A Report on the Informal Conference held during
Annual Meeting of Entomological Society of America in Montreal, Canada
on December 05, 2000
L. L. Larson, Conference Convener
Dow AgroSciences, Discovery Research
9330 Zionsville Road, Indianapolis, Indiana 46268-1053
The symposium was introduced by Larry Larson who indicated the many changes occurring in entomology as we enter the new millennium. Biotechnology will add another dimension to insect control research. Consolidation in the industry will lead to fewer research-based firms capable of new product development. Many companies are becoming generic suppliers without a significant new products, research base. The EPA has provided the industry with incentives by granting priority to reduced-risk pesticide registrations. Finally, the Food Quality Protection Act (FQPA) continues to change the landscape of older products available for use. These changes were, to a large degree, anticipated by the industry. A decade ago the industry adopted product goals that included environmental safety (low use rates, short soil half lives, low soil leaching, and high human safety); performance, (reliable, effective, selective, and flexible in timing and application method), and good economics for the customer and the company to finance product research efforts.
The first paper presented by Ty Vaughn of the Monsanto Company covered new transgenic crop alternatives and their place in pest management. He talked about the mode of action of Bacillus thuringiensis (Bt) endotoxins and their unique place in transgenic crop protection. He painted a picture, starting with corn, where the current Cry1Ab systems will be joined by another Bt designed to increase the spectrum of activity. In addition, a Cry3Bb toxin is under development for corn rootworm control. Information was presented indicating better root protection than conventional granular at-plant products. A Bt gene is also under development for soybean protection, stacked with the Roundup-Ready trait. Active on stem borers, velvet bean caterpillars, and loopers at 110 sites, it gave over 90% control of soybean foliar pests. In cotton, a second gene will join the current Cry1Ac gene for corn earworm, tobacco budworm, and pink bollworm control. These new genes will result in increased yields with fewer inputs, lower costs, and increased feed safety. In addition, farmers will have new biotech crops with fungal resistance, modified oils, enhanced vitamins, proteins, and pharmaceuticals. Adoption rates for biotech crops in the United States continue to be high, and systems are evolving to combine these methods with already existing pest management systems.
Joel Wierenga of Rohm and Haas Company brought us up to date on the molt accelerating compounds (MACs) begun by the company in the early 1980s. His talk, entitled "Proactive stewardship of the MAC insecticides globally: A common sense resistance management approach for the new millennium," covered new information on the status of resistance monitoring especially with tebufenizide (Confirm) and methoxyfenizide (Intrepid and Runner) around the world. These materials are broad-spectrum lepidoptera control agents acting to accelerate the molting process, initiate new cuticle development, and lead to head capsule slippage. They also inhibit eclosion hormone release. For resistance development, they selected for study five species known to exhibit resistance to other materials: the codling moth, oblique-banded leaf roller, beet armyworm, Oriental fruit moth, and the tufted apple bud moth.
Larry Hull at Pennsylvania State studied oblique-banded leaf roller populations in Pennsylvania, Michigan, the Pacific Northwest, and Northern California. He found a wide range of susceptibility, but no cross-resistance between methoxyfenozide and tebufenizide. There was less than a ten-fold difference in susceptibility and no change in the baseline over the last 3 years. The codling moth studies were conducted first in the Pacific Northwest and recently expanded to the Eastern United States. They found a three-fold increase in the susceptibility of a strain from organically grown apples. All other populations had been within a normal range with no changes in sensitivity over the course of the study.
Tim Dennehy at the University of Arizona studied strains of beet armyworm around the world. In particular, they saw a problem with resistant beet armyworm around Bangkok, Thailand, where there is continuous exposure to sublethal amounts of toxicants due to the irrigation washing it off. Tebufenizide had been removed from the market after 2 years due to a high level of resistance. Selections of these strains gave up to a 30-fold resistance ratio. These strains were synergized with piperonyl butoxide indicating enhanced mixed function oxidase involvement. Studies on glutithion S-transferase, cuticular penetration, and target site sensitivity were negative. The strain did exhibit increased excretion and decreased absorption of the toxicant. Rohm and Haas have used these data to develop a resistance management strategy. They recommend treating 2-3 generations over 80 days, then rotate with indoxacarb, emmamectin benzoate, spinosad, or chlofenopyr. If they detect a shift in sensitivity, they will reduce sales in the affected area.
Keith Dorschner with the IR-4 program at Rutgers University gave a presentation on "The IR-4 Project: New pest management tools for minor crops." Designed to register new materials on minor crops, IR-4 is a partnership between USDA, EPA, land-grant universities, state agricultural experiment stations, agrichemical companies, growers, and grower organizations. Minor crops are low in acreage but high in value, fruit and vegetable crops. The value for these so-called minor crops was $40 billion in 1997, compared with $98.1 billion for the major high acreage commodities. Minor crops comprise a large portion of the American diet. Their distribution is mainly coastal, with California the biggest minor crop state at $14.5 billion. Alaska and Hawaii have almost all minor crops with major value. IR-4 is a national project with a management committee. There is also a liaison committee composed of representatives from USDA’s CREES andARS and others. The program, headquartered out of Rutgers began in the early 1960s when much of the industry was based in New Jersey. The regional laboratories include University of California-Davis in the West, University of Florida in the Southeast, Cornell University in the Northeast, and Michigan State University in the North Central region.
The IR-4 process begins with a project clearance request that identifies a pest control problem and a solution. These requests are forwarded to headquarters where they are evaluated and prioritized annually with input from the EPA, growers, community representatives, and the crop protection industry. Support from industry is critical because the products owner is the registrant. Study directors then develop program protocols with input from the registrants, field coordinators, and lab directors. The Grow Crops Unit applies the treatments under good laboratory practices (GLP). Once the trials are complete, samples are analyzed, and reports are created, the entire process is reviewed for quality assurance and final review from the study director assures that the petition reflects the raw data. Then tolerances are proposed, checked with the registrant, and the petition sent to EPA for review. A tolerance, the amount legally remaining on the crop following harvest, is set; a label can then be issued so that growers can legally use the material.
In recent years, FQPA has effected minor crop registrations adversely. This is because minor crops are a major part of the human diet, but low in market potential. As companies decide which crops to add to their risk cups, often minor crops are the first to be eliminated. IR-4 has responded by increasing its reduced-risk projects from 45 in 1997 to 82 today. In 1999, 165 new uses were added to the spinosad label covering nearly every requested registration. Sugar beets, radish, strawberry, and litchi were added to the MAC labels, and new labels are pending for thiamethoxam, pymetrazine, buprofezin, bifenzate, and pyriproxifen.
Paul Bystrak of Mycogen Seeds talked about "Corn rootworm: New options for management with transgenic corn." Rootworm causes $1 billion in damage every year to the corn crops. Currently there are three options for control of the rootworm complex – crop rotation, insecticides, and crop tolerance. Now it appears that in part of the Corn Belt, crop rotation has become ineffective due to the soybean biotype of the Western corn rootworm. Several biotech products are nearing commercialization that will help farmers cope with this continuing threat. Monsanto plans to have registration in 2001 for MaxGuard, the Cry3Bb toxin containing hybrids with narrow-spectrum beetle activity. Dow, in cooperation with Pioneer, has a new amorphic inclusion protein toxin from the PS 149 B1 Bt strain in the event-sorting stage with an EUP planned for 2001 and marketing as early as 2003. This protein has no known homologies with other proteins and no sign of activity on adults. This material has also shown activity levels better than at-plant insecticides. Also discussed was W-14, a protein isolated from Photorhabdis luminescens, a symbiotic bacterium found in entomophagous nematodes. Dow is developing this protein in collaboration with the University of Wisconsin. The spectrum of the protein includes corn rootworm and lepidopterous pests. Protein A has been expressed in corn and gives control. Currently this gene is in the event production and sorting stage behind PS 149 B1. Host-plant resistance will soon be an option for the management of corn rootworm. This will result in the reduced use of chemical pesticides, and with the existence of multiple effective proteins, resistance management should be easier.
Rod Kepner of Gowan Company gave a review of the acaricide, hexythiazox, discovered 20 years ago, but acquired by Gowan in 1994. It is known as Savey in the crop markets and Hexigon in the ornamental and nursery markets. They currently have special local-needs registration in hops, cotton, apples, strawberries, stone fruit, and almonds. They are pursuing registrations in greenhouses and the other nuts. Gowan currently markets a 50 WP, a 50 DF, and a 2 lb/gal EC (cotton only) formulations. They are pursuing registration through IR-4 on mint, caneberries, and dates. The active ingredient is a crystalline solid with low vapor pressure. It is a stable product with very little ultraviolet degradation. It exhibits long-term activity in the field and is non-mobile in the environment. It is safe to mammals, moderately toxic to aquatics, and safe to avian species and honeybees. It is a selective acaricide effecting all tetranychidaide mites. It is active on eggs and immature forms and is believed to interfere with chitin synthesis. The ovicidal activity is exhibited by direct spray or residual contact. In the first 48 hours, eggs are quite susceptible. They are up to 200-fold less susceptible later. Unlike other products, the material affects all 3 immature stages equally well. There is little acute toxicity to adult females, but they lay sterile eggs upon 3-5 days of exposure on treated surfaces. All eggs laid within 2 days of exposure are not viable. Hexythiazox shows excellent performance compared to abamectin and gives 9-10 weeks of control in almonds, 28 days of control in peaches, excellent residual performance in strawberries and cotton, and 75 days of residual against date mites. The effects on predaceous mites are minimal, and the IOBC working group deems hexythiazox harmless to all beneficials. Resistance to hexythiazox has occurred in Japan, Australia, Europe, and the United States. Some cross-resistance has been seen to clofentezine. In Brazil, Russia, Denmark, Sweden, and Portugal, resistance has never been seen. Here use of the product is limited to one application per season. Gowan has restricted the use of hexythiazox to 1 application per year and recommends rotation with chemistries with different modes of action. They recommend using the lowest effective use rate with proper timing and application methods. Hexythiazox can be an ideal pest management tool with low use rates, safety on beneficials, effective at low temperatures, and broad efficacy on all immature stages.
John Andaloro of DuPont Crop Protection gave a talk on the stewardship of the unique attributes of indoxacarb in global IPM and resistance management programs. Indoxacarb is an oxidiazine reduced-risk pesticide available in the United States as Avaunt 30WG or Steward 15%SC. EPA granted registration in October 2000 and it will be commercial in 2001. The material has optimal traits for pest and resistance management. It is reduced risk and favorable to the environment and beneficials. It has a relatively short residual, is effective at action thresholds under varying conditions, and effective on resistant pests. Indoxacarb exhibits little soil movement due to its high lipophilicity. The material is safe to predators due to a lack of bioactivation. On the other hand, lepidopterous pests are highly efficient activators of the molecule. Non-lepidopterous pests also tend to be less effective converters of the molecule. The material does not penetrate well through the tarsi of sucking predators. They do not appear to ingest enough from their prey; however, if they feed on leaves they can be affected. There is an effect on coccinelids, especially lady beetles. Fire ants are also affected as they preen and ingest the product. The material tends to be slow, although feeding cessation takes place rather quickly. They recommend waiting 3 days to assess the activity of the material. Because of this slow activity, especially with cryptic feeders, they recommend spraying from egg lay to egg hatch for optimal control. The material is safe to many parasitoids. Trichogramma can be sprayed directly with no adverse effects. The material exhibits very broad lepidopterous activity and activity against ants, beetles, flies, and hemipterous pests such as tarnished plant bug and stinkbugs. The mode of entry of the material is through ingestion (1x) or direct contact (2-10x less active) or residual contact (50-100x less active). There are sublethal effects at 100-fold less than the LC50 on the beet armyworm that delays pupation up to 8-9 days. The material works as a sodium channel blocker at a novel site. They are monitoring susceptibility on target species around the world with leaf feeding assays. The material is stable from pH 5-10, and 34-120 degrees F. It has great wash off and ultraviolet light stability and a positive temperature coefficient. Its limitations are the need for good coverage and accurate timing. This information needs to be communicated to the growers.
David Rogers from Bayer presented information the company’s new chemicals for mite and insect control in fruits and nuts. BAJ 2740 is a novel broad-spectrum acaricide being developed by Bayer around the world. It is a phenyl tetronic acid derivative named of Envidor 240g/l SC. It is a good, environmentally safe product with low hazard to birds and beneficial insects, although it is slightly harmful to predatory mites. It exhibits rapid degradation with soil half lives of 0.5-5.5 days and shows no leaching and microbial effects. It is active against all mite stages, although adult females take higher concentrations for adequate control. There is a slight delay in onset of activity, but excellent residual control capabilities. European red mite control for 6-7 weeks was exhibited in apples. The material acted faster than etoxazole and was better than tebufenpyrad against resistant strains. In California, 200 g/1,000 liters of the material gave control on almonds for 35 days. Against citrus rust mite at 100 g/1,000 liters, it gave 7 weeks of control. Against Brevipalpus, the material gave 12 weeks of 99-100% control. The speed of action was between the acute materials and the chitin inhibitors, 2-3days. Effects on predatory mites appeared between hexythiazox, which is safe, and fenaziquin, which drops beneficial mite populations dramatically. The material interferes with mite development. The females tend to retain their eggs. The effects are rate related, and at lower concentrations, there is reduced fecundity and fertility. There is no cross-resistance to the METI acaricides or pyridiben. They recommend only one application per season, and plan to submit registeration in 2001 for the product in citrus, pome fruit, stone fruit, tree nuts, and grapes.
Amy Wyman from Bayer talked about Calypso a new foliar-applied insecticide in pome fruits and cotton. Thiacloprid, or WRC 2894, is a new neonicotinoid or chloronicotinyl product from Bayer. It will be available in a 4F-, 2F-, 36WG-, or 70 WG-formulation under the trade name Calypso. It is a contact and stomach poison that binds to the postsynaptic nicotinic receptor. Unlike other nicotinoids, thiacloprid is harmless to pollinators, so it can be sprayed during flowering. Its half life in soil is 7-21 days, so it is not recommended as a soil-applied material. It is immobile and does not leach. It has low vapor pressure and low acute toxicity. It is similar to imidachloprid in beneficial testing – slightly harmful to hover flies and lacewing, moderately harmful to parasitic wasps, but harmless to honeybee. At 5 and 24 hours after contact, it was 2-3 orders of magnitude safer than the current materials. Effects on foraging showed equivalent foraging to untreated crops at 100 g/Ha. It will be labeled in the United Stayes for vegetable whitefly, aphid, flea beetle, and pepper weevil control. In cotton, it will be labeled for whitefly, aphids, tarnished plant bug, leafhopper, pink bollworm, and Heliothis sp. In pome and stone fruit, it will be labeled for aphids, pear psyllid, leaf miners, leafhoppers, codling moth, Oriental fruit moth, plum curculio, and apple maggot. The lepidoptera species are new to neonicotinoid activity and information was presented showing good control of codling moth down to 0.0048%. Here it appears that the egg stage is the target. Bayer is also looking at a complimentary approach using combinations and alternations with Guthion. Information was also presented on control of apple maggot which looked good, over 80% control at 0.094%. In cotton, Provado and Calypso were very close in activity against cotton aphid, but Calypso showed better residual activity through 21-28 days. Against the silver-winged whitefly on cantaloupe, Calypso did very well through 14 days and on squash against melon aphid, it showed good knockdown and residual activity through 28 days.
Larson gave concluding remarks in which he summarized the talks and focused on the transitions toward an exciting new future for pest management that these tools represent. The industry will continue to evolve as a result of changing customer needs and advancing technology. During these transitions, we will continue to make more effective use of our already-registered materials with appropriate resistance management plans. The focus will continue to be on discovering pest management tools that vary in mode of action and are more effective with lower adverse impacts on the environment.