Welcome to April! It has continued to be a beautiful Spring. I can not imagine people with any inclination toward gardening not being inspired by our products and services this year. Not only are gardeners inspired, but people in struggling traditional agriculture crops are looking for new opportunities. New requests for beginning nursery information continues to come in to our office. Liners also continue to be extremely short and could offer opportunities to Alabama nurseries. With the starting of new nurseries comes questions about irrigation. We are targeting some of our research efforts at this area, trying to find more controlled ways to apply irrigation more efficiently and effectively. Below is an article I submitted to the Alabama Nurserymen's Association summarizing some of our findings. Continue to enjoy your spring. Let us hear from you. As always, we welcome your comments and questions.
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.
Featuring the following articles:
SMALL STEPS TO IMPROVING YOUR IRRIGATION SYSTEM, REDUCING LABOR AND INCREASING YOUR BOTTOM LINE
PLANT GROWTH REGULATORS AND FOUR BEDDING PLANT SPECIES
HELPFUL HINTS FOR SUCCESSFUL LANDSCAPES
SOUTHERN FOREST NURSERY ASSOCIATION CONFERENCE 2000
WAVE PETUNIAS NAMED MS MEDALLION WINNERS
SPRING PEST UPDATE
MID SOUTH GREENHOUSE GROWERS CONFERENCE
USEFUL WEB SITE ABOUT FLOREL
PLANT PATHOLOGY REPORT
SMALL STEPS TO IMPROVING YOUR IRRIGATION SYSTEM, REDUCING LABOR AND INCREASING YOUR BOTTOM LINE
Dr. Ken Tilt
Irrigation is one of our most critical cultural practices in the production of nursery crops and yet it is one that we offer the least attention at most nurseries and in our research. A good thing about the water/plant relationship is that plants have evolved to tolerate extremes in water availability to account for nature's fickle schedule of irrigation. However, in the nursery BUSINESS, we do not strive just to keep plants alive. Our goal is to produce quality plants in the shortest time possible, using the minimum space and impact on the environment while reducing costs with efficient and effective use of our other resources. While a large segment of our industry is still made up of small family farms and plant lovers, a common comment often heard is that "the plants I like the most at my nursery are the ones that are going on the back of a truck and heading out to my customers". It is a business and the objective is not to keep plants around the nursery any longer than necessary. Competition and our production, business and marketing knowledge has increased over the years. We do not keep plants "past their time". One area we can improve on to shorten a plant's time on our nurseries is to improve our irrigation practices.
We have added some automation aids over the years, primarily to reduce labor. We are beginning to see some small advances in improving our irrigation practices as a result of environmental pressures and the great motivator, "MONEY"! There is a number of hardware and software irrigation factors we can adjust, improve and maintain to increase plant growth. The design of our nursery, the media we use and the container designs can also improve our irrigation efficiency and effectiveness.
Irrigation hardware includes items that get the quality (pre-tested) water from the water source to the plants. Pumps, filters, pipes, backflow devices, emitters and pressure compensators fall into this category. A professional should design hardware so that a uniform volume of clean water reaches each plant. If you do not treat all plants within a group the same, how can you get uniformity of growth or diagnose problems when they go wrong? We are not just watering plants to keep them alive, we are trying to use irrigation management to get maximum growth. Hardware needs to be maintained and tested frequently for uniformity. Replacement parts should be parts designed for the system and not ones that just fit.
Irrigation software involves the mechanisms and equipment involved for scheduling and applying the appropriate volumes of water to meet the demands of the plants. This can be as simple as sticking your finger in the substrate to feel the wetness (our manual sensor) or using irrometers to electronically quantify the moisture in the soil or how fast the plant is using it. This is the area where our research is moving.
We began thinking complete automation by running wires all over the nursery with irrometers in a number of pots to measure the water loss to the atmosphere and the plant and try to replace that water each day and replace it with minimal leaching. The irrometers were not very accurate, so we cooperated with our electrical engineers to write a complicated fuzzy logic computer program so the computer could monitor and "learn" the variability of the instrument and make corrections. We grew a crop of plants in the greenhouse to test the technology and it did great except you needed 100 wires and your own electrical engineer to make adjustments to the program. It can be done and I am sure it will be in the future but it is a big jump from the greenhouse and 40 plants to a nursery of millions of plants of different species, sizes, and highly variable water requirements even within the same species and container size.
Our plan of attack now is to just do a better job than we are currently doing and take practical, economically feasible baby steps to improved irrigation application and efficiency. This involves combining current technology to partially automate irrigation and make the same normal, manual adjustments to environmental conditions that you would do if you had the time to stand by the tap all day and turn it on and off. We can use timers, light, rain, wind, evaporation, relative humidity Class A evaporation pans and temperature sensors. We can also adjust the substrate and container design so that it will hold more water while still maintaining a balance of air space. We know that as light, temperature and wind increase, plants will demand more water and conversely as these factors decrease and relative humidity goes up or it rains, we must reduce our irrigation to adjust for the plants lower water needs. That is simple. The problem is time and having experienced, knowledgeable people to be monitoring and adjusting for all these factors, complicated by the large number of species and sizes of plants. We need to use our experience to calibrate the electronic aids so that they can be monitoring the environment night and day and taking our place at the on/off switch.
The first thing to adjust is the substrate and water reserve. By adding 10 to 25 percent of peat moss or coir, we can increase the amount of water held in reserve, the easily available water, and reduce the frequency of watering. Research conducted at Auburn University on red maples in 15 gallon pot-in-pot production using media combinations of 4:1 pinebark:peat and pinebark:coir and 100% pinebark resulted in a 17% and 12% increase in height in the pinebark and peat over the other two media, respectively. We thought that we could adjust the water to compensate for the lower water holding capacity of the 100% pinebark mix. But, we found that the peat or coir added more available water and possibly greater nutrient holding capacity to generate more growth with the species we tested. Other research at Auburn has also found potential increase in growth by raising container holes and reducing them in size to limit leaching and increase the water reserve. A side benefit is the control of rooting out in pot-in-pot production, which Dr. Patricia Knight at Mississippi State University has investigated. We are doing follow up research on these factors to verify and fine tune the results that will hopefully continue to be positive.
Changing the volume applied and the frequency of application can also increase available water, reduce fertilizer loss and runoff from the nursery. This cultural practice is termed cyclic irrigation. The normal water volume you apply at one application is divided into equal amounts and applied 3, 6, or more times a day. Research has shown that this technique will give equal or increased growth with the added benefit of reduced runoff. This practice has proven effective in many research projects and is worthy of trying at your nursery.
Glenn Fain grew red maples in 15 gallon pot-in-pot containers under 1,3 and 6 cycle irrigation treatments at Auburn University. Red maples had a 23% and 17% increase in dry weight while receiving the same total volume of water in 3 cycles and 6 cycles, respectively, over dry weight production of trees under a single application of water. Total nitrogen leached per pot was reduced by 99% in the 6 cycle treatment over the 1 cycle treatment with an obvious increase of nitrogen in the containers receiving 6 cycles. More available nitrogen (within safe limits) yields greater growth. Rob Trawick, who just completed his research at Auburn, reported similar increased growth with cyclic irrigation on white cedar and Arizona cypress in 3 and 7 gallon containers, respectively. The volume of irrigation applied in this research was 0.59 gallons per 3 gallon container daily (unless interrupted by 1/2 inch of rain) from April to mid June. The volume increased to 0.81 gallons until mid-July and peaked at 1.0 gallon per pot from July until mid September. The 7 gallon Arizona cypress received a total application water volume during each of the above intervals of 0.63, 1.0, and 1.03 gallons at each application. Volume of water applied is based on replacing moisture loss during the day and is explained below.
Future research will look at applying the irrigation at different times of the day with varying volumes to adjust for the different water demands as you go through the day. You can calculate the approximate water to add each day by watering the plants on a bright, hot day, allow for drainage to stop, then weigh the container to determine the weight at the maximum water holding capacity or "container capacity". At the same time the next day, weigh the plants again. Container capacity weight minus the weight the next day in grams equals the daily water loss in milliliters. Use this as an estimate on the total volume of water to apply each day. This is basing your water needs on the extreme case of clear days and high temperatures. This volume could be adjusted with data coming from temperature, light, wind and relative humidity sensors. Applying water in smaller increments or using cyclic irrigation, you increase the volume of water held in the container and fertilizers are not leached. The other adjustment method is to use cyclic irrigation and monitor the amount of leaching after irrigating. You would like to minimize the total leachate to less than 15 to 20% of the total water applied. Some of the cycles in the heat of the day may not have any leaching.
If you are going to consider cyclic irrigation (and all the research points to positive results), you will need a controller or a computerized monitoring system. Controllers and timers are less expensive ranging from $200 to over $2000. There are many different irrigation jobs that you manage on the nursery including propagation and monitoring various sized containers and species of plants with inherent variability among and between species. They are also at varying stages of growth. The flexibility of a computer system may be the economic and sound business choice to manage it all. Computer irrigation management systems range from $5000 to $10,000 or more, obviously depending on the size of nursery. Two companies that offer this equipment are Q-COM in Santa Ana, California (949-837-8418) and World Wide Water, Inc., Apex, NC. (919 362-4200). These management systems allow you to take a big step towards controlling and monitoring your irrigation. It is a big capital expenditure but no more costly than many media mixers or other equipment used on the nursery and equally or more important than these other cultural practices.
The next step is to begin to monitor the amount of water applied and keep records for future scheduling. As water restrictions continue to tighten, you will be required to measure your water use. Flow meters are added to the system to help you monitor and adjust duration and volume of irrigation. A Mini Clik or an Electronic Rain Gauge ($100) can be added to turn off the water when a critical amount of rain falls on the plants. This certainly makes sense to add one of these devices rather than irrigating automatically during a blinding rain storm or running back and forth to the valve to manually shut off the irrigation and reschedule. With an irrigation management system, if you received 1/4 inch of rain, simple commands could be added to skip one or two cycles of irrigation that day. This same flexibility can be applied for temperature, light and relative humidity sensors. Our current research is evaluating the value of these sensors, individually and in concert to determine an economic, practical system to partially automate your irrigation while increasing growth or at least reducing labor and runoff into groundwater systems. The system does not replace you but it sure saves miles of running each week and a few premature gray hairs from worrying about if plants got irrigated and if it was too much or too little. You train your electronic eyes and finger in the field to keep data of what is going on and to alert you if things are not going as you instructed. (If we can adapt this technology to attach to our kids, we will be clicking glasses with Bill Gates.) A deviation in the flow to the containers at a set percentage, too much or too little, signals the computer to sound the alarm or call one or several people to let them know a problem exists or it can call every day at a specified time to let you know all stations were irrigated. So, this is not a system just for the large nurseries. It also offers peace of mind and a free day or possibly two away from the nursery for the small nursery manager.
We can do better than what we are doing and make it profitable to take the small steps to improve. There will be a learning curve in the beginning to fine tune your electronic finger and eyes to manage the irrigation, but after you get your system up and running you will find you will have much more freedom, peace of mind, and reach the ultimate objective of uniform quality plants heading out the nursery gate. Many universities in nursery states are working on these irrigation opportunities. Stay alert as new information develops for improving your irrigation effectiveness and begin to take small steps to improve your irrigation management.
GROWTH REGULATORS AND FOUR BEDDING PLANT SPECIES
The use of plant growth regulators is important in the nursery industry. What is problematic is that different plants require different plant growth regulators (PGRs) in varying amounts. Growing zones also impact dramatically on the amount of chemicals required.
A study was recently done to determine required amounts of PGRs on four different bedding species (Salvia Vista Red, Marigold Tangerine Safari, Zinnia Short Stuff, and Vinca Cooler Strawberry). Flowers were planted in four-inch pots in Florida. Sprays were applied at 2 quarts per 100 square feet. (Note that in the northwest or New England the rate would be 1/4 that required in the south).
If chemicals are not applied exactly right there can be over-stunting. Bonzi and Sumagic are problematic in this regard. B-Nine is less difficult to use and potentially less toxic but more applications are required.
Following are reported results: SALVIA: Growers have height-control problems. B-Nine alone is not active enough; for significant control relatively high rates of Bonzi are needed. Sumagic at 5 ppm rate and the 60-ppm rate of Bonzi had about the same effect. The best options probably are Sumagic or a tank mix of B-Nine and Bonzi.
MARIGOLD: Relatively high rates of Bonzi are needed. Greatest control options are Sumagic at a higher-than-average rate, and the B-Nine/Cycocel tank mix.
ZINNIA: Zinnia Short Stuff does not require much size reduction as it is a rather compact plant. Bonzi and Sumagic at higher rates produced very good plants. For more control, B-Nine and the tank mix might be better.
VINCA: To control the height of vinca, Bonzi works but often causes leaf spotting. Sumagic is effective without the spotting. Use Bonzi and Sumagic with great care, though, as there is a very small margin of error. B-Nine/Cycocel tank mix is an effective and safe option on vinca. Another effective PGR on vinca and pansy is A-Rest at rates of 5-10 ppm applied once or twice as needed - provides good control with less risk of too much stunting and possible leaf damage.
(from an article by Jim Barrett, published in GPN, March 2000).
HELPFUL HINTS FOR SUCCESSFUL LANDSCAPES
by Ken Tilt, Auburn University
- Always think Site, Design, Installation and Maintenance (Interrelated)
- Study residential landscapes for ideas and read books on the subject
- Evaluate the site. Inventory your assets and liabilities. Existing features can become valuable assets (frame your views and screen your eyesores)
- Plan on paper before breaking ground. At least do some rough sketches.
- Think of landscaping as an extension of the building and creating functional outdoor living spaces or rooms.
- Function first, then select appropriate medium to serve the function. Draw rooms or areas and determine flow through the landscape. Landscaping is primarily moving the eye through the area, hopefully providing some pleasure along the way
- Good bed lines are essential for a pleasing landscape (leads the eye and define areas, should be strong and flowing)
- Using line, color and texture, repeat design elements and plant material to get continuity and comfort. Coarse to fine texture = distant plus tapered bed line to heighten effect. Warm colors (red, orange, yellow) excite; blue, green for calming effect.
- Balance evergreens (for consistency, structure and richness of color) with deciduous plants which typically have more seasonal appeal.
- Introduce variety for interest.
- Think maintenance. (Group plants with similar requirements, use right plant for site and use low maintenance plants, use large beds, proper plant spacing and size variation)
- Make the landscape user friendly. (Walks and paths with plenty of room. No dead ends unless for effect, change texture of paving to direct)
- Night lighting for the crowning touch
- If you don't enjoy it or have little talent for it, hire a professional designer - usually 5% or less of the cost of installation.
SOUTHERN FOREST NURSERY ASSOCIATION CONFERENCE 2000
There is another nursery program that operates almost entirely independently from the horticulture industry. It is the Forest Nurseries industry. Their research and the way they produce plants have developed separate from us. I think we can learn a great deal from the way they do things and also share some things from our side. I noticed that they have a program scheduled for June 26th through 29th in Mobile. I am putting it on my schedule. Take a look at the program below and see if it offers anything for your business.
"Growing Green in the New Millenium" is the title of the Southern Forest Nursery Association Conference 2000 which will take place at the Adams Mark Hotel in Mobile. Following are some of the presentation topics:
- Food Quality Protection Act
- Ir-4 listing of Herbicides
- Software Applications for Nurseries
- Chloropicrin, eptam and PGPR for Managing Soilborne Pests in Pine Nurseries
- Seedling Production and Pests
- Fungi Associated with Containers
- Container vs. Beds
- Current Seed Research
- Nursery/Silviculture Interactions
- Rhizopogon/Mycorhizal Uses
- Clonal Propagation
- Hardwood Center at Purdue
- Longleaf Alliance Trends
There will also be a nursery field trip as well as a banquet on the Cotton Blossom Riverboat. Registration by June 1 is $185.00 (after that, $210.00). For more information phone 334-898-7013, fax: 334-898-1149, or e-mail: GenevaSF@forestry.state.al.us
We are grateful for the work that is done by Extension Horticulturists at Louisiana State University. The three articles that follow are from Norman Winter, Ron Strahan, and Dale Pollet. Thank you also is extended to Allen Owings who puts it all together in the Ornamental Horticulture and Turfgrass E-Mail Update from the LSU AgCenter
WAVE PETUNIAS NAMED MS MEDALLION WINNERS
(by Norman Winter, MSU Extension Horticulturist)
The first flower to have its own web site has garnered another honor, the 2000 Mississippi Medallion Award. This prestigious honor goes to the Wave series of petunias, whose web site can be found at http://www.wave-rave.com. The Mississippi Medallion program has become known statewide for bringing the toughest, most beautiful plants to Mississippi gardeners. The first Mississippi Medallion winner in 1996 was New Gold lantana which is still one of the most loved plants by gardeners and landscapers alike. Last year's winner, Biloxi Blue verbena, was so popular it sold out quickly and has already been in big demand this year. 2000 is geared to be another stellar year for the Mississippi Medallion program with the Wave petunias.
The Wave series began in 1995 with the debut of Purple Wave. This petunia has become the standard for which all other petunias are judged. It is a ground hugging, heat tolerant selection that will spread up to 4 feet. The Pink Wave was next in the series and is equally impressive. It has a slightly more upright and compact habit. It has shown remarkable heat tolerance and landscape performance. Last year, the two new selections that hit the marketplace were Rose Wave and Misty Lilac Wave. Misty Lilac spreads like Purple Wave but is slightly more upright in growth habit. Rose Wave is similar to Pink Wave in habit and has been perhaps the heaviest bloomer. Purple Wave and Misty Lilac Wave combine for one of the prettiest landscape combinations available to today's hurried gardener. Purple Wave and the 1996 Mississippi Medallion Award winning New Gold Lantana, or the 1997 winner Melampodium create an exceptional bed of complementary colors.
Not only are the Wave petunias winners in the landscape, but they excel in baskets, mixed containers and window boxes for a long season of color around the porch, patio or pool. Choose a site in full sunlight for best performance. Prepare your beds by incorporating 3 to 4 inches of organic matter and fertilizer at the rate of 2 pounds per 100 square feet. I prefer a slow release blend such as 12-6-6 with minor nutrients. You also can use an 8-8-8, 13-13-13 or something similar, but do use a slow release form of nitrogen. Till the organic matter and fertilizer to a depth of 8 to 10 inches. Plant at the same depth the flowers are growing in the container and remember to space accordingly for the Wave you are buying. Mass plant several to give the best landscape look. Add a good layer of mulch to keep out weeds, moderate soil temperatures and prevent moisture loss through evaporation. Feed your Waves every four weeks by side dressing with light applications of the fertilizer.
Don't be afraid to give the petunias a light trimming or shearing to stimulate new growth and blooms well into the fall. The selections and quality are greatest now and Waves are available at a super value in sizes ranging from large baskets to 4- and 6-inch containers. So get the beds prepared and shop early. More Mississippi Medallion winners will be announced in different categories over the next few weeks, so pay attention to your TV, radio and newspaper. The Mississippi Medallion program is sponsored by the Mississippi Nursery and Landscape Association, Mississippi Plant Selections Committee, Mississippi State University Extension Service and the Mississippi Agricultural and Forestry Experiment Station.
(Ron Strahan, LSU AgCenter Extension Associate)
Torpedograss is a perennial that spreads by rhizomes. Seeds that are produced are not considered to be viable. What this means is that every time the yard is mowed or the weed is hoed the homeowner is probably spreading the weed with the clippings or stem fragments. Once it is in the lawn it is very difficult to remove. Here are some things that can be done with torpedo in certain situations: Remember: Vantage/Poast or Fusilade kills only grasses (safe on broadleaf crops or shrubs). In a vegetable garden in broadleaf vegetables only: Poast [same as Vantage (sethoxydim)] or Fusilade II (fluazifop). Use a surfactant. It will still probably take 2 or more applications. Fusilade is more effective than Poast on perennial grasses.
In a flower bed:
Vantage or Fusilade - again I like Fusilade much better than Vantage/Poast.
In a lawn:
Bermudagrass only - MSMA will not work on this weed. About all you get is some temporary burning. BASF has released a new herbicide, Drive (quinclorac) that can be used for controlling torpedograss in bermudagrass turf only. It does a good job on torpedo and also controls a lot of other broadleaf weeds plus it is very effective on annual grasses both pre and postemergence (barnyardgrass, broadleaf signal grass, crabgrass). It can be used on golf course fairways and roughs (not on greens) plus home lawns that have bermudagrass. The rate is 1 lb product followed by 1 lb in about 20 or more gallons per acre of water. Be careful of spraying near plants that are in the tomato/pepper family. These plants are extremely sensitive to Drive. By the way, Drive is actually the same herbicide as Facet, which is used in rice.
Centipede: Vantage is the only herbicide that you can use for grass control in centipede. It may take 2 or 3 applications. You will only be moderately satisfied with the control you get from this one. It will not be a one shot thing.
St. Augustine: You are out of luck. St Augustine makes a beautiful yard but once you have weed control problems there are very few things that you can do about it. About all you can do with torpedograss is spot spray with Roundup at about 4 oz/gallon of water. You will end up with a lot of dead areas that can be resprigged or sodded in a couple of weeks.
Roundup: It can look great sometimes and sometimes you end up with regrowth. It will probably take two applications any way you look at it. If you have torpedograss creeping into flower beds I recommend Fusilade. It just works better and you will not kill flowers. Just be careful not to get it on your lawn.
SPRING PEST UPDATE
(by Dale Pollet, LSU AgCenter Extension Entomologist)
There seems to be a plethora of insects making a nuisance of themselves at this time.
These aggravating little pests are feeding very heavily in flowers of all kinds now. They were very bad in blueberries and other fruits. Hopefully the rain will help them disperse to the normal grasses and weeds. Malathion, diazinon, Orthene 75S, and dimethoate, depending on the commodity infested, are very good. They will cause scarring on fruit they feed on usually lowering the sale value. This is also true on citrus. Check flowers for infestations and treat when 15% of the blossoms have thrips.
They are back and with a vengeance. Populations are stripping the foliage on several ornamentals and trees. Dust these plants with Sevin or spray them late in the afternoon. Those who find heavy infestations in their yards should spray the yards with Sevin as well to kill the adults that are hiding in the grass and upper soil during the day. Check the turf for the immatures, this rain will cause a mass movement to the soil surface in preparation for pupation and adult emergence. Where sufficient larva are present use either Sevin or Mach 2 (IGR) . Be sure to water these materials into the soil. The biggest reason most people get no control is that the material is applied only to the soil surface and not watered into the soil structure where the pests reside. FOLLOW THE LABEL.
Usually we don't have this problem until late April or May but we are having an infestation of another species now, particularly in the western half of the state - large numbers for the past two weeks. Probably means we can expect 3 swarm seasons this year. That is this one and the 2 we normally have.
Crickets and Grasshoppers
Hopefully this rain will get the endemic fungi in the soil going and they can help to keep down the populations. Otherwise we could have an explosion of these two critters.
Spiders and Wasps
Several people have called about the high populations of spiders and wasps around their homes and offices. This is due to the white lights left on outside and the warm weather. It's part of the food chain: lights, bugs, spiders, wasps, geckos. By changing the light to an amber or yellow light you can reduce the bugs and therefore the others in reverse order.
Eastern and Forest Tent Caterpillars
These are also out and about eating foliage and scurrying about the yard. Unlike the buck moth caterpillar and its stinging associates they cause no harm except to the trees and shrubs infested. Bt's or Orthene, sevin or pyrethroids are effective in controlling these caterpillars.
Buck Moth Caterpillars
Enough said. Remember things like toothpaste, tobacco juice, meat tenderizer, baking soda and Clorox or ammonia will effectively reduce the stinging.
MID SOUTH GREENHOUSE GROWERS CONFERENCE
The Ramada Inn Southwest Conference Center in Jackson, MS, is the site of the 2000 Mid South Greenhouse Growers Conference on June 6-8. The program begins at 1:00 p.m. on June 6th and ends with lunch on June 8th. The registration fee is $65.00. For hotel reservations call the Ramada Inn at 601-944-1150 (conference rate is $62 per night).
USEFUL WEB SITE ABOUT FLOREL
For those growers who need help with a mistletoe remedy and something to get rid of sweet gum balls this site will tell you the rates and timing for the use or Florel. The URL is: http://www.montereylawngarden.com/info/florel.html
(from the Weekly NMPRO e-mail. The source is Ron Milbery, 301-734-5255).
PLANT PATHOLOGY REPORT
from Jackie Mullen, Extension Plant Pathologist, Auburn University
MONTHLY PLANT PROBLEM REPORT
Most of our February samples were landscape ornamentals and two-thirds of the problems were abiotic. Biotic diseases included the following: Cercospora leaf spot on azalea; Pestalotia leaf spot on azalea, usually as a secondary or weak pathogen; Botrytis blight and Pythium root rot on begonia; Kabatiella leaf spot on daylily; impatiens necrotic spot virus on New Guinea impatiens; Botrytis stem rot on New Guinea impatiens; Cercospora leaf spot and bacterial leaf spot on Indian hawthorn; Botrytis canker on marigold.
Impatiens necrotic virus was diagnosed on New Guinea impatiens. The sample initially showed symptoms of only Botrytis stem rot. After several days, black spots and blotches began to develop on the leaves. About 5-7 days after the initial spot-blight symptoms began, the small pants were dead. ELISA testing gave a very high color (positive) reaction for impatiens necrotic spot virus (INSV). This is a difficult disease to control in a greenhouse setting due to the thrips mode of transmission. Thrips must be controlled and eliminated from the area. Also, the virus may over-winter in weeds so weed control is very important. Many plants are susceptible to INSV. But rotation of the area to a non-host plant type is recommended.
Botrytis, gray mold, was observed on marigold, begonia, and New Guinea impatiens as a stem rot. When plants were placed into a humid environment, Botrytis sporulated into the light gray mold that is characteristic. Control of Botrytis usually involves sanitation and protective fungicide sprays. See the Alabama Pest Management Handbook.
Bacterial leaf spots (small, water-soaked, angular spots) were observed on Indian hawthorn. Ground level irrigation is recommended with bacterial foliage diseases. Use of bactericide sprays may help. See the Alabama Pest Management Handbook for labeled products.
Recently, we have been receiving numerous samples of landscape shrubs with dieback. These samples do not show any evidence of foliate disease. it is our belief that damage has resulted from root damage. At this time of year root damage usually relates to environment stress. Drought is a common cause of winter root damage, especially when winter months have been unusually warm. Pruning, watering and appropriate fertilization this spring is recommended. If root damage is not too severe, the plants should recover.
DISEASES SEEN IN THE PLANT DIAGNOSTIC LAB IN FEBRUARY 2000
PLANT DISEASE COUNTY Azalea Cercospora Leaf Spot Dale Azalea Pestalotia Leaf Spot (Secondary) Choctaw Begonia Botrytis Blight Lee Begonia Pythium Root Rot Lee Daylily Kabatiella Leaf Spot Mobile Impatiens, 'New Guinea' Botrytis Stem Rot * Impatiens, 'New Guinea' Impatiens Necrotic Spot Virus * Indian Hawthorn Bacterial Leaf Spot Baldwin Indian Hawthorn Cercospora Leaf Spot Baldwin Marigold Botrytis Canker *
*Locations are not reported for nursery and greenhouse samples.
DISEASE POSSIBILITIES FOR FEBRUARY
An unusually warm-weather winter has caused early bloom and spring development of many landscape and crop areas. Sporadic freezing night temperatures in February may have caused cold damage on some field and landscape plantings. With woody ornamentals, watch for bark splits and leaf edge browning to occur from the time of the cold injury to about 4-10 weeks thereafter. Bark splits are not always noticed, and branch dieback noted in April-May may be related to cold injury several weeks earlier.
The list below includes some common disease problems received in the lab during March and early April of the past few years. Comments on control practices are brief. Refer to the fact sheets, timely informations, 1999 spray guides and the Alabama Pest Management Handbook for details.
DISEASE DESCRIPTIONS AND BRIEF CONTROL COMMENTS
ON SOME COMMON DISEASES OFTEN SEEN IN FEBRUARY
PLANT DISEASE DESCRIPTION CONTROL AZALEA Botryosphaeria
Sunken cracked lesions on branches. Often this canker follows cold injury or some other type of wound. Stressed plants are often involved. Sanitation. AZALEA Botrytis Petal Blight Large irregular areas of blossoms turn brown; brown areas are covered with a gray delicate webbing during humid weather. See the Alabama Pest Management Handbook. AZALEA Cercospora Leaf Spot Roughly circular-angular brown-black spots (about 0.5 cm diam.); spots are usually associated with stressed plants. Sanitation of fallen leaves. Maintain proper fertility and watering schedules. Protective sprays of Cleary's 3336 may be applied. AZALEA Colletotrichum Leaf Spot Roughly circular brown-black leaf spots (about 0.5 cm diam.). Spots often associated with stressed plants. See Cersospora Leaf Spot. AZALEA Exobasidium Gall Blossoms and leaves develop green-pink-white fleshy galls. Sanitation; see Alabama Pest Management Handbook. AZALEA Ovulinia Petal Blight Small white-brown spots enlarge to become large browned areas on the blossoms. See the Alabama Pest Management Handbook. AZALEA Pestalotia Blight
Gray-white dried blotches on foliage, often along leaf edges. Sanitation. AZALEA Phytophthora Crown
& Root Rot
Crowns and roots become brown and water-soaked, then dried. Sanitation; see Alabama Pest Management Handbook. AZALEA Rhizoctonia Aerial
Medium-dark brown spots or blotches on lower leaves may involve 50-100% of leaf area. Dead leaves will fall. See Alabama Pest Management Handbook. BOXWOOD Macrophoma Blight-Stress During the winter, boxwood may change color and take on a reddish tint. These discolored plants sometimes develop a more serious yellowing and blight with tiny black dots scattered on yellowed leaves; cankers may develop. This is generally a problem of stressed plants. Pruning; proper maintenance. CAMELLIA Algal Leaf Spot
Green or green-red, slightly raised leaf spots with slightly wavy margins. Old spots have white centers. See the Alabama Pest Management Handbook. CAMELLIA Colletotrichum Leaf
Round, light brown, circular spots which may contain brown-white-orange specks that are the spore bodies. Sanitation. Cleary's 3336 protective sprays. CAMELLIA Ring Spot Virus Yellow or brown rings develop on leaves. Plants may be stunted. Maintain plants with proper fertilization and water schedules. CEDAR,
Cedar Apple Rust
Large (1-3 inch diameter), woody galls on stems develop orange, jelly-like projections (one or more inches long) which protrude from the entire surface of the gall. Remove galls before orange "fingers" develop. Apply protective fungicide sprays to apple and crabapple. See Alabama Pest Management Handbook. CHERRY LAUREL Bacterial Leaf Spot
Medium to dark-brown circular or slightly irregular spots develop. As spots age, they dry and eventually the whole spot may fall out. Small, faint halos present sometimes. Sanitation; basic copper sulfate may give protective control. See Alabama Pest Management Handbook. CHERRY LAUREL Cercospora Leaf Spot Irregular brown spots of variable size. Sanitation of leaves in the fall. CLEYERA Anthracnose (Colletotrichum) Reddish circular-irregularly shaped spots, blotches (about 5 mm diam.) scattered on leaves. Sanitation; Cleary's 3336 or Domain protective sprays. EUONYMUS Anthracnose
Brown circular-angular lesions on leaves. Sanitation; see Alabama Pest Management Handbook. GERANIUM Bacterial Blight
Black, angular, water-soaked spots on leaves and stems; wilt; dieback. Sanitation; see the Alabama Pest Management handbook. GERANIUM Pythium Stem &
Lower stems become black and rotted; roots also become brown or black and decayed. See the Alabama Pest Management Handbook. GREENHOUSE/
Bacterial Leaf Spot Small-large, irregular, dark, wet-looking spots which often become dry in their centers and may have yellow zones or borders at their outer edges. Sanitation. GREENHOUSE/
Botrytis Blight See Azalea. See Alabama Pest Management Handbook. Decrease humidity. GREENHOUSE/
Downy Mildews Diffuse yellow spots on upper leaf surfaces with corresponding areas on lower leaf surfaces showing darker color, often with tan-gray fungal growth. See Alabama Pest Management Handbook for specific controls. GREENHOUSE/
Roots become brown, decayed, water-soaked; the outer cortex easily pulls away from the inner tissues. Sanitation. Check soil water relations and fertilizer levels. Chemical control depends on plant type./td> HOSTA Pythium Crown Rot Brown, wet, water-soaked decay at lower stem near the soil line. Sanitation; improve soil drainage; rotate away from hosta; subdue 2E afer test treatment. INDIAN
Reddish spots with black centers. Sanitation. Protective fungicide sprays. IRIS, BEARDED Heterosporium
Brown, usually elliptical, sometimes large (1-2 cm) spots. Sanitation; protective sprays of Cleary's 3336. JUNIPER Cedar Apple Rust
Spherical woody galls develop on twigs and branches; with warm wet weather, orange, jelly-like projections or fingers extend from the galls. Sanitation. See the Alabama Pest Management Handbook. LEYLAND CYPRESS Phomopsis Twig Canker Sunken circular or elliptical brown lesions on twigs. Sanitation; protective spray of Cleary's 3336. LEYLAND CYPRESS Cercospora Blight Blight usually starts on lower inner needles. Pruning, sanitation; protective sprays of Cleary's 3336. LEYLAND CYPRESS Macrophoma,
Brown needles with tiny black specks that are the spore bodies of these fungi. Usually occurs on stressed or weakened plants. Sanitation. LEYLAND CYPRESS Macrophoma,
maybe Secondary or
Small, sunken, brown lesions on twigs and small stems; black specks of spore bodies present on lesion surfaces sometimes. Sanitation; protective spray of Cleary's 3336. LILAC Bacterial Leaf Spot Black, angular, water-soaked spots. Sanitation; see Alabama Pest Management Handbook. LILAC Pythium Root Rot Roots are off-color, decayed, water-soaked. Sanitation; improve soil drainage; crop rotation. MAGNOLIA Phyllosticta Leaf Spot Small-large (0.5-1 cm)light brown usually circular spots. See the Alabama Pest Management Handbook under 'Leaf Spot'. MONDOGRASS Anthracnose
Brown or reddish brown blotches on leaf blades. Often blotches are along leaf edges or tips. See the Alabama Pest Management Handbook. NANDINA,
Roots become water-soaked, brown and eventually dried. Foliage shows dieback, wilt, poor growth. Sanitation. PEAR, BRADFORD Fireblight (Erwinia) Black-colored dieback, blossom blight, twig-tips may have a shepherd's crook. Sanitation; see Alabama Pest Management Handbook. PERIWINKLE Pythium Root Rot Roots become brown and water-soaked. Sanitation; see Alabama Pest Management Handbook. PETUNIA Phytophthora
parasitica Crown Rot
Cankers and blight areas develop on foliage. Sanitation. Daconil, Echo, Thalonil, and Alietta are labeled. PETUNIA Pythium Root Rot See Periwinkle. See Periwinkle. PHLOX
Powdery Mildews Buff or white powdery patches on leaves and stems; some distortion of new growth. Sanitation; Cleary's 3336 may be used. PHLOX
Rhizoctonia Blight Lower leaves become brown blotched with whole leaves and stems sometimes affected. Sanitation; Cleary's 3336 may be used. PHOTINIA Armillaria Root Rot Decline of plant. Check the lower trunk or roots for a thin, white mycelial layer under the bark. Also look for honey-colored mushrooms. Sanitation of plant and roots. Crop rotation. See ANR-907. PHOTINIA Entomosporium Leaf Spot Dark red spots (usually 3-4 mm or 1/8 inch diam.) on upper and lower leaf surfaces. Spots often coalesce. Pruning. Fungicide treatment; see circular ANR-392 or Alabama Pest Management Handbook. PINE,
quercum f. sp.
Rusty, powdery coating appears on the surface of fusiform (elliptical-shaped) swellings on branches and trunks. (Near-by oaks will develop small black leaf spots in late spring). Sanitation in landscape settings; protective fungicide sprays available for nursery situations. See the Alabama Pest Management Handbook. PINE,
Cream-colored pustules (2-3 mm or 1/8 inch wide and high) develop along the edges of needles. ---. PINE
Rhizoctonia Root Rot Brown lesions, often shriveled, on roots. Sanitation. PINE,
Sunken, elliptical lesions on branches and trunks covered with pine resin. Sanitation. PINE,
Cream-colored pustules (2-3 mm or 1/8 inch wide and high) develop along the edges of needles. ---. PRIVET Cercospora Leaf Spot Large (1/4-1/2 inch diam.), medium brown circular or irregular spots. See Alabama Pest Management Handbook; sanitation. RED CEDAR Phomopsis Dieback Tips of twigs are brown. The dieback will extend further down the twig as time progresses; canker. Sanitation; see Alabama Pest Management Handbook. RHODODENDRON
Elongated, elliptical, sunken, brown cankers with margins that are often cracked. Sanitation. RHODODENDRON Cercospora Leaf Spot Brown spots (5-10 mm or 1/4-1/2 inch diam.) usually circular. Protective sprays of Cleary's 3336 or Domain. Sanitation. ROSE
Nectria Canker Sunken cane lesions with some callus production around lesion edges. Sanitation. Protective fungicides labeled for black spot. ROSE Coniothyrium Canker A brown oval or roughly oval sunken lesion on rose canes. Microscopic exam usually required to distinguish this canker from some others. Sanitation. Apply protective fungicides labeled for black spot control THRIFT (Phlox
Brown or reddish-brown spots, blotches (1-3 mm diam.) develop. Spot coalescence. Sanitation; protective sprays of Cleary's 3336 or Domain may help. THRIFT (Phlox
The stem (crown) at the soil-line becomes brown, dried, and rotted. Crop rotation; possibly soil solarization. TULIP Fusarium and
Penicillium Bulb Rots
Bulbs develop sunken brown-gray dried lesions. Penicillium sporulation may occur as a blue-gray mold on the surface of the sunken rotted area. Sanitation; bulb dips. See the Alabama Pest Management Handbook. VINCA, ANNUAL Rhizoctonia Stem Rot Dark brown, dried, sunken lesion(s) on stems. Dieback of affected stems. Sanitation; remove damaged plants; Chipco 26019, Cleary's 3336, or Domain protective sprays; see Alabama Pest Management Handbook.
UPCOMING EVENTSMarch 18, 2000 - September 17, 2000:
Japan Flora 2000 'Communication Between Man and Nature'.
Awaji Island, Japan. See http://web.pref.hyogo.jp/jpnflora/english/index.htm or Meg VanSchoorl at MVANSCHOOR@agr.wa.gov
June 6-8, 2000:
Mid-South Greenhouse Growers Conference.
Ramada Inn - Southwest Conference Center in Jackson, MS.
Registration fee is $65.00. Contact Allen Owings, Extension Horticulturist at LSU for more information. For hotel reservations call the Ramada Inn at 601-944-1150 (conference rate is $62 per night).
June 26-29, 2000: Southern Forest Nursery Association Conference 2000.
Adams Mark Hotel, Mobile, AL.
Registration $185.00 by June 1 ($210.00 after that date). For more information phone 334-898-7013; fax: 334-898-1149 or e-mal: GenevaSF@forestry.state.al.us
July 8-12, 2000:
Ohio Florists' Association Short Course and Trade Show.
Greater Columbus Convention Center. Contact OFA at 614-487-1117; e-mail firstname.lastname@example.org; web: http://www.ofa.org
July 11-16, 2000:
American Nursery & Landscape Association Annual Convention.
Location TBA; contact ANLA at 202-789-2900; http://www.anla.org
July 16-19, 2000:
American Society for Horticultural Science 97th International Conference.
Disney Coronado Springs Resort, Orlando, FL. Contact ASHS at 703-836-4606; fax 703-836-2024; e-mail email@example.com
August 3-6, 2000:
SNA 2000 - Southern Nurserymen's Association Researchers' Conference and Trade Show.
Georgia World Congress Center, Atlanta, GA. Contact SNA at 770-973-9026; SNA Infoline at 770-973-4636; http://www.ag.uiuc.edu/~isa
September 15-16, 2000:
Alabama Christmas Tree Association Annual Meeting.
Tuscaloosa, Alabama. Contact Ken Tilt by phone: 334-844-5484 or e-mail at firstname.lastname@example.org for further information.
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 email@example.com
October 8-11, 2000:
Southern Region International Plant Propagators' Society.
Norfolk, VA. Contact David Morgan at 817-882-4148; fax 817-882-4121, SR IPPS, P.O. Box 1868, Ft. Worth, TX 76101; e-mail firstname.lastname@example.org
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 email@example.com
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 firstname.lastname@example.org
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: email@example.com
Send horticultural questions and comments to firstname.lastname@example.org.
Send questions and comments to email@example.com.
Letters to Bernice Fischman - 101 Funchess Hall - Auburn University, AL 36849.