Chemical fungicides applied to corn seed and other crops generally protect the seed and emerging seedling from certain fungal diseases. But these fungicides do not provide season-long protection to the root system. Enter natural biological products.

According to the company, test plots with this biological have shown Dr. Gary Harman, a University plant pathologist and acting CEG of a new company called BioWorks Inc., believes season-long root protection can make plants more efficient and more productive. Pathologists’ company. BioWorks was formed to produce and market biological pesticides, one of which was discovered and developed by Harman and other Cornell plant pathologists. The product is T-22, sold as a planter box or in-furrow treatment. The active ingredient is a special hybrid strain of a beneficial, naturally occurring fungus, Trichoderma harzianum, strain T-22, selected and improved in a microbial breeding program at Cornell. When placed in the soil with seeds or seedlings, this biological protectant is claimed to colonize the plant’s root system 100 times better than its natural counterpart. The fungus feeds on substances given off by the roots rather than competing with the plant for nutrients. At the same time, it aggressively protects the plant’s roots against invasion by fungi like Pythium, Fusarium and Rhizoctonia. "Once the beneficial fungus has ‘colonized’ the roots, the fungus will challenge and kill pathogenic fungi attempting to penetrate the roots and this translates into healthier plants and often better yields. Diseases come and go. "Since weather conditions and pathogen levels differ from year to year, using T-22 may seem like a roll of the dice. Where we see advantages from it is when soil-borne diseases become a problem." says Dr. Chris Hayes, BioWorks’ director of research and product development.

Unlike chemical fungicidal seed treatments, the protection afforded by this new biological fungicide seed treatment stays with the plant throughout the season, helping the plant fight off invading root fungi and allowing a better, stronger, healthier in favor of the treated beans," he says. Reserving judgment. While he’s pleased with the results this year from T-22, Corman wants to reserve judgment until he’s had a chance to look at it in a couple of "more normal" years.

John Corman, Spring Mills, PA, put out several strips of side-by-side soybean tests at two locations "Across the plots with all varieties, the T-22 treated beans averaged around 3 bu./acre better. In one plot, they were 4.6 bu. better, and I had one strip where the difference was 9.9 bu. Gothenberg, NE, applied T-22 biological fungicide to alfalfa and was surprised by good plant survival in irrigated field corners acre for both corn and soybeans. Cost of the product is approximately $3 per acre for corn and $5/acre for soybeans.

Dr. David Pieczarka, BioWorks’ director of sales and marketing, says T-22 has proven to be beneficial in such crops as alfalfa, corn, soybeans, cotton, wheat, sweet corn, dry beans, potatoes, sugar beets and many vegetable crops.

For more information contact
BioWorks Inc., Dept.
345 Woodcliff Dr.
First Floor
, Fairport, NY 14450,
800-877-9443 ext 257

BIOLOGICAL FUNGICIDE
by MICK LANE

Disease control is essential in maintaining the quality of greenhouse crops. Good control generally means more marketable plants and higher profits. Protecting plants from disease often means regular use of fungicides and fumigants, which can push up labor costs and increase risk to workers, while adding up to higher production costs. However, a hybrid fungicide -Tritoma harzianum (strain T-22) - developed by researchers in a special microbial breeding program at Cornell University is being used by growers to prevent potentially harmful fungi from damaging roots.

Called RootShield (formerly sold as BioTrek), the patented fungus establishes a symbiotic relationship with growing plants, living on root exudates and, in turn, preventing potential diseases such as Rhizoctonia, Pythium, and Fusarium. And because it is a living organism and multiplies as root mass increases, one treatment provides long-term protection, thus reducing labor costs. Available from BioWorks, Inc., RootShield encourages a healthier, more efficient root system. Here are several growers who have found success with this biological fungicide.

Working It Into The Mainstream
One of the most important crops at Mainstream Farms, Elma, WA, is poinsettias. Dana and Melissa Main buy rooted cuttings in oasis and transfer them to 4-, 6-,7-, 81/2-, and 12-inch pots to finish. With the use of Root-Shield, the Mains cut back on the amount of poinsettias they lost to disease during the 1997 season. "We bought 5000 cuttings last year, and lost fewer than five to root disease problems," Dana says. In addition to poinsettias, the Mains also used RootShield on primrose plugs and geranium cuttings and on a number of different vegetables and bedding plants grown from seed. "We’re not an organic grower, but we try to keep our chemical use to a minimum," Dana says. "In the past, if we did not use chemical fungicides to protect the roots of young plants, our losses ran in the 5%-10% range. Since we started drenching with RootShield, though, we’ ve had a much higher percentage of salable plants. They grow better, they’re healthier, and because of that, they’re often ready to move out ahead of schedule."

Considering The Environment
Todd Nakamura of Star Lake Greenhouse, Auburn, WA, tried RootShield for the second time this year on his poinsettias. His results weren’t as remarkable as the Mains', but, says Nakamura, "I think I know why. In 1996, we had the RootShield mixed into the soil we used in transferring poinsettia cuttings to flats. The results were pretty good. "My intent was to use a drench this year instead of having the product mixed into the soil. My soil supplier added it anyway, so I decided not to follow through with the drench. Again, the results weren’t bad, but not as good as if I’d have followed through with the RootShield drench," he says. His plan for this year’s poinsettia crop is to drench the rooted cuttings he buys with a fungicide when they're moved to pots to prevent initial losses. He’ll then come back with a Root-Shield drench about a week later. Nakamura is a strong proponent of biological products. His greenhouses are completely surrounded by homes that built up around Star Lake, from which the business gets its name. He feels biologicals can help him be a better neighbor in addition to being better for the environment and safer for his workers than chemical fungicides.

Testing It Out
Tom Wilkins grows nursery plants on Vashon Island in Puget Sound, WA. One plant that he grows is kinnikinnik (also known as bearberry), a widely-adapted ground cover used in many locations around the country. This plant, which is mostly propagated by cuttings, is often very difficult to pro-duce and often succumbs to various root diseases. Wilkins grows kinnikinnik from cut-tings to finished plants in 4-inch or l-gallon pots. He says root diseases can be a problem at any stage during production. To protect the growing roots during their life cycle in the nursery, Wilkins has tried various fungicides. Lately he found that RootShield is an effective component in managing the health of his plants. "It encourages the plant to develop a better quality root system," he says. "It’ s not a silver bullet in preventing all problems. But assuming you’ ve done a good job with your cultural practices, RootShield really seems to help prevent diseases and promote good growth." To find out what RootShield could do, Wilkins treated a group of 400 kinnikinnik cuttings that were compared to a large untreated control group. "About 98% of the treated cuttings developed into marketable plants, while t only 65% of the group of untreated plants made it to market," he says. Wilkins says that RootShield is one of the easiest products to use, since it is available in a drench formulation that can be watered into roots, or as a granular product that can be mixed in the soil. Because of its mode of action, plants don‘ t need to be retreated.

Compatible With Tissue Culture
Head Grower Joe Jaskowiec-Jackson of Oglesby Plants International, Nursery Division, Altha, FL, started using RootShield to protect roots on a variety of ornamental plants, like anthurium, spathiphyllums, ginger, and dwarf banana. All of these are grown from tissue cultures, mainly using 72- and 98-cell flats. These plants are sold to growers who pot and finish them for use in homes, hotels, motels, and businesses. "The cost of applying RootShield is minimal, compared with the value of the plants we’ re selling, so it seemed like a low-cost way to protect plants from root diseases," he says. Jackson starts with a tissue culture from the company’ s laboratory and inserts it into a cell in a flat filled with clean soil. Flats are placed under misters to keep them moist. When roots begin to develop, he stops misting and allows the flats to dry out. He then drenches them with a RootShield solution and allows them to harden off. "While we start with sterile soil, we can‘ t be assured it will stay that way during the time it takes for the plant to develop and be sold," he says. "We often had problems with Pythium, Rhizoctonia, Fusarium, and other soil-borne root diseases, and occasionally we’ ve had complaints from customers about these. We’ ve had no complaints about root problems since we began using this product." Suitable For Vegetables

Steve and Mike Porter, Elba, NY, produce organic vegetables for super markets in the Buffalo and Rochester areas. "We grow all our transplants in our own greenhouse, so we can have control of the entire process," Steve says. They’ ve been using RootShield for a couple of years now, and have helped Russ Wallace, BioWorks’ manager of field research, in researching and demonstrating the product on cabbage and peppers, mostly. "We drenched the plants in flats by hand, as soon as there was a root to protect," Steve says. Under Wallace’ s direction, they planted a side-by-side test using three different varieties of bell peppers. "We left some of the trays untreated in the greenhouse and then planted the treated and untreated peppers in replicated plots in the field, so we had four or five reps of each variety." Porter says the treated peppers of one variety did really well on the initial picking. On later pickings, yields were similar from the treated and untreated varieties, but overall, they got higher yields from the treated varieties, largely due to a bigger first picking.

For more information on RootShield and other products containing strain T-22, contact 345 Woodcliff Drive
First Floor Fairport, NY 14450
Phone (800) 877-9443
Fax (800) 903-2377.
Or you can visit its web site at www.bioworksbiocontrol.com.

About the author: Mick Lane is a free lance writer based in Ankeny, IA 50021. May 1998 l Greenhouse Grower