The Bagworm in Missouri

The most important species of bagworm in the United States is Thyridopteryx ephemeraeformis (Haworth). This native moth is found extensively throughout the eastern and southern states and reportedly feeds on 128 plants species.  The most commonly attacked host plants are arborvitae, red cedar and other juniper species, black locust, maple and sycamore.

The bagworm can be a constant threat to evergreen and deciduous shrubs used for landscaping. Attached plants usually are partially defoliated, weakened and rendered unsightly. It is not uncommon for complete defoliation to occur.

Biology

The most noticeable or visible sign of a bagworm infestation is the presence of silken bags attached to a branch. The bag somewhat resembles a Christmas tree ornament hanging from a limb.

From late May to mid-June, bagworm larvae (caterpillars) begin emerging, a larva starts to produce its own protective bag or case about its body. With its head and legs free, it is able to move about the plant as it feeds on the foliage. As the larva grows, it increases the size of its bag and incorporates into it bits of twigs and leaves for strength and camouflage protection.

A larva will spend its entire life within its bag, passing through four molts. The full-grown larvae are about 1 inch long. The head and thoracic regions of the body are yellowish and spotted with black, while the rest of the body is dark brown.

When a host plant becomes defoliated, the larvae will crawl off it with their bags and search for a new plant to feed on. When populations are high, this can lead to a “pedestrian” migration of thousands of larvae. Because of this behavior, i.e., colonizing new host plants by walking, bagworm infestations spread from one area to another relatively slowly. However, bagworms can also disperse as ballooning larvae and as eggs in cases floating in rivers and streams. In mid-August the mature larvae stop feeding and attach their bags, now close to 2 inches long, firmly to a twig. They close the open end of the bag and pupate within it.

By mid-September the bagworm has completed its development, and adult males begin emerging from their bags. The male moth has a black, furry body and a feathery antenna. The four wings are almost transparent and have a wingspan of about 1 inch. The males fly about infested plants seeking out females. After mating, the male moth dies.

The adult female bagworm does not look like a moth and never leaves her bag. She is about 0.75 inch long and lacks eyes, antennae, wings, legs or functional mouth parts. She is maggotlike in appearance, soft-bodied and yellowish white. A mated female lays between 500 and 1,000 eggs within her bag, after which she dies. The eggs remain within the bag throughout the winter until they hatch the following spring. There is one generation each year.

Control

Some species of birds (e.g., sapsuckers and woodpeckers) are able to tear open the bags and feed on the larvae. The bagworm also is attacked by some insect predators and parasitoids that usually are effective in controlling small to moderate populations. However, these natural enemies seldom control large bagworm populations until after extensive damage has occurred.

The cheapest method of controlling bagworms on small trees and ornamentals is to hand-pick the bags. Be sure to pick off all bags and destroy them.

For larger plants where hand-picking is not practical, the bagworm can be controlled chemically. Apply the insecticide in the spring (typically the first week of June) as soon as the eggs hatch and small larvae begin emerging from the overwintering bag. Spray applications are most effective if made during this time. Chemical control becomes less effective as the season progresses because of the increased size of the larva and its bag.

Some of the insecticides that can be used against the bagworm are shown below.

Acephate: Ortho Systemic Insect Killer

Bacillus thuringiensis (Bt): American Brand Thuricide Concentrate

Carbaryl:
Bayer Advanced Complete Insect Killer for Gardens
Ferti-lome Liquid Carbaryl Garden Spray
GardenTech Sevin Concentrate Bug Killer
Gordon’s Liquid Dura-Spray Carbaryl

Cyfluthrin: Bayer Advanced Triple Action Insect Killer for Lawns & Gardens

Permethrin:
Bonide Eight Vegetable, Fruit & Flower Concentrate
Hy-Yield Lawn, Garden, Pet & Livestock Insect Control

Spinosad: Fertilome Borer, Bagworm, Tent Caterpillar & Leafminer Spray

Articles reprinted from the University of Missouri Extension. Author Bruce A. Barrett

Sidedressing Annual Flowers

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 four to six 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 2/3 pound (1.5 cups) fertilizer per 100 square feet.
Blood Meal (12-1.5-.6): Apply 14 ounces (1.75 cups) fertilizer per 100 square feet.
Urea (46-0-0): Apply 4 ounces (½ cup) fertilizer per 100 square feet.
Ammonium Sulfate (21-0-0): Apply 0.5 pounds (1 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 1/3 pound (3/4 cup) per 100 square feet. Be absolutely sure that the lawn fertilizer does not contain an herbicide.

Articles reprinted from the K-State Research & Extension Horticulture Newsletter

Deadheading Flowers

Some plants will bloom more profusely if the old, spent flowers are removed, a process called deadheading. Annuals especially, focus their energy on seed production to insure that the species survives. If you remove old flowers, the energy normally used to produce seed is now available to produce more flowers. Perennials can also benefit bylengthening the blooming season. However, some gardeners enjoy the look of spent flowers of perennials such as sedum or purple coneflower. Also, the seed produced can be a good food source for birds.

Not all plants need to be deadheaded, including sedum ‘Autumn Joy’, melampodium, impatiens, most flowering vines, Lythrum, periwinkle (Catharanthus), and wishbone flower (Torenia). Those that do increase bloom in response to deadheading include hardy geraniums, coreopsis, petunias, marigolds, snapdragons, begonias, roses, campanulas, blanket flowers, delphiniums, zinnias, sweet peas, salvia, scabiosa, annual heliotrope, geraniums (Pelargonium), and yarrow.

Deadheading is easily accomplished by removing spent flowers. With some plants, pinching between a thumb and finger can do this, but tough, wiry stems will require a scissors or pruning shears.

Articles reprinted from the K-State Research & Extension Horticulture Newsletter

Does My Ash Tree Have Chicken Pox?

Ash rust, caused by the fungus Puccinia sparganioides, produces orange leaf spots as shown in the photos. In addition, the fungus can cause swelling and distortion in the leaf stems, causing leaves to twist and turn in unusual directions. Ash rust usually is not a serious disease in Kansas and no control is needed. Like the cedar-apple rusts, this fungus also requires an alternate host to complete its lifecycle. The alternate hosts are cordgrass (Spartina spp.) and saltgrass (Distichlis spp.).

Articles reprinted from the K-State Research & Extension Horticulture Newsletter

What’s Going on with Silver Maples?

Have you noticed that silver maples are leafing out sparsely? You are not the only one. I’ve seen it and so have a few others. The silver maples produced a tremendous amount of “helicopters” (samaras) this year.

I think what happened is that the trees put such a major effort into reproduction that they are leafing out a little thinly this year. Trees only have so many resources (energy) to use for different types of growth. For the botanically inclined out there: A samara is an achene with wings. What is an achene? A single-seeded, dry, indehiscent fruit. That is: one seed, dry, and does not open (dehisce) on its own. A sunflower is another type of achene, for example. A samara is a single-seeded, dry, indehiscent WINGED fruit.

Articles reprinted from the K-State Research & Extension Horticulture Newsletter

Fireblight in Crabapples & Flowering Pear

Fireblight has been active recently in eastern Kansas. Fireblight is caused by a bacterial species called Erwinia amylovora. It affects many plants in the rose family including apple, crabapple, pea (including ornamentals), hawthorn, quince, and cotoneaster.

The pathogen survives the winter in cankers. In the spring the disease is most active during wet weather when temperatures are about 65-85 F. During wet spring weather the bacteria ooze out of cankers and are spread by rainsplash, wind and insects to blossoms. This causes “blossom blight.” The pathogen can also infect succulent new leaves and shoots, especially tissue that has been wounded by pruning or hail. The diseased shoots become brown (on apple) or black (on pear) and often have a curled top, referred to as a shepherd’s crook (see photo). Infected shoots can also produce sticky, orange ooze.

The bacterium can move systemically within the infected tree. In
commercial apple plantings the bacterium is most damaging when it moves down into the rootstock, eventually killing the entire tree.

There are several cultural practices to help manage fire blight. The
pathogen is most infective on lush, new growth. Avoid fertilization,
especially later in the season. When the shoots harden off and stop growing they are much less susceptible to infection.

Diseased areas can be pruned out in the summer, but do not prune in wet weather. Make the cuts at least 12-18 inches below the lowest visibly diseased tissue. Disinfect tools between each cut with 70 ethanol or 10% bleach (if you use bleach be sure to clean and oil your tools after use to avoid damage).

Pruning in winter is often a simpler, easier method. Remove dead shoots and cankers. As with summer pruning make the cut below visible diseased tissue, at least 8-10 inches to be safe, and sanitize tools between cuts.

Chemical controls are available but are most effective at bloom so this year we have passed the window of chemical control. In addition, it can be difficult to get the timing and applications correct, so I would encourage home fruit growers to concentrate on the cultural practices.

Commercial apple growers should follow the recommendations in the Midwest Tree Fruit Spray Guide. The content is available online for free at this address: http://www.extension.iastate.edu/publications/pm1282.pdf Or, contact me (Kennelly@ksu.edu) for ordering information. In addition to antibiotics, commercial apple growers can use a growth regulator called Apogee. Apogee should be applied in the spring when shoots are 1 to 3 inches long, and again a few weeks later. Apogee reduces succulent shoot growth and there have been reports that it also stimulates natural defenses in the tree but the mode of action remains unclear. The Apogee label is available here: http://www.greenbook.net/docs/Label/L50185.pdf

Articles reprinted from the K-State Research & Extension Horticulture Newsletter

Mowing Lawn Has Calming Effect

This info is via an article published Aug 27, 2009 at FoxNews. But it helps support the benefits of healthy grass to people and the environment.

Had a particularly stressful day at work? Go home and mow your lawn.

Scientists have found that a chemical released by freshly cut grass makes people feel content, London’s Daily Mail reported. As an added bonus: That same chemical also boosts memory in old age.

The researchers, who worked at the University of Queensland, Brisbane in Australia, even put their findings in a bottle – a perfume called Serenascent.

Dr. Nick Lavidis, a neuroscientist at the University of Queensland said he got the idea for the “perfume” or air freshner, after he vacationed at Yosemite National Park.”I didn’t realize it at the time, that it was the actual combination of feel-good chemicals released by the pine trees, lush vegetation and the cut grass that made me feel so relaxed,” Lavidis said. “Years later, my neighbor commented on the wonderful smell of cut grass after I had mowed the lawn, and it all started to click into place.”

Lavidis said the aroma regulates the part of the brain known as the amygdala and the hippocampus, which are responsible for the flight or fight response and the endocrine system, respectively.

More information about the study can be found at the Australian News.

Articles reprinted from the K-State Research & Extension Horticulture Newsletter

Thatch Control in Warm-Season Lawns

Thatch control for cool-season lawn grasses such as bluegrass and tall fescue is usually done in the fall but now is the time we should perform this operation for warm-season turfgrasses such as bermudagrass and zoysiagrass. Because these operations thin the lawn, they should be performed when the lawn is in the best position to recover. For warm-season grasses that time is June through July. Buffalograss, our other common warm-season grass, normally does not need to be dethatched.

When thatch is less than one-half inch thick, it is not much of a concern; on the contrary, it may provide some protection to the crown (growing point) of the turfgrass. However, when thatch exceeds one-half inch in thickness, the lawn may start to deteriorate. Thatch is best kept in check by power-raking and/or core-aerating. If thatch is more than 3/4 inch thick, the lawn should be power-raked. Set the blades just deep enough to pull out the thatch. The lawn can be severely damaged by power-raking too deeply. In some cases, it may be easier to use a sod cutter to remove the existing sod and start over with seed, sprigs or plugs.

If thatch is between one-half and a 3/4- inch, thick, core-aeration is a better choice. The soil-moisture level is important to do a good job of core-aerating. It should be neither too wet nor too dry, and the soil should crumble fairly easily when worked between your fingers. Go over the lawn enough times so that the aeration holes are about 2 inches apart.

Excessive thatch accumulation can be prevented by not over-fertilizing with nitrogen. Frequent, light watering also encourages thatch. Water only when needed, and attempt to wet the entire root zone of the turf with each irrigation.

Finally, where thatch is excessive, control should be viewed as a long-term, integrated process (i.e., to include proper mowing, watering, and fertilizing) rather than a one-shot cure. One power-raking or core-aeration will seldom solve the problem.

Articles reprinted from the K-State Research & Extension Horticulture Newsletter

‘Turf & Tree Wars’ & Vandalism

As State Turfgrass Extension Specialist, I get calls and questions on a wide variety of things. Frequently when I do a workshop, someone will come up to me after class and try to get me involved in a marital dispute. Usually one person in the marriage thinks that the other is doing something wrong in the yard and they want me to set them straight. It is a weird position to be in, between these two people hoping for answers, when you know this couple have probably been arguing about this subject for so long. Why am I talking about this? It is because of a photo I took recently. I was not involved with the property owners here, so I can only guess and speculate what happened, but I think the picture speaks for itself. It looks like a tree was planted some time ago….recently the property was surveyed (there is one property marking stake in the picture and several more around the lot) and it was discovered that the tree was on the line, and so it was pruned in-half. If that is truly right, then, all I can say is wow, it must be interesting living next to these guys. My wife was with me when I took the photo, (with people staring and trying to drive around me as I stopped in the middle of the road) and she makes a good point….why not just leave it there. The tree will provide nice shade for both neighbors when it matures.

Like I said, I don’t know the truth. Maybe it was winter or wind damage, but it looks suspicious. Anyway I thought I’d share this fun photo with you. Life’s too short to be that mad at your neighbors.

That brings me to my second point, vandalism. It is kinda related to turf and tree wars. A few times this spring, I’ve received emails and calls about vandalism and chemical spills. I wanted to pass on this one tip that I think can be very helpful. Unfortunately bad people will vandalize nice turf areas with gasoline or other chemicals that kill the lawn. Without the physical evidence, ie gas cans, herbicide jugs, chemical smell, it is usually very difficult to determine the type of product that was applied to the area. Typically the area is reseeded. But sometimes the seed will germinate and die shortly after germination. It can be hard to tell if the product used in the vandalism has prevented the seed from growing and the soil needs to be replaced or if other factors are hindering the germination and growth of the grass. To determine if something on the surface is preventing the grass seed from germinating and/or if I want to determine how deep the chemical is in the soil, I like to do the core side-seed test. Essentially, one takes a core of soil from the affected area and one from a non-affected area. (a golf course cup cutter works good for this…something about 3-4 in diameter and 4-10 deep.) Remove any grass from the top and place the cores on their sides. Cut some 1/8 inch grooves in the side and sprinkle it with tall fescue or ryegrass. Water and watch them grow. If the chemical in the soil is inhibiting the germination you should see no or very few seedlings near the top of the core and more and more seedlings as you move down the length of the core. It should give you an indication of how much if any soil you need to remove and replace. If grass on both cores dies, then something else is wrong….poor management, poor seed, poor nutrition or irrigation.

Articles reprinted from the K-State Research & Extension Horticulture Newsletter