SEPTEMBER - 2000

Greetings from Ken Tilt--

Painless Education: September says get ready for Southern Region International Plant Propagators Meeting in Chesapeake, VA on October 8-11. DON’T YOU MISS IT! Shame on you if you have not sent in your registration already. I tell nursery people every year that if there is only one meeting you can attend each year, this meeting will do you more good than any other. The educational program is great and is outlined below but this is a minor part of the program. This is a meeting where you get to look into the closets and back rooms of successful nurseries and learn their secrets of success and the also share their screw-ups.

The IPPS motto is Seek and Share. If you are seeking, they are sharing! This is an organization where growers support each other. There is a sprinkling of University types, like myself, because we begged to be a part of something this special. We learn from each other. Do you have stupid questions (at least in your mind) that need answering? There is a question box that you put those in and the whole group has a live, in-person chat room to share the experiences they have had with that same stupid question. There is plenty of social time where you can kick back and have some “painless learning”.

You go home and wonder where you came up with these new great ideas and decide it must have come from the dinner conversation at IPPS. YOU DO NOT HAVE TO BE A MEMBER THE FIRST YEAR! Come see if you like it. There is a catch for all this free(?) information. You have to be willing to share if you become a member and help others as you have been helped. I have heard that phrase before; it must have been at IPPS. If you are a new struggling grower and you are not investing in this meeting and your future, we can not be responsible for the consequences. I hope you will come and join us. We have a great time and I always get some good “Painless Education”. I also always meet some great new people that I can call when I have a stupid question, which happens often.

Have a great month and let us know if we can help you with anything.


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

ATTEND THE 25TH ANNUAL IPPS SOUTHERN REGION OF NORTH AMERICA MEEETING

FIREBLIGHT POUNDS BRADFORD PEAR STATEWIDE

Loropetalum chinensis IN THE SPRING: USDA HARDINESS ZONE 7

SNA AND AUBURN UNIVERSITY

EFFECTS OF CYCLIC MICRO-IRRIGATION AND COPPER CONTAINER TREATMENTS ON THE GROWTH OF WHITE CEDAR AND 'BLUE ICE' ARIZONA CYPRESS

GROWTH REGULATION EFFECTS OF GOLD FLAME HONEYSUCKLE

EFFECTS OF COPPER AND SUBSTRATE ON ROOT CONTROL
OF x Cuppressocyparis leylandii IN POT-IN-POT PRODUCTION

SLUGS

INTERNATIONAL GARDEN PRODUCTS GROWS

INVASIVE SPECIES COUNCIL SEEKS INPUT

LOOSESTRIFE

DISCONTINUATION OF DIAZINON

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.


ATTEND THE 25TH ANNUAL IPPS SOUTHERN REGION OF NORTH AMERICA MEEETING

This year's meeting will take place at the Holiday Inn Chesapeake in Chesapeake, Virginia. See the UPCOMING EVENTS section for more details. The function of this article is to whet your appetite. Some of the highlights of the meeting are as follows: On Sunday, October 8, attendees will be bussed to various nursery tours. A budding and grafting workshop and poster presentations will follow.

On Monday there will be a presentation on the JC Raulston Arboretum, as well as a session on pre- and post-hurricane considerations. Plant breeding and a discussion on whether we need a nursery environmental program will follow. After student talks there will be a discussion about plant hybridization and improvement. The afternoon will present opportunities for more nursery/farm tours.

Tuesday's program features sessions on benefits and opportunities with mycorrihizal fungi in nursery propagation and production systems, invasive plants and the nursery industry, new perennials for zones 7, 8, and 9, small practical steps to better irrigation (by our own Ken Tilt), over-wintering liner practices, fiber for your plants, automatic handling and grading for vegetative propagation, followed by more tours.

Wednesday, the last day of the meeting, is also full of sessions: avoiding the staking dilemma, microclimate manipulation for improved plant growth, conifer selection and propagation, weed control in woody liner production; evalating plants for tomorrow's landscapes as well as evaluating expanded polystrene as a substitute for perlite in rooting media. The last scheduled activity is a tour of the Ford Truck Plant.

Make your reservations now!!!


FIREBLIGHT POUNDS BRADFORD PEAR STATEWIDE

By Austin Hagan
Extension Plant Pathologist and Professor
Department of Entomology and Plant Pathology, Auburn University

Fireblight, which is caused by the bacterium Erwinia amylovora, is a perennial problem across Alabama on the trees and shrubs in the apple subfamily (Pomoididae). In landscape plantings, selected cultivars of apple, crabapple, flowering pear, Indian hawthorn, and cotoneaster are the main targets of this disease. In some years, other members of the apple subfamily may be hit by fireblight. Typically, several successive days of mild, cloudy, wet weather during bloom is all that's needed to start an outbreak of fireblight. Apparently, those conditions were met over a sizable portion of Alabama, i.e. at least as far as the ever popular and over-planted `Bradford' pear is concerned.

Over the past few weeks, numerous reports of fireblight damage on flowering pears, especially on the cultivar `Bradford' have been received from county agents and specialists across much of Alabama. Personally, I have seen numerous dead shoots or "strikes" on 'Bradford' pears in landscape plantings in Baldwin, Mobile, and Escambia Counties. Typically, the leaves on the dead shoots have turned reddish to dark brown in color and there may literally be 100 or more blighted shoots seen on a large flowering pear. Although the damage on some pears may appear serious, often the individual shoots have been killed back only about 6 inches to about a foot or so. Also, noticeable fireblight damage was also seen last month in a planting of `Becky Lynn' Indian hawthorn at the Brewton Experiment Field.

Bactericides are effective against fireblight only when applications are made during bloom. Since the recent hot and often dry weather patterns have probably stopped disease spread in landscape plantings, new damage is unlikely to appear and protective bactericide treatments at this late date are unnecessary. Several sprays of Agrimycin 17 (streptomycin sulfate) @ 0.5 lb. per 100 gal. (100 ppm) of spray volume beginning when the flowers open through petal fall will do a good job of controlling fireblight. However, the uniform and timely applications of a bactericide to a large pear will present a real challenge because most landscapers and all homeowners don't have access to the necessary spray equipment. Anyway, fireblight damage on `Bradford' pear is largely cosmetic and rarely presents a serious threat to tree health. Yearly, preventative bactericide treatments may be required, however, to protect susceptible flowering pears such as `Aristocrat' from significant fireblight damage.

Pruning out the "strikes" may be possible on shrubs or smaller trees but is out of the question on a mature `Bradford' pear. To avoid accidentally spreading this disease, pruning cuts must be made 6 to 8 inches below the end of the blighted shoot and the pruning tools must be cleaned before each cut is made with denatured alcohol or similar surface disinfectant. Folks should not use Cloro4 (bleach) to clean metal tools. It's a very strong oxidant and will quickly corrode pruning tools and knives. Ideally, pruning should be delayed at least until shoot growth has stopped and preferably should be done in early winter after the trees have gone dormant.

The over use of nitrogen can greatly increase shrub and tree sensitivity to fireblight. In fact, heavy fertilization in late fall or early spring can easily make a normally resistant cultivar highly susceptible to this disease. Fireblight-damaged shrubs and trees may be lightly fertilized anytime from June through the end of August. After that date, fertilizing a pear tree is just like stoking a fire. Given the right weather, the tree will likely get blasted the following spring.

Planting a fireblight resistant selection remains the best defense against this disease. Of the available flowering pears, `Bradford' is the most fireblight resistant. As we've already seen, resistance can under ideal conditions for this disease mean that some blighting may be seen but the level of damage on a `Bradford' is usually far less than what typically would be seen on a fireblight-susceptible pear such as `Aristocrat'.

ANR-542, Fireblight on Fruit Trees and Woody Ornamentals was updated last year and is a good source of control information and contains a complete list of fireblight resistant and susceptible cultivars of apple, crabapple, pear, flowering pear and several other shrubs and trees.


Loropetalum chinensis IN THE SPRING:
USDA HARDINESS ZONE 7

from research conducted by Richard E. Bir and J. L. Conner,
North Carolina State University

Ten years ago the red leaf, pink flowered forms of Loropetalum chinensis, var. rubrum, burst onto the southeastern nursery scene. A rush of selections followed which were offered under many names. An example being the trademarked 'Plum Delight' which was also listed as 'Hines Purpleleaf', 'Hines Burgundy' and 'Pizzazz'. Equal confusion existed when recommendations concerning hardiness were made. Plants were thought to be reliably hardy in USDA Zones 7 through 9.

In an attempt to determine hardiness, a trial was established in full sun in Fletcher, North Carolina, which is listed as USDA Zone 6b but for the duration of the test, only Zone 7 winters occurred. Three-gallon container grown plants of the green leaf, cream flowered species, two selections that have not made it to the commercial trade, 'Blush,' 'Burgundy,' 'Plum Delight,' 'Sizzlin' Pink' and 'Zhuzhou Fuchsia' were planted in clay-loam soil, pH 5.8. Plants were fertilized with 1 ou. Nitrogen from 10-10-10 each spring in April. Plants were not irrigated nor was any pest control beyond a directed spray of Roundup for post emergence weed management employed for the four years of this study.

The first week of May in the springs of 1997, 1998, 1999 and 2000 plants were evaluated for winter injury. Annual lowest temperatures were between 5, and 10 degrees F. All plants survived and were hardy. Occasional winter dieback on the ends of stems was observed on the cultivars 'Blush' and 'Sizzling Pink.'Appearance of plants in the landscape during spring is obviously important to nursery professionals. One cultivar consistently was both flowering and had attractive foliage on May 1 - 'Zhuzhou Fuchsia.' It was as hardy and floriferous as the straight species. All other cultivars either displayed dead twigs, damaged foliage, limited flowering or an unsightly yellowing of older leaves. 'Blush' was the most unattractive. However, dead twigs were quickly masked by new growth. Yellow foliage dropped by mid May with attractive new foliage replacing it by late May of each year.

SIGNIFICANCE TO THE INDUSTRY:

One cultivar of Loropetalum chinensis var. rubrum consistently survived USDA hardiness Zone 7 winters with attractive foliage and abundant flowers - 'Zhuzhou Fuchsia.' 'Blush,' 'Burgundy,' 'Plum Delight' and 'Sizzlin' Pink' all displayed slight winter injury or were unattractive due to yellow leaves.

SNA AND AUBURN UNIVERSITY

The graduate and undergraduate students in the Auburn University Horticulture Department have an excellent track record of winning recognition for their research. This year is no exception.

Congratulations to LAURA BRUNER, masters degree student in the Horticulture Department at Auburn University. She was a double winner at the SNA meeting in Atlanta. She won 3rd place in the masters student division of the Bryon L. James Student Research Competition, winning a $200 prize. She was also a winner of the prestigious Sidney B. Meadows Scholarship which carries an award of $2,500. Way to go, Laura!

We traditionally publish student and faculty papers from the research section of the annual Southern Nurserymens Association annual meeting in Atlanta. Some of the technical information related to the papers has been omitted for easier reading. If you would like a copy of the original paper please send an email and we'll be happy to send you a copy.


EFFECTS OF CYCLIC MICRO-IRRIGATION AND COPPER CONTAINER TREATMENTS ON THE GROWTH OF WHITE CEDAR AND 'BLUE ICE' ARIZONA CYPRESS

Research presented at the SNA meeting in Atlanta in August by
Robert C. Trawick, Ken M. Tilt, Harry G. Ponder,
Gary J. Keever and James E. Altland
Auburn University, Department of Horticulture, 36849

The objectives of this study were to test the effects of cyclic micro-irrigation on the growth of Atlantic white cedar, Chamaecyparis thyoides; and Blue Ice cypress, Cupressus glabra 'Blue Ice' and to evaluate the effects that two commercial copper container treatments have on root growth during growth in containers and after transplanting from their respective container treatment.

Cyclic Irrigation:
With the prospect of increasing regulation of water usage in container nurseries, efficiency of irrigation systems has become of prime importance to the nursery industry. Cyclic irrigation, a relatively new practice where a plant's daily water allotment is broken up into a series of irrigation events, may be a possible solution to this problem. Recent research indicates that cyclic irrigation can actually increase irrigation efficiency by as much as 38% when compared to a single irrigation event without an adverse effect on plant growth and often an increase in plant growth.

The volume of water required for each plant was determined and was then applied to the plants daily in one application or the volume was divided into three or six applications. The volume of water applied was adjusted monthly throughout the growing season. Irrigation was applied through Maxijet spray stakes (Maxijet Inc., Dundee, FL). Height, canopy widths, caliper measurements, and root ratings were recorded monthly from April through November, 1999.

Irrigation efficiency was improved for those plants receiving cyclic irrigation by as much as 52% for plants receiving three or six irrigation events compared to a single irrigation application. Growth index and caliper of white cedar were increased by as much as 9% and 11% with cyclic irrigation. Arizona cypress receiving cyclic irrigation experienced a linear increase in growth index of 7% in 1998 and a quadratic increase of 6% in 1999. There was a linear increase in caliper of 14% in 1999 for plants receiving cyclic irrigation. Irrigation had no effect on copper root control treatments.

Copper container treatments:
Circling roots of plants grown in an incorrect sized container or from improper placement of a vigorously rooting plant in a container that is too small can cause permanent injury to a plant. Copper container treatments offer relief from these problems. Root-bound plants are slower to establish following transplanting into a larger container or the landscape. Copper applied to the inner surface of containers is effective in reducing surface root development by chemically pruning roots as they encounter the container wall. However, some growers have noted that roots of plants treated with Spin Out® continued to be suppressed once removed from a copper free environment. Currently there are two copper treated containers available in the nursery industry, Spin Out® (Spin Out®, Lerio Corporation, Mobile, AL) containers coated with copper hydroxide and Root RightTM (Nursery Supplies Inc., Chambersburg, PA) containers impregnated with copper chloride.

Both white cedar and Arizona cypress grown in Root RightTM containers were significantly less root bound than those grown in control containers but significantly more root bound than those plants grown in Spin Out® treated containers. White cedar grown in Root RightTM and Spin Out® treated nursery containers had a 5% and 11% larger caliper, respectively, than plants grown in untreated containers. Container treatment had no significant effect on root regeneration once transplanted to a copper-free environment, however it was visually noted that plants grown in Spin Out® treated containers had an uneven distribution of regenerated roots over the surface of the root ball indicating that some areas of the root ball were still being suppressed by the copper treatments. Plants grown in Root RightTM containers had regenerated root systems that were evenly distributed over the surface of the root ball.

Significance to Industry: Water conservation is becoming more important to ornamental producers due to water shortages and environmental regulations. Cyclic irrigation produced growth equivalent to or better than a single irrigation application.

Root-bound plants are slower to establish in the landscape. These results show that Root RightTM and Spin Out®treated containers effectively control excessive root growth. Nursery producers can expect less problems with establishment by using copper treated containers.


GROWTH REGULATION EFFECTS OF GOLDFLAME HONEYSUCKLE

Research presented at the SNA meeting in Atlanta in August by
L. L. Bruner, G. J. Keever, R. A. Kessler, and C.H. Gilliam
Auburn University, Dept. of Horticulture, Auburn, AL 36849

Climbing honeysuckles fill a unique niche in the landscape due to their twining, climbing habit and long flowering period. Goldflame honeysuckle is characterized by shoots 10 to 20 ft. long with continuous flowering throughout the spring and summer as long as new growth occurs. Carmine flower buds expose a yellow corolla. Due to their rapid growth, honeysuckle species often grow to a large size and intertwine with adjacent plants. Hand pruning is the typical method of controlling excess shoot growth and increasing branching. However, hand pruning is time consuming, labor-intensive, and often removes flowers. In spite of often repeated prunings, growth is usually concentrated at the top of the plant and sparse on lower portions. Plant growth regulators (PGRs) are effective in suppressing growth of numerous woody landscape plants and can promote lateral branching. Atrimmec, which is labeled for use on numerous woody landscape plants, but not Goldflame honeysuckle, is both a growth regulator and branching agent and may offer benefits in the production, shipping, and marketing of Goldflame honeysuckle. The objective of this study was to determine the effects of Atrimmec on pruned and non-pruned Goldflame honeysuckle.

Results and Discussion: Pruning suppressed shoot elongation initially. At all sampling dates, increasing rates of Atrimmec suppressed shoot elongation linearly or quadratically in pruned and non-pruned plants.

30 DAT (non-pruned plants)
0 - Control
1 - 1.5 oz/gal. Atrimmec
2 - 3.0 oz/gal. Atrimmec

Shoot length was consistently suppressed with Atrimmec. Compared to untreated control plants, tip number increased with increasing Atrimmec rate.

30 DAT (pruned plants)
0 - Control
1 - 1.5 oz/gal. Atrimmec
2 - 3.0 oz/gal. Atrimmec

Based on observations, there was a slight delay in flowering for Atrimmec treated plants compared to untreated. However, both treated and untreated plants began heavily flowering between 4 and 6 weeks after treatment, resulting in an obvious reduction in the rate of shoot elongation.

Significance to Industry: Pruning alone was effective in controlling shoot elongation. Results of this experiment show that used alone or in combination with pruning, Atrimmec provides an effective means of controlling shoot length and increasing branching during production of Goldflame honeysuckle.


EFFECTS OF COPPER AND SUBSTRATE ON ROOT CONTROL
OF x Cupressocyparis leylandii IN POT-IN-POT PRODUCTION

Research presented at the SNA meeting in Atlanta in August by
Robert C. Trawick, Ken M. Tilt, Harry G. Ponder, Gary J. Keever, and James E. Altland

Containers offer production and marketing advantages not available to field grown plants. However, container production does have drawbacks. Container-grown plants can be blown over easily and root systems, which are not as hardy as stem and leaf tissues, can be injured easily by extreme temperature fluctuations. To address these problems associated with container growing, a method of production was used wherein a "socket" pot is permanently placed in the ground and an "insert" container plant is placed inside the socket container.

Pot-in-pot (PIP) production incorporates many of the benefits of field growing with the production and marketing advantages available to container growing. Through the use of this system, roots are protected from thermal extremes. This system has resulted in improved tree roots due to harvest of 100% of the roots compared to digging and removing a large percentage of the roots required in traditional field grown tree systems. However, a shortcoming soon noted with the PIP system was the propensity of plant roots to grow out of the container drainage holes and into the surrounding soil. Rooting depth in the field is dependent upon moisture availability in the soil. As moisture is depleted, roots extend deeper into the soil to access available water. While methods of controlling rooting out with chemicals has had moderate success, growth was reduced in some form. Additionally, research has shown that roots treated with copper effectively reduced root elongation thus preventing roots from becoming root bound.

The objective of this study was to determine if a Root RightTM (Nursery Supplies, Inc., Chambersburg, PA) container, impregnated with copper chloride, combined with three container substrates could effectively reduce rooting-out into the surrounding soil from the planted container without reducing plant growth.

The volume of water applied was adjusted monthly throughout the growing season. Irrigation was applied through Maxijet spray stakes (Maxijet Inc., Dundee, FL). Height, canopy widths, caliper measurements, and root ratings were recorded monthly from April through November. Further study is warranted to determine if cyclic irrigation is solely responsible for reduction in rooting-out.

Significance to the Nursery Industry
Pot-in-pot production offers advantages not inherent in traditional above ground container production. However, the problems of confined roots becoming root bound coupled with the additional problem of roots growing into surrounding soil are an issue. This research offers evidence that Root RightTM containers, while yielding similar growth, successfully prevented roots from becoming root-bound. Pine bark:peat at a 4:1 ratio was more successful at lowering root ratings than other substrates tested when combined with copper treated containers.


SLUGS

From a Richard E. Bir Memorandum to Extension County Agents with Nursery Crops

The following is taken from an article in the August 2000 Grower Talks magazine. The article was written by Tom Thomson from Monterey Chemical Company in California:

SANITATION. Cleanliness and good maintenance are the first methods of control. Eliminate the areas where they spend their daylight hours. Clean up weeds and undesirable plants in and around your crops. Water early in the day to eliminate moist areas where they congregate. Clean up all wood, rocks and other areas where they hide.

BIOCONTROL. In some areas, decollotate snails can be used for biological control. They live on the eggs of snails and slugs and eat rotting plant materials, but they won't eat live plants. Over a period of six months or longer, they can eliminate the population of brown garden snails and reduce the population of slugs. Release them at the rate of 1,000 per acre.

CHEMICAL CONTROL. Everyone has heard about beer, salt and other home-grown snail and slug controls. These aren't practical under production conditions, however. Metaldehyde baits, first introduced in the 1930s, are the most commonly used control. Metaldehyde is usually formulated as a meal bait or pellet from 2 to 7.5% active ingredient and sold under various trade names; one product is Deadline, a 4% metaldehyde gel formulation. Metaldehyde kills through both ingestion and contact. If a slug or snail crawls across the metaldehyde bait, the metaldehyde is taken up into the mollusk's system, causing death. Some baits have a combination of metaldehyde and carbaryl. Metaldehyde baits are registered for use on ornamentals, tree fruits, greenhouse ornamentals, berry crops, vegetables and grasses grown for seed and turf areas. Don't allow the bait to contact any edible portions of any food or feed crop. Phytotoxicity has been observed in some ornamentals, including daylilies and clematis. Apply when plant damage first appears, and don't apply to a dry soil. Evening applications are preferred. For heavy infestations, a second application may be required in 7 to 10 days. Metaldehyde baits are extremely toxic to pets, so keep them out of treated areas.

Measurol (methiocarb) is a sprayable molluscicide/insecticide that's registered in the U.S. on greenhouse and field ornamentals. It's applied as a foliar spray up to four times per season. Measurol controls snails and slugs when they feed on treated foliage. Once ingested, feeding stops. Mesurol also controls aphids and mites. It's not for use on food or forage crops.

The newest bait to hit the market is Sluggo (iron phosphate). Developed in Germany, it's registered in the U.S. for use on ornamentals, greenhouse vegetables, citrus, fruit crops, field crops, vegetables and grasses grown for seed, turf and landscape areas. The active ingredient is incorporated into a pasta-type product. Sluggo can be used up to the day of harvest on food or forage crops. One of the biggest advantages of Sluggo is that it's safe for pets and animals. It has no effect on earthworms, birds, insects or other nontarget species. Iron phosphate, the active ingredient, occurs naturally in the soil and is used in medicine to correct iron deficiency. It breaks down in the soil into iron and phosphate, both of which are used by plants as fertilizer. The inert ingredients are all biodegradable food additives. Unlike metaldehyde baits, Sluggo must be ingested to be effective; it doesn't kill on contact. Once heavy metal (iron) is ingested, it becomes toxic to the pest. The snails or slugs stop feeding immediately and go back to their nesting area to die. You won't see unsightly piles of dead snails or slugs when using iron phosphate bait. Apply Sluggo around the plants to be protected. It may even be scattered over the top of ornamentals and vegetables. Evening is the best time to apply the bait. Reapply as bait is consumed.


INTERNATIONAL GARDEN PRODUCTS GROWS

International Garden Products acquired Briggs Nursery in Olympia, Washington. IGP has acquired 8 hort companies including Iseli Nursery, Weeks Nursery and Skagit Gardens. Briggs Nursery and IGP were in negotiations for 2 years. Bruce Briggs, NMPRO Grower of the Year for 1999, who died in February, was in favor of the business action, said his wife Doris.
(from Weekly NMPRO newsletter).

INVASIVE SPECIES COUNCIL SEEKS INPUT

The federal Invasive Species Council will publish a draft of its National Invasive Species Management Plan next month and is calling for a 60-day public comment period before the report is finalized. Gordon Brown, invasive species coordinator, said the delay is intended "as a way of securing greater stakeholder input." The council was established by executive order February 3, 1999, and given 18 months to prepare and issue the plan to make recommendations and outline specific measures for federal efforts concerning invasive species of plants and animals. "We’ll be late, but the public input will assure a better product," Brown said.
(from Weekly NMPRO newsletter).

LOOSESTRIFE

Following Nebraska’s lead, Virginia has declared purple loosestrife a noxious weed. Sale or transport of Lythrum salicaria and L. virgatum, including all hybrids and cultivars, is now illegal. According to the Virginia Department of Agriculture, loosestrife is already widespread throughout the state and the legislative action is designed to prevent new infestations.
(from Weekly NMPRO newsletter).

DISCONTINUATION OF DIAZINON

The greenhouse use of diazinon will most likely be discontinued in the near future. The EPA has requested that new data be developed to continue certain uses of diazinon, in compliance with FQPA, but Novartis decided it would no longer support diazinon's indoor uses, which include greenhouse applications. "We regret that Novartis has had to make the business decision to no longer support indoor uses of diazinon," said product manager Pat Willenbrock." We regret the loss of this valuable tool, particularly for our colleagues in the ornamental and structural pest control markets. Unfortunately, sales in these sectors no longer justify the heavy commitment of resources now required to support any indoor uses."
(from Weekly NMPRO newsletter).

PLANT PATHOLOGY REPORT

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

AUBURN PLANT DISEASE REPORT - JULY (J. Mullen)

Despite the severe drought of this summer, we still managed to receive the same number of samples as last year. The difference between samples this year and last year is that 70% of the samples received this past month (and also in June) have been environmental problems–many being drought-related. And, one-half of the diseases (biotic) seen in July were turf samples. The non-turf samples included a variety of mostly fruit, ornamentals, and garden. Fusarium has been frequently associated with root rotted tissues, and Fusarium is known to be more aggressive when conditions are dry. With turf, very high levels of ring nematode have been associated with dieback areas of bermuda, zoysia and some other warm-season grasses.

July Plant Diseases Received at the Auburn Plant Diagnostic Lab
PlantDiseaseCounty
AloeFusarium Stem RotLee
AucubaBotryosphaeria CankerMarion
BahiaDollar Spot (Sclerotinia)Barbour
BentgrassRing Nematode Damage (Criconemella)Jefferson, Shelby
ChrysanthemumPhytophthora & Pythium Root RotLee
HydrangeaPythium Crown & Root RotDale
MarigoldPhytophthora & Pythium Root RotLee
NandinaVirus *
Pear, BradfordAnthracnose (Colletotrichum)Mobile
PetuniaPhytophthora Stem RotLee
PeriwinklePhytophthora Root RotLee
PeriwinklePhytophthora Stem RotLee
PhotiniaEntomosporium Leaf SpotGeneva
Popcorn TreeRoot Knot Nematode (Meloidogyne) *
SyngoniumPhytophthora Root RotLee

*Counties are not reported for greenhouse and nursery diseases.

BIRMINGHAM PLANT DISEASE REPORT - July (J. Jacobi)

The drought continued into July in the Birmingham Metro Area with another month of below normal rainfall. However, we recorded 64 samples during the month of July. Diseases of woody ornamentals, turfgrass (zoysiagrass and St. Augustine), and tomatoes were most common samples received during this month of July.

July Plant Diseases Received at the Birmingham Plant Diagnostic Lab
PlantDiseaseCounty
AzaleaPhomopsis DiebackJefferson
BentgrassSod WebwormJefferson
BoxwoodPythium Root RotJefferson
BoxwoodOstershell Scale, Volutella BlightJefferson
ClematisOverwatering, Pythium Root RotShelby
Cherry LaurelBotryosphaeria DiebackJefferson
Cherry LaurelShot Hole (Xanthomonas spp.)Jefferson
DianthusPythium Root RotJefferson
DogwoodLeaf ScorchJefferson
Holly, JapanesePythium Root RotJefferson
Holly, FostersBotryosphaeria CankerShelby
JuniperPhomopsis BlightJefferson
Juniper, ShoreDrought StressJefferson
Juniper, ShorePhytophthora Root RotShelby
Maple, RedSunscaldJefferson
Pine, LongleafPine WebwormTallapoosa
Pistache, ChineseLeaf ScorchJefferson
Privet, JapaneseCercospora Leaf SpotJefferson
VincaPhytophthora BlightJefferson
Vinca MinorPhyllosticta Leaf SpotJefferson
Yew, JapaneseEnvironmental StressJefferson

DISEASE POSSIBILITIES FOR AUGUST

Many of the same diseases of vegetables and ornamentals are problems throughout the summer. In addition to the following list, refer to disease lists for June and July.

As August progresses, we will probably see an increase in the number of fungal leaf spot diseases on a variety of crops especially shade trees. Often, these spots occur on trees that are experiencing some type of stress including nutritional or water stresses. Alternaria, Cercospora, Septoria, Phyllosticta, and a variety of anthracnose fungi are some of the many fungi seen on trees in the late summer and early fall. Leaf spot diseases developing at this time of year on trees are generally of no concern. Advise clients to collect and destroy fallen leaves this fall.

In August, bacterial scorch disease may become evident on infected sycamore, elm, maple (red), oaks (oaks in the red and black group: pin oak, southern red oak, laurel oak, water oak) and mulberry. Symptoms include leaf edge scorch on lower branches which will slowly spread upward in the tree canopy during the following 2-5 years. Scorched foliage will develop branch dieback, usually, the following year. This disease is caused by the bacteria Xylella which is believed to be transmitted by leaf hoppers. The bacteria cause xylem plugging. Tree removal is the only control recommendation. If you suspect bacterial scorch disease, please send the sample for a lab diagnosis. We have ELISA materials at the Auburn lab, and we would like to determine the distribution of this disease. From ELISA testing done previously, we know it does exist on sycamore in the southern and central sections of the state.

For specific disease control recommendations, see the Alabama Pest Management Handbook. Also remember that sanitation is a necessary component of most disease control programs.

Brief Disease Descriptions and Control Recommendations for Diseases Often seen in August
PlantDiseaseDescription Control
AJUGA Sclerotium rolfsii Crown Rot Stems collapse at soil line; a white mold with brown mustard-seed sized sclerotia present. Sanitation; Solarization.
ARBOR-VITAE Phytophthora Root Rot Roots show a wet, brown decay Sanitation. See AL Pest Management Handbook.
AUCUBA Botryosphaeria Canker (Blotch) Black, large, irregular lesions on leaves and stems; dieback beyond cankers. Sanitation; Cleary's 3336, Domain, or benomyl labelled for ornamentals.
AUCUBA Helminthosporium Leaf Spot Brown, elongate leaf lesion. Sanitation. Cleary's 3336.
AZALEA Phytophthora
Crown/Root Rot
Crowns/roots become brown and wet or water-soaked. See the Ala. Pest Management Handbook.
BAHIA GRASS Dollar Spot White spots/ lesions on leaf blades; whole sections of turf -beginning with dollar spot size areas may become blighted. A problem during dry periods. Frequent cutting.
BEGONIA Pythium Root Rot-Rhizoctonia/Fusarium Lower Stem/Root Rot Lower stem brown and decayed. See the Ala. Pest Management Handbook.
BEGONIA Ring Nematode
(Criconemoides)
Areas of turf yellow and die. Avoid stressful situations. Commercial turf areas may apply treatment.
BOXWOOD Phytophthora Root Rot Roots are cream-colored; outer cortex slips readily away from the central core. Sanitation. Improve water relations. See AL Pest Management Handbook.
BOXWOOD Pythium Feeder Root Rot Roots are cream-colored; outer cortex slips readily away from the central core. Sanitation. Improve water relations. See AL Pest Management Handbook.
CHRYSANTHEMUM Bacterial Leaf Spot
(Pseudomonas)
Dark brown/black, small (2-4 mm diam.), angular spots; sometimes with water-soaked edges. Sanitation.
CHRYSANTHEMUM Botrytis Blight Brown spots, blotches. See Ala. Pest Management Handbook.
CHRYSANTHEMUM Fusarium Wilt Yellowing/wilt of leaves, beginning at the bottom of the plant and moving upward. Sanitation; rotation for 7-10 years or solarization.
CHRYSANTHEMUM Pythium Root Rot Roots become brown and water-soaked. Sanitation; protective fungicide drenches of Captan, Subdue, or Banol; solarization or crop rotation.
COLEUS Phytophthora Crown Rot Roots become brown & water-soaked. Sanitation.
CRABAPPLE Scab (Venturia) Olive-brown circular, slightly raised spots (4-5 mm diam.) develop on leaves and fruit. See Ala. Pest Management Handbook.
DAISY, GERBERA Phytophthora Leaf Blight/Crown Rot Leaves develop brown blotches; lower stem develop brown lesions; plants collapse. See the Ala. Pest Management Handbook.
DAYLILY Southern Blight
(Sclerotium rolfsii)
A wet rot at soil line; sometimes a white fluffy mat of fungus at soil line. Sanitation; solarization.
DOGWOOD Cercospora Leaf Spot Leaf spot on lower leaves of tree; angular to irregular leaf spots (2-6 mm) which are light brown or gray in the center and dark brown or purple on borders. Sanitation.
DOGWOOD Powdery Mildew
(Phyllactinia)
Powdery white dusting on leaves; foliage distortion and death. Sanitation in the fall; See Al. Pest Management Handbook.
DOGWOOD Septoria Leaf Spot Leaf spots on lower leaves of tree; angular to irregular tan or brown spots (2-6 mm) sometimes with faint yellow halos. Sanitation.
DOGWOOD Spot Anthracnose
(Elsinoe)
Tiny red spots on flowers, leaves. Sanitation in fall; See Al. Pest Management Handbook.
EUONYMUS Anthracnose
(Colletotrichum)
Small, whitish spots (1/16 in. diam.) on foliage. Recommend fungicide sprays. See Ala. Pest Management Hand-book.
FATSIA Phytophthora Root Rot Roots become brown, water-soaked, decayed; outer cortex slips easily away from the central core of the root. Sanitation; improve moisture levels in the soil.
FERN Rhizoctonia Root Rot Dark brown, dried, decayed roots. Sanitation; See Ala. Pest Management Handbook.
FORSYTHIA Anthracnose Brown, leaf spots/ blotches. Sanitation. See Ala. Pest Management Handbook.
Gomphrena glabosa Fusarium Crown Rot Brown, dried, decayed lower stem. Sanitation; Crop rotation.
HOLLY, JAPANESE Phytophthora Root Rot Roots become brown and water-soaked; plants become yellowed with dieback. See the Ala. Pest Management Handbook.
HOSTA Impatiens Necrotic Spot Virus Yellow ring spots on leaves; plants become stunted. Sanitation. Control thrips.
HOSTA White Mold
(Sclerotium rolfsii)
Lower trunk or stem is rotted and generally soft and limp. Sanitation; possibly solarization.
HYDRANGEA Cercospora Leaf Spot Brown, circular or angular leaf spots. Sanitation. See Ala. Pest Management Handbook.
HYDRANGEA Powdery Mildew White powdery dusting on leaf & stem surfaces. Sanitation. See AL Pest Management Handbook.
HYDRANGEA Pythium Crown/Root Rot Wet, water-soaked brown lesions on crowns and roots. See the Ala. Pest Management Hand-book.
IMPATIENS Phytophthora Root Rot Wet, water-soaked brown lesions on roots. See the Ala. Pest Management Handbook.
IMPATIENS Rhizoctonia Crown and Root Rot Crowns and roots become brown and dry rotted. Sanitation; solarization may help.
IVY, ENGLISH Anthracnose Irregular or circular dark brown or black leaf spots. Sanitation; See AL Pest Management Handbook.
IVY, ENGLISH Bacterial Leaf Spot Dark brown-black angular leaf spots. Sanitation. Do not water over-head. See AL Pest Management Handbook.
IVY, ENGLISH Colletotrichum Leaf Spot Brown leaf spots that are circular or irregular. See the Ala. Pest Management Handbook.
IVY, ENGLISH Phomopsis Canker Brown, gray lesions on stems; dieback. Sanitation; Cleary's or benomyl protective sprays.
IVY, ENGLISH Phytophthora Root Rot Roots become brown and water-soaked. See the Ala. Pest Management Hand-book.
JUNIPER Pestalotiopsis Needle Blight Needles turn brown in patchy areas on branches. Sanitation; see Ala. Pest Management Handbook; avoid stress.
JUNIPER Phytophthora Root Rot See Holly, Japanese. See Holly, Japanese.
MAPLE Anthracnose
(Kabatiella)
Small-large brown blotches develop on leaves, often following along veins +/or leaf edges. See the Ala. Pest Management Handbook.
MAPLE Phyllosticta Leaf Spot Small (4-8 mm diam.) leaf spots develop with brown-purple borders and brown-cream centers. See the Ala. Pest Management Handbook, under 'Leaf Spot'.
MAPLE, SUGAR Monastichella
hysterioidea
Leaf Spot
Brown irregular spots. Sanitation.
MARIGOLD Alternaria Leaf Spot Black irregular spots 0.5-2 mm diameter. When spots numerous, plant death may result. See Ala. Pest Management Handbook, under 'Leaf Spot'.
MONDOGRASS Anthracnose
(Colletotrichum)
Gray, brown spots on leaves. Sanitation; See Ala. Pest Management Handbook.
OAK Anthracnose
(Apiognomonia)
Small to large brown blotches develop on leaves, often following along veins +/or leaf edges. See the Ala. Pest Management Handbook.
OAK Bacterial Scorch Disease
(Xylella)
Leaf edge turn brown in scattered locations in tree; gradual dieback over 2-3 years. Remove tree.
OAK Oak Leaf Blister
(Taphrina)
Light brown leaf spots that are circular and concave-convex. Sanitation; See Ala. Pest Management Handbook.
PANSY Pythium Root Rot Roots become brown and water-soaked; plants become yellowed and finally die. See the Ala. Pest Management Handbook.
PERIWINKLE Anthracnose
(Colletotrichum)
Brown, sunken cankers on stem sections. Sanitation; Cleary's 3336, Domain, or a benomyl WP labelled for ornamentals.
PERIWINKLE Phytophthora Aerial
Blight
Dark brown lesions appear on stems; dieback. Sanitation; Aliette.
PERIWINKLE Phytophthora Root Rot Roots become dark brown decayed and water-soaked; foliage shows yellowing/ dieback. Sanitation; solarization.
PERIWINKLE Rhizoctonia Aerial
Blight
Lower stems and leaves become browned and dry-rotted. Some mycelial webbing may occur. Whole plants will eventually die. Sanitation. Protective sprays of Cleary's 3336, Domain, or a benomyl WP labelled for ornamentals.
PERIWINKLE Rhizoctonia/Fusarium
Crown Root Rot
Dried, brown lesions on lower stem and roots. Cleary's drenches will help provide some protection.
PETUNIA Phytophthora &
Pythium Root Rot
Roots brown and water-soaked, rotted. Sanitation. See AL Pest Management Handbook.
PINE, VIRGINIA Fusarium Pitch Canker Sunken lesions that ooze sap. Sanitation.
PINE, VIRGINIA Lophodermium
(Ploioderma) Needle
Cast
Last year's needles become spotted and browned; eventually they drop. Needles have tiny football-shaped, hard black bodies scattered over their surfaces. See the Ala. Pest Management Handbook.
PINE, VIRGINIA Rhizosphaeria Needle,
Twig Blight (Suspect
Stress Related)
Needles and twigs become brown and dead. Apply Bravo 720 at rate of 5½ pints per 100 gallons or Bravo 500 at 8 pts. per 100 gallons after shearing when growth is ½ inch and again when new growth is 2 inches long.
POINSETTIA Bacterial Stem Rot
(Erwinia)
Lower stem becomes blackened and rotted; usually occurs on small plants. Sanitation.
POINSETTIA Fusarium Root Rot Roots become dry and decayed. Symptoms may be confused with Rhizoctonia. Sanitation; Cleary's 3336 protective sprays/drench.
POINSETTIA Pythium Root Rot Roots water-soaked, decayed. Sanitation; protective drenches fungicide; See Ala. Pest Management Handbook.
POPLAR Alternaria Leaf Spot Brown, irregular spots (8-15 mm diam.) develop on leaves. Sanitation. Chemical treatment not usually recommended.
RED CEDAR Phomopsis Blight Tips of branches become brown with damage spreading into the lower sections of the branches. See the Ala. Pest Management Handbook.
ROSE Aerial Blight
(Rhizoctonia)
Brown, irregular blotches on leaves. Sanitation; Cleary's 3336 would give protective control.
ROSEMARY Fusarium & Pythium
Root Rot
Dried, decayed roots. Sanitation; avoid environmental stresses.
SYCAMORE Anthracnose (Discula) Brown irregular blotches develop along leaf veins and/or along leaf edges. Defoliation may follow. See the Ala. Pest Management Handbook.
SYCAMORE Scorch (Xylella) Leaf edges become browned. Foliage dies but usually remains on the tree. The following year leaves may be smaller than normal, some die-back may occur. Edge browning occurs mid-late summer. Remove diseased trees.
VINCA MINOR Alternaria Leaf Spot Dark brown angular leaf spots; leaf blight. Sanitation; Chipco 26019.
VINCA MINOR Rhizoctonia Aerial
Blight
Leaves or stems become blighted, spotted. Sanitation; Cleary's or benomyl protective treatments.
WEEPING WILLOW Crown Gall
(Agrobacterium
tumefaciens
)
Rounded, woody gall on lower trunk and possibly large roots. Sanitation; solari-zation. Root zone soil replacement; control soil insects.
WISTERIA Phomopsis Stem Blight Dieback and brown, dried sunken lesions. Sanitation; Cleary's 3336.

Please remember to advise clients that August through September is typically the best time to sample for soil nematode analysis. The charge for soil nematode analysis is $10 per sample.


UPCOMING EVENTS

Setember 15-16, 2000:
Alabama Christmas Tree Association annual meeting
Sheraton Four Points Hotel, Tuscaloosa, Alabama
Contact Ken Tilt for more information: 334-844-5484; ktilt@acesag.auburn.edu

September 15-16, 2000:
TNA's "Tennessee America's Nursery" Trade Show and Conference.
Opryland Hotel Convention Center, Nashville, TN. Contact TNA at 931-473-3971; fax 931-473-5883; e-mail tnurseryassn@blomand.net

October 1-4, 2000:
Eastern Region International Plant Propagators' Society Annual Meeting.
Hyatt Regency Oak Brook, Chicago, IL. Contact Margot Bridgen, 26 Woodland Road, Storrs, CT 06268; phone 860-429-6818; e-mail mbippser@neca.com

October 6-7, 2000:
Middle Tennessee Nursery Association Horticultural Trade Show.
McMinnville Civic Center, McMinnville, TN
931-668-9601; email: mtna@blomand.net
www.mtna.com or www.tnnursery.com/mtna

October 8-11, 2000:
Southern Region International Plant Propagators' Society.
Holiday Inn Chesapeake, Chesapeake, VA. 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 1-3, 2000:
21st Annual Alabama Fruit and Vegetable Growers Association Conference.
Gulf State Park Resort Hotel, Gulf Shores, Alabama
For more information contact Joe Kemble - 334-844-3050 or jkemble@acesag.auburn.edu

January 27-31, 2001:
Southern Region American Society for Horticultural Science Annual Convention.
Fort Worth, TX. Contact Paul Smeal at 1107 Kentwood Drive, Blacksburg, VA 24060-5656, 540-552-4085; fax 540-953-0805, e-mail psmeal@vt.edu

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

January 27 - January 31, 2001:
Southern Region American Society for Horticultural Science Annual Convention.
Fort Worth, TX. Contact Paul Smeal, 1107 Kentwood Drive, Blacksburg, VA 24065-5656; phone 540-552-4085; fax 540-953-0805; e-mail: psmeal@vt.edu

August 2-5, 2001:
Southern Nursery Association Resarcher's Conference and Trade Show.
Georgia World Congress Center, Atlanta, GA. Contact SNA at 770-973-9026; SNA Infoline: 770-973-9026; SNA Infoline: 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 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

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.