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After last year’s deadly outbreaks of E. coli in the
The purpose of the REACH system is to encourage companies to switch to safer alternatives. Companies that submit applications for authorization must include an analysis of alternatives and a substitution plan where a suitable alternative exists.
The cry for sustainable business practices and environmental consciousness has helped catapult sales of organic products. What started as a microcosm in food production has morphed into a multibillion-dollar universe that covers multiple industries from cleaning supplies and pet food to textiles and personal care. The
Retail value of organic cut and potted flowers doubled from $8 million in 2003 to $16 million in 2005, OTA reported.
Certified organic
Companies like floral retailer Organic Bouquet have led the organic floriculture charge. The California-based company was formed in January 2001 with the goal to establish the national market for organic flowers. Its grower network uses organic growing practices, and all growers are Veriflora Certified. Veriflora, from Scientific Certification Systems, is
And OTA is fighting to advance organic agriculture in the 2007 Farm Bill.
“Our goal is for existing USDA programs to meet the needs of organic farmers,” said Caren Wilcox, executive director of OTA.
OTA wants Congress to provide USDA with funds to provide technical assistance for conversion of conventional to organic practices; create appropriate risk management tools; fund organic research; and enhance current agency programs so the National Organic Program can keep pace with growth.
Greenhouse owners can’t go organic or switch to biocontrol measures overnight -- it’s a lengthy process. But adopting integrated pest management will help growers better understand the organic movement. IPM doesn’t equal organic. And don’t loosely throw around the term organic. If you put it on a label or a pot, you’d better be certified.
Insect biocontrol
Growers can use biopesticides and other natural predators and parasites to control insects. Growers wishing to use biocontrols need to discontinue applying insecticides with long residual activity at least one to two months prior to introducing the biocontrols. Insecticide residues on plants and greenhouse fixtures can be deadly to biocontrol agents. Incorporating biocontrols into an IPM program is a major step. Growers should do extensive research and ask lots of questions before implementing biological control, because not all products are compatible with natural enemies.
“It is important to know which biorational pest control materials, such as insecticidal soap, horticultural oil, microbials and related compounds, are compatible with natural enemies,” said Ray Cloyd, associate professor of entomology at Kansas State University. “The best way to avoid any harmful effects to natural enemies is to make releases several days after an application; although applying biorational pest control materials may still decrease host quality, thus increasing parasitoid or predator mortality.”
Applications of biorational pest controls may kill a majority of the hosts, which reduces the amount available for natural enemies, Cloyd said.
Direct spray applications and short-term residues of insecticidal soap and horticultural oil are toxic to most natural enemies, especially parasitoids. However, once the residues have dissipated, they are less harmful.
In general, sprays of Bacillus thuringiensis (Bt) are safe to most predators, but larval stages of green lacewing and ladybird beetles are more susceptible to Bt sprays than adults.
Direct applications of spinosad are extremely harmful to parasitoids including Aphidius colemani and Encarsia
Bugs on bugs
“We find the hot spots and pinpoint problem areas or crops and inoculate only those areas with the beneficial insects,” said Dan Gerace, grower manager at
Gerace releases a parasitic wasp (Aphidius coelmani) to control aphids and applies a parasitic nematode (Steinernema carpocapsae or S. feltiae) as a soil drench for fungus gnats. He also uses
“It’s not a weekly spray and pray program,” Gerace said. “With any biological control program, you’ve got to have good scouts and spend lots of time looking in the greenhouse. IPM uses a lot of different tools, and it can make you a better grower.”
Gerace uses conventional pesticides in other greenhouses, and he’s yet to find an effective biological control for thrips, his “No. 1 insect,” he said.
Disease biocontrol
Diseases in greenhouse vegetables and floriculture crops can be managed effectively with biofungicides, said Cathy Thomas, IPM coordinator at the Pennsylvania Department of Agriculture. A biofungicide is composed of beneficial microorganisms, such as specialized fungi and bacteria that attack and control plant pathogens and the diseases they cause. These specialized fungi and bacteria are microorganisms that normally inhabit most soils, she said.
“Biofungicides can be a viable alternative to chemical fungicides and can be used as part of an integrated disease management program to reduce the risk of pathogens developing resistance to traditional chemical based fungicides,” Thomas said.
To optimize the effectiveness of any biofungicide, apply it before the onset of disease development since it will not cure pre-existing pathogens. Early application of a biofungicide protects the roots against pathogenic fungi, allowing for better development of root hairs. Always use biofungicides in conjunction with standard disease cultural controls including sanitation and weekly scouting.
A biofungicide shields the roots by forming a defensive barrier around the roots, preventing the harmful fungi from attacking the root.
An antibiosis biofungicide produces a chemical compound such as an antibiotic or other toxin that kills the target organism. Predation or parasitism biofungicides attack and feed on pathogens. Some biofungicides trigger the plant to turn on its own defense mechanisms.
Most biofungicides are safer to use and have a lower reentry interval than chemical fungicides, and in most cases they are less phytotoxic.
There are some drawbacks to biofungicides. They don’t eradicate the disease or “rescue”
the host plant from infection and they sometimes have a shorter shelf life than traditional chemical controls.
A personal choice
When Alison Kutz-Troutman and her husband Paul started Cascade Cuts 26 years ago, she intended to grow herbs and cut flowers organically.
“I looked at it from an ethical standpoint,” she said. “Because I was growing herbs that would be eaten, my impetus was to start out organic. But the market 26 years ago wasn’t exactly conducive to warrant the additional costs of growing ornamentals in that fashion.”
Kutz-Troutman faithfully uses sustainable practices including organic soil, compost tea and organic sprays. The couple has added other crops to the mix, including bedding plants, perennials and forced bulbs.
The organic soil is complete with a high degree of micronutrients, compost and Azomite, a rock powder that contains 70 micronutrients. Plants also are inoculated with compost tea, a pivotal step in production.
“We inject the tea into the automated fertilizer system. We’ve eliminated much of our fungicide use with the compost tea,” she said.
They’ve alleviated the disease pathogen Fusarium from their cyclamen crop with compost tea applications.
“With these techniques, we grow healthier plants,” she said. “The plants are less vulnerable to environmental stresses. The organic soil and the compost tea keep fertility going on a continuous basis -- like spoon-feeding the plants.”
Depending on the time of year and crop, Kutz-Troutman can cut conventional fertilizer use by half.
Her organic practices work with conventional production.
“Some of the most well-integrated operators are the folks using dual methods,” she said. “The smartest growers use macro- and micro-biological tools, not just bugs with legs.” Kutz-Troutman also owns Sound Horticulture, a consulting firm for compost tea.
For more: Organic Trade Association, (413) 774-7511; www.ota.com. Organic Bouquet, (877) 899-2468; www.organicbouquet.com. Scientific Certification Systems, (858) 437-7436; www.scscertified.com/csrpurchasing/veriflora/index.html. Ray Cloyd, (785) 532-6154; rcloyd@ksu.edu.
IR-4 designates high-priority issues
The IR-4 Ornamental Horticulture Program at
1. Phytophthora (soil borne) efficacy.
2. Phytophthora (foliar) efficacy.
3. Pythium efficacy.
4. Thrips efficacy.
5. White grubs and root weevils efficacy.
For more: IR-4 Project, (732) 932-9575; http://ir4.rutgers.edu.
Predators, parasitoids have different characteristics
Before starting a biological control program, it’s important to recognize the characteristics and uses of predators and parasitoids.
* Predators can be beetles, mites, mantids, flies and bugs. Predators kill and consume prey.
* Parasitoids develop within the body of a host, killing it directly. Parasitoids are typically smaller than their prey. They attack pests such as aphids, whiteflies, caterpillars, leaf miners, flies and scale.
* Parasites, such as entomopathogenic nematodes, have a symbiotic association with bacteria (Xenorhabdus spp.) that are lethal to many soil-dwelling insects, but do not affect animals and plants. Nematodes require moist soil to be effective and soil temperatures should remain between 60°F and 90°F. Nematodes can be applied with a pull-behind sprayer, fertigation system or backpack sprayer.
* Pathogens, such as entomopathogenic fungi (mycoinsecticides), infect and kill insects. Fungal spores must have direct contact with insects to be effective. As spores attach to the insect cuticle, they germinate and the fungus grows into the host’s body cavity.
New product watch
Pharm Solutions Inc. in Port Townsend,
IPM Laboratories in
“Without sustenance, natural enemies will be forced to leave the greenhouse, exposing crops to pest infestation,” Glenister said.
In 2006 Syngenta Bioline introduced Thripline ams, a system of aggregation pheromone and traps for Western flower thrips.
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For more: Pharm Solutions, (805) 927-7400; www.pharmsolutionsinc.com. IPM Laboratories, (315) 497-2063; www.ipmlabs.com. Syngenta Bioline, (805) 986-8265; www.syngenta-bioline.co.uk.
- Kelli Rodda
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There’s a connection between plant nutrition and disease
Margery Daughtrey,
There’s a connection between plant nutrition and disease
Are we watering our crops or obliging the pathogens by moving them around? When we fertilize a crop, are we feeding the plants, or are we feeding its pathogens?
Some of the most common abiotic diseases (those not caused by microorganisms) are due to errors in plant nutrition. One that is seen very commonly in the greenhouse is iron or manganese toxicity, which can occur on some cultivars of geranium or
Good general health and vigor will help plants resist many pathogens that can take advantage of stressed hosts. Low fertility appears to predispose geraniums to Alternaria leaf spots.
Botrytis blight in chrysanthemums can be staved off with less nitrogen. A pH greater than 6.2 or a nitrate form of nitrogen may help mums fight Fusarium wilt. Less salinity protects mums from Phytophthora root rot. Pythium root rot in geranium may decrease with less nitrogen. And a pH of less than 5.0 in the soil helps protect poinsettias from Thielaviopsis root rot.
Margery Daughtrey is a senior extension associate at Cornell’s Long Island Horticultural Research and Extension Center, (631) 727-3595, mld9@cornell.edu.
Know the basics of organic soil, amendments
Suzanne Wainwright-Evans, Buglady Consulting
Know the basics of organic soil, amendments
The term “organics” is usually used in association with the production of fruits and vegetables. But organics has broken out of its food-industry shell and has moved into ornamentals.
A key question is, “Why would an ornamental plant grower go in this direction?” One reason: Market demand. Your customers may want plants grown with organic practices. Secondly, some excellent products are available. Third: Worker safety. Softer, less toxic products reduce risks.
Consider organic soil mixes, biostimulants and beneficial microorganisms in your production.
What do organic soil mixes have to offer? They usually include compost, which provides a ready source of organic matter for plants. Compost also provides a better environment for beneficial microbes to thrive. Organic wetting agents also are available for use with soils.
Biostimulants contain natural products such as cytokinins and humic acids, which benefit plant growth. Biostimulants may enhance plant metabolism, increase chlorophyll efficiency and production, enhance nutrient availability, increase soil water-holding capacity and increase antioxidants. Cytokinins promote plant growth by enhancing plant cell division and they help seeds break dormancy. Under drought conditions, humic acids help balance water and assist plant transpiration.
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Inoculating soil with beneficial microorganisms can help food uptake and prevent against some root diseases.
Suzanne Wainwright-Evans is an ornamental entomologist and owner of Buglady Consulting, (610) 767-9221, www.bugladyconsulting.com.
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