NCC Comments to EPA Regarding Dicrotophos

In response to EPA's September 25, 2015 Federal Register notice opening a public comment period on EPA’s draft human health and ecological risk assessments for the registration review of a group of 35 different pesticides known as sulfonylureas and other identified chemicals, the NCC provided comments related to the importance of the pesticide dicrotophos as an insect management product and urged its continued registration.

Published: February 24, 2016
Updated: February 24, 2016

February 23, 2016

OPP Docket
Environmental Protection Agency Docket Center (EPA/DC), (28221T)
1200 Pennsylvania Ave. NW
Washington, DC 20460-0001

Mr. Khue Nguyen, Pesticide Re-Evaluation Division (7508P)
Office of Pesticide Programs
Environmental Protection Agency
1200 Pennsylvania Ave. NW,
Washington, DC 20460–0001

Re: Docket ID No. EPA–HQ–OPP–2008-0440.

Dear Mr. Nguyen:
In response to the Environmental Protection Agency’s (EPA) September 25, 2015 Federal Register notice opening a public comment period on EPA’s draft human health and ecological risk assessments for the registration review of a group of 35 different pesticides known as sulfonylureas and other identified chemicals, the National Cotton Council (NCC) appreciates the opportunity to provide the following comments related to the importance of the pesticide dicrotophos as an insect management product.

The NCC is the central organization of the United States cotton industry.  Its members include producers, ginners, cottonseed processors and merchandizers, merchants, cooperatives, warehousers and textile manufacturers.  A majority of the industry is concentrated in 17 cotton-producing states stretching from Virginia to California. The NCC represents producers who cultivate between 10 and 14 million acres of cotton.  Annual cotton production, averaging approximately 16 to 20 million 480-lb bales, is valued at more than $5 billion at the farm gate.  The downstream manufacturers of cotton apparel and home furnishings are located in virtually every state. Farms and businesses directly involved in the production, distribution and processing of cotton employ more than 230,000 workers and produce direct business revenue of more than $27 billion.  Accounting for the ripple effect of cotton through the broader economy, direct and indirect employment surpasses 420,000 workers with economic activity well in excess of $120 billion. In addition to the cotton fiber, cottonseed products are used for livestock feed, and cottonseed oil is used as an ingredient in food products as well as being a premium cooking oil.

The cotton insect situation in the U.S. cotton belt has undergone major shifts following boll weevil eradication and the introduction of Bt cotton.  As the weevil was eliminated, coupled with planting Bt cotton for caterpillar control, thrips and the piercing-sucking insects like aphids, plant bugs, fleahoppers, stink bugs, and leaf footed bugs have emerged as the major insect pests for U.S. cotton production. According to the annual cotton insect pest survey by Dr. Michael Williams, Mississippi State University ( resources/croplosses /2013loss.asp) for 2013, thrips were the most widespread insect pest in cotton infecting more than 6.7 million acres, followed by stink bugs, aphids, and Lygus.  

Piercing/sucking cotton pest such as thrips, aphids, and plant bugs have long presented a challenge to cotton production.  Aphids and thrips often feed on the underside of leaves making it difficult to provide coverage with contact control materials.  Plant bug adults are very mobile - moving in and out of fields.  Plant bug adults and nymphs often feed on small squares inside bracts of the plant, which reduces the effectiveness of contact materials. 

The use of cotton seed treated with neonicitinoids has greatly enhanced the ability to control these early season cotton pests.  The ability of neonicotinoid products to move systemically through the sap overcomes the problem of direct pesticidal contact. However, the effectiveness of seed treatments is limited to about 30-40 days following planting.  It is typically after this time that the use of dicrotophos is critical as a rotational chemistry and as a critical tool for control of some difficult pests.  Although the use of dicrotophos has declined over time, it remains a critically important component of many cotton Integrated Pest Management (IPM) systems.  The reduction in use should be viewed as judicious use as needed and should not be viewed as lack of need.

Dicrotophos is an essential product to effectively manage stink bugs and plant bugs in the cotton production areas.  Plant bugs feed on cotton squares and very small bolls.  Cotton is particularly susceptible to plant bug damage for several weeks in mid to late season.    To manage the heavy plant bug infestations adequately, it is necessary to have the ability to apply dicrotophos at either 0.33 lbs ai/ac three times, or at 0.5 lbs ai/ac two times during the period that plant bugs attack cotton fruit.  Stink bugs feed mostly on small to medium size bolls, and dicrotophos serves as a critical tool to control these pests in many areas.

The NCC has reached out to university experts across the cotton belt in order to understand their view of the importance of dicrotophos as a crop protection tool for cotton. These experts were asked to comment on three points:  1) the value of dicrotophos (Bidrin) as a pest management tool in cotton; 2) how an untreated buffer would impact cotton insect pest management; and 3) the importance of maintaining the retreatment interval of 14 days.  Attached, we have included the letters we received from 9 experts representing 8 different states.  All of these experts confirm that dicrotophos (Bidrin) is a valuable tool for managing various insect pests of cotton.  Some ( i.e., Alabama) point to particular uses and niches that are not filled by other products while others emphasize the situation where Bidrin provides effective control of multiple pests simultaneously present in a field rather than requiring growers to treat the field with multiple products at once.

These experts express opposition to untreated buffers in fields because such requirements do not meet sound IPM practices.  The allowance of untreated strips or buffers on field edges provides a nursery source for pest densities to increase and re-infest fields more frequently, not to mention the yield loss potential.  If alternative products are allowed to be used on the buffer area, it adds economic cost for additional trips to treat the field margins.  The treatment loses economies of scale and becomes an excessively costly treatment.  Additionally, these experts express concerns that buffers around a field edge greatly impacts small fields disproportionately.  In such a case, one should question if such a policy exerts excessive economic burdens on small operations.

To the last point addressing a potential expansion of the retreatment interval, these experts emphasize the current 14 day retreatment intervals already challenge the ability to effectively use the product to control damaging pests, and that an extension of the retreatment interval would restrict effective use of the product forcing producers to use less effective products, treating more frequently, and having fewer modes of action as treatment options.

EPA has adopted a new practice and policy by implementing a 10X safety factor on all organophosphate chemistries.  EPA refers to “new” epidemiology studies, particularly a study at Columbia University, as a claim to justify the adoption of the 10X safety factor.  The NCC believes EPA has deviated from normal procedure of engaging stakeholders prior to adopting new practice or policy.  The NCC, along with several others, has urged EPA to remove the 10X safety factor until EPA has engaged all stakeholders to provide comments and critique the merit of such a policy change.  The NCC has particular concerns with the adoption of a 10X safety factor that does not contain specific exposure links to dicrotophos. The NCC believes EPA has numerous studies that do not support a causal effect implicated by the Columbia University study and believes EPA has granted tremendous weight to the Columbia University study without justification.  Therefore, the 10X safety factor should not be used in the risk assessment process.

EPA has, with the 10X safety factor, implicated drinking water concerns for the dietary risk assessment.  The drinking water concern is based on theoretical modeling and does not reflect many years without detection in actual drinking water monitoring data.  The NCC urges EPA to recognize that a theoretical model is a tool that could be used to identify potential needs for real world data, but should not be used to override real world data.  EPA should refine the drinking water assessment to reflect actual real world measurements.

EPA has stated some concerns for ecological risks, but again the concerns are based on theoretical modeling. Dicrotophos has been used for many years and the NCC is not aware of real world data supporting ecological concerns with labeled uses.  Again, the NCC urges EPA to recognize that theoretical modeling results, which do not reflect real world data, demonstrates error in modeling assumptions.

Clearly, dicrotophos is an important IPM tool for cotton production with low use and great value.  The NCC respectfully urges EPA to continue the registration of this product rather than removing it and forcing additional reliance on a few chemistries – thereby increasing selection pressure on the few alternatives.  The NCC urges EPA to recognize the benefit of this product to control niche pests, as a rotational chemistry, and as a critical component of cotton IPM. 

Respectfully submitted,
Reece Langley
VP – Washington Operations
National Cotton Council