Pest Management Guidelines - Ornamentals




Published in: Hawaii Landscape, Official Publication of the Landscape Industry Council of Hawaii. Sept/Oct 2000. Vol. 4, No. 5, p. 7.

By: A. H. Hara

CTAHR, Dept. of PEPS, Beaumont Agric. Res. Center, University of Hawaii-Manoa, 461 W. Lanikaula St., Hilo, Hawaii 6720, Phone (808) 974-4105

The U.S. Environmental Protection Agency (EPA) and the manufacturer Dow Agro Sciences have agreed to ban the widely-used pesticide, chlorpyrifos, for all purposes where children could be exposed. The chemical is commonly known under the brand names Dursban or Lorsban. 

Specifically, Dursban will not be manufactured and sold to homeowners for home, lawn and garden uses by 2001. All outdoor use areas where children could be exposed (schools, parks, resorts) will be cancelled by 2001.

In addition, in outdoor areas where children are not generally exposed (golf courses, road medians and industrial plant sites) application rates will be reduced. By the end of 2005, use of Dursban to control termites in buildings and new construction will be completely phased out. 

Agricultural and ornamental nursery production uses will be extremely curtailed by classifying chlorpyrifos as a Restricted Use Pesticide (RUP), which will require a pesticide applicator's license. Restricted entry intervals (REI) and preharvest intervals (PHI) for food crops will be lengthened for chlorpyrifos.

Why such negative action against Dursban and other organophosphates? EPA Administrator, Carol M. Browner states, "Chlopyrifos is part of a class of older, riskier pesticides, some going back 50 years. Exposure to these kinds of pesticide s can cause neurological effects. Now that we have completed the most extensive scientific evaluation ever conducted on the  potential health hazards from a pesticide, it is clear the time has come to take action to protect our children from exposure to this chemical."

Both American Farm Bureau Federation (AFBF) and the American Nursery & Landscape Association (ANLA) have said they're concerned that EPA’s recent actions on chlorpyrifos were based more on politics than on sound, science-based policies.

Dow AgroSciences claims to steadfastly believe in the safety of chlorpyrifos as documented in more than 3,600 studies that have examined critical aspects of chlorpyrifos products as they relate to health and safety. Dow claims that currently labeled uses of chlorpyrifos products provide wide margins of safety for both adults and children.

Diazinon Also Lost In related news, Novartis Crop Protection recently decided not to pursue research requested by EPA to support indoor applications of Diazinon, which will eliminate its uses in greenhouses, residential settings, commercial buildings, hospitals, schools, and warehouses.

"We regret that Novartis has had to make a business decision to no longer support indoor uses of Diazinon," Novartis announced. "We regret the loss of this valuable tool, particularly for our colleagues in the ornamental and structural pest control markets. Unfortunately, sales in these sectors no longer justify the heavy commitment of resources now required to support any indoor uses."

To complicate the decisions on Dursban and Diazinon, a committee chartered by the prestigious U.S. National Academy’s National Research Council (NRC) concluded in a report release in July that chemical pesticides will continue to play a significant role in U.S. agriculture for at least the next decade.

The NRC’s Committee on the Future Role of Pesticides in U.S. Agriculture found no justification for completely abandoning chemical pesticides because effective and affordable alternatives are not yet widely available.

"Chemical pesticides should remain part of a larger toolbox of diverse pest-management tactics in the foreseeable future," said the Committee's chairperson, M.R. Berenbaum, professor of entomology, University of Illinois. "No single pest management strategy will work in all ecosystems, so chemicals need to be part of an ecologically-based framework that can safely increase crop yields."

This is the case for pest management in Hawaii’s nurseries and landscapes. There is no single alternative pest control strategy to replace the effectiveness and affordability of Dursban or Diazinon against insect pests on ornamental plants, especially in situations where no biological control agents exist. A multitude of pesticides will be needed to replace the spectrum of pest control offered by these products.

Alternatives will include other organophosphate (Malathion, Orthene), carbamate (Closure, Sevin) and pyrethroid (Mavrik, Talstar, Decathlon) insecticides, but these products are also in jeopardy with limited or canceled registrations.

New chemistry pesticide alternatives, such as Conserve, Marathon or Merit, does not have the same spectrum of activity against insect pests and appear very costly to users compared to Dursban or Diazinon. Cost-effectiveness studies are needed to convince pest managers that the more expensive, new chemistry pesticides use lower rates and, if properly applied, are highly effective against certain pests.

Applied research supported by both public and private sectors is needed when an effective and affordable pesticide such as Dursban or Diazinon is abruptly removed from the manager's pest control toolbox.

The NCR recommended that more government-sponsored research and incentives are needed to spur the development and use of alternative pesticides or new chemical pesticides that pose fewer risks to humans and the environment, and that are not too costly to use. 

For more information call 974-4105, fax 974-4110 or e-mail

Dr. Arnold Hara is a professor in entomology in the Department of Plant and Environmental Protection Sciences at the
University of Hawai`i Manoa, College of Tropical Agriculture an Human Resources, stationed at Beaumont Agricultural Research Center in Hilo.



Use pesticides safely. Follow the pesticide label. Consult with the Cooperative Extension Service or the Hawai'i State Department of Agriculture for authorized special local need registrations or additional information. The user is responsible for the proper use, application, storage, and disposal of pesticides.


Reference to a company or product name does not imply approval or recommendation of the product by the College of Tropical Agriculture and Human Resources, Cooperative Extension Service University of Hawaii, or the United State Department of Agriculture and does not imply its approval to the exclusion of other products that may be suitable. All materials should be used in accordance with label instructions or manufacturer's directions.