December 2007

News and Views in Chemicals By Paige Worthy

For GPN's 10th year covering greenhouse chemical trends, we're taking a different approach: a roundtable featuring the opinions of six experts in the fields of pests, diseases and plant growth regulators. In the next few pages, these industry-leading researchers will provide you with their keen insight on the current state of chemicals and let you know what to expect in the coming year and beyond.

In the past 12 months, what new developments have occurred in your field?

James Bethke: I surveyed my contacts, and not much. There are still a few new compounds being developed, but they're years away. The most common changes are label enhancements and some reformulations.

Raymond Cloyd: Although it is difficult to determine what is meant by "new developments" one "new development" is based on the interest in "organic" and "sustainability," in which companies are now attempting to get products registered for use in "organic" production or OMRI (Organic Materials Review Institute) listed. Manufacturers are starting or continuing to include the Insecticide Resistance Action Committee (IRAC) mode of action designation (www.iraconline.org) on insecticide and miticide labels.

A.R. Chase: The most action in new fungicides will actually be occurring in the next 12 months. We have quite a few combination products that will reach our market. The first (which may already be labeled) is 26/36 a combination from Cleary that combines two industry standards, iprodione (such as Chipco 26019 and Chipco 26GT) and thiophanate methyl (like 3336). This combination of active ingredients should make control of both foliar and soil-borne diseases easier. Pageant is a new combination product from BASF that will hopefully be available in the second quarter of 2008. It has a very broad spectrum of activity and is especially active on anthracnose, dieback and Fusarium crown rot. Pageant contains Insignia (a newly registered strobilurin) and boscalid (an active ingredient not available on its own in ornamentals). Finally, Palladium is a combination product from Syngenta. This product is especially strong on Botrytis and Sclerotinia but also has all of the control characteristics of fludioxinil (Medallion). The other active ingredient is cyprodinil (not available as the sole ingredient for ornamentals).

Margery Daughtrey: The new materials in fungicides are Hurricane (essentially a SubdueMAXX plus Medallion mix) and Insignia (the latest in the strobilurin class). OHP has taken over the Chemtura fungicides (Terraclor, Terraguard, Terrazole). IR-4 has been focusing on Pythium, developing a lot of data on control of this omnipresent pathogen by newer chemistry.

Joyce Latimer: The biggest development in PGRs this year has been the labeling of Configure (benzyladenine, Fine Americas) for enhancement of branching of hosta, echinacea and Christmas cactus.

Jim Barrett: The most significant occurrence in PGRs for me was the startup of trials on the ABA product being developed by Valent Biosciences. While ABA is still 1-2 years from being approved by EPA, this is a unique product that has the potential to be significant for growers. ABA is the natural plant hormone that causes stomates to close in response to drought stress. Treating plants with ABA causes the stomates to close and significantly delays wilting, which can be important in many retail settings.

If there have been few developments, why do you think that is?

James Bethke: Companies are looking for ways to save because development of new compounds in the United States is very costly, and one of those ways is to look backward at the old arsenal — older compounds that had promise in the past but were ignored in favor of the ones we have now. They are looking to see whether there is sufficient merit to give them a new look. Companies are buying other companies' old chemistries to mine for compounds with possibility.

Margery Daughtrey: Companies have been focusing on getting products registered for control of Phytophthora ramorum, the agent of Sudden Oak Death. This and the high cost of fuel have possibly indirectly affected how much investment has gone into new products for the ornamentals industry.

Jim Barrett: In the area of growth regulators used for size control, there were no big developments. There are several different good products on the market, and there is not strong motivation for chemical companies to introduce new ones.

What is the most difficult challenge growers face in the coming year?

James Bethke: Insects that are already tolerant to the current chemistries like the leafminer, the western flower thrips, and the Q biotype sweet potato whitefly. Disease vectors like western flower thrips. Boring beetles that are very difficult to contact. Q biotype that is already resistant to IGRs and some neonicotinoids. The ever-present and difficult to contact mealybug. Mites other than spider mites, such as Eriophyids and Tarsonemids. Another issue is being able to develop good management strategies over the life of a crop. For instance, what should a grower start and finish with on a poinsettia crop that lasts from August to November?

Margery Daughtrey: The most difficult specific disease is the downy mildew on coleus. Growers can't even see that it is present, but under favorable environmental conditions it causes severe symptoms (massive leaf drop) on the most highly susceptible cultivars. Some growers are giving themselves the challenge of doing pest management organically, and that is a real challenge. Growing for the mass market brings big challenges, because often only a few cultivars are grown, and if one of these is highly susceptible to a common disease, a third of the crop can be lost very quickly. This is creating more of a monoculture production system than we have had in the past for ornamentals.

Raymond Cloyd: The most important challenge to greenhouse growers is to avoid the potential for insect and mite pest populations developing resistance to currently available pest control materials (insecticides and miticides). As such, greenhouse growers need to develop and implement rotation programs that involve using insecticides and miticides with different modes of action. In addition, proper scouting will assist greenhouse growers in properly timing applications of insecticides and miticides. Another challenge is dealing with the introduction of new arthropod pests including the chilli thrips and Q biotype whitefly, which again means that greenhouse growers must be familiar with the mode of action of insecticides and miticides.

Jim Barrett: There are many different crops, varieties and production styles and new plant introductions every year. Market pressures are so tight that growers can't afford crop losses from poor results of growth-regulator usage. Add the variable of the need to alter use rates with weather changes, and it's a real challenge for growers to get it right every time.

Joyce Latimer: The challenges aren't new. We continue to have new crops to produce and integrate into the PGR plans but growers are becoming more familiar with how to run their own PGR rate trials and work from their own experiences. With the generic versions of the PGRs, growers have more options for growth regulation than they've ever had before. But I think that most of the growers know what they want to use and read the labels.

A.R. Chase: I think the most difficult problem is finding disease-free plants to start with. This impacts the specialty propagator as well as the production facility: Diagnosing diseases, especially those caused by viruses, is very costly and time consuming. It is also a serious problem when so many of our new crops are virtually unknown. We often don't even know what to check them for. Many broad-spectrum products are used under conditions when the problem is not accurately identified. The results are not always lack of control but sometimes can end up with loss of the crop due to phytotoxicity that need not have occurred.

What are the biggest production concerns for a grower implementing new strategies using these chemicals?

Margery Daughtrey: If using Hurricane, they will need to be aware that any Pythium or Phytophthora that is insensitive to SubdueMAXX will also be insensitive to Hurricane. They will need to rotate with Banrot if they want to use pre-mixes, or to bring other active ingredients into their rotation.

Raymond Cloyd: Greenhouse growers need to develop and implement rotation programs that utilize insecticides and miticides with different modes of action in order to avoid or minimize the prospect of insect and mite populations developing resistance. Additionally, greenhouse growers need to test tank mixtures prior to applying to the entire crop in order to determine if the tank mixture is phytotoxic or not. It is also important to develop tank mixtures that make "sense" and avoid tank-mixing products with the same mode of action.

Jim Barrett: The past couple of years, we have been talking about new strategies for using growth regulators to achieve better height control. Examples are the use of low-dose drenches applied early in poinsettia production and dipping rooted cuttings and plugs in growth regulator solutions prior to transplanting. Growers know the potential problems with making mistakes using growth regulators and they know the level of precision needed to be successful. Therefore, most growers are generally conservative when it comes to changing their procedures. So, it takes some time for growers to learn how new strategies work in their own situation.

Joyce Latimer: The biggest production concern for using new PGRs or new PGR application methods is the physical handling of the crop — in other words, grouping crops that need more frequent PGR applications, or crops that are treated with the liner dip to prevent their subsequent treatment with PGR sprays. We still have concerns about PGR drenches on some of the perennials, like daylily, where there is an excessive reduction in flower stalk height. It's just not an exact science, and we are finding some unexpected plant responses. Growers still need to trial new crop and PGR combinations.

What developments do you predict for 2008? Farther down the road?

James Bethke: A few pesticides will come to fruition, such as Valent's (Pyridalyl, S-1812). Further down the road there are the new tetronic acids (spiromesifen and spirotetramat) and spinosyn variants (spinetoram, a second-generation spinosyn). Numerous miticides and biopesticides (Bt variants and Beauveria variants that are more host specific).

Margery Daughtrey: I don't know, but what we need are more choices for effective Pythium and Botrytis control. Some are in the works.

Ray Cloyd: There will likely be "fewer" new active ingredients introduced compared to what has become common in the past. Again, this means that greenhouse growers need to implement proper stewardship of currently available insecticides and miticides in order to preserve their longevity.

Jim Barrett: We will certainly learn more about ABA and its potential for the industry, but it will likely be 2009 before it is available to growers. Tiberon is a new product labeled for promoting branching of trees and shrubs. In the next couple years we are likely to find ways to use it on greenhouse crops.

Joyce Latimer: I think that we will see more emphasis on developing or refining application techniques to simplify rate selection and REI issues. Farther down the road, I expect to see more work on new formulations to enhance ease of application and application uniformity, especially in the larger nursery-type production settings, as seen with perennials.

What is your opinion on generics? How are they impacting the market?

James Bethke: Generics are nothing new, really. They create challenges to the original stakeholder in that they now have to find ways to make their products look better because of the formulation, but in the long run it's good for the grower because it lowers costs, to a certain extent. You will constantly hear the refrain that generics may not be as effective, but in many cases the products are identical because they are buying the actual product directly from the manufacturer and just repackaging it.

Raymond Cloyd: Since imidacloprid (Marathon) went off patent, there have been a number of generic products available, such as Benefit; however, generics are simply sold by distributors. There is no technical service provided. So if any problems occur after an application, companies that sell generics will not be available to provide assistance. Because many companies that are associated with selling the neonicotinoid insecticides such as Flagship (thiamethoxam), TriStar (acetamiprid), Celero (clothianidin), and Safari (dinotefuran) to greenhouse growers have been around for awhile, I don't think that the generics will have a major impact, in terms of pricing, for two or more years.

Jim Barrett: Several of our growth regulators are older chemicals that are now off patent. However, I feel the issue is not simply generic chemicals. The important issue is how a company supports its grower customers and the greenhouse industry. It is a significant investment for chemical companies to develop new products and information on how to use them on floriculture crops requires. Growers should notice which companies are sponsoring university research, developing new information and delivering the information to growers. Our industry is relatively small in the agricultural chemical world, and we need to support those companies that are investing in the future of our industry.

Joyce Latimer: I don't think that generics are bad. In choosing their PGRs, growers need to look at the combination of product efficacy and cost, and the company support. In general, we are not finding significant differences in efficacy between the original and generic products. Product cost and support does vary with location (distributors) and company. Ask questions and compare the answers. Obviously, I think that a good PGR company should continue working in research and development of their products and new products to support the industry.

A.R. Chase: Over the past few years we have seen post-patent fungicides enter the ornamental marketplace. They are sometimes less costly and usually have a very similar label to the brand name fungicides we are familiar with. We have also started seeing products with similar active ingredients (such as phosphonates and Aliette) marketed as the same or superior. The companies that sell post-patent fungicides do not routinely trial their product against the better-known trade-name fungicide. At Chase Horticultural Research, Inc., we compare fungicides with the same or very similar active ingredients in side-by-side trials. These comparisons can result in one of three conclusions: 1) the post-patent and brand-name products give the same level of control, 2) the trade-name product gives better control than the post-patent product or 3) the post-patent product gives better control than the brand-name product. If you choose generic products based on cost alone, you may be successful, and you may not.

Anything else GPN readers should know about?

James Bethke: Clothianidin, the neonicotinoid from Arysta, is now Valent's product and includes the trade names Celero (ornamentals) and Arena (landscape). OHP has acquired Crompton/Uniroyal's line of ornamental products, including diflubenzuron (Adept) and novaluron (Pedestal).

Ray Cloyd: If possible, greenhouse growers should consider implementing biological controls (i.e., natural enemies), as this has proven to be a viable method of controlling insect and mite pests in greenhouses. However, there needs to be a firm commitment by everyone associated with a greenhouse facility for this pest management strategy to be successful. Finally, as our research has demonstrated, the implementation of proper sanitation practices will assist greenhouse growers in minimizing problems with insect and mite pests.

Joyce Latimer: PGR use is still an art, not just a science. Nothing replaces experience and home-based trials.