Fungal diseases causing damping off and Fusarium basal rot take a significant toll on the Northeast onion crop, and can be particularly devastating on red varieties, says Jan van der Heide, Cornell University extension vegetable crop specialist. Different types of applications and on two different red onion varieties planted on a marginal muck soil with about 20% "we generally control these diseases with routine fungicidal programs," he states. But as we all know, fungicides can be costly and, in years when disease pressures are high, we still see losses. Van der Heide conducted preliminary research trials last year with a new biological fungicide to find whether it might be effective against Fusarium basal rot. He used the product, T-22@, in different types of applications and on two different red onion varieties planted on a marginal muck soil with about 20% organic matter. "The field has a history of heavy Fusarium basal rot infestation," he adds.

The active ingredient in T-22 is Trichoderma harzianum, strain T-22. Trichoderma harzianum is a beneficial fungus that occurs naturally in many soils. When this fungus happens to come in contact with plant roots, it grows alongside the root system and then aggressively fights off any intruding fungi that might attack the roots. T. harzianum strain T-22 is a hybrid fungus, developed in a special microbial breeding program at Cornell University. Dr. Gary Harman, a Cornell research plant pathologist, headed up the program. He is now acting CEO of BioWorks, Inc., a company formed to produce and market this and other future biological protectants. Looked at Numerous Strains Harman says the Cornell program looked at numerous strains of T. harzianum in developing the root protectant. He says that T-22 is up to 100 times more effective than naturally occurring T. harzianum in colonizing and protecting plant roots. It is particularly effective against Rhizoctonia, Pythium and Fusarium. Dr. Christopher Hayes, BioWorks’ director of research and product development, says the relationship between T-22 and the plant’s root system is completely symbiotic. The fungus feeds on root exudates rather than on the roots themselves, so does not harm the plant nor compete with it for soil nutrients. "Once the beneficial fungus has ‘colonized’ the roots, the fungus will challenge and kill pathogenic fungi attempting to penetrate the roots and feed on them, since this is a threat to the beneficial fungus’ food source," explains Harman.

Unlike chemical fungicides, the protection afforded by T-22 stays with the plant throughout the season, helping it fight off invading root fungi and allowing a better, stronger, healthier root system to develop. "In most crops this translates into healthier plants and often better yields," Harman says. Dr. David Pieczarka, director of sales and marketing for BioWorks, says the company has several T-22 formulations on the market for use in various crops. T-22 Planter Box is recommended for direct-seeded crops like corn, beans and potatoes and is applied at planting. T-22 Granules are available for in-furrow applications or as a broadcast treatment for high value crops. RootShield was developed for vegetable and greenhouse growers and nursery stock producers. Pieczarka adds that two new sprayable formulations will soon be launched for the control of certain foliar diseases. All products are manufactured by the company at its Geneva, NY headquarters and sold through major distributors. Van der Heide says that his initial intent in studying the product in red onions last year was to find whether it could reduce Fusarium basal rot. "We used it as a planter box treatment for direct seeded Mercury onions. We also used RootShield as an in-furrow drench treatment at seeding for the same variety. Also, we used T-22 Planter Box in solution as a dip treatment for Mars onions at transplanting," he says. "The planter box treatment didn’t show us any control of Fusarium basal rot, but the drench did. We put it on at rates of both 1 and 5 lbs. per acre and found that both reduced the disease by 50%," he says. "As we looked at the trials, we also noticed that where we used the drench treatment, we had a 100% stand. Where we used no fungicide, we had only 30-40% stand," he says. "It appears that it also gave us control of damping off caused by Pythium, but since we did not check for this initially, it’s hard to say this as a certainty. The study was not designed to compare T-22 with other fungicides in effectiveness against Pythium."

Dr. Russ Wallace, BioWorks’ field research manager, says the company sponsored several T-22 studies on onions this past year in which yield data were collected as well as disease information. They harvested better yields even though Van der Heide did not see better Fusarium basal rot control where he used the T-22 Planter Box treatment, he harvested about 5% more than the untreated onions. Where the RootShield in-furrow drench was used, production was 26% more than in the untreated control. Where the Mars variety sets were dipped in a solution of 1 lb. T-22 per gallon of water just prior to transplanting, Van der Heide found yields were 5% better. He points out that labeling to allow commercial use of T-22 and RootShield on onions is still pending, but is expected before spring planting begins. Based on the rates Wallace and Van der Heide used in studies this past year, the cost of using T-22 or RootShield on onions is in the ballpark with the cost of one application of a chemical fungicide. "And the fact that it takes only one application of T-22 or RootShield to give season-long protection gives it an even bigger advantage over chemical fungicides which may require two or more applications." Van der Heide notes that while he has only one year of research with T-22, he considers the results promising. "It was enough to suggest we need to do more research with this product on onions," he says."We’re setting up experiments for 1998 in which we’ll look at T-22 more intensively. We’ll make comparisons between T-22 and other traditional chemical fungicides in addition to comparisons with no fungicide at all. I need to be sure that what we saw last year is repeatable before I can recommend using it. If growers are interested in trying this out as a biological alternative to chemicals, I’d suggest they go to their county extension advisors for help in setting up some on-farm tests," he adds.

For more information on T-22 and RootShield write to BioWorks, Inc., 345 Woodcliff Drive First Floor, Fairport, NY 14450, or telephone 800-877 9443. Contact them by FAX at 315-781-1793. Or you can look them up on the internet at http://www.bioworksbiocontrol.com.

BioWorks and RootShield are registered trademarks, and T-22 is a trademark of BioWorks, Inc., Fairport, New York.

Research in 1997 found that T-22 (Trichoderma harzianum) is able to colonize and protect the roots as well as the tubers of potatoes from planting through to vine-kill. Studies conducted by BioWorks researchers found tuber colonization was at sufficiently high levels to potentially offer protection against Rhizoctonia tuber infections. As you know, growers can lose a lot of money to Rhizoctonia tuber infections because of the small black sclerotia that infect the surface. These do nothing to the flesh of the tuber, but consumers do not want to purchase tubers with "black spots" on them.

NEW TRIALS
BioWorks, in cooperation with Wilbur-Ellis Co., and several large growers will be conducting trials this winter to evaluate the influence of T-22 on Rhizoctonia tuber infections and yield quality.

David Kelly of the Ohio State Potato Growers Association "trialed" T-22 Planter Box as a seed-dust treatment in strip trials with several growers. One trial, I believe, was washed out by heavy rain, but in the other trial, I visited with the grower and was told that the mancozeb/"Nubark + T-22 treatment had fewer Rhizoctonia stem lesions and root damage than did the chemical fungicide alone, or the untreated.

T-22 Planter Box has often been shown to improve yields that are low or marginal when stress is occurring, but may not be as effective if conditions are optimal. But how often are conditions optimal, and which fields do you expect to have optimal conditions? T-22 is good as added protective insurance.

Paul Tresham from Wilbur-Ellis Co., in Umatilla, OR, conducted trials and found some good results.

(Editor’s Note: Wallace is field research manager for Bio Works Inc.)

New York company unveils T-22 BioWorks Inc. of Geneva, NY, has announced the registration of the first biological fungicide for the potato industry. Developed and licensed at Come1 University, the fungicide, presently named T-22, has passed field tests in 1995 and 1996 and has shown to produce greater yields-up to 1.8 ton an acre. The fungicide controls root diseases in several crops including potatoes, corn, soybeans, peanuts and cotton. It is available in a planter box formulation for ‘97 planting.    BY GARY RAWLINGS, EDITOR

According to Paul Treshman, growers who used T-22 in ‘96 as a seed-piece treatment experienced typical dollar returns of about $200 per acre. Running product trials across the U.S. for Wilbur-Ellis Co., Treshman said overall yield increases averaged 10 percent.

PATENTED STRAIN
The active ingredient in T-22 is a patented strain of the beneficial fungus Trichoderma harzianum. It grows on roots as they develop from stand establishment through to harvest and provides a season-long control barrier. T-22 seems to increase the percentage of large tubers which result in contract bonuses for growers selling potatoes to the french fry market, Treshman explained.

Dave Pieczarka, product manager, said work on the biological fungicide has been on-going for about 15 years. It took about two years to get complete registration through the EPA, he explained. Pieczarka said the product is one of the Fit biological fungicides growers will see come to the marketplace over the next 10 years. It is also being sold and used successfully in greenhouse potting mixes, applications on turf, and in positive-displacement applicators for growers. T-22 is a strain of a natural fungus taken from a root and put through a breeding program. This has led to its successful development and implementation on all the crops mentioned.

Wilbur Ellis is marketing the product under its branded name of "TurfShield." BioWorks is applying for federal trademark protection for the product names used in other areas.

F O R M E D I N ‘ 93
The company was first formed in June 1993 under the name TGT Inc., by Dr. Gary Harman, Dr. Thomas Stasz and Rustin Howard. The company was formed to commercialize the patented product developed by Drs. Harman and Stasz at Cornell and Eastman Kodak Company. Under a license arrangement with Cornell Research Foundation Inc., Kodak had participated in product development and EPA registration activities, which included Kodak's funding of the required toxicology testing and EPA registration applications. Kodak later transferred all of its rights in the technology to Cornell Research Foundation. The technology and patent rights are now licensed exclusively to the Company by Cornell Research Foundation Inc., which holds an equity position in the company in return for its exclusive license of the patented technologies. All three of the BioWorks principals have connections to Cornell. Howard holds an MBA from the New York school; Stasz is a Magna Cum Laude graduate of the Syracuse Law School and holds a Ph.D. in plant pathology from Cornell; and Harman, principal inventor of the company’s core technologies, is a full professor at Cornell and an internationally respected research scientist. Director of Marketing Pieczarka holds a Ph.D. in plant pathology from Cornell.

RESEARCH RESULTS
According to Dr. Phil Nolte of the University of Idaho who did trial work for BioWorks, the product looks real promising but needs more testing. Nolte said it finished at the top of trials the last two years. Used as a granular application and banded, it has good activity, he reported. "It appears to have other properties that change the micro-floura and are beneficial on plants." Nolte tested it on soil-borne pathogens only. It looks good controlling fusarium, which leads to seed-piece decay, and dry rot, Nolte said. Results of the Idaho trials were similar in ‘9.5 and ‘96, showing about 25-30 sacks more per acre, the most vigor after six weeks, and the highest for 10-ounce and No. 1s. Tom Cummings, a research technician for Dennis Johnson, Washington State University potato pathologist, said their work last summer showed no difference in yields than Tops or Maxim. Cummings said there was a slight yield increase in over lo-ounce. He also said T-22 did better with mancozeb than it did by itself. The pair also noted that it had no action on the stems of plants. Cameron said fungicides perform differently in Washington than in other areas. "Here they all seem to perform about the same." Gary Pelter, WSU extension agent, said he tried the product by itself in commercial field situations and had yield increases. Rangers went up 5 percent and Norkotahs 6 percent. He also noted a slight increase in over 10-ounce.