Yard & Garden Line News Volume 3 Number 13                                                               August 15, 2001

Features this issue: A Primer on Natural Organic Fertilizers Some Commonly Held Misconceptions About Seeding Grass Plant Iris Now for Beauty Next Spring New Threat to Daylilies Bottoms Up: Blossom End Rot Insects of Summer Editorial Notes

A Primer on Natural Organic Fertilizers
Bob Mugaas, Extension Educator-Horticulture, Hennepin Co.

Some fertilizer choices. Photo credit: Bob Mugaas

People's interest and desire to use naturally derived fertilizer products for their lawns and gardens continue to increase. Availability and choices of naturally derived fertilizers has also increased. While many of these are perfectly acceptable fertilizers, people often view the results as disappointing. Part of the reason for this is people expect natural organic fertilizers will perform identically to the inorganic fertilizers they have been using (e.g., ammonium nitrate, 10-10-10, ammonium sulfate and many others). As a result, use of natural organic fertilizers has been slower to "catch-on" with people who often revert back to their inorganic fertilizers when the results seem less evident and predictable with the natural products.

The purpose of this article will be to point out some of the basic differences between organic and inorganic fertilizers along with some suggestions for effectively using them.

Some Definitions
To begin, it is important to establish some common understanding regarding the terminology used in describing fertilizer products especially those derived from natural sources. At the legal level, state law defines organic fertilizer to be any "material containing carbon and one or more elements other than hydrogen and oxygen essential for plant growth".

To carry this a step further, state law also defines both natural inorganic fertilizers and natural organic fertilizers. A natural inorganic fertilizer is considered to be any "mineral fertilizer source that exists in or is produced by nature and may be altered from its original state only by physical manipulation" (e.g., reducing larger rock material into finer particles to facilitate spreading and incorporation into a garden soil; ground limestone as a lime source would be a good example).

A natural organic fertilizer would be any material "composed of fertilizer materials derived from either plant or animal products containing one of more elements, other than carbon, hydrogen, and oxygen that are essential for plant growth. These materials may be subjected to biological degradation processes under normal conditions of aging, rainfall, sun curing, air-drying, composting, rotting, enzymatic or anaerobic/aerobic bacterial action, or a combination of these. These materials may not be mixed with synthetic materials or changed in any physical or chemical manner from their initial state except by manipulations such as drying, cooking, chopping, girding, shredding, hydrolysis or pelleting."

What about compost?

Fully composted organic material. Photo credit: Beth Jarvis

It is also important to remember that under most situations, compost is not generally considered an organic fertilizer, but rather an important and valuable soil amendment because of its organic matter contribution. While compost can provide small amounts of plant nutrients, the quantity and availability of those nutrients can be quite variable and therefore should not be relied on as a primary nutrient source for our lawns and gardens.

Soil organic matter and organic fertilizers are not, and should not, be equated with each other. Soil organic matter is carbon based material deposited and accumulated in the soil over time as a result of plant and animal decomposition. Over time, as further decomposition of these materials continues, a certain portion of the "bound" plant nutrients are released to the soil and become available for plant uptake. In fact, one of the recent changes in reporting University of Minnesota soil test results to people has been the adjustment downward of the nitrogen requirements as "credit" is given for nitrogen anticipated to be available for plant growth through organic matter decomposition. That adjustment is based on the organic matter content determined by standard soil test procedures.

A real-life gardening example of this phenomena occurs where, over the years, people have added lots of organic material (e.g., leaves, compost, etc.) to their vegetable or flower garden soils. The complaint is that now, they find it difficult to grow anything but vigorous, lush vegetative plants. Occasionally, even more fertilizer, including nitrogen, is added in an attempt to "encourage" fruit and flower production. However, that practice often only aggravates the situation or at least does not create the desired effect of increasing flowering or fruiting. On the opposite side of the coin, excessive amounts of poorly decomposed compost added in the spring to garden soil can cause severe stunting and often yellowing of the plants as the microbes compete ferociously with plants for the available soil nitrogen to carry on the decomposition process. (Incidentally, the microbes nearly always win the contest, at least temporarily, for available soil nitrogen.)

Using and Applying Natural Organics
Natural organic fertilizers are lower in nutrient value when compared with many of our synthetic fertilizers. This does not make them better or worse; it merely means that you will have to apply more of a natural organic fertilizer to get the same of amount of nutrition applied to a given area when compared to a higher analysis synthetic inorganic fertilizer.

Careful application by curb. Photo credit: Erica Davis

For example, suppose a University of Minnesota soil test recommendation calls for .2 pounds of actual N per 100 square feet of a vegetable garden soil. Let's suppose we have two choices of fertilizers, a natural organic fertilizer with the analysis of 5-3-3 and an inorganic synthetic fertilizer such as 10-10-10. Remember that for every one pound of our natural organic fertilizer there is 0.05# of N (5% of 1 pound = 0.05# N) and for every one pound of our synthetic inorganic product there is 0.10# of N (10% of 1 pound = 0.10# N). Therefore, we would need 4# (.2# N divided by .05# N times 1# of product = 4# of product); or twice as much of our 5-3-3 natural organic fertilizer compared to 2# (.20# N divided by .10# N times 1# of product = 2# of product) of our 10-10-10 inorganic synthetic fertilizer.

Again, the point is that with the lower amount of nutrients present in natural organic fertilizers, more material is required to apply a given rate of nutrient per unit area compared to typically higher analysis synthetic inorganic fertilizer products. That may or may not be problematic. However, it can create handling problems with the increased amount of material required to provide the same amount of nutrition.

Natural organics and phosphorus
As most of our natural organic fertilizers contain small amounts of phosphorus in addition to the nitrogen and potassium, we may actually be adding more phosphorus to the environment with a natural organic than with a synthetic inorganic fertilizer containing the same amount of phosphorus.

For example, a natural organic with the analysis of 5-3-3 will apply 5 times more phosphorus per 1000 square feet of lawn area compared to a 25-3-3 synthetic inorganic fertilizer. The reason for this is that the natural organic contains only 1/5 of the nitrogen compared to the synthetic inorganic. Since lawn fertilizer rates are based on applying one pound of nitrogen per 1000 square feet of lawn, it will take 5 times (25 divided by 5) the amount of our natural fertilizer to apply the same amount of nitrogen as our 25-3-3 synthetic inorganic fertilizer. Given that the percentage of phosphate is the same in both, we have actually applied 5 times more phosphate with the 5-3-3 natural organic fertilizer than with the 25-3-3 synthetic inorganic.

In addition, organic forms of phosphorus are usually quite water soluble and more vulnerable to loss by leaching or runoff until they have been broken down into inorganic forms by soil microbes. From a water quality standpoint, that may not be a desirable feature. However, once in the inorganic form, they bind quite readily and tightly to particles of soil and organic matter making them very stable and much less vulnerable to loss by runoff or leaching.

Aside from the phosphorus issue mentioned above, natural organic fertilizers are often applied at rates greater than the 1# N per 1000 square feet of lawn area typically suggested for lawn areas when quick release sources of nitrogen are used. The reason is that in order to get somewhat quicker results, more material is needed such that more of the easily broken down organic materials contained in the fertilizer become available sooner and in sufficient quantity to provide the desired effect. Again, with fertilizers containing even small amounts of phosphorus, that could be viewed as problematic from a water quality standpoint since even more than the standard 1# of N per 1000 square feet is being applied. With natural organic fertilizers, the burning issue or growth surge is much less of a concern than with synthetic inorganic fertilizer sources. While the potentially higher rates of N used with natural organic fertilizers is usually not harmful, I would still stay within label rates suggested for any particular product.

Finally, it is important to remember that the lower analysis of natural organic fertilizers does not make them bad or good products or that they are better or worse than more conventional synthetic inorganic products. They are however, different products and require an appropriate understanding as to how to use them most effectively in our lawns and gardens.

Fate of natural organic fertilizers once applied to the lawn or garden.

Comparison: urea on left, 10-4-4 on right. Photo credit: Bob Mugaas

Organic fertilizers do provide some organic matter to the soil along with the nutrients they are carrying. However, the plant nutrients are generally not in a form that plant roots can take them up until soil microbes have broken them down to various inorganic forms that can be readily absorbed by plant roots. It is also important to remember that plant nutrients can only be absorbed by plant roots in specific, usually inorganic forms regardless of what was the original nutrient source, either organic or inorganic.

Because of this required breakdown process, natural organic fertilizers have a "slow-release" characteristic as not all of their nutrients are available as soon as they are watered into the soil as would be the case for a typical, synthetic inorganic fertilizer. This can be a very desirable characteristic when there is the need to provide a longer period of nutrient availability, especially nitrogen. This also avoids a large "flush" of growth often associated with quick release forms of nitrogen common to most synthetic inorganic products. Most often this is a desirable characteristic especially in lawn fertilizers where a more even, sustained rate of growth is desired. It is usually less desirable in flower and vegetable garden fertilizers where you may want to encourage a more rapid rate of growth and establishment.

This slower release characteristic contributes to a much lower burn potential of natural organic fertilizers compared to our synthetic inorganic products. A lower burn potential means that there is less chance for the fertilizer to cause leaf and/or root damage or death when high concentrations of these fertilizers are inadvertently placed too close to plants. However, when large quantities organic fertilizers are accidentally placed too close to living plants, some damage can potentially still occur. The point is to always apply fertilizers correctly whether or not they are organic or inorganic.

Since soil microbes are key to breaking down organic products, any environmental or site condition that is unfavorable to a healthy soil microbial community will affect the breakdown and release of nutrients from these organic fertilizer products. This is one of the main reasons for the variability in plant response when organic fertilizers are used as the primary source of plant nutrients. Soil microbes function most efficiently in warm moist soils typical of those we would experience in late spring through late summer. When soils become too dry, too wet, too hot or too cold, microbial activity related to breakdown of organic fertilizer products slows way down. As a result, nutrients contained in that organic matter are not being released to the soil for absorption by plant roots. This again creates a variable or non-response in the plant to the fertilizer we have applied. To the extent that we can modify our soil environments such as through watering, using mulches or increasing soil drainage, will help keep the soil environment as favorable as possible for the microbes. This will also help achieve a more consistent release of nutrients when organic fertilizers are utilized in lawns and garden areas.

Since natural organic fertilizers are often derived from plant and animal waste products, they can be a good means of positively utilizing those products rather than simply disposing of them. Used properly, they can be a valuable source of plant nutrients and soil organic matter. Hopefully, this short primer will encourage you to explore using them in your own gardens, lawns and landscapes.

Some Commonly Held Misconceptions About Seeding Grass
Deborah Brown, Extension Horticulturist

Vertical rake or dethatcher helps prepare seeding site. Photo credit: U of M Extension Service

Early autumn should have us thinking about planting and repairing lawns – especially this year! Before planning on a course of action, take a look at these common misconceptions about seeding grass:

* Spring is the best time to plant.
* If you seed thickly, new grass will choke out weeds.
* Don't fertilize, it will burn newly-seeded grass.
* You must keep grass seeds and young grass constantly wet.
* You shouldn't mow young, thin-bladed grass.

Spring is actually the second-best time to plant grass seed. In Minnesota, planting sometime between mid-August and mid-September gives you your best shot at success.

For starters, weather is usually cooperative. Warm daytime temperatures encourage rapid sprouting. This means there should be plenty of time for good roots to develop before hard frosts signal the end of this year's growth. At the same time, nights are growing longer and cooler. And by September, anyway, the likelihood of rainfall increases.

Weeds can be a terrible problem when you plant grass seed. Many weed seeds lie dormant in the soil for years, biding their time until conditions are right. The tender loving care you afford newly seeded areas will coax those weed seeds to sprout just as surely as the grass seeds you desire. And they'll compete for moisture and nutrients.

Luckily, most weed seeds are programmed to sprout early in the season. If you sow seed in autumn, far fewer weeds will pop up to compete with young grass.

Perennial weeds are a different story. Not only do they sprout from seeds the way annuals do, they come back every year from roots that survived over winter. Since weed-killers will damage or destroy young grass, it's best to rid the area of perennial weeds before you plant.

(If you're overseeding a thin lawn, spot spray them with a non-selective herbicide such as glyphosate --sold as Round Up -- or glufosinate -- Finale --, a week or so before seeding. To start a new lawn or completely renovate an existing lawn, you'll need to spray the entire area before seeding.)

If you're averse to using herbicides you could pull or dig out the worst weeds, then use a sod cutter to slice off the upper layer of soil and remaining vegetation. Be aware, however, that some roots will remain in the soil and sprout again.

Though excessive amounts of fertilizer can burn grass, it's important to incorporate mild fertilizer into the soil when you plant grass seed. You don't need to wait until after grass is up or looking well-established. In fact, your best opportunity to work phosphorus and potassium into the root zone is before planting, since they don't move much in most types of soil.

If you've never had your soil tested, this would be a good time to find out exactly which nutrients to add for good grass growth. Or you could simply apply a starter fertilizer or mild organic fertilizer such as Milorganite or Sustane. Don't use any fertilizer and weed-killer combination ("weed & feed" products) in areas where you plan to seed.

Contrary to common belief, you needn't keep grass seeds constantly wet. This is good since it would be almost impossible to accomplish, anyway.

Watering lightly a couple times a day should prove adequate in all but the hottest weather. Then as seeds sprout and begin to grow, gradually shift to deeper but less frequent watering. Overwatered, saturated soil leads to root rots and other lawn problems. Don't kill your new grass plants with kindness!

Don't be afraid to mow young grass. It's not at all helpful to let grass grow too tall and floppy.

Don't scalp it, though. When newly planted grass reaches a height of three and a half or four inches, cut it back an inch. Just be sure your lawnmower blade is sharp so it doesn't rip the grass. Gradually reduce the height as temperatures cool. If you've overseeded thin areas of existing lawn, mow whenever the older, more established grass needs it. It shouldn't hurt your new grass one bit.

Plant Iris Now for Beauty Next Spring
Deborah Brown, Extension Horticulturist

Iris 'Ola Kola'. Photo credit: Deb Brown

This has been such an unusual gardening year -- first too cool and wet, then too hot and dry -- that it seems strange to be looking ahead to next spring already. But sure enough, in order to enjoy the beauty of iris next spring, you've got to get busy and plant them soon.

Iris typically come through our challenging winters far more reliably than tulips and other spring-flowering bulbs. Assuming, that is, you choose hardy varieties and plant them not much past Labor Day so they'll have ample time to grow new roots and become established before really cold weather sets in.

Though hundreds of species of iris are grown world-wide, there are only a few we see quite commonly in Minnesota gardens. Chief among them are the tall bearded iris that produce such huge showy ruffled blossoms. Available in an extraordinary rainbow of colors and combinations, most are delicately perfumed, and are prized for use indoors as cut flowers as well as outdoors as part of the landscape.

These iris arise from fleshy rhizomes or "swollen" underground stems. Tall bearded iris may grow as much as three feet in height, but there are also intermediate, standard dwarf and miniature dwarf bearded iris that are considerably shorter. Keep plant height, flowering characteristics and bloom time in mind when choosing varieties for your garden.

Bearded iris are not difficult to grow, but as with most flowering perennials, your success will depend in large part on where you plant them. Choose a sunny, well-drained site for your iris garden -- the sunnier the better. Don't put them in a low-lying area where water collects in spring or after heavy summer rains. Their fleshy rhizomes are likely to rot when soil stays too moist.

Planting Iris Rhizomes

Divisions from friend, cultivar unknown. Photo credit: Beth Jarvis

Shortly after blooming, bearded iris go into a period of summer dormancy or slowed growth. It is during this summer dormancy, mid-July through early September, that they may be lifted, divided and replanted. You can also plant rhizomes purchased from local iris specialists, garden centers or mail order catalogs.

Before you plant iris rhizomes, incorporate plenty of organic matter such as peat moss or leaf compost into the soil. Work in one pound of 5-10-10 garden fertilizer for every fifty square feet of garden area to be planted. Then decide how you want to arrange the plants. A single division of a bearded iris plant will have a thickened rhizome with a fan of leaves at one end and fat roots coming from the rhizome.

If you're planting several rhizomes of one variety, plant them in drifts with their leaf fans facing the same direction. Another option is to place the rhizomes in a tight circle with all the fans pointing outwards. If you're planting several different iris cultivars, space them at least eight inches apart to allow for expansion, with leaf fans facing out from the center of the garden.

Iris rhizomes must be planted just below the soil surface. Dig a shallow hole for each rhizome, making a ridge in its center. Position the rhizome on the ridge, spreading its roots out to both sides. Then firm some soil over the plant and water it.

Caring for Iris Plants
Bearded iris need the same routine maintenance that most flowering perennials require:
* thorough watering in dry weather
* regular weeding to reduce competition for moisture and nutrients
* fertilizing once or twice each year in early spring and mid-summer
Though you'll want to remove flower stems as soon as the blossoms have faded, don't cut foliage back until later in the season when it begins to yellow.

Since we can't always rely on good snow cover, plan to provide some winter protection for your bearded iris. Mulch them with straw or weed-free hay in November, after a hard frost. But first, cut the foliage down to four to six inches and rake and dispose of the debris. This will give you a leg up on eliminating iris borers that overwinter as eggs on the old foliage.

Purple iris. Photo credit: Beth Jarvis

In spring, remove the mulch over a period of several days as sun and warmer weather melt the ice holding it together. Be particularly careful not to injure the center portion of the fans, where flower buds are developing. If you've had a lot of trouble with iris borers in past growing seasons, spray the plants with dimethoate, a systemic insecticide sold as Cygon, once as new growth is four to six inches tall.

If iris borer eggs are allowed to hatch, tiny caterpillars will bore into the leaves and eat their way down into the rhizomes. This sounds bad enough, but the worst part is that they introduce bacteria, causing a soft rot that ultimately turns leaves brown and destroys the plants.

Dividing Iris
It's really easy to lift and divide large clumps of iris. Established plants usually benefit from division every third or fourth year.

* Use a spading fork to lift the entire clump.
* Wash off the soil so you can see what you're doing.
* Use a sharp knife to separate rhizomes into individual fans.
* Discard the "woody" bloomed-out center portion of the rhizome.
* Cut leaves four to six inches and trim off any broken roots.
* Replant in a sunny, well-drained location.

New Threat to Daylilies
Janna Beckerman, Extension Plant Pathologist

Daylily rust symptoms are cultivar dependent.

Pustules form quickly  and allow airborne spread of spores. Photo credits: Univ. of Florida

Daylily and hosta are perhaps the most popular landscape perennials in the United States. The fact that both these plants are remarkably disease resistant has played a major role in their popularity. However, a new disease, daylily rust, may change the (mis)perception that daylilies are disease free. Daylily rust has been found in Minnesota this summer at two separate locations.

Daylily rust is an exotic introduction from Asia. The disease was found in Georgia and later, Florida, in the year 2000. This disease and current planting practices may combine to create an explosive disease situation. The disease infects the foliage and appears on both sides of the leaves. The variation of symptoms is cultivar dependent. Symptoms, which range from undetectable to dramatic, appear in 2-3 days. Bright yellow spots and/or water soaked lesions appear prior to the development of yellow to dark rust colored pustules on the underside of the leaves. Spore development requires between 1 to 2 weeks, whereupon reinfection of the plant can occur.

The pathogen, Puccinia hemerocallidis is a heteroecious (het-er-o-ee-shus) rust, a big word meaning that this fungus requires two plants to complete its lifecycle. This means that after infecting and reinfecting the daylily, spores produced on the plant need to infect another plant, in this case, members of the genus Patrinia (Valerianaceae). Fortunately, these plants are unusual in home gardens, but are occasionally sold as "golden valerian." Unfortunately for us, many of these plants, including Patrinia scabiosifolia, are considered zone 4 hardy and have been successfully grown in the Twin Cities. Upon infection of Patrinia spp., the fungus is able to sexually reproduce, creating greater genetic diversity and longer lived overwintering structures. Without the alternate Patrinia host, it is unlikely that any daylily rust infection can overwinter in Minnesota. However, the United States Department of Agriculture New Pest Advisory Group (USDA/NPAG) has determined that this disease is a quarantine-significant pest. Until the spread and overwintering status of the disease is determined, it is going to be handled under emergency status. Because of the potential of this disease, growers have been exceptionally proactive with chemical treatment or eradication of infected plants.

Like other introduced pathogen, the prognosis for this disease is grim. Earlier this summer, federal plant pathologists concluded that daylily rust would be impossible to contain by regulatory means. The disease develops so quickly that it is impossible to expect plant inspectors to identify and eliminate infected plants before spores are wind disseminated. Rust spores will likely be able to infect daylily nationwide within a relatively short time frame. Like wheat stem rust, it is believed that daylily rust will follow a "Puccinia Pathway" in North America. This model predicts that the rust will overwinter in the southern states and spread northwards on a yearly basis. This means that regardless of its overwintering ability, daylily rust may be a perennial problem.

What should a homeowner do? Try to buy locally grown daylily and inquire to be certain that the growers have not obtained their daylilies from states that have reported incidents of the rust. You may wish to segregate newly acquired plants from your established plants (not a bad idea with any new purchase). Some varieties are known to be more susceptible than others. Some of the most susceptible varieties include: 'Pardon Me,' 'Gertrude Condon,' 'Crystal Tide' and the beloved, 'Stella d'Oro.'

Remember, daylily rust will produce yellow to orange colored spores-no other daylily disease will do so. If you think you may have daylily rust, call the Minnesota Department of Agriculture (not the Yard and Garden Clinic!) at 651-296-8328. Heavily infected plants serve as an inoculum source for all your other daylilies (and all your neighbors' daylilies, too). Destruction of infected plants is at the homeowners' discretion.

Bottoms Up: Blossom End Rot
Janna Beckerman, Extension Plant Pathologist

Blossom end rot results in tomatoes that appear inedible. Photo credits: Plant Disease Clinic

Somehow, our cold, wet spring has changed into an incredibly hot, dry summer. Usually, hot dry weather results in an arrest of disease development. However, one problem in particular, blossom end rot of tomato, actually gets worse under these droughty conditions.

Symptoms of blossom end rot begin as a small water-soaked lesion at the blossom end of the fruit. This may appear while the fruit is green or during ripening. The lesion develops as the fruit enlarges and ripens. However, the lesion becomes sunken, and often turns black. This black color is due to secondary pathogens that invade the lesion, often rendering the fruit inedible (although the reality is that they are just too ugly to eat (Fig. 1). It is safe to cut off the affected end and eat the unaffected portion).

Blossom end rot is a physiological disorder. That is, the problem results due to how the plant is growing, not because of another organism. Several factors have been implicated in blossom end rot. The most common cause of blossom end rot is inconsistent watering. Try to ensure uniform soil moisture. If you are uncertain about the thoroughness of your watering practices, dig a small hole 1 foot deep to be certain that the water penetrated to that depth 24 hours after watering, Home gardeners should provide even moisture throughout fruiting by controlled watering and mulching.

Another common cause of blossom end rot is overenthusiastic fertilizing. Excessive nitrogen fertilization can result in excessive vegetative growth that outpaces the uptake of calcium. For this reason, it is impossible to determine if blossom end rot is due to overfertilization or calcium deficiency without a soil test. Most Minnesota soils have adequate lime (calcium carbonate), but pH prevents its uptake to the plants. A soil test will enable you to determine if there is a "true" calcium deficiency, or an induced problem due to high pH or excessive nitrogen fertilizer. Calcium from the soil is most available to plants at pH 6.5. Foliar applications of calcium have been shown to be unsuccessful at combating this problem. Fertilize to keep plants normally green and vigorous. Use nitrate nitrogen as the fertilizer nitrogen source. Nitrogen in the form of ammonia has been implicated to increase blossom-end. Plant tomatoes on sites that are well draining, but not too sandy, and remember to mulch plants thoroughly.

Several tomato varieties are known to be more resistant to blossom end rot. These varieties are designated 'BER' for blossom end rot-resistant. Gardeners who have problems with blossom end rot may wish to consider using the following slicing/canning varieties such as: Walter (Villemarie), Mountain Spring Hybrid, Manalucie or New Yorker.

Finally, for the sake of completeness, other members of the Solanaceae do get blossom end rot. Watch for it on your peppers or eggplant. Usually, the symptoms in these cases are often mistaken for sunscald. The reasons for the problems are the same and can be treated accordingly.

Test your diagnostic savvy monthly with Disease Watch at: http://www.extension.umn.edu/projects/yardandgarden/PlantPathWeb/Plpa.htm

Insects of Summer
Jeff Hahn, Assistant Extension Entomologist

Cicada.

Katydid.

Soldier beetle.

Grape pelidnota.

Hermit flower beetle.

Cicada killer.

Sphex. Photo credits: Jeff Hahn

There have been a variety of unfamiliar insects that have been conspicuous in the landscape recently. When you don't recognize an insect, you wonder whether to treat it as a pest. However, once an insect in identified and its biology learned, it is easier to understand its role in your garden and landscape. Although many of the following insects have been accused of damaging plants, they are not considered to be pests.

Cicadas are present from mid to late summer, although they are more often heard than seen. They produce a high-pitched sound during the day that resembles a powerline hum. Cicadas have a stout, one inch long body. They have conspicuous, clear wings which are folded over their back. Cicadas have been occasionally described as beetles with wings sticking out. Sometimes people describe the nymphs as ‘beetles that turn into flies'. Cicadas are actually more closely related to leafhoppers, planthoppers, and spittlebugs.

The immature nymphs live in the soil feeding on the roots of various plants, especially perennials. When the nymphs are in their last development stage, they emerge from the soil, attache themselves to an object, like a tree trunk or fence post, and molt into adults. Despite their size, cicadas are harmless to people and garden plants. Cicadas can, however, potentially injure trees when they use their sharp ovipositor to lay eggs in twigs.

Katydids are green and about 1 ˝ inches long (not including the antennae). They have enlarged back legs (for jumping), long antennae (about the length of their body), and are grasshopper-like. Like grasshoppers, they possess chewing mouthparts.

Katydids are normally found in trees and shrubs where they feed on foliage, although they are not known to injure woody plants. They may also be found resting on herbaceous plants. Although katydids can potentially feed on garden plants, any injury is probably minor. If there is a lot of feeding, check instead for pests like variegated cutworms or slugs. It should not be necessary to control katydids to protect your plants.

Katydids are also known for their ‘singing'. Their distinctive sound is produced at night by males to attract a mate. They rub their wings together, resulting is a rapid pulsed sound that can be repeated over and over. This singing can continue for most of a night and can occur for several consecutive nights or in some cases, for weeks. There is no practical control for katydids, especially when they are in trees. It is best to tolerate them and wait until they finish on their own.

Soldier beetle are very common on flowers from mid to late summer. They readily fly and can resemble wasps when in flight. They are about ˝ inch long, yellowish to tannish brown with soft wing covers. There is a black spot on each wing cover. Like other beetles, soldier beetles have chewing mouthparts. They are closely related to fireflies but lack the light-producing organs that fireflies possess.

As larvae, soldier beetles are predaceous on other insects. Not much is known about the adults, although they apparently are also predaceous on other insects. Despite the large numbers that may be noticed in gardens, they do not damage flowers or other plants. It is not necessary to control them, just ignore them.

Scarab beetles are a common, diverse group of beetles. There have been a couple large-sized scarab beetles that have been noticed in the landscape recently. Grape pelidnotas, Pelidnota punctata, are tan to reddish brown in color with three black spots on each wing cover. They are about one inch long, oval, and robust. They look similar to June beetles, although they are more closely related to Japanese beetles. Also known as spotted grapevine beetles, they feed primarily on grape leaves. Fortunately, their feeding is not serious and control is usually not necessary.

Another scarab beetle that may be observed is a type of flower beetle, Osmoderma eremicola. Sometimes known as the hermit flower beetle, this beetle is about one inch long and is dark brown to black. It is somewhat similar to June beetles but is not quite as oval. The larvae feed in decaying wood and the adults are associated with loose bark and tree cavities. They are not a pest of trees and do not need to be controlled.

Sphecid wasps are a type of solitary wasp. They are known to nest in soil, in plant stems, or in cavities in buildings. Although they live by themselves, they can live gregariously, i.e. other sphecid wasps of the same species may nest nearby. Sometimes many individuals are present (Note: You can distinguish between ground-nesting sphecid wasps and ground-nesting yellowjackets by observing how many nest openings there are. A yellowjacket nest will have many different individuals entering and leaving a single nest opening while there will be more than one nest opening (sometimes many) for sphecid wasps.

Sphecids prey on other insects which they feed to their young. They sometimes can be observed carrying insects back to their nest. Although sphecids may sting to protect themselves, they are nonaggressive towards people and the incidence of stings is very, very low. Sphecid wasps rarely need to be controlled because if the risk of stings.

Cicada killers, Sphecius speciousus, are a striking black and yellow patterned sphecid. They are very large, 1 - 1 ˝ inches long and nest in the soil. Like their name suggests they often prey primarily on cicadas. Despite their size, there is little concern for stings. The males are not able to sting and although females can sting, they are very unaggressive.

People may also see Sphex pensylvanicus, a 1 - 1 1/4 inch long black sphecid. The wings are a smoky black with a violet iridescence. They also capture large-sized insects, such as katydids and nest in the ground. This wasp has been occasionally seen visiting flowers. Although it's just feeding on nectar, it has been accused of injuring plants. However, they do not harm plans, and any damage seen where this sphecid is present is coincidental. Sphecid wasps do not need to be controlled to protect plants.

Get the low down on this month's insect pests at Insects http://www.extension.umn.edu/projects/yardandgarden/EntWeb/Ent.htm
Editorial Notes

Lisianthus. Photo credit: Beth Jarvis

Here's one of my favorite annuals, lisianthus (Eustoma spp.). They come in white, pink and blue, rose-lavender and white with blue edged petals. I saw some in a Burpee catalog that grow to 8" tall but they're usually 15-24". You need to either buy plants or start them early, indoors. They need to be started indoors 10-12 weeks before putting them outside, but what else does a gardener have to do in February? Oh, my reference says to plant them in peat pots because they dislike transplanting and the seeds can take 3 weeks to germinate. I started some years ago in a campus greenhouse but the mice ate them!

The Minnesota Dept. of Health has yet to send the promised article on tetanus, so since time's awasting and fall clean up will be upon us all too soon, here's the URL for Mayo Clinic's tetanus page:
http://www.mayohealth.org/home?id=5.1.1.20.11

Jeff Gillman, Nursery Specialist, will share his experiences coping with Japanese beetles in Georgia, plus offer his thoughts on the various control measures available. This is scheduled for Sept. Mary Meyer will be sharing "What"s New in Ornamental Grasses" with us a bit later. It will be in plenty of time for winter catalog dreaming and garden planning. Also in time for next winter, Doug Foulk, Ramsey-Washington, will talk about pears, what to know and how to grow. I'm also lining up articles on other plant breeding projects and will give you an inside look as they are available.

Deb Brown will be at the Minnesota State Fair! On Saturday, August 25th, at 10 a.m., she and Dale Bachman, of Bachman's, will answer questions from WCCO radio's (830 AM) booth.

Deb will answer gardening questions Friday, August 31, from 9 a.m. to 11 a. m. on Minnesota Public Radio's (MPR) "Midmorning" program. Katherine Lanpher hosts the program that is broadcast on KNOW 91.1 FM, and available state-wide on the MPR news radio stations. If you miss it, the Midmorning show is archived for a week on MPR's site.

Please feel free to cut and paste any of the articles for use in your own newsletters. All we ask is that you give our authors credit.

Back issues Yard & Garden Line News are on the Yard & Garden Line home page at www.extension.umn.edu/yardandgarden/. Our home page has clickable links to most of the components of the Yard & Garden Line, such as Bell Museum of Natural History, INFO U and the Soil Testing Lab.

If you have gardening questions, please call the Yard & Garden Line at (612) 624-4771.

If you would like to receive an e-mail reminder when the next issue of the Yard & Garden Line News is posted to the web, just send an e-mail to: listserv@lists.umn.edu (note: the second E in listserve is omitted), leave the subject line blank, then in the body of the message, type: sub yglnewslist
or to unsubscribe, enter: unsub yglnewslist

Happy gardening!

Beth Jarvis
Yard & Garden Line Project Coordinator


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