Decision Document: Carbofuran

22 December 1995
ISBN: N/A
Cat. No. N/A
(E95-05)

Help on accessing alternative formats, such as Portable Document Format (PDF), Microsoft Word and PowerPoint (PPT) files, can be obtained in the alternate format help section.

In June 1990, Agriculture and Agri-Food Canada (AAFC) announced, pursuant to Section 19 of the Pest Control Products (PCP) Regulations, a special review of carbofuran insecticide in response to concerns raised by the Canadian Wildlife Service (CWS) of Environment Canada regarding the impact of this insecticide on vertebrate wildlife, especially birds. The special review focused on the risk of carbofuran-containing products to birds and other vertebrates, and the value of carbofuran to agriculture.

In July 1993, AAFC published Discussion Document D93-02 entitled Special Review of Carbofuran Insecticide:  Effects on Avian Fauna and Value to Agriculture. The purpose of the document was to provide summaries of the data reviewed by AAFC and CWS on the risks and value of carbofuran, and to present possible regulatory options regarding the future registration status of carbofuran and each of its registered uses.

Approximately 90 groups and individuals representing a wide range of interested parties submitted written responses to the Discussion Document. Respondents included growers and grower associations, provincial government departments, environmental conservation organizations, crop protection specialists, pesticide retail outlets, the registrants of carbofuran, and concerned individuals. Recommendations expressed by the respondents ranged from continued registration to cancellation of registration of carbofuran products.

The purpose of this Decision Document is to announce and explain the outcome of the special review for each of the uses of carbofuran.

Table of Contents

• 1.0 Furadan 10G (Sand Core Granular)
• 2.0 Furadan CR-10 (Corncob Granular)
• 3.0 Furadan 5G (Corncob Granular)
• 4.0 Furadan 480F (Liquid Formulation)
  • 4.1 Cereals, Headlands, Pastures, Roadsides
  • 4.2 Canola, Mustard, Sunflowers
  • 4.3 Alfalfa
  • 4.4 Corn (sweet, field, silage)
  • 4.5 Potatoes, Green Peppers
  • 4.6 Raspberry, Strawberry
  • 4.7 Sugar beets
  • 4.8 Turnip, Rutabaga
• References

1.0 Furadan 10G (Sand Core Granular)

Furadan 10G is a sand core granular formulation, containing 10% carbofuran by weight, which is registered for use on corn, potatoes, carrots, onions, sugar beets, turnips and rutabagas. Information regarding the risk of Furadan 10G to birds was presented in the Discussion Document (AAFC 1993)¹ and the wildlife risk assessment (Mineau 1993).

Most of the commentary received from provincial government departments and working groups in response to the Discussion Document supported removal of Furadan 10G.

In light of the information presented in the wildlife risk assessment, a regulatory decision has been made not to renew registration of Furadan 10G (Registration Number 10827), pursuant to Section 14 of the PCP Regulations, after registration expires on December 31, 1995.

In the United States, a special review of the sand core granules by the Environmental Protection Agency (EPA) resulted in a negotiated agreement with FMC Corporation to phase out all but five minor uses of this formulation.

2.0 Furadan CR-10 (Corncob Granular)

Furadan CR-10 is a corncob-based granular formulation which contains 10% carbofuran and is used for control of flea beetles on canola and mustard. Granules are mixed with the canola seed, usually by seed dealers, and applied with seeding equipment at planting. Of concern is the risk both to resident birds breeding in or on the edges of treated fields and to the large numbers of migrating birds that land in freshly treated fields.

Government agencies from the Prairie provinces were of the opinion that the information presented in the Discussion Document was insufficient to fully assess the risk of the corncob formulations to wildlife.

Since publication of the Discussion Document (AAFC 1993) and the wildlife risk assessment (Mineau 1993), additional information regarding the risk of Furadan CR-10 has been received. This information includes results from studies which show that birds consume corncob granules, either as grit or food, and from a field monitoring study which showed mortality of birds following operational use of Furadan CR-10. These new data have now also been considered.

In light of the available information, the sale of Furadan CR-10 (Registration Numbers 17940 and 18175) will be discontinued, pursuant to Section 16 of the PCP Regulations. Stocks of Furadan CR-10 in the possession of dealers and users will be permitted to be exhausted through normal channels of sale and use until December 31, 1997.

In the United States, canola growers in Montana, Minnesota, North Dakota, Idaho and Washington can use the CR-10 formulation for control of flea beetles on canola under a state (local need) registration. The United States EPA intends to complete an assessment of the risk of this product to wildlife prior to the 1997 use season.

3.0 Furadan 5G (Corncob Granular)

Background

Furadan 5G is a corncob-based granular formulation containing 5% carbofuran. Like Furadan CR-10, its primary use is for control of flea beetles on canola and mustard. Granules are mixed with the canola seed, usually by seed dealers, and applied with seeding equipment at planting.

Flea beetles are one of the most significant insect pests of canola in the Prairie provinces. Information on the value of carbofuran for flea beetle control was summarized in the Discussion Document (AAFC 1993).

Granular treatments (carbofuran or terbufos) are used on 10-15% of the total area planted with canola in the Prairie provinces. Most granular use occurs in Manitoba where flea beetle populations, and potential for crop loss, have in the past been high. Although Manitoba accounts for only approximately 16% of the canola production area in the Prairies, 48-79% of the total granular use between 1983 and 1990 was in Manitoba (Deloitte and Touche 1990).

Since publication of the Discussion Document (AAFC 1993) and wildlife risk assessment (Mineau 1993), additional information regarding the risk of the corncob granular formulations of carbofuran has been received. The salient information is summarized below.

The concern is the risk of Furadan 5G both to resident birds breeding in or on the edges of treated fields and to the large numbers of migrating birds that land in freshly treated fields. A wide variety of bird species use agricultural fields during the canola planting season. In addition to the resident species (e.g., Savannah and Clay-coloured sparrows), extremely high density flocks of migrant passerines (e.g., Lapland longspurs) are occasionally present in seeded fields.

Carbofuran is highly toxic when ingested. Although a single 5G granule contains half the amount of active ingredient as a single granule of the CR-10 formulation, a 5G granule of average weight still contains approximately 0.11 mg of carbofuran which represents approximately three times the LD₅₀ for a sparrow-sized bird of average toxicological susceptibility to carbofuran. However, the toxicity of neither of the corncob-based granular formulations to birds has been empirically tested.

Corncob granules are attractive to birds either as food or grit. This has been demonstrated by field incidents and results from a study (FMC 1989) showing mortality of starlings in a pen treated with corncob granules. In another study where sparrows were offered blank sand core and corncob granules as grit (Best and Gionfriddo 1993), sand core granules were preferred; however, corncob granules were also consumed.

Engineering studies show that all commonly used seeding equipment (press drill, hoe drill, air seeder) leaves some exposed granules on the soil surface. The following machines are ranked in order of percent of applied granules remaining on the soil surface (values represent range in averages for four seeding conditions), based on information from a published study (Maze et al. 1991): air seeder (in-furrow placement) 0.13-0.92%; hoe drill 0.37-0.74%; air seeder (broadcast) 1.7-4.2%; press drill 3.6-7.0%. Recent surveys indicate a trend of increasing canola acreage being planted with the preferred planting equipment (i.e., air seeder in-furrow). For in-furrow application with air seeders, the concentration of exposed Furadan 5G granules is calculated to be 0.3-2.2 granules/m². This does not account for spillage.

While incidents of bird mortality have been documented following operational use of the CR-10 (10%) formulation in the risk assessment (Mineau 1993) and a low-intensity survey of canola fields in Saskatchewan (Mineau 1994), there have been no documented incidents of wildlife mortality following operational use of the 5G (5%) formulation.

Governments from the three Prairie provinces in their responses to the Discussion Document commented on the need for monitoring of impacts on wildlife associated with the corncob granular formulations.

Regulatory Decision

In light of the available information, the PMRA has concerns regarding the risk of Furadan 5G to birds. The regulatory decision is as follows.

Registration of Furadan 5G (Registration Numbers 10666 and 10826) has been granted until December 31, 1997 conditional upon the following:

1. 1. The labels for Furadan 5G must state: "Do not apply by double-disk press drill or any discer-type seeder. Do not broadcast, whether or not followed by harrowing." Given current seeding practices, this will limit seeding to infurrow application with air seeders and hoe drills.

   The labels must also include the following warnings: "Before seeding, adjust the seeding equipment so that the required weight of seed and Furadan is sown per hectare. Locate and bury any spills such as those which may occur during calibration or when the seeder is lifted to make turns at field edges. Ensure that the seed and Furadan granules are completely covered with soil in order to minimize exposure to birds and other wildlife."

2. The registrants must submit to the PMRA a detailed communication plan for informing growers of the new use restrictions.
3. Use will be restricted to mustard and canola.
4. The registrants must undertake a field monitoring study to measure the effectiveness of these measures in reducing risk to birds to an acceptable level.

The registrants have agreed to amend the label of Furadan 5G as above and have also agreed to carry out the required field monitoring study.

The field monitoring study will focus on both resident breeders and migrant birds. The study must be of high scientific calibre and should be performed under standards equivalent to U.S. General Laboratory Practices. The study must also be of sufficient scale to account for variation in allowable seeding implements, as well as variations in seeding and soil conditions, grower performance, and presence of birds in treated fields. The avian monitoring work must be accompanied by a survey of the fields for surface granule presence.

Following provincial recommendations, it is proposed that a small technical committee be struck to assist in the design and supervision of the studies, and to comment on the results. In addition to representatives from the PMRA, the CWS and the registrants, one or more recognized experts in Prairie songbird populations, provincial biologists as well as representatives of the major stakeholders will be invited to participate on the committee. Invitation will also be extended to the U.S. EPA to participate in this technical committee in light of their interest in also reviewing this formulation. Draft protocols for this study should be provided by April 1, 1996. Final study protocols acceptable to the technical committee must be finalized by December 31, 1996. The final study report must be submitted to the PMRA no later than September 30, 1997.

The registration status of Furadan 5G will then be subject to re-examination in light of the monitoring data which emerges.

4.0 Furadan 480F (Liquid Formulation)

The liquid formulation of carbofuran is registered for use on a variety of crops, including cereals, vegetables and small fruits, and on non-crop areas. Information regarding the risk of Furadan 480F to birds was presented in the Discussion Document (AAFC 1993) and the wildlife risk assessment (Mineau 1993). A discussion of each use is presented below.

4.1 Cereals, Headlands, Pastures, Roadsides

The major use of Furadan 480F has been for control of grasshoppers on cereals and non-crop areas on the Prairies. Furadan 480F has also been registered for control of orange wheat blossom midge on wheat.

The primary concern regarding the use of Furadan 480F on the Prairies is the risk to the Burrowing Owl, which has been designated an endangered species by the Committee on the Status of Endangered Wildlife in Canada. Information regarding the risk of Furadan 480F to the Burrowing Owl and other avian species was presented in the Discussion Document (AAFC 1993) and the wildlife risk assessment (Mineau 1993).

In their responses to the Discussion Document, individual provincial government departments from the Prairies recommended different options regarding the use of Furadan 480F for grasshopper control. These included retaining all registered uses for grasshopper control, maintaining uses for crop protection only (eliminate use on non-crop areas), and eliminating all use of Furadan 480F within the historical range of the Burrowing Owl.

In light of the information presented in the wildlife risk assessment, the registration of all uses of Furadan 480F (Registration Numbers 10363 and 10828) for control of grasshoppers and orange wheat blossom midge will be discontinued and the registration of Furadan 480F will be amended pursuant to Section 13 of the PCP Regulations to remove these uses from the label, effective December 31, 1995. Stocks of Furadan 480F currently labelled with the grasshopper use and in the possession of dealers and users will be permitted to be exhausted through normal channels of sale and use until December 31, 1997.

4.2 Canola, Mustard, Sunflowers

Furadan 480F has been registered for use on canola and mustard for control of flea beetles and red turnip beetles, and on sunflowers for control of sunflower beetles. The main concern regarding use of Furadan 480F on these crops is the risk to the Burrowing Owl on the Prairies.

Applications of Furadan 480F for control of flea beetles, red turnip beetles and sunflower beetles are considered to pose a lower risk to the Burrowing Owl than are applications for grasshopper control. The product is applied early in the season for flea beetle control at a time when the owls are not likely to be foraging in canola fields. Also the rate of application for flea beetle control is lower than that for grasshoppers. Similarly, the Burrowing Owl is unlikely to be foraging in sunflower fields at the time when Furadan 480F is applied for control of sunflower beetles (i.e., in mid-season when the crop is established).

The registrations of Furadan 480F (Registration Numbers 10363 and 10828) will be amended, effective December 31, 1995, pursuant to Section 13 of the PCP Regulations to limit the maximum rate of application for control of flea beetles on canola and mustard to 0.072 kg ai/ha. The reduced rate, together with the existing 250-metre buffer zone around Burrowing Owl nests, represent meaningful risk reduction measures.

4.3 Alfalfa

Furadan 480F has been registered for control of grasshoppers, alfalfa weevil and alfalfa blotch leafminer on alfalfa. Numerous species of birds and small mammals live in and around alfalfa fields. One of the main concerns is the risk to the Burrowing Owl on the Prairies.

In their responses to the Discussion Document, provincial government departments from the Prairies supported removal of all uses of Furadan 480F on alfalfa. Alternative insecticides are registered for control of each of the target pests (one or more of azinphos methyl, carbaryl, deltamethrin, dimethoate, malathion, methidathion, phosmet).

In light of the available information regarding the risk of Furadan 480F to the Burrowing Owl, the registration of all uses of Furadan 480F (Registration Numbers 10363 and 10828) on alfalfa will be discontinued and the registration of these products will be amended pursuant to Section 13 of the PCP Regulations to remove the alfalfa uses from the label, effective December 31, 1995. Stocks of Furadan 480F currently labelled with alfalfa uses and in the possession of dealers and users will be permitted to be exhausted through normal channels of sale and use until December 31, 1997.

4.4 Corn (sweet, field, silage)

Furadan 480F has been registered for use on corn for control of European corn borer, western corn rootworm (adults) and northern corn rootworm (adults). Although registered for use on sweet, field and silage corn, Furadan 480F is essentially used only on sweet corn in eastern Canada and on field corn in western Canada (approximately 50,000 ha total per year).

Of primary concern is the risk to songbirds in field edges. Mortality of songbirds has been documented in field trials conducted in corn at twice the Canadian rate (Mineau 1993). Field edge contamination predicted for Canadian corn fields is similar to that observed in U.S. alfalfa fields where songbird mortality was also documented (the U.S. alfalfa rate is the same as the Canadian corn rate). However, no mortality has been reported from corn fields in Canada. On the other hand, there has been no monitoring of Canadian fields.

Although not specifically mentioning corn, most provinces in their responses to the Discussion Document recommended imposing restrictions on how Furadan 480F is used as a means of reducing risk to wildlife. In the United States, the EPA is currently exploring mitigative measures for use of Furadan 480F on corn as a means for reducing risk to wildlife.

In light of the available information, the PMRA has concerns regarding the risk to birds from use of Furadan 480F on corn. The registration of Furadan 480F (Registration Numbers 10363 and 10828) will be amended, effective December 31, 1995, pursuant to Section 13 of the PCP Regulations, as follows to reduce risk to wildlife: a) restrict use on field corn to western Canada only; b) limit the total number of applications per season to two; c) restrict applications by air to fields greater than five hectares; d) include precautionary statements on the label regarding the potential hazard of spray drift to wildlife; and e) include label statements which identify measures which should be taken to reduce drift to field margins and other non-crop habitat.

Registration of this amended use pattern has been granted until December 31, 1997. Registration beyond this time will be re-examined in light of any new information submitted and the outcome of the risk mitigation efforts in the United States. Should no new information be forthcoming, the PMRA may request bird monitoring information from the registrants.

4.5 Potatoes, Green Peppers

Furadan 480F has been used for control of foliar insects (i.e., aphids, Colorado potato beetle, potato flea beetle, potato leafhopper, tarnished plant bug) on potatoes and European corn borer in green peppers. The main concern regarding these uses is the risk to songbirds in field edges.

Continued registration of Furadan 480F for use on these crops was supported by some provinces in their responses to the Discussion Document. Although not specifically mentioning potatoes or green peppers, most provinces recommended imposing restrictions on how Furadan 480F is used as a means of reducing risk to wildlife.

In light of the available information and concerns which the PMRA has regarding the risk to birds, the registrations of Furadan 480F (Registration Numbers 10363 and 10828) for use on potatoes will be amended, effective December 31, 1995, pursuant to Section 13 of the PCP Regulations, as follows: a) restrict application to ground equipment only; b) discontinue use for control of aphids (this represents the highest rate of application for potatoes at 0.816 kg ai/ha); c) limit the maximum rate of application for Colorado potato beetle to 0.264 kg ai/ha in Western Canada, and 0.528 kg ai/ha in Eastern Canada; d) limit the total number of applications per season to two; e) include precautionary statements on the label regarding the potential hazard of spray drift to wildlife; and f) include label statements which identify measures which should be taken to reduce drift. In addition to these risk mitigation measures, the registrants will also include a resistance management statement on the label recommending that chemicals of different modes of action be used in rotation with Furadan 480F should repeated applications of insecticide be required for control of the target pest.

Regarding use on green peppers, registrations of Furadan 480F will be amended, effective December 31, 1995, pursuant to Section 13 of the PCP Regulations, as follows: a) limit the maximum number of applications per season to three, and b) restrict application to ground equipment only. The current restriction, limiting use to Ontario only, will remain.

4.6 Raspberry, Strawberry

Furadan 480F has been registered for control of bud and root weevils on raspberries in British Columbia only. It has also been registered for control of root weevil and spittlebug on strawberries in British Columbia, and control of strawberry blossom clipper weevil and tarnished plant bug on strawberries in eastern Canada.

Of primary concern is the risk to songbirds in field edges as well as to those birds nesting in, or otherwise frequenting, the fields. Although field data are lacking for the impact of Furadan 480F on birds in and around raspberry or strawberry fields, risk is presumed based on the high rate of application and the demonstrated risk to birds at lower rates of application on other crops (i.e., alfalfa, corn), as presented in the Discussion Document. The post-harvest use is also of concern because birds may enter the fields at this time to feed on discarded or unharvested fruit.

In their responses to the Discussion Document, the Ontario and British Columbia departments of agriculture recommended continued registration of Furadan 480F for uses on raspberries and strawberries.

There is no effective chemical alternative registered for control of root weevils. There is one chemical alternative for control of strawberry blossom clipper weevil (cypermethrin); however, it is considered by Ontario to be more harsh on predatory mites than is carbofuran.

The registrations of Furadan 480F (Registration Numbers 10363 and 10828) will be amended, effective December 31, 1995, pursuant to Section 13 of the PCP Regulations, as follows to reduce risk to wildlife: a) restrict application to ground equipment only; b) restrict raspberry use to a single early-season application; c) restrict use on strawberries in British Columbia to a single post-harvest application during August/September to control overwintering root weevils; and d) restrict application in eastern Canada to a single early-season application (before first bloom). The current restriction limiting use on raspberries to British Columbia only will remain.

4.7 Sugar beets

Furadan 480F has been registered for use as a drench application for control of sugar beet root maggot on sugar beets. Application is made at the early stage of sugar beet root maggot activity, usually around the first week of June.

The main concern regarding use of Furadan 480F in sugar beet fields is the risk to wildlife from field puddling following application. However, the Alberta Sugar Company and Alberta Sugar Beet Growers' Marketing Board, in their response to the Discussion Document, state that the sugar beet root maggot is most often a problem on medium-to light-textured soils which are not prone to puddling.

The Alberta Sugar Company and Alberta Sugar Beet Growers' Marketing Board also commented on the value of Furadan 480F to sugar beet production. Economic infestations of sugar beet root maggot are sporadic and there is currently no way to accurately predict either the severity or extent of infestation. The only alternatives to Furadan 480F are granular insecticides (aldicarb, terbufos)² applied as preventative treatments at planting. The Alberta Sugar Company and Alberta Sugar Beet Growers' Marketing Board have stated that, since the first registration of Furadan 480F for control of sugar beet root maggot in 1989, there has been a significant reduction in area requiring insecticide treatment because growers need not rely solely on insurance treatments with granulars.

After consideration of all relevant available information, the PMRA is satisfied that Furadan 480F (Registration Numbers 10363 and 10828) applied as a drench for control of sugar beet root maggot on sugar beets does not pose an unacceptable risk to wildlife.

4.8 Turnip, Rutabaga

Furadan 480F has been used for control of cabbage root maggot and flea beetles on turnips and rutabagas. These uses represent the highest registered rate of application for Furadan 480F (i.e., 2.52 kg ai/ha).

Of concern is the risk to birds in and around treated fields, particularly fields conducive to flooding or puddling. An incident of bird mortality following use of Furadan 480F in a British Columbia turnip field has been documented (Mineau 1993). Evidence suggests that mortality in this incident resulted from exposure to contaminated puddles.

In light of the available information, the registration of all uses of Furadan 480F (Registration Numbers 10363 and 10828) on turnips and rutabagas will be discontinued and the registration of these products will be amended pursuant to Section 13 of the PCP Regulations to remove these uses from the label, effective December 31, 1995. Stocks of Furadan 480F currently labelled with turnip and rutabaga uses and in the possession of dealers and users will be permitted to be exhausted through normal channels of sale and use until December 31, 1997.

References

AAFC (Agriculture and Agri-Food Canada). 1993. Special Review of Carbofuran Insecticide: Effects on Avian Fauna and Value to Agriculture. Discussion Document D93-02, dated July 30, 1993. 53 pp.

Best, L.B. and J.P. Gionfriddo. 1993. An evaluation of house sparrow preferential consumption of five carriers used to formulate insecticide granules. Unpublished report, Miles Inc., Report No. 103220, dated March 20, 1993. 30 pp.

Deloitte and Touche. 1990. An economic assessment of the benefits of granular and liquid formulations of Furadan insecticide/nematicide in Canada. Deloitte & Touche Management Consultants, Guelph, Ontario. Unpublished report, dated December 20, 1990. 117 pp.

FMC (FMC Corporation)). 1989. Simulated pen studies with European starlings exposed to different formulations of Furadan 15G. [D.W. Fletcher and C.A. Pedersen] Unpublished report, dated July 3, 1989. 56 pp.

Maze, R.C., R.P. Atkins, P. Mineau, and B.T. Collins. 1991. Measurement of pesticide residue in seeding operations. Trans. Am. Soc. Agric. Eng. 34(3):795-799.

Mineau, P. 1993. The hazard of carbofuran to birds and other vertebrate wildlife. Canadian Wildlife Service Technical Report Series No. 177. Environment Canada, Ottawa. 96 pp.

Mineau, P. 1994. Consolidated Wildlife Incident Report. Carbofuran - Kills from corn cob granular formulations - summer of 1994. Unpublished report, Canadian Wildlife Service, Environment Canada, Ottawa.

¹ As of April 1, 1995, responsibility and resources for pesticide regulation were consolidated within the Pest Management Regulatory Agency (PMRA) under Health Canada.

² Furadan 10G will no longer be available (see Section 1.0).