July 2001

The following articles are featured in this month's Something to Grow On:

DIXIE DREAM HOLLY

NURSERY BUDGETS AVAILABLE

LONG TERM MAGNOLIA STUDY YIELDS RESULTS

A GENEROUS ENDOWMENT

BENLATE CANCELLED

DIAZINON UPDATE - GOOD NEWS

A GENEROUS ENDOWMENT

ATRAZINE'S FATE

CONTROLLING ALGAE IN NURSERY IRRIGATION PONDS

ULTRASONIC PEST DETECTION TOOL INVENTED

THE CONTINUING STRENGTH OF PERENNIALS

THE BARE ROOT MARKET

INFLUENCE OF BENZYLADENINE DIPS ON GROWTH OF HOSTA CULTIVARS

WILBRO ORGANIC LIQUID-FEED

THE EFFECTIVENESS OF ROOTS DRY FORMULA BIOSTIMULANT

EARTHGREEN BIOSTIMULANT STUDIED

INVASION OF THE WEB WORMS

CHOOSE THE BEST MULCH

ALL-AMERICA SELECTION WINNERS FOR 2002

CONCERNS OF SMALL-BUSINESS NURSERY OWNERS

PLANT PATHOLOGY REPORT

UPCOMING EVENTS


DISCLAIMER: Please remember that all information presented is a summary of research and not an endorsement of any product or a recommendation of chemicals. The official labels from the manufacturing companies offer the legal and proper use and handling information for all products.


DIXIE DREAM HOLLY

Ken Tilt

Dr. Cecil Pounders, who is now working at Mississippi State, is a plant breeder and certified plant nut of long standing. He works with many ornamental plants but about 3 years ago he gave me a flat of rooted cuttings of Dixie Dream holly (Ilex cassine x Ilex opaca). He was looking for a better Foster Holly for the nursery industry. Foster holly is a great plant but, as you know, we have to shear it several times a year like a Christmas tree to keep it tight. Landscapers plant it as a corner planting and discontinue the shaping process. As a result, after the first year or two you have long internodes develop and a funny tree sitting on top of a sheared plant from the nursery.

I planted some of his plants side by side with a Foster Holly, forgot about them for 3 years and the pictures you see below are the results. Dixie Dream is a much denser, uniform plant and a more shrubby (may not be in Webster's but it works) plant rather than tree form. It is slower growing but you can not have everything. Many home gardeners call in and ask for a fast growing screen that will jump to12 feet in a year or two and then stop. Nurseries are the same way. They want a 3 or a 5 gallon plant in one year and then for it to slow down and maintain quality until they can sell it. Dixie Flame, as you can see, may solve the problem of the rambling growth habit of a Foster Holly.

Dixie Dream HollyFoster Holly

Dixie Dream Holly
Foster Holly

Dixie Dream on the left; Foster Holly on the right

Cecil also released two other hollies of the same cross, Dixie Star and Dixie Flame. I have not seen these two. Dixie Flame is a seedling from Tanager but unlike Tanager will withstand our heat much better and has very prolific large berries. Dixie Star has lustrous dark green leaves and a tight growth habit. Cecil thinks it is actually a better replacement for Foster Holly. I will have to see if I can beg some free plants to test them out. This is not a commercial but they are being offered through PDSI (334-964-6778) in Loxley. You can give Jim Berry or Ray French a call to see what availability is. If you buy some, drop a couple off by Auburn on your way back to the nursery.


NURSERY BUDGETS AVAILABLE

We have added a new page to our Landscape/Horticulture Nursery site. On the homepage is a button for nursery and on the nursery page is another button:

A recent graduate of Auburn University's Agricultural Economics program studied the economics involved in growing three species of trees (Crapemyrtle, Leyland Cypress and Dogwood) using three different methods (pot-in-pot, in-field and above ground containers). Information was compiled from a broad range of sources and provides very specific information about how much land, time and money are needed to operate a nursery. We have published many of these tables to provide you with important information you will not find elsewhere.


LONG TERM MAGNOLIA STUDY YIELDS RESULTS

Jeff Sibley, Greg Creech, Charles Gilliam, David Williams, and John Owen

In 1980 a long term study of over 200 species of large trees was established at Alabama Agricultural Experiment Station's Piedmont Station in Camp Hill, Alabama. In 1983 12 southern magnolia (Magnolia grandiflora) selections were added. The results of this study are helping to identify the best magnolia cultivars for Alabama. The site is of great value to nurseries who are rarely able to do this kind of long term study. The trees were evaluated on growth characterists and leaf quality.

Certain growth and leaf characteristics are important in the nursery industry. The upper side of leaves are ideally deeply green and glossy; the undersides should be a fuzzy with a rich brown color. Leaf drop should be minimal throughout the year. An extended period of blooming is a very desirable trait as well as trees that grow symmetrically and exhibit consistent growth patterns. Ideal tree shapes vary depending on the tree's place in a landscape. Taller, more conical trees are needed for narrow spaces and wide-spreading trees are best in open areas.

Some of the results of the long term study are as follows:

The Magnolia grandiflora seedlings were among the most aggressive growers in the study, but were highly variable from tree to tree in form, leaf morphology, anatomy and canopy density. Seedlings have potential for genetic variabilty which means it is difficult to expect certain traits.

Aldridge, a seedling strain from Aldridge Nursery in Von Ormy, Texas, had little variability in growth characteristics and blooming began in the second year of the study. However, the foliage was the lightest green of all selections and leaf drop was common during stress.

The benefits of AAES tree evaluations are significant. Such long-term observations are rarely feasible in commercial nurseries primarily concerned with growing and marketing the best selling plant materials. Such plantings also are unlikely to occur in a replicated fashion in long-term sites, such as arboreta that are primarily concerned with the display of numerous species in limited quantities. Furthermore, environmental conditions change such that long-term field observations are particularly valuable as a reference point for landscape use as opposed to the often rapid and somewhat artificial growth responses available from short-term container studies. The Auburn University Shade Tree Study site continues to be maintained for grower observations, seed collection, and tours.

(from an article in Online Highlights, AAES at Auburn University).


A GENEROUS ENDOWMENT

The California Association of Nurserymen recently set up a $1.1 million endowment at the California Polytechnic State University, San Luis Obispo. The CAN Endowment Fund will pay out at least $50,000 a year in perpetuity to fund projects that benefit the nursery industry. The endowment supports research, career development and educational programs such as teacher curricula, student resources in horticulture and statewide organizations such as "Agriculture in the Classroom".

(from the Weekly NMPRO e-mail).

BENLATE CANCELLED

Dupont announced on April 19 that is going to stop manufacturing benomyl (sold under trade name of Benlate) by the end of this year. The company expects to phase out distribution and sale of all benomyl products by the end of 2002. Dupont emphasized that this is not a product recall and all existing stocks can be used according to label instructions.

Approximately 1 million pounds of benomyl are used annually in this country on some 70 fruit, nut, vegetable and field crops.

One of the main reasons Dupont decided to withdraw benomyl is that the company is no longer willing to bear the high and continuing costs of defending the product in the U.S. legal system. Dupont says that this system allows other factors than good science to influence decisions.

Dupont remains fully confident that this 30-year old fungicide is safe when used as directed. (W. Burr, 23 Apr 01; Ms. Env., Vol. 29, No. 3.)

(from the Alabama Pesticide Information sheet, May 2001).

DIAZINON UPDATE - GOOD NEWS

Earlier this year EPA announced that diazinon would be canceled. This included all home, garden, and agricultural uses. However, many agricultural uses will be retained according to the EPA. An agreement between Makhteshim-Agan of North America, Syngenta Crop Protection and EPA will allow a number of agricultural uses to remain. Comments from consumers and the fact that the agricultural uses were not being canceled due to dietary concerns but were a voluntary business decision by the registrants, changed the EPA's mind.

The use of diazinon on bananas, celery, cucumbers, ground squirrel/rodent burrow/dust stations for public health use, parsley, parsnips, peas (succulent), peppers, potatoes (Irish and sweet), squash (winter and summer), Swiss chard, and turnips (roots and tops) will be retained as Section 24-c states special local needs uses. Spinach, strawberries and tomatoes will retain their Section 3 (full label registration) registrations. (W. Burr, 23 Apr.01).

(from the Alabama Pesticide Information sheet, May 2001).

METHYL BROMIDE ALTERNATIVES

As the methyl bromide phase-out continues, alternatives are being identified. Methyl iodide and propargyl bromide have been examined as alternatives and neither are risks to ozone. A mixture of dichloropropene (Telone) and chloropicrin is being used with metam sodium (Vapam) in strawberry production.

Some 'natural' compounds are being touted such as BioFume (derived from herbs) and DiTerra (a microbial product). Benzaldehyde and glucosinolates are produced by the Brassica family (e.g., cabbage). (Ag. Research 1-01, Farm Chem. 12-00,Chem. Speaking, 1-01, via.Ga. Pest Mgt. News., Vol. 24, No.4).

(from the Alabama Pesticide Information sheet, May 2001).

ATRAZINE'S FATE

EPA's preliminary risk assessment for atrazine has drawn strong reaction from the registrant, Syngenta Crop Protection, and several trade associations. They both say that the methodologies and assumptions used by the EPA Office of Pesticide Programs (OPP) and Health Effects Division (HED) were inaccurate. The assessment did downgrade atrazine's cancer risk to "not likely." It also says that most exposure risks are acceptable.

However, the main sticking-point is that EPA is trying to enforce the additional 10X safety factor as allowed by the Food Quality Protection Act (FQPA). Their reasoning is that atrazine poses an "endocrine disruptor" risk. In a rat study they found a delay in puberty and prostate inflammations. They claim this proves that atrazine is an "endocrine disruptor." Critics say they used inappropriate techniques by employing a strain of test rats that are not relevant to humans.

On the other side of the debate, several environmentalist groups contend that the herbicide is carcinogenic and an endocrine disruptor and should be banned. Atrazine is the most widely used herbicide in the U.S. The Natural Resources Defense Council, the World Wildlife Fund, and the Environmental Working Group all submitted letters urging EPA to either ban or restrict the use of atrazine. (Pest.& Toxic Chem. News, Vol. 29, No. 27).

(from the Alabama Pesticide Information sheet, May 2001).

CONTROLLING ALGAE IN NURSERY IRRIGATION PONDS

by Mark Halcomb, University of Tennessee Area Nursery Specialist

Some types of algae can be killed in small ponds with a handful of copper sulfate in an old sock. It is a simple procedure, but there are several comments and precautions concerning this practical approach.

This easy solution is more effective on planktonic algae that may appear as green pea soup. It will control some types of filamentous algae, but copper sulfate will not control aquatic weeds, either submersed or floating. Actually, planktonic algae can stifle the more serious weeds by preventing their germination and growth by reducing light penetration. Commercial dyes are used to provide the same effect.

When copper sulfate crystals are spread over the water surface many settle to the bottom before they dissolve without killing the algae. The chemical becomes tied up with the sediment quickly and is rendered harmless. Dissolving the copper sulfate and spraying it onto the water surface is effective. But the sock method eliminates both the need for a sprayer and the time required for spraying. Placing the copper sulfate in a cloth bag or sock prevents it from falling to the bottom and becoming unavailable to kill algae. Tie the sock to a floating device and secure the float away from the pond edges. Use 1 sock for each half acre in a pond. The algae will be killed in a matter of hours. The water will clear. If nothing happens, refill the sock in a few days.

The water may turn brown or even grayish during the decay process if a lot of algae dies at one time. As mentioned earlier, clear water is not necessarily desirable. When the green algae growth returns, fill the sock. You will learn how to gauge the amount and frequency with experience. As long as there is a problem with algae, copper sulfate can be applied on an as needed basis, and as often as needed.

Aquatic herbicide rates are frequently expressed as amount per acre-foot of water. One acre-foot of water is one surface acre of water, one foot deep. For example, a 3 acre pond averaging 5 feet deep would contain 15 acre-feet of water. Another term to express treatment rates is parts per million (ppm). One ppm is 2.7 pounds of chemical (copper sulfate for example) per acre foot. A half pound of copper sulfate per acre foot would provide 0.2 ppm. Low rates of copper sulfate are safe for irrigation water, fish survival, fish consumption, livestock drinking and swimming. One ppm can kill fish in low alkalinity water. But remember, it binds with algae and sediment quickly, and does not stay around in the water very long. One pound per surface acre may kill enough algae and should not kill fish.

Concentrations greater that 0.2 ppm could be phytotoxic to ornamental plants. It would be best to apply the copper sulfate after the daily irrigation to allow time for the chemical to work on the algae. The concentration is reduced rapidly as it binds with the algae and sediment. The concentration would likely be safe the next day in time for the next irrigation.

Copper sulfate is considered safe for water used for irrigation, fishing, watering livestock and swimming. There are no restrictions placed on its use.


ULTRASONIC PEST DETECTION TOOL INVENTED

Scientists with USDA ARS and Acoustic Emission Consulting Inc. have invented a new tool for monitoring stem-boring and soil pests. The hand-held device allows users to hear the insects while drowning out background noises. The ultrasonic tool can distinguish and identify pests by their feeding noises and relay that information on a read-out. For more information contact Richard Mankin at rmankin@gainesville.usda.ufl.edu

(from the Weekly NMPRO e-mail).

THE CONTINUING STRENGTH OF PERENNIALS

Perennials continue to be a hot plant category. According to last month's NMPRO online poll, 42.9% of growers said their perennial production has increased more than 10% from last year. This month's question deals with weeds, insects and diseases. To participate, go to http://www.greenbeam.com/adlinks/nmpro.stm


THE BARE ROOT MARKET

Ken Tilt, Jeff Sibley, Floyd Woods, Arnold Caylor, and Chazz Hesselein

In the past 10 to 15 years a major marketing avenue for nursery crops -- bare root tree field production -- has declined. What was once a profitable mainstream production method for many nurseries has dwindled due to increasing demand for year-round planting and the greater flexibility of container production to meet that demand. Research underway through the AAES is looking at new production options to rejuvenate the bare root market.

Plants are shipped and sold in the containers (usually plastic pots) in which they are grown. Container production allows producers to grow plants in higher densities, using land that is not suited for field production, and these plants tend to have higher survival rates and do not require root pruning. They also can be shipped and even planted practically year-round. However, container production also has its drawbacks. Producers must water and fertilize plants more frequently, give them more winter protection, and worry about plants becoming root-bound and sometimes being knocked over by wind. Containers also are costly and it can be more expensive to transport them because of the added weight of growing media and pots.

Bare-root plants are usually grown in the field, harvested when they are dormant, and shipped or sold with no soil around their roots. They are also are typically less expensive to buy and ship and are easier for home gardeners to handle. The problem with this production method is that the plants are only shipped while they are dormant (usually late winter and early spring), which limits the time of year that they will be available to consumers. Bare-rooted plants also have been root-pruned in the process of digging, leaving some of the roots behind when plants are harvested.

In today’s nursery industry, bare root plant production is primarily used for liner (transplant) production. With increasing global markets and demand for exporting nursery crops, higher fuel prices and shipping costs, and increased production costs and shortages of labor, bare root production still has a niche in the nursery business. Since field production of nursery tree liners requires cutting of roots to harvest trees, container production of bare root liners with roots intact may offer a better alternative for liners destined for container production or transplanting to the field. Bare root trees for the landscape would offer obvious weight and space reduction for shipping over equivalent sized container trees. Bare root trees are desirable and/or required for export to many countries. Furthermore, if bare root trees offer similar transplant success and growth in the landscape compared to equal sized container trees, this would suggest a new niche for nursery producers.

An AAES study sought to compare bare root tree production in five-gallon containers using Profile™ (a commercial, nonorganic, kiln fired, calcined clay ceramic aggregate medium) with traditional container-grown trees using pinebark or pinebark:peat container mediums. The study also compared effects of pruned bare root liners to nonpruned liners potted in containers to simulate current practice of using pruned, bare root field dug liners (see table below). In addition, the study looked at the relative ease or difficulty of removing trees bare root from containers containing the Profile medium, and evaluated effects of storage, transport, and transplanting trees to a landscape site to compare the survivability and growth of traditional container trees with the bare root trees.

Profile™ (above left) is a commercial, kiln-fired, calcined clay ceramic aggreate medium that can be easily removed from the roots of container-grown plants, (above) by minimal shaking to free the plants from the surrounding medium.

On April 1, 1998, 72 18- to 36-inch, container-grown, bare root liners of Ulmus americana Liberty elms were planted in five-gallon RootMaker™ Grounder containers at the Ornamental Horticulture Station in Mobile. RootMaker containers were selected because they feature numerous small drainage holes that prevent fine particles of Profile from leaching out the bottom of the container. Prior to planting, half the trees were root pruned with approximately 50% of the roots removed to simulate bare root tree liners from the field. Roots were left intact on the other half of the elms.

HEIGHT OF PRUNED AND NONPRUNED LINERS GROWN IN
PROFILE AND PINEBARK BASED MEDIA
.ProfilePinebark
Pruned7.55.5
Nonpruned7.77.1

The elms were planted in two media: Profile and a pinebark:sphagnum peat moss (4:1,volume to volume). Profile was used successfully as an amendment to container media. Media were amended with 1.5 pounds per cubic yard Micromax. Pinebark medium included five pounds per cubic yard of dolomitic limestone. Lime was omitted from the Profile medium due to the inherent high pH of the medium. Media were topdressed with 4.2 ounces of Osmocote fertilizer 15-9-11. Irrigation was used to ensure proper growth. Plants were harvested and measured for height and caliper (the diameter of the trunk measured at 12 inches above the soil line) on February 26, 1999. Profile was easily removed from roots by gentle shaking. Used Profile media was collected in a central area for reuse in the next production cycle. Bare root trees were placed in plastic bags and stored in a cooler at 38o F for eight weeks until planting at the North Alabama Horticulture Station (NAHS) in Cullman on May 3, 1999. Twelve container and 36 bare root trees were planted at a 15-foot spacing in a landscape setting to evaluate the survival and growth of the trees after transplanting. Height and caliper were taken on January 25, 2000.

Elms grown in Profile medium in 1998 had greater height at 7.6 feet compared to 6.2 feet in the pinebark:peat medium, and Profile-grown trees also increased growth among the nonpruned liners (7.5 feet) compared to pruned liners (6.9 feet). There was no difference detected when contrasting pruned and nonpruned treatments within the Profile medium or between the nonpruned treatments of Profile and pinebark based media.

There was no difference in caliper among the treatments. Profile medium had a high pH ranging around 7.5 and some chlorosis was noted on the elms grown in Profile medium. There was 100% viability following transplant at the NAHS of the 36 bare root plants and the 12 container plants after one year in the landscape. Caliper growth of transplanted trees was greater in the container/pinebark based medium (1.3 inches) at the end of the 1999 growing season than the bare root/Profile-grown trees (1 inch).

There was no difference in height for the trees planted bare root or in containers. Trees were 8.8 feet and 8.7 feet tall, which represented an average (mean) increase over the growing season of 2.7 feet and 1.2 feet for container and bare root elm trees, respectively. Height of root-pruned container liners after one year in the landscape (8.4 feet) narrowed the height deficit between the nonpruned trees (9.1 feet) to a difference that was not statistcially significant.

Although new Profile medium was used in the study, physical properties of some previously used Profile with the new medium were compared. No differences were found between them for each of the properties evaluated including airspace (12.4% and 15.0%, respectively), water holding capacity (40.5% and 39.6%), total porosity (53.0% and 54.6%), and bulk density (0.53 and 0.51 grams per cubic centimeter) for new and used media, respectively. It is important to be able to reuse the material due to the cost.

Results of this research offer evidence of a potential niche market for production of bare root trees in containers that can be successfully stored, exported, or transplanted to the landscape with similar growth results. Reduction in growth of root pruned elm liners in the pinebark based media suggests potential increased growth of container bare root liners over field-grown root pruned liners. Further research is needed with additional species to verify this conclusion. Container size, root pruning treatments, or time-in-production adjustments need to be investigated for several species, including aggressive rooting species to evaluate the ease of Profile or other media removal from the roots. Previous studies with river birch trees (Betula nigra) under similar conditions resulted in root bound tree roots that could not be separated from the Profile medium.

(from an article in Online Highlights, AAES at Auburn University).


INFLUENCE OF BENZYLADENINE DIPS ON GROWTH OF HOSTA CULTIVARS

As we have said many times before in this newsletter, hostas are a very important herbaceous perennial. Nursery owners may want to consider a foliar application of benzyladenine (BA), a synthetic cytokinin, to promote lateral growth by inducing the outgrowth of rhizomic, vegetative buds. BA can be applied onto the leaves or as a dip treatment.

Foliar application, though, can only be performed after the plants have leafed out. The BA-induced offsets become fully developed within 30 to 60 days after application. Growers may wish to induce offset development earlier in the growing season so that plants would be ready for early spring sales. Growers may benefit from BA application to bareroot hosta transplants before fall potting to promote the enhanced lateral growth upon their emergence in the spring.

Treatment in this manner could allow growers to market larger plants during periods of peak market demand, but dip applications of BA were not as effective in promoting offset development as foliar application to growing plants. Dip applications may also have growth retarding or phytotoxic effects when applied to bare-root hosta transplants at high rates. Application by immersion in BA solutions higher than 125 ppm may reduce overall growth.

(from "The Influence of Benzyladenine Dips on Growth of Hosta Cultivars" by James M. Garner and Allan M. Armitage from the Center for Applied Nursery Research, The University of Georgia).

WILBRO ORGANIC LIQUID-FEED

Wilbro Organic Liquid-Feed 8-7-7 Plus Minerals and Trace Elements is promoted as an aid to the production of healthy, robust seedlings, flowers, trees, etc. An evaluation was conducted to ascertain the effectiveness of this product.

Plants (Abelia grandiflora and Lagerstroemia x 'Natchez') were treated with the Wilbro product, Peters 20-20-20 with minors, and the Control in the evaluation was No Foliage Spray.

Quality ratings are listed in the table below:

TREATMENTNo Foliar SprayPeters 20-20-20
Foliar spray
Wilbro 8-7-7
1:200 Dilution
Abelia75.377.384.7
Crape Myrtle79.374.777.0
*Excellent = 100; Good = 80; Average = 60; Questionable = 40; Poor = 20

Quality rankings placed the Wilbro treatment for the Abelia crop better than the other two treatments. Plants looked larger, more dense and had greater numbers of flowers. For the Crape Myrtles, the No Foliar Spray ranked best. All treatments in both crops were judged to be above average in quality. Results of quality ranking indicate that the Wilbro treatment is effective in producing better Abelia grandiflora and Lagerstroemia x 'Natchez' with five applications (each four weeks apart) during the production season. Wilbro was more effective in producing better quality plants than foliar sprays of Peters. The Wilbro product could be beneficial on nursery crops that need an extra boost during the production season.

(from "Evaluation of Willbro Organic Liquid-Feed (Organic Blood and Bone)" by Dr. James T. Midcap, published by the Center for Nursery Research, University of Georgia).

THE EFFECTIVENESS OF ROOTS DRY FORMULA BIOSTIMULANT

ROOTS Dry Formula is being advertised as a product that will increase root growth, reduce transplant losses, increase drought tolerance, and reduce fertilization requirements. Research was conducted to determine the effectiveness of this product regarding containerized ornamentals.

Cuttings for the study were taken from Rhododendron 'Coral Bells', Ilex crenata 'Compacta', and Ligustrum japonicum 'Recurvifolium'. The author of the study concluded that incorporation of ROOTS Dry Formula in the container media can increase growth of some container-grown plants (holly and ligustrum), but may decrease growth of others (azalea). ROOTS will compensate for reductions in fertilizer supplied by other sources, but is not a cost effective replacement for fertilizer.

(from "Effect of ROOTS Dry Formula Biostimulant on Growth and Fertilizer Rates of Three Containerized Ornamentals" by Dr. Tim Smalley; published by the Center for Nursery Research, University of Georgia).

EARTHGREEN BIOSTIMULANT STUDIED

Another product being touted as a substance that will increase root growth, reduce transplant losses, increase drought tolerance, and reduce fertilization requirements is Earthgreen. It is a commercial biostimulant that contains humic substances. Containerized ornamentals used in this study were Rhododendron 'Miss Augusta', Ilex crenata 'Compacta', and Ligustrum japonicum.

Earthgreen can increase growth of plants, and can reduce fertilizer requirements of container grown woody ornamentals but more research is needed to better understand application frequency and the monetary and environmental costs for Earthgreen applications.

(from "Effect of Earthgreen Biostimulant on Growth and Fertilizer Rates of Three Containerized Ornamentals" by Dr. Tim Smalley; published by the Center for Nursery Research, University of Georgia).

INVASION OF THE WEB WORMS

Fall web worms are everywhere. Their webs are in pecans, cherry, willow, river birch and several other trees. This little pest will be with us the rest of the year as long as the trees have leaves. They have a generation every 30 days. It is important to address these early populations to reduce the pressure from succeeding generations. There are two color phases, a light one and a dark one. These color phases alternate and every other one will be alike. The adults can cross breed and the generations are usually light colored.

Treatment for these pests are easy. Timing is important to assure they get contact with the control. Bt's are good and for commercial programs there is Confirm as well, which is a growth regulator. Either should be sprayed in the late afternoon as the worms will leave the webbing to web in surrounding leaves for additional food. If these leaves are sprayed just before dark the material will be on the foliage when the caterpillars web it into the nest. Use a little spreader sticker if needed and be sure the water pH is below 9 or you will lose some of the effectiveness of the spray. This spray system is effective for all webbing caterpillars, eastern tent, mimosa webworm, ugly nest caterpillar, etc.

(by Dale Pollet, Extension Entomologist, from the Ornamental and Turfgrass email, Allen Owings, LSU).

CHOOSE THE BEST MULCH

What's best for a site depends on the needs of the situation. Although mulch producers often make claims about the durability, composition or color, little research exists to confirm such claims. A team of Florida researchers evaluated the characteristics of organic mulches to define their qualities and usefulness for certain situations. The researchers obtained commercially available mulches derived from cypress, pine bark, pine needles and utility trimmings, and tested them for chemical, allelopathic and decomposition properties.

1. Nutrients.
The most nutrient-laden mulch was the utility trimmings, which makes sense considering that this material included green leaves. (To put this into perspective, even this mulch contained less than 1 percent nitrogen.) Pine straw also was relatively rich in nutrients.

2. Decomposition.
The most decomposition-resistant materials were pine straw and bark and cypress. This is consistent with measured levels of lignin (which is highly decay-resistant), which were lower in the utility trimmings. Lower decomposition rates result in longer intervals before mulches need to be reapplied.

3. Allelopathy.
All of the mulches tested were initially allelopathic due to the presence of certain aromatic compounds. However, the most allelopathic mulches were pine straw and the utility trimmings, which both suppressed seed germination after 1 year. The other mulches lost their allelopathic qualities within a few months. (The researchers measured allelopathy in terms of germination suppression. This could be an advantage for weed suppression, but whether this could affect established landscape plants is less clear. More research is needed to clarify this.)

4. Acidification.
All mulches lowered the pH of the underlying soil. The initial soil pH was 5.0. after 1 year; utility trimmings lowered it to 4.7; and cypress and pine bark lowered to 4.6. However, pine straw dropped pH the most -- to 4.4.

5. Color.
Pine bark and cypress both largely retained their original color after 1 year. Other mulches changed.

Based on these results, the researchers concluded that the best all-around mulches they tested were cypress and pine bark. However, if you desired more nutrient release, pine straw or utility trimmings would be better choices. Though the researchers considered soil acidification a drawback (which it obviously can be), this trait can also be beneficial depending on initial soil pH and whether existing plants prefer acid soils. Thus, pine straw could be advantageous rather than problematic.

Although this study shows that no perfect mulch exists for all situations, it is helpful to understand the differences between materials. Such an understanding should help grounds managers choose the most ideal mulch for a given site.

(by Tom Koske, Extension Horticulturist, from the Ornamental and Turfgrass E-Mail by Allen Owings, LSU).

ALL-AMERICA SELECTION WINNERS FOR 2002

Several bedding plants have been named AAS winners for 2002. The most exciting of these are 'Lavender Wave' petunia and 'Tidal Wave Silver' petunia. 'Lavender Wave' is a new color addition to the Wave series of petunias - other colors are misty lilac, pink, purple, and rose. 'Lavender Wave' flowers a few days earlier than 'Purple Wave'. Crop time is 90 days. 'Tidal Wave Silver' petunia is a new color addition to the Tidal Wave series of petunias. These petunias are referred to as hedge or hedgiflora petunias (they reach heights of 3 feet with a 2-3 foot spread). This variety has a bicolor flower pattern - silvery white blooms with dark purple centers. Crop time is 11- 15 weeks depending on the pot size.

Other new AAS winners for 2002 in the bedding plant category include:

(by Allen Owings, from the Ornamental and Turfgrass E-Mail, LSU).

CONCERNS OF SMALL-BUSINESS NURSERY OWNERS

ANLA polled its small-business members on some of the biggest industry concerns. Labor shortage and estate taxes seemed to be their biggest problems. 77% of respondents stated they had difficulty finding labor and more than 75% said they would use a more simplified H-2A program if it were available. Almost 90% said they would be affected by estate taxes currently in place. http://www.anla.org

(From NMPRO e-mail, Todd Davis, Editor).

EXTENSION PLANT PATHOLOGY REPORT

Jackie Mullen, Extension Plant Pathology Specialist-Auburn
Jim Jacobi, Extension Plant Pathology Specialist-Birmingham

2001 MAY PLANT DISEASES SEEN IN
THE PLANT DIAGNOSTIC LAB AT AUBURN
May was generally good for plants and diseases, with normal rainfall (or slightly above normal) in most parts of the state. Some parts of the southern state sections were below normal in rainfall.

May-July tend to be our busiest months and this past May was typically busy with 154 plant samples.

Oak leaf blister has been more prevalent than in the previous dry years. The leaf spots usually are slightly puckered with one leaf side being concave and one side being convex. Some oak species are characteristically more puckered than others. This leaf spot disease (as with most leaf spot diseases on large trees) is not a serious threat to the overall health status of the tree. Severe leaf spot may cause early leaf fall. Leaf fall after mid July does not typically significantly affect the tree's health. Leaf fall before July will cause some weakening of the tree, but established trees will refoliate later in the season or the following spring. Several early leaf falls over consecutive years will weaken the tree and could cause decline problems. Sanitation of fallen leaves in the fall is always a good idea, although, with this disease, some spores lodge in bark crevices until they germinate next spring. With small trees, protective fungicides are recommended, with application at bud swell next spring. See the Ala. Pest Management Handbook.

Take-all patch was noted on centipede, St. Augustine, and zoysia. Patchy areas tend to yellow and thin out due to decay lesions of stolons and roots. See ANR-823.

Diseases Seen at the Auburn Plant Diagnostic Lab in May
PLANTDIAGNOSISCOUNTY
AmaryllisBacterial Soft RotCalhoun
AmaryllisFusarium Bulb RotCalhoun
BermudaBrown Patch (Rhizoctonia)Montgomery
BermudaSpring Dead Spot (Gaeumannomyces
graminis var graminis
)
Jefferson, Pickens
CentipedeTake-all Patch (Gaeumannomyces graminis var graminis) Clarke, Covington, Shelby
CrabappleCedar Apple Rust (Gymnosporangium juniperae-virginianae)Lee
DaylilyCercospora Leaf SpotMarshall
FescueAnthracnose (Colletotrichum)Cullman
FescueBrown Patch (Rhizoctonia)Madison
IrisAnthracnose (Colletotrichum)Lee
IrisBacterial Soft Rot (of Corm)-RhizomeCalhoun
JuniperFusarium Needle BlightCullman
LiriopeAnthracnose (Colletotrichum)Houston
MaplePythium Root RotElmore
Maple, JapanesePythium Root RotLimestone
MarigoldBacterial Leaf SpotLee
OakOak Leaf Blister (Taphrina)Lee, Montgomery
PearFireblight (Erwinia amylovora)Montgomery
PetuniaPhytophthora Crown RotLimestone
Pine, LoblollyNeedle Rust (Coleosporium)Tuscaloosa
RoseBotrytis Blossom BlightMobile
SnapdragonPhytophthora Crown & Root RotGeneva
St. AugustineTake-all Patch (Gaeumannomyces graminis var graminis) Barbour, Colbert, Houston,Lee, Pike, Tallapoosa, Tuscaloosa
WillowRust (Melampsora)Mobile
ZoysiaBrown Patch (Rhizoctonia solani)Covington, Cullman
ZoysiaPythium Foliage & Root DecayMontgomery
ZoysiaTake-all Patch (Gaeumannomyces graminis var graminis) Tuscaloosa
*County locations for nursery/greenhouse problems are not reported.

2001 MAY PLANT DISEASES SEEN IN
THE PLANT DIAGNOSTIC LAB AT BIRMINGHAM
Rainfall and temperatures in May were slightly above average, providing favorable conditions for plant diseases. Of the 120 samples during May, problems related to the drought and cold winter temperatures continue to be very common. Two of the common diseases seen were azalea gall (or leaf gall) and Phytophthora blight on petunia. Azalea gall is caused by the fungus, Exobasidium vacinii and infects leaves, blossoms, and occasionally young twigs and shoots. Developing leaves and flowers are thickened, fleshy and distorted. As the galls develop, they become white or pink with masses of spores being produced. In addition to azalea, rhododendron and blueberries are also susceptible to this disease. A similar disease occurs on camellia and is caused by the fungus Exobasidium camelliae. The most practical control in the landscape is to hand remove and destroy all galled leaves before they become white or pink with spores. See ANR-942, 'Azalea Gall', for more information on controlling this disease; including a list of azalea cultivars that are resistant to infection. Phytophthora blight was seen on several 'wave' petunia samples brought to the lab. This disease is very hard to control and persists in infected beds for several years. Possible replacements for petunia and vinca (also very susceptible) in Phytophthora-infected beds include ageratum, begonia, celosia, coneflower, geranium, marigold, scabosia, thyme, verbena, and zinnia. See ANR-1023, 'Diseases of Annual Vinca in the Greenhouse and the Landscape', for more information.

Diseases Seen In The Birmingham Plant Diagnostic Lab in May
PLANT DISEASE/INSECT PROBLEMCOUNTY
AucubaPhytophthora Root RotJefferson
AzaleaAzalea Leaf GallShelby (2)
AzaleaPhomopsis DiebackJefferson
BarberryScale, Botrosphaeria CankerJefferson
BermudaHelminthosporium Leaf SpotJefferson (3)
BoxwoodPhytophthora Root RotJefferson
CentipedeBrown PatchJefferson
CentipedeFairy RingShelby
Chaste TreeAlternaria Leaf Spot/BlightJefferson
CrabappleApple ScabJefferson
Cypress, HinokeSpider MitesJefferson
DahliaPowdery MildewJefferson
EleagnusVole DamageJefferson
Fescue, TallBrown PatchJefferson
Holly, YouponPythium Root RotJefferson
IrisDidymellina (Cladosporium) Leaf SpotWalker, Jefferson
Jack-In-The-PulpitRust (Uromyces spp.)Marshall
JuniperPhomopsis Tip BlightJefferson
JuniperPhytophthora Root RotJefferson (2)
JuniperSpider MitesJefferson (2)
Leyland CypressBotryosphaeria CankerShelby
Maple, FloridaAnthracnoseJefferson
Maple, RedAnthracnoseSt. Clair, Jefferson
Oak, Southern RedOak Leaf BlisterJefferson
Oak, WhiteOak Vein Leaf Gall (Vein Pocket Gall)Shelby
PecanShoot CirculiosJefferson
PetuniaPhytophthora BlightJefferson (3)
St. AugustineBrown PatchJefferson
St. AugustineTake-All Root RotJefferson
ZoysiaBrown PatchJefferson (5)
ZoysiaFairy RingJefferson
*County locations for nursery/greenhouse problems are not reported.

Disease Possibilities For June
So far in June, the following are some of the disease samples we have seen: fireblight on Bradford pear; powdery mildew on dogwood; anthracnose on iris; Botrytis on rose; Septoria leaf spot on cherry; lots of oak leaf blister on oak; brown patch on bermuda; take-all on St. Augustine, zoysia, and centipede grass; brown patch on St. Augustine grass; Rhizoctonia blight on thrift. To see brief disease descriptions and control recommendations for diseases often seen in June please go to the Disease Reports button on our home page:


UPCOMING EVENTS

July 24 - 28, 2001:
Cullowhee Conference: Native Plants in the Landscape.
Western Carolina University in Cullowhee, North Carolina
For more information call 770-922-7292.

August 2-5, 2001:
SNA 2001 - Southern Nurserymen's Association Researcher's Conference and Trade Show.
Georgia World Congress Center, Atlanta, GA. Contact SNA at 770-973-9026; SNA Infoline at 770-973-4636;
http://www.sna.org

September 30 - October 3, 2001:
Eastern Region International Plant Propagators' Society Annual Meeting.
Lexington, KY. Contact Margot Bridgen, 26 Woodland Road, Storrs, CT 06268; phone 860-429-6818; e-mail mbippser@neca.com

October 5-7, 2001:
Annual meeting of Alabama Christmas Tree Association combined with Georgia Christmas Tree Association.
Bill Murray's farm in Cordele, Georgia. Contact Ken Tilt (334-844-5484) for more information.

October 12-13, 2001:
Middle Tennessee Nursery Association Horticultural Trade Show.
McMinnville Civic Center, McMinnville, TN
phone: 931-668-7322; fax: 931-668-9601; e-mail: mtna@blomand.net,
http://www.mtna.com or http://www.tnnursery.com/mtna

October 18-21, 2001:
Southern Region International Plant Propagators' Society.
Houston, TX. Contact David Morgan at 817-882-4148; fax: 817-882-4121; SR IPPS, P.O. Box 1868, Ft. Worth, TX 76101; e-mail: dmorgan@bsipublishing.com

November 30 - December 1, 2001:
The Great Southern Tree Conference.
Contact Heather Nedley at hnedley@fnga.org; 1-800-375-3642.

October 11-12, 2002:
Middle Tennessee Nursery Association Horticultural Trade Show.
McMinnville Civic Center, McMinnville, TN
phone: 931-668-7322; fax: 931-668-9601; e-mail: mtna@blomand.net,
http://www.mtna.com or http://www.tnnursery.com/mtna

April to October, 2002:
Floriade 2002.
See the AmeriGarden (5,400 square feet), part of the world horticulture exhibition in the Netherlands.
For more information call 808-961-6660 or visit http://www.floriade.nl or http://www.amerigarden2002.com

Send horticultural questions and comments to ktilt@acesag.auburn.edu.

Send questions and comments to bfischma@acesag.auburn.edu.

Letters to Bernice Fischman - 101 Funchess Hall - Auburn University, AL 36849.