Dr. Chris Hayes,
Director of R&D and Marketing
BioWorks, Inc.

Poinsettia plants are one of the most sought after plants during the Christmas season. Traditionally, grandparents, parents, spouses, sweethearts and even coworkers are presented this treasured plant as a sign of respect and or love. The demand for this festive plant continues to rise in the U.S. and other parts of the world. The consumer desires both the traditional plant, e.g. Freedom Red, as well as new varieties that include alterations in both bract and leave coloration and shape. Plant breedershave met the challenge of supplying consumers with poinsettia varieties by producing a wider rangeof products, but not without some limitations.

Some of the new varieties, and even some of the traditional ones, are susceptible to root rotting fungi, one of the most prevalent being Pythium root rot. Diseases caused by this pathogen can occur at any time during the growing period, which may be from 3 - 5 months and even longer. To combat the problem, growers drench the soil with a combination of fungicides, typically every month. The constant bombardment of the roots with chemicals may stress the plant causing variability in growth and development. In addition, disease resistance is developing, rendering the chemicals ineffective.

Coming to the aid of the grower is a new class of fungicides, biological fungicides or biofungicides. RootShieldÒ is a biofungicide that prevents pathogens from damaging the root system. It is a fungus that "eats" holes in fungal diseases, it feeds on Pythium, Fusarium, Rhizoctonia, Thielaviopsis and Botrytis to name just a few. This active ingredient is the fungus, Trichoderma harzianum strain T-22, since it is living this biofungicide grows along with the expanding root system providing prolong protection. RootShield provides the first line of preventative disease control when the roots are being challenged under low to moderate disease incidence. If pathogens have already attacked the roots before the application of RootShield, or if the disease level becomes overwhelming, curative chemicals should be employed. Thus, RootShield will not eliminate the need for chemical fungicides; instead it should be used on "clean" roots as the first line of defense against pathogen attack. In many cases, it will be all that is needed to naturally protect the root system, healthy roots - healthy plants.

Growers from around the country have seen the benefits of using RootShield. "Mid-American Growers was founded in 1971...(its greenhouse operation)... now covers over 40 acres and is still growing. We grow about 750,000 spring bedding flats and 900,000 flowering baskets. We grow Easter lilies, and about seven different crops of hardy garden mums. We propagate 900,000 poinsettias, which we sell both finished and pre-finished. In May of 1998, I became interested in RootShield drench. Since then we have used RootShield on two crops of summer pansies...it helped control Myrothecium and stimulated more vigor overall. We are on our second crop of cactus using RootShield. .had our most vigorous, broadest-leafed crop of dracaena spikes ever, after using RootShield on the seedlings last year and plan to use it again this year...1999 was our first year using RootShield drench on poinsettia...the increased root development we see is promising...To repeat the headline printed in one of the trade publications, 'Don't trial biological fungicides, use them.' They work!" (Lois Steil, Mid-American Growers, IL). "I have been totally amazed at the results I am getting from RootShield. I used it for the first time on my Poinsettia cuttings ... very impressed with the little loss that I had, compared to other years. I drenched my first batch of Fuchsia cuttings and did not lose one, unbelievable! Next was the New Guinea cuttings, that's when I really noticed the difference in the root system. If I was not sold yet on RootShield, I was then. ...I could count on one hand the number of New Guinea's that I lost. Out of 11,534 Vinca cuttings I lost 8! ... My Zonal and Ivy Geraniums have come out the best I have ever seen. .. I am also having wonderful results with foliage plants - Kalanchoe, Pepperomias - etc... I drenched one half of a bench of Piggy Back 8 inch hanging baskets. You could tell 4 weeks later, by looking down the bench, which side had been drenched with RootShield. Please keep me posted on any new information that might be helpful and keep up the good work!" (Lynette Sass, Casa Verde Growers/Petitt Garden Centers, OH).

This patented, hybrid strain was developed at Cornell University in the 80's. Because of hybrid vigor, this microbe is capable of growing in all media types used in the greenhouse, e.g. peat, bark, and core based systems, at a pH range of 4 - 8 and a soil temperature range of 48 - 95 oF. Strain T-22 has shown preventative control of Pythium, Rhizoctonia, Fusarium and Sclerotinia on the roots, as well as control of Botrytis and Powdery Mildew on the foliage. The product, RootShield, is one of the first EPA registered biofungicides, and is the first to carry a 0 hour REI (restricted entry interval). It is safe for workers and the environment, a point illustrated by the fact that the product is listed as "exempt from residue tolerance" by the EPA and is listed for organic production by OMRI (Organic Materials Review Institute). RootShield should be used in a normal growing program, fertilizers, insecticides, plant growth regulators, wetting agents, soil conditioners and most fungicides do not effect T-22.

Strain T-22 extends with the actively growing root system occupying spaces a pathogen would attack. Early application gives T-22 squatter's rights; if a pathogen tries to invade the roots, proteins released from T-22 digest it. By protecting the roots against root nibbling fungi, RootShield allows the root system, especially feeder root hairs, to fully develop. A well-developed root system is capable of countering environmental stress, which can occur at any time during the growth cycle. More complete uptake of nutrients and moisture occurs because of the healthy root system and greater soil exploration. In addition to disease control, recent research has shown that T-22 is capable of solubilizing nutrients in the soil making them more available to the plant. Thus, T-22 forms a "shield" on the root system protecting the plant against disease and environmental stress.

Growers have reported theses additional benefits when using RootShield. "It has been over 3 years since I started using RootShield. I have seen it provide both fungicidal qualities, as well as increased plant growth. Roots are healthier, more vigorous and take in fertilizer better. On Poinsettias, Lilies, bedding plants and foliage plants, the crops finish 20% faster with RootShield. My seed Geraniums finished two weeks faster" (Bob Bodemer, Van Hoekelen Greenhouses, PA). "We have found RootShield to be a safe and effective product. We have seen a significant reduction in chemical and labor cost. RootShield is one of the best products to hit the market in a long time. I am very satisfied with the results" (John Lybrand, Baucom's Nursery, SC). "The disa orchid is perhaps the most brilliantly colored orchid known and the most demanding in its cultural requirements. Their roots grow in very wet conditions and if conditions are right, a brown root rot can take over and destroy the entire collection. This rot is caused by two fungi; Cylindrocladium and Rhizoctonia. My collection was hit by this rot and with a treatment of a fungicide, the rot was arrested. I then started to use RootShield and within a month I saw new root growth, new tubers emerging on the plants, and a healthier looking plant, and no signs of the rot returning. The collection is now treated every spring with RootShield. I recently applied RootShield to 500 disa seedlings. In the past I never applied anything to the delicate seedlings. I am now seeing healthier and faster growth in the seedlings than ever before. I am totally sold on the benefits of using RootShield on my disa orchids" (Jim Pluskota, . Wildcliff Orchids, NY).

Proper applications must be made to optimize the effectiveness of RootShield. Two formulations are available so a grower has versatility in application. RootShield Granules can be mixed into a growing mix, 1.0 - 1.25 lbs. per cubic yard, or added as a top-dressing. The wettable powder, RootShield Drench at 8 - 12 ounces per 100 gallons of water, should be applied through the irrigation system. To improve the movement of RootShield Drench through an irrigation system, it is recommend that a grower follow the "Decanting Procedure" provided by the manufacturer. Poinsettia stock plants will benefit from a RootShield treatment at any time, be sure the roots are "clean" before treatment. If need be, drench the roots with a standard chemical fungicide, followed by an application of RootShield to provide extended protection. Unrooted cuttings placed in OasisÒ plugs should not be drenched with RootShield. Rooted cuttings can be protected by T-22 if they are stuck into pots containing media supplemented with RootShield Granules, or irrigated with RootShield Drench (add approximately one cup of water per 6 inch pot). Hence the grower has several options, applications of RootShield Granules as a custom mix (most soil mixing companies already mix in RootShield Granules upon request) or on site; application of RootShield Drench to the pot. In fact, Bill Turner (Van de Wetering, NY) and David Lee (Sunshine Botanicals, FL) have RootShield incorporated into their propagation mix. Both report a reduction in production costs by using RootShield.

Early application of RootShield is the most effective way to optimize prevention of root damage and promote root growth, however RootShield can be effective at any stage in the development of a plant. The key is the application of RootShield to a healthy root system. Pathogens can attack at any time during a plant's growth cycle, so continual prevention is important in maintaining optimal plant health. Application of RootShield Drench or topdressing with RootShield Granules can be made at any time during a plants development to prevent a disease from damaging the root system.

Strain T-22 is a living organism that competes with other microbes in the mix. In addition, the organism may grow away from the roots to attack pathogens in the soil before they reach the root system. Therefore after time, the level of T-22 on the roots will drop. Continual protection requires the presence of T-22 on the outside of the roots. To keep the level of T-22 on the roots at an optimal level, a second application of RootShield should be made approximately 10 - 12 weeks after the initial. If stepping up, transplants can be placed in mixes containing RootShield Granules or apply the granules as a top dressing. Alternatively, RootShield Drench can be used. Both products can be applied at half to normal rates. Higher rates of RootShield have been tested with no phytotoxic effects recorded.

RootShield is a highly effective biofungicide for preventative control of fungal diseases. Under most conditions, it will provide a "shield" against disease and environmental stress. As part of this protection, RootShield enhances plant health and development. This protection will extend beyond the life of the plant in the grower's operation. The consumer benefits from the "shield", both in safety and plant survival in their hand.

This summer, BioWorks will be introducing PlantShield®, a wettable powder for soil drenching and foliar spraying. This product will take the place of RootShield Drench. BioWorks will still be offering RootShield Granules; together with PlantShield a grower now has chemical alternatives to prevent most fungal rots on both the roots and the foliage - total plant protection.