil moisture levels are very high. Actually, watering may be needed much sooner than you expect. Excessive rain can drive oxygen out of the soil and literally drown roots.
Therefore, as we enter hotter, drier weather, the plants with damaged root systems may be very susceptible to a lack of water. Don’t forget to check your plants for signs of wilting or leaf scorching and water as needed.
 
If irrigation is called for, water deeply and infrequently. Usually once per week is sufficient depending on the weather. Soil should be moist but not waterlogged. (Ward Upham)
 
Contributors: Raymond Cloyd, Extension Entomologist; Holly Schwarting, Entomology; Ward Upham, Extension Associate; Jeff Whitworth, Entomology

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K-State Horticulture Newsletter 2015, No. 29

7/21/2015

2 Comments

 

Video of the Week:
Spider Mites

Ornamentals:
Tubakia Leaf Spot of Oak

Tubakia on red oak
This leaf spot disease of oak is showing up earlier and is more severe this year than normal.  Members of the red oak group are more likely to be affected than those in the white oak group, but members of both groups are showing symptoms now. Red oaks often have distinct round spots as well as dead areas that follow the veins. White oaks also have the dead areas that follow the veins and large blotches of dead tissue but lack the distinct spots.  Leaves severely damaged may drop.  However, trees rarely lose enough leaves to harm the health of the tree.  No fungicide sprays are recommended. (Ward Upham)

Squirrel Damage to Trees

squirrel damaged tree
Tree squirrels can cause a couple types of tree damage. Most commonly they clip the tips of branches. The length of severed branches is often 2 to 3 feet though they can be longer or shorter. When squirrels snip off a branch, they cut it at about a 45-degree angle and the cut is rather tattered. This is a nuisance type of damage and normally does not hurt the health of the tree.

More serious damage is caused when squirrels strip the bark off of limbs or rarely, the trunk.  Wounds can be quite large and the squirrel can effectively girdle the branch by removing all the bark completely around the circumference. Branches girdled in this way will die and the tree may be ruined if those branches are major.

Why squirrels do this is still a bit of a mystery. Some people think it is simply a means to sharpen their teeth or that they are seeking nesting material or water. Other people think that there are certain squirrels that are high-strung and cause this damage out of nervous energy.

If the damage is limited to snipping the ends off of branches, it is probably best to ignore the activity as the tree suffers little harm. But if real damage is occurring due to extensive bark removal, try feeding and watering them. If that doesn’t work, control may be necessary. Fox and gray squirrels are game animals and can be hunted in season where it is legal and safe to do so.  They can also be trapped and moved away from the area they are causing damage. For more information on control, see http://www.bookstore.ksre.ksu.edu/pubs/L863.pdf .  (Ward Upham)

Pests:
Cicada Killer Wasps

Cicada killer wasp
These large (1-1/3- to 1-5/8-inch long) wasps fly slowly above the ground. Cicada killers have a black body with yellow marks across the thorax and abdomen. Wings are reddish-orange. Although these wasps are huge, they usually ignore people. Males may act aggressively if they are threatened, but are unable to sting. Females can sting, but are so passive that they rarely do. Even if they do sting, the pain is less than that of smaller wasps such as the yellow jacket or paper wasp and is similar to the sting of a sweat bee.

The cicada killer is a solitary wasp rather than a social wasp like the yellow jacket. The female nests in burrows in the ground. These burrows are quarter-size in diameter and can go 6 inches straight down and another 6 inches horizontally. Adults normally live 60 to 75 days from mid-July to mid-September and feed on flower nectar and sap. The adult female seeks cicadas on the trunks and lower limbs of trees. She stings her prey, flips it over, straddles it and carries it to her burrow. If she has a tree to climb, she will climb the tree so the can get airborne and fly with cicada back to the nest. If not, she will drag it. She will lay one egg per cicada if the egg is left unfertilized. Unfertilized eggs develop into males only. Fertilized eggs develop into females and are given at least two cicadas. Cicadas are then stuffed into the female’s burrow. Each burrow normally has three to four cells with one to two cicadas in each.  However, it is possible for one burrow to have 10 to 20 cells.

Eggs hatch in two to three days, and larvae begin feeding on paralyzed cicadas.  Feeding continues for four to 10 days until only the outer shell of the cicada remains. The larva overwinters inside a silken case. Pupation occurs in the spring. There is one generation per year.

Cicada killers are not dangerous, but they can be a nuisance. If you believe control is necessary, treat the burrows after dark to ensure the female wasps are in their nests. The males normally roost on plants near burrow sites. They can be captured with an insect net or knocked out of the air with a tennis racket during the day. Carbaryl (Sevin) or permethrin may be used for control.

If you would like more detailed information on cicada killers, see Bob Bauernfeind’s article in the July 10, 2015 Kansas Insect Newsletter at http://entomology.k-state.edu/doc/Newsletters/2015/KSInsectNewsletter12.pdf  (Ward Upham)

Look for Bagworms Now

bagworm
Most calls on how to control bagworms come in late July to early August when damage appears. Bagworms are difficult to control when they are that large. They are much easier to kill while small. Bagworms overwinter as eggs inside the dead female’s bag. Young larvae normally hatch and emerge during mid to late May in Kansas. Now would be a good time to use control measures if you haven’t already sprayed.  However, make sure the bagworms are present by looking for a miniature version of the mature bagworm.  Also, check to be sure the bagworms are alive before spraying. Predators and parasites  can sometimes naturally control this pest.

Insecticides commonly used for controlling bagworms include acephate (Orthene), permethrin (numerous trade names), cyfluthrin (Bayer Vegetable and Garden Insect spray), bifenthrin (Bug Blaster II, Bug-B-Gon Max Lawn and Garden Insect Killer), lambda-cyhalothrin (Spectracide Triazicide, Bonide Caterpillar Killer) and spinosad (Conserve; Borer, Bagworm, Leafminer and Tent Caterpillar Spray; and Captain Jack's Dead Bug Brew). Spinosad is an organic control that is very effective on this pest.  Thorough spray coverage of foliage is essential for good control with any of these products. (Ward Upham)

Blister Beetles

Blister beetle
These beetles are notorious for quickly stripping vegetables (especially tomatoes) and ornamentals of their foliage. There are several species of blister beetles which vary in size (often between 0.5-0.75 inch long) and color (such as black, gray or brown-striped), but most are recognized by their elongated, narrow, cylindrical, soft bodies with middle body part (thorax) narrower than the head or wingcovers.

Some home gardeners like to use hand picking as a nonchemical method for controlling these large insects. However, wear gloves and use caution because these beetles contain a substance called cantharidin. This chemical is an irritant capable of blistering internal and external body tissues exposed to the chemical. On tender human skin, body fluids of adult blister beetles may cause large, erect, watery blisters.

Chemical control of blister beetles is also possible. Cyfluthrin (Bayer Vegetable and Garden Insect Spray) and gamma- or lambda-cyhalothrin (Spectracide Triazicide, Bonide Beetle Killer, Bonide Caterpillar Killer) can be used for control. Cyfluthrin has a 0 day waiting period and lambda-cyhalothrin has a 5-day waiting period on tomatoes. (Ward Upham)

Squash Vine Borer

squash vine borer
If you have squash or related plants that suddenly wilt and die, you may have squash vine borer. This insect will bore into the stems of squash, zucchini, pumpkins and gourds. Hubbard squash are a favorite, and butternuts are less likely to be attacked than other squash. Cucumbers and melons are usually not a target, although both can be affected by a disease that causes similar symptoms, known as bacterial wilt.

The adult of this insect is a clear-winged moth that resembles a wasp. The forewings are a dark metallic green but the rear wings are clear. The abdomen is orange with black spots. The larva is cream-colored and rather wrinkled. Adults emerge in the spring and lay eggs on or near susceptible plants. Larva bore into the plant and feed for about a month as they move toward the base. Mature larva will exit the plant, burrow into the soil and pupate where they remain until the next year. Each plant can have numerous borers. If you suspect squash vine borer, split the stem of a collapsed plant near where it enters the ground. Infested plants will be hollowed out and mushy and may contain borers. Unfortunately, there isn't much you can do at this late stage. Control measures should center on prevention.

Suggested preventative controls would include crushing the dull red eggs before they hatch, excavating larvae from stems before they cause much damage or using insecticide applications. Applications should begin when the vines begin to run (too late for that) and reapplied every seven to 10 days for three to five weeks. Direct the spray at the crown of the plant and the base of runners. Chemicals used for borer control in gardens are permethrin (Bug-No-More Yard & Garden Insect Spray; Eight Vegetable, Fruit & Flower Concentrate; Lawn, Garden, Pet and Livestock Insect Control; Lawn & Garden Insect Killer), bifenthrin (Hi-Yield Bug Blaster II, Bug-B-Gon Max Garden Insect Killer) or carbaryl (Sevin), applied as sprays or dusts. Continue on a 7 to 10 day reapplication schedule for 3 to 5 weeks. If plants wilt, look for the presence of holes and ooze. However, in extreme heat, these plants will wilt in the afternoon even if undamaged by this insect. (Ward Upham)

Miscellaneous:
Watering May Be Needed This Summer

slowly watering a tree
Many areas of Kansas went through an extremely wet spring.  Gardeners may assume that little watering may be needed this summer as the soils were completely recharged.  However, many will likely need to do more watering than they expect. 

Rain saturated soils can damage root systems.  Excess water drives oxygen out of the soil as pore spaces are filled with water. Every living cell in a plant must have oxygen to live. If there is no oxygen, roots will die. Therefore, many of our plants may need to be babied through the summer.

Newly planted trees are especially vulnerable as they have not established the extensive root system needed to absorb enough water during hot, dry, windy summers. Even trees two or three years old should receive special care even if the root system was not damaged by saturated soils. 

Deep, infrequent watering and mulching can help trees become established. Newly transplanted trees need at least 10 gallons of water per week, and on sandy soils they will need that much applied twice a week. The secret is getting that water to soak deeply into the soil, so it evaporates more slowly and is available to the tree’s roots longer. One way to do this is to drill a small hole (1/8") in the side and near the bottom of a 5-gallon bucket and fill it with water. Let the water dribble out slowly next to the tree. Refill the bucket once, and you have applied 10 gallons. Very large transplanted trees and trees that were transplanted two to three years ago will require more water.

A perforated soaker hose is a great way to water larger trees, a newly established bed or a foundation planting.  See the accompanying article for an inexpensive way to water trees.

In sunbaked soil, you may need to rough up the surface with a hoe or tiller to get water to infiltrate easily. It may be helpful to set the kitchen oven timer, so you remember to move the hose or shut off the faucet. If you are seeing surface runoff, reduce the flow. 

Regardless of method used, soil should be wet at least 12 inches deep. Use a metal rod, wooden dowel, electric fence post or something similar to check depth. Dry soil is much harder to push through than wet. Record the time that was required to reach 12 inches and then use a time clock for any future waterings.  (Ward Upham)

Inexpensive Method of Watering Trees

Y-Adapter to attach to soaker hose
We mentioned in an accompanying article about using a soaker hose to water trees.  We thought it might be helpful to provide more details. 

Soaker hoses are notorious for non-uniform watering. In other words, you often receive too much water from one part of the hose and not enough from another.  Hooking both the beginning and the end of the soaker hose to a Y-adapter helps equalize the pressure and therefore provide a more uniform watering.  The specific parts you need are shown in the photo above and include the soaker hose, Y-adapter and female to female connector.

It is also helpful if the Y-adapter has shut off valves so the volume of flow can be controlled.  Too high a flow rate can allow water to run off rather than soak in.  

On larger trees, the soaker hose can circle the trunk at a distance within the dripline of the tree but at least ½ the distance to the dripline. The dripline of the tree is outermost reach of the branches. On smaller trees, you may circle the tree several times so that only soil which has tree roots will be watered.  (Ward Upham)

Contributors: Ward Upham, Extension Associate

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Horticulture Newsletter 2014 No.23

6/10/2014

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Video of the Week:
Bacterial Spot on Peach Trees

Ornamentals:
Rust on Hollyhock

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Watch for rust on hollyhock. This is the most common disease on hollyhock and can cause serious injury as leaves are progressively killed through the summer. Look for yellow spots on the surface of the leaves and orangish to brown pustules on the underside. Infections can also take place on stems and green flower parts.

The first line of defense is to remove all hollyhock stalks, leaves and other debris in the fall and destroy them. Remove any infected foliage you see now. Just be sure the foliage is dry so you don’t spread the
disease. Continue to remove diseased leaves as soon as they show spots. Try using a fungicide such as sulfur or myclobutanil (Immunox or Immunox Plus) to protect healthy foliage. Note that sulfur may burn leaves if the air temperature is over 85 degrees within 24 hours of application. Follow label directions for timing and rate. (Ward Upham)

Vegetables:
New Potatoes

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Many gardeners look forward to harvesting new potatoes this time of year. New potatoes are immature and should be about the size of walnuts.  Pull soil away from the base of the plants to see if the tubers are the desired size. If they are, dig entire plants and allow the skins of the  exposed tubers to dry for several hours before gathering. These young potatoes are very tender and prone to the skin “slipping” unless they are given a few hours to dry. Even then these immature potatoes will not store well. Red-skinned varieties are often preferred as they are the earliest to produce. (Ward Upham)

Mulching Garden Crops

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Now is a good time to mulch garden vegetables if you haven’t done so already. Mulches provide several benefits including weed prevention, reduced watering due to less evaporation and cooler soils that enhance root growth. Straw and hay are popular mulches in Kansas due to their availability. However, both may contain weed seeds that will germinate if the thatch layer is not thick enough. Grass clippings can also be used if the lawn has not been treated with weed killers. Add only a thin layer of clippings at a time and allow to dry for 2 to 3 days before adding more. A thick layer will form a mold that is almost impervious to water. A mulch layer one-half to three-quarters inch thick is about right for grass clippings but hay or straw should be at a depth of 2 to 4 inches. (Ward Upham)

Do Not Over-Fertilize Tomatoes

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Though tomatoes need to be fertilized to yield well, too much nitrogen can result in large plants with little to no fruit. Tomatoes should be fertilized before planting and sidedressed with a nitrogen fertilizer three times during the season.The first sidedressing should go down one to two weeks before the first tomato ripens. The second should be applied two weeks after the first tomato ripens and the third one month after the second. Common sources of nitrogen-only fertilizers include nitrate of soda, urea, and ammonium sulfate. Blood meal is an organic fertilizer that contains primarily, but not exclusively, nitrogen.
Use only one of the listed fertilizers and apply at the rate given below.

Nitrate of soda (16-0-0): Apply 2/3 pound (1.5 cups) fertilizer per 30 feet of row.
Blood Meal (12-1.5-.6): Apply 14 ounces (1.75 cups) fertilizer per 30 feet of row.
Urea (46-0-0): Apply 4 ounces (½ cup) fertilizer per 30 feet of row.
Ammonium Sulfate (21-0-0): Apply 0.5 pounds (1 cup) fertilizer per 30 feet of row.
If you cannot find the above materials, you can use a lawn fertilizer that is about 30 percent nitrogen (nitrogen is the first number in the set of three) and apply it at the rate of 1/3 pound (3/4 cup) per 30 feet of row. Do not use a fertilizer that contains a weed killer or weed preventer. (Ward Upham)

Fruit:
Fruit Reminders

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* Remove fruit from heavily loaded apples and peaches (if the flower buds weren’t killed by frost) to improve fruit size and prevent limbs from breaking. Apples should be spaced every 4 inches and peaches every 6 to 8. Note that is an average spacing. Two fruit can be closer together if the average is correct.

* Remove sucker growth from the base of fruit trees and grape vines.

* Remove water sprout growth from fruit trees. Water sprouts grow straight up.

* "Comb" new growth on grape vines so these new shoots hang down for greater exposure to sunlight.

* Continue disease and insect control to prevent fruit damage. (Ward Upham)

Pests:
Lecanium Scale

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There are about a dozen different species of soft scales collectively known as lecanium scale. But life histories are similar enough to treat them as a single entity for the purposes of this article. Normally, damage from lecanium scale is slight with "honeydew" raining down on anything under affected trees. Sooty mold, a fungus that feeds
on the honeydew, can turn branches and leaves black. Branch dieback is possible with large populations. Predators and parasites normally keep lecanium scale under control, but there are times when the population of beneficials is too low to provide immediate control. Unfortunately, later instars and adults are virtually impossible to control with insecticides. Only the crawler stage is susceptible, and the time of crawler emergence varies from year to year.

If you feel insecticides are necessary, target the crawler stage as it migrates from the dead mother's body to the leaves. This usually occurs about the time yucca plants flower. Trapping adults has shown that this week is a good time to apply treatments in Wichita as the crawlers are out. Apply a followup spray in another 10 days. More northern locations may want to wait until the yucca flowers. Registered products include permethrin (numerous trade names) cyfluthrin (Tempo, Bayer Vegetable and Garden Insect Spray), dinotefuran (Ortho Tree & Shrub Insect Control Ready To Use Granules), carbaryl (Sevin) and malathion. Though too late to apply now, imidacloprid (Bayer Tree and Shrub Insect Control, Bonide Systemic Granules IC) can be applied in the fall. (Ward Upham)

Now is Time to "Nail" Those Bagworms

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It is now time to “do battle” (I love military metaphors) with that “infamous” of insect pests known as the bagworm (Thyridopteryx ephemeraeformis). Throughout most of Kansas, bagworm eggs have hatched and the young caterpillars are out-and-about feeding on both broadleaf and evergreen trees and shrubs. Bagworms were first considered a pest of primarily conifers but over the years they have expanded their host range to include a number of broadleaf plants including rose, honeylocust, and flowering plum. I have even seen them “eating chicken wire” at the Sunset Zoo (Manhattan, KS).

At this time of year, what is the best way to deal with bagworm caterpillars and thus prevent them from causing damage? Handpicking any small caterpillars (along with their accompanying bag) and placing them into a container of soapy water will kill them directly. This is highly therapeutic and, if feasible, will quickly remove populations before they can cause substantial plant damage. You should consider having a weekend “bagworm handpicking party” with prizes awarded to those individuals that collect the most bags. For those less interested in the pleasures of handpicking, there are a number of insecticides labeled for use against bagworms including those with the following active ingredients (trade name in parentheses): acephate (Orthene), Bacillus thuringiensis subsp. kurstaki (Dipel/Thuricide), cyfluthrin (Tempo), lambda-cyhalothrin (Scimitar), trichlorfon (Dylox), indoxacarb (Provaunt), chlorantraniliprole (Acelepryn), and spinosad (Conserve). Many of these active ingredients are commercially available and sold under different trade names or generic products. However, several insecticides may not be directly available to homeowners. The key to dealing with bagworms when using insecticides is to make applications early and frequently enough in order to kill the highly susceptible young caterpillars that are feeding aggressively on plant foliage. Older caterpillars that develop later in the season, in the bags, may be 3/4-inches long, and are typically more difficult to kill with insecticides. In addition, females tend to feed less as they prepare for reproduction, which reduces their susceptibility to spray applications and any residues. The bacterium Bacillus thuringiensis subsp. kurstaki is active on young caterpillars; however, the active ingredient must be consumed to be effective, so thorough coverage of all plant parts and frequent applications are required to avoid having to deal with later stages. This compound is sensitive to ultra-violet light degradation and rainfall, which reduces any residual activity. Spinosad is the active ingredient in a number of homeowner products (including Borer, Bagworm, Tent Caterpillar & Leafminer Spray; Captain Jack’s DeadBug Brew; and Monterey Garden Insect Spray) and works by contact and ingestion (stomach poison); however, it is most effective when ingested and it can be used against older or larger bagworm caterpillars. Cyfluthrin, lambda-cyhalothrin, trichlorfon, chlorantraniliprole, and indoxacarb may be used against both the young and the older caterpillars. However, thorough coverage of all plant parts, especially the tops of trees and shrubs, where bagworms commonly start feeding, and frequent applications are required.

The reason why multiple applications will be needed when bagworms are first detected is because bagworms “blow in” (called ‘ballooning’) from neighboring plants. If left unchecked, bagworms can cause significant
damage, thus ruining the aesthetic quality of plants. In addition, they may actually kill plants, especially evergreens since they don’t usually produce another flush of growth, and newly transplanted small plants. If you have any questions regarding the management of bagworms, contact your county horticultural agent, or university-based or state extension entomologist. (Raymond Cloyd)

Contributors: Raymond Cloyd, Entomologist; Ward Upham, Extension Associate
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    Authors

    Ward Upham runs the Horticulture Response Center in the Department of Horticulture and Natural Resources at Kansas State University. Other contributors include K-State Extension Specialists.

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