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No. 6, March 16, 2006
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It’s a good year for mealybugs and aphids New Michigan greenhouse energy resource website
Thielaviopsis (black root rot)
Scouting for weeds: Hairy bittercress
2006 agricultural water use reporting
Wildfire-resistant landscape plants for Michigan |
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David Smitley
Entomology
When Tom Dudek finished reading the scouting reports from greenhouses this week he sighed, then called me with the news: lots of mealybugs and aphids. The mealybugs probably came on rooted cuttings and other plant material brought in months ago. We are seeing them now because they have had time to complete one or two generations, which can increase the infestation 100-fold. Mealybugs have been found mostly on Ipomea, but they are capable of feeding on many other plants as well. The aphid problems have been reported to be on Ipomea, peppers, Springerii, spikes, Digitalis, Shasta daisy, gerber daisies, dusty miller and licorice plant. Because mealybugs and aphids are closely related, the same insecticide products will be effective for both. The only difference is that mealybugs are notoriously difficult to get rid of, so growers may want to pitch the most heavily infested plants and spray all the remaining plants in the area. The best products to use for mealybugs and aphids are systemic insecticides absorbed by the roots. This includes:
Marathon
Discus
Celero
Safari
Aria
Flagship
All of the above products should be applied as a soil drench, or as a spray directed to the surface of the soil, followed with enough overhead watering to wash them into the soil. Stop watering before water begins dripping out the bottom of the pots. Avoid over-watering for the next two days to all plenty of time for the insecticides to be absorbed. Marathon, Discus and Celero may take a week or more before you see dead mealybugs and aphids, but they also last the longest (six weeks or longer). Safari and Flagship work somewhat faster, and you may dead insects within a few days to a week. They should continue working for at least 2 to 4 weeks. Aria will work very quickly, with dead insects being seen in one to three days. Most of the Aria will be gone from the plant within a week.
The products listed above can also be used as a foliar spray. Foliar sprays work because of contact activity. Most of the benefit from the foliar sprays is in the first week after spraying. For heavy infestations a soil drench and a foliar spray can be used at the same time or close together to help bring the aphids or mealybugs under control quickly. In addition to the products listed above, the products below can also be used as a foliar spray:
Tristar
Orthene
Azatin
BotaniGard
Endeavor
Enstar II
Ornazin
Talstar |
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Matthew Blanchard and Erik Runkle
Horticulture
The cold weather is mostly behind us now, but energy prices are likely not to subside. In an industry with declining profit margins and with the surge in fuel prices, there is increasing need to grow greenhouse crops in an energy-efficient manner throughout much of the year. The best approach is to attack this industry threat using a variety of strategies.
In collaboration with horticulturists, agricultural economists and agricultural engineers at Michigan State University, Rutgers University, University of Georgia and University of Florida, we have drafted and compiled information on production strategies and technologies that greenhouse growers can use to consume less energy and improve production efficiency. This resource document was first made available to participants of greenhouse energy meetings coordinated by the MSU Floriculture Area of Expertise Team held throughout Michigan in January and February 2007 and is now available online at: http://www.hrt.msu.edu/energy/Notebook.htm
This online resource includes articles, many of which have appeared in popular trade magazines, on the following topics:
- Greenhouse lighting
- Temperature and scheduling
- Energy-saving technologies
- Alternative fuels
- Energy grants and loans
Development of some of these articles and the energy website were made possible by funding from the Michigan Floriculture Growers Council. The Council received a grant from the USDA Rural Development Office in early 2006 to help subsidize the costs of performing this feasibility study to identify greenhouse energy conservation strategies. In addition, Project GREEEN has provided funding to generate research-based information to improve our knowledge of how to optimize temperature and light to increase greenhouse cropping efficiency and thus reduce energy consumption.
As we and our colleagues develop additional research-based information, we will update the website to provide the most recent information to help floriculture companies decide how to best constrain energy costs and maintain profitability. |
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Jan Byrne
MSU Diagnostic Services
Thielaviopsis has long been known in the greenhouse industry as a root rot pathogen that particularly affects pansies, petunias and vinca. Many perennials are also susceptible to this disease. Over the last year, I have seen an increasing number of perennials and woody ornamentals with Thielaviopsis, including Digitalis, Gaillardia, Geranium sp., Ilex, Leucanthemum, Phlox subulata, Phlox paniculata, Taxus cuspidata and Viola. Greenhouse growers, nurseries and landscapers working with perennials should be aware of this disease and the symptoms that it causes.
(view images)
Thielaviopsis basicola is a fungus that infects roots of susceptible plants. Infection of the roots causes both above and below ground symptoms. Infected roots are darkly colored, hence the common name for the disease, black root rot. The dark coloration is created by the reproductive structures of the pathogen, which have a dark outer surface. Above ground symptoms are more readily noticeable and include chlorosis (yellowing), stunting, lack of vigor and plant death. Chlorosis caused by Thielaviopsis is easily mistaken for symptoms of a nutrient deficiency. However, unlike symptoms caused by a nutrient deficiency diseased plants do not respond positively to increased fertility. Infected woody ornamentals also develop chlorosis as well as defoliation after the root systems become significantly infected. Large or well established plants may not show obvious symptoms until the root systems are heavily infected.
Definitive diagnosis of this disease is not possible based exclusively on disease symptoms. Diagnosis requires microscopic evaluation of infected plants to confirm the presence of the reproductive structures (chlamydospores) on root tissue. This type of analysis can be readily done by any plant diagnostic lab.
Thielaviopsis is soil-borne, and the reproductive structures of this pathogen are well adapted to persist for several years in soil and plant debris, even without a live host plant. Soil conditions influence disease development. The disease is more severe in cool soils that have a pH range of 6 to 7. Observations suggest that wet soils are more conducive to disease development than dry soils.
Prevention is the best and most practical control strategy. Take the time to carefully inspect plant material when it is received and again when it is installed in a landscape. Randomly pick a few plants to remove from their containers and closely examine the root system. Diseased plant material should not be installed in the landscape as its condition will only deteriorate and soil at the site will become infested with the long-lived chlamydospores of this pathogen. Effective fungicide treatments options are available, but treatment is most efficient with plants that are still in containers at the greenhouse or nursery. On site, soil drench applications can be done, but these treatments are best when done preventatively rather than curatively.
Thielaviopsis is most often a problem in situations where containers or media is reused. Containers and media from infected plants should not be reused. If containers are reused, they should be carefully sanitized with commercial sanitizing products. Extra care needs to be used to remove all residual media or soil particles before treating the containers with a sanitizing product. Soil or media residue left on the inside surface of the containers prevents direct contact of the sanitizing products with chlamydospores that may be present, thereby decreasing efficiency of the sanitation process.
Diseases of Woody Ornamentals and Trees in Nurseries, 2001. Edited by R.K. Jones and D. M. Benson. The American Phytopathological Society (St. Paul). |
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Steven Gower, MSU Diagnostic Services
Mike Marshall, Horticulture
Editor’s note: The identification information is from the new field guide An IPM Pocket Guide for Weed Identification in Nurseries and Landscapes. For ordering information, call 517-353-6740 or visit: http://www.ipm.msu.edu/pdf/pocketGuidesLandsc07.pdf
Hairy bittercress (Cardamine hirsuta L.)
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Family. Brassicaceae (Mustard)
Life cycle. Rapidly growing winter or summer annual.
Leaves. Round cotyledons on long petioles are followed by heart- to kidney-shaped first two true leaves. Subsequent leaves are compound with two to eight alternately arranged leaflets and larger terminal leaflet. Leaflet margins are shallowly toothed to lobed. Mostly hairy leaves initially develop from a basal rosette, followed by a few smaller, narrow stem leaves. Basal leaves are persistent through maturity.
Stems. Mostly erect, smooth, angled stems branch mainly at the base. Stems are less than 12 inches tall.
Flowers and fruit. Very small, white flowers with four petals are arranged in terminal clusters. Fruit are very narrow, about 1-inch-long, flattened, upward-pointing capsules that explosively eject numerous small seeds.
Reproduction. Seeds. Multiple generations may be produced in a single year.
Smallflowered bittercress: Cardamine parviflora L.
Differs by having up to six leaflet pairs and basal leaves that are not present at maturity. |
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Tom Dudek
District Extension Horticulture and Marketing Educator
Greenhouse growers and other agricultural irrigators in Michigan need to be aware of a couple of changes in the 2006 Water Use Reporting Act. These include: The need to have GPS coordinates (latitude/longitude) for each of your “groundwater withdrawals.” This does not include any surface water withdrawal sites. Also the one time option to report as part of your 2006 water use report the available capacity of your irrigation systems “Baseline Capacity.” This is the available capacity of the system and would be reported as pump capacity in gallon per minute along with the pump and system description compatible with the well log. Baseline capacity applies to both wells and surface water withdrawals. If you do not report your baseline capacity in 2006, the highest amount recorded in your 2004 or 2005 water use report will be used as your baseline capacity.
Click here to see a great summary of what you need to know if you have irrigation systems in your business that have the combined capacity to pump 70 gallons per minute or more. If you have never reported water use in the past and you have this capacity with your pumps, you need to report for 2006, otherwise any new pumps you add will be treated as a new water withdrawal subject to the stricter rules, which includes a local public hearing before your well permit is issued.
If you need a copy of the forms and the necessary water conservation checklist that must be included visit http://web1.msue.msu.edu/stjoseph/anr/Irrigation%20LK/2006Wateruseregform.pdf
Deadline for reporting to the Michigan Department of Agriculture is April 2, 2007. |
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Tom Dudek
District Extension Horticulture and Marketing Educator
Wildfire-resistant Landscape Plants for Michigan is the title of a new MSU Extension Bulletin (E-2948) that will be of interest to retail ornamental plant sellers and growers that grow and sell ornamental plants wholesale to Michigan mass marketers. There is a niche for selling plants that are wildfire-resistant that this bulletin addresses. Wildfires do occur in Michigan and have involved areas like the homes located in the sand dunes along the any of the Great Lakes, wooded home sites in oak or pine stands, and areas where grass fires occur each spring.
I encourage you to obtain a copy from your local MSU Extension office or through the MSU Extension Educational Materials Distribution Center www.emdc.msue.msu.edu. The publication contains lists of ground covers, perennials, shrubs, trees and vines that are fire-resistant. Step outside the box and look at new ways to market existing plants! |
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