Evaluation Report ERC2011-09, Phoma macrostoma strain 94-44B

This content was archived on June 24, 2013.

Pest Management Regulatory Agency
21 November 2011
ISSN: 1911-8082 (PDF version)
Catalogue number: H113-26/2011-9E-PDF (PDF version)

Summary

Table of Contents

• Registration Decision for Phoma macrostoma strain 94-44B
• What Does Health Canada Consider When Making a Registration Decision?
• What Is Phoma macrostoma strain 94-44B?
• Health Considerations
• Environmental Considerations
• Value Considerations
• Measures to Minimize Risk
• What Additional Scientific Information Is Being Requested?
• Other Information

Registration Decision for Phoma macrostoma strain 94-44B

Health Canada's Pest Management Regulatory Agency (PMRA), under the authority of the  Pest Control Products Act and  Regulations, has granted conditional registration for the sale and use of Scotts EcoSense Weed-B-Gon Technical Bio-Herbicide, Scotts EcoSense Weed-B-Gon Manufacturing Use Concentrate, Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control Herbicide, Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control and Scotts Phoma P Commercial, containing the technical grade active ingredient Phoma macrostoma strain 94-44B, to control a broad spectrum of broadleaf weeds in established turfgrass and new seeding of grasses and in field grown nursery and ornamental plants and trees and container grown ornamentals.

An evaluation of available scientific information found that, under the approved conditions of use, these products have value and do not present an unacceptable risk to human health or the environment.

Although the risks and value have been found acceptable when all risk reduction measures are followed, the registrant must submit additional scientific information as a condition of registration.

This summary describes the key points of the evaluation, while the Science Evaluation of Evaluation Report ERC2011-09, Phoma macrostoma strain 94-44B provides detailed technical information on the human health, environmental and value assessments of Scotts EcoSense Weed-B-Gon Technical Bio-Herbicide, Scotts EcoSense Weed-B-Gon Manufacturing Use Concentrate, Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control Herbicide, Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control and Scotts Phoma P Commercial.

What Does Health Canada Consider When Making a Registration Decision?

The key objective of the Pest Control Products Act is to prevent unacceptable risks to people and the environment from the use of pest control products. Health or environmental risk is considered acceptable if there is reasonable certainty that no harm to human health, future generations or the environment will result from use or exposure to the product under its proposed conditions of registration. The Act also requires that products have value when used according to the label directions. Conditions of registration may include special precautionary measures on the product label to further reduce risk.

To reach its decisions, the PMRA applies modern, rigorous risk-assessment methods and policies. These methods consider the unique characteristics of sensitive subpopulations in humans (for example, children) as well as organisms in the environment (for example, those most sensitive to environmental contaminants). These methods and policies also consider the nature of the effects observed and the uncertainties when predicting the impact of pesticides. For more information on how the PMRA regulates pesticides, the assessment process and risk-reduction programs, please refer to the following:

• Protecting Your Health and the Environment
• Pesticide Registration Process
• Pesticide Risk Reduction Program

What Is Phoma macrostoma strain 94-44B?

Phoma macrostoma strain 94-44B is a fungus which is used as a microbial pest control agent (MPCA) to control weed seeds and established broadleaf weeds on turf, in field grown nursery and landscape ornamentals and in container grown ornamentals. The fungus colonizes roots and produces bioherbicidal compounds (macrocidins) which cause photobleaching and root inhibition in susceptible plants, ultimately resulting in plant death. The 94-44B strain of Phoma macrostoma was originally isolated from Canada thistle. Dicotyledonous plants demonstrate various levels of susceptibility to Phoma macrostoma strain 94-44B whereas monocotyledonous plants show resistance.

The three new end-use products, Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control Herbicide, Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control and Scotts Phoma P Commercial contain Phoma macrostoma strain 94-44B as the active ingredient. Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control Herbicide and Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control are for domestic-class biological control of weed seeds (pre-emergent) and established broadleaf weeds (post-emergent) on turf. Scotts Phoma P Commercial is for commercial-class biological control of weed seeds (pre-emergent) and established broadleaf weeds (post-emergent) on turf, in field grown nursery and landscape ornamentals, and in container grown ornamentals.

Health Considerations

Can Approved Uses of Phoma mactostoma strain 94-44B Affect Human Health?

Phoma macrostoma strain 94-44B is unlikely to affect your health when Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control Herbicide, Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control and Scotts Phoma P Commercial are used according to the label directions.

People can be exposed to Phoma macrostoma strain 94-44B when handling and applying the products. When assessing health risks, several key factors are considered: the microorganism's biological properties (for example, production of toxic byproducts); reports of any adverse incidents; its potential to cause disease or toxicity as determined in toxicological studies and the level to which people may be exposed relative to exposures already encountered in nature to other isolates of this microorganism.

Toxicological studies in laboratory animals describe potential health effects from large doses in order to identify any potential pathogenicity, infectivity and toxicity concerns. When Phoma macrostoma strain 94-44B was tested on laboratory animals, there were no signs that it caused any toxicity or disease. Furthermore Phoma macrostoma strain 94-44B showed minimal to no growth in the range of 35°C to 45°C and no adverse effects from Phoma macrostoma strain 94-44B were reported in the published scientific literature.

Residues in Water and Food

Dietary risks from food and water are not of concern.

As part of the assessment process prior to the registration of a pesticide, Health Canada must determine whether the consumption of the maximum amount of residues, that are expected to remain on food products when a pesticide is used according to label directions, will not be a concern to human health. This expected maximum amount of residues is then legally established as a maximum residue limit (MRL) under the Pest Control Products Act for the purposes of the adulteration provision of the  Food and Drugs Act. Health Canada sets science-based MRLs to ensure the food Canadians eat is safe.

As there are no direct applications to food, there is no concern for risks posed by dietary exposure of the general population, including infants and children, or animals to Phoma macrostoma strain 94-44B.

Occupational Risks From Handling Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control Herbicide, Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control and Scotts Phoma P Commercial

Occupational risks are not of concern when Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control Herbicide, Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control and Scotts Phoma P Commercial are used according to label directions, which include protective measures.

Workers using Scotts Phoma P Commercial can come into direct contact with Phoma macrostoma strain 94-44B on the skin, in the eyes, or by inhalation. For this reason, the label will specify that workers exposed to Scotts Phoma P Commercial must wear waterproof gloves, long-sleeved shirt, long pants, shoes plus socks, eye goggles when handling and a dust/mist filtering respirator/mask (NIOSH approval number prefix TC-21) or NIOSH approved respirators (with any N-95, P-95, R-95 or HE filter).

Users of the domestic-class end-use products, Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control Herbicide and Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control, are expected to have infrequent contact with Phoma macrostoma strain 94-44B on the skin, in the eyes or by inhalation. For this reason, the labels for the two domestic-class end-use products will instruct users to avoid contact with eyes, wash hands thoroughly with soap and water after handling; and to remove contaminated clothing and wash before wearing them again.

For the general population, exposure could occur during maintenance or recreational activities on treated turf, but it is not expected that bystander exposures will pose an undue risk on the basis of the low toxicity/pathogenicity profile for Phoma macrostoma strain 94-44B. Therefore, health risks to bystanders are not of concern.

Environmental Considerations

What Happens When Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control Herbicide, Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control and Scotts Phoma P Commercial Are Introduced Into the Environment?

Environmental risks are not of concern.

Following application, Phoma macrostoma strain 94-44B is likely able to survive in the outdoor soil under suitable environmental conditions (i.e. temperature, moisture), but over time populations of Phoma macrostoma strain 94-44B are expected to return to natural background levels.

The effects of Phoma macrostoma strain 94-44B on beneficial and/or environmentally important insects were examined. The studies showed that Phoma macrostoma strain 94-44B was not toxic to beneficial insects (i.e. bees, ladybird beetles and parasitic wasps). The effects of Phoma macrostoma strain 94-44B on avian species were also examined. Phoma macrostoma strain 94-44B was shown to be non-toxic and non-pathogenic to birds.

Although wild mammal, earthworm and microorganism testing were not conducted, adequate information was available to determine that significant adverse effects to these non-target terrestrial organisms are not expected. The information included Phoma macrostoma strain 94 44B showing minimal to no growth in the range of 35°C-45°C, and no adverse effects on laboratory mammals from human health and safety studies. Also, there are no published reports of disease associated with Phoma macrostoma strain 94-44B in wild mammals, earthworms and microorganisms.

The potential hazard to non-target terrestrial plants was addressed in studies that examined the host range of the Phoma macrostoma strain 94-44B. Although Phoma macrostoma strain 94-44B is pathogenic to a number of plant species, there are significant differences in host susceptibility depending on the rate of application and plant species. In general, monocotyledonous plants are resistant whereas dicotyledonous plants demonstrate various levels of susceptibility. Therefore, a precautionary statement will warn users to avoid contact with desirable plants, fruits and vegetables.

The effects of Phoma macrostoma strain 94-44B on aquatic non-target organisms were examined. The studies showed that Phoma macrostoma strain 94-44B was not toxic or pathogenic to fish. Also, Phoma macrostoma strain 94-44B was shown to have low toxicity to aquatic invertebrates and was pathogenic to aquatic plants. Minimal exposure to aquatic organisms is anticipated from the use pattern of the end-use products. Furthermore, label statements will be added to the label requiring handlers to not contaminate irrigation or drinking water or aquatic habitats by cleaning of equipment or disposal of wastes.

Value Considerations

What Is the Value of Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control Herbicide, Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control and Scotts Phoma P Commercial?

End-use products containing Phoma macrostoma strain 94-44B, a pre-emergence as well as a post-emergence bioherbicide, control a broad spectrum of broadleaf weeds in established turfgrass, new seeding of grasses, in field grown nursery and ornamental plants and trees, and container grown ornamentals.

A single pre-emergence application of Phoma macrostoma strain 94-44B provides effective control of numerous broadleaf weeds including dandelion, scentless chamomile and English daisy and provides suppression of white clover, Canada thistle, black medic, chickweed, broadleaf plantain, common ragweed and wild mustard.

Two to three post-emergence applications of Phoma macrostoma strain 94-44B provide effective control of white clover and black medic and provide suppression of dandelion, Canada thistle and broadleaf plantain.

A single pre-emergence spot application or two to three post-emergence spot applications of Phoma macrostoma strain 94-44B provide effective pre-emergence or post-emergence control and/or suppression of all the weeds listed above.

Phoma macrostoma strain 94-44B is a reduced-risk / non-conventional herbicide and as such, would not be included in the list of pesticides prohibited for sale by many provincial and municipal legislations; and therefore this active ingredient represents a viable alternative in the control of broadleaf weeds in lawns.

Measures to Minimize Risk

Labels of registered pesticide products include specific instructions for use. Directions include risk-reduction measures to protect human and environmental health. These directions must be followed by law.

The key risk-reduction measures being proposed on the labels of Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control Herbicide, Scotts EcoSense Weed-B-Gon Ready To Use Lawn Weed Control and Scotts Phoma P Commercial to address the potential risks identified in this assessment are as follows:

Key Risk-Reduction Measures

Human Health

As with all microbial pest control products, there are concerns with users developing allergic reactions through repeated high exposures to Phoma macrostoma strain 94-44B. Therefore, anyone handling, mixing/loading, or involved in clean-up/repair activities of Scotts Phoma P Commercial must wear waterproof gloves, long-sleeved shirt, long pants, shoes plus socks, and a dust/mist filtering respirator/mask (NIOSH approval number prefix TC-21) or NIOSH approved respirators (with any N-95, P-95, R-95 or HE filter).

For the domestic-class end-use products, users must wash hands thoroughly with soap and water after handling; and to remove contaminated clothing and wash before wearing them again.

Environment

As a general precaution, the label for the commercial class end-use product prohibits the direct application of the product to aquatic habitats (such as lakes, streams and ponds). The labels on the end-use products prohibit contamination of irrigation or drinking water supplies or aquatic habitats by cleaning of equipment or disposal of wastes. The labels further advise users to avoid contact of the end-use products with desirable plants, fruits and vegetables.

What Additional Scientific Information Is Being Requested?

Although the risks and value have been found acceptable when all risk-reduction measures are followed, the registrant must submit additional scientific information as a condition of registration. More details are presented in the Science Evaluation of Evaluation Report ERC2011-09, Phoma macrostoma strain 94-44B or in the section 12 Notice associated with these conditional registrations. The registrant must submit the following information within the time frames indicated.

Product Characterization and Analysis

To confirm the manufacturing methods and quality assurance for final commercial production, the registrant is required to provide confirmation of production methods, a five batch analysis for microbial contaminants and confirmation of product guarantee from production lots of Scotts EcoSense Weed-B-Gon Technical Bio-Herbicide and its associated end-use products from the manufacturing sites.

Value

Data are required from additional field trials in which the efficacy of Phoma macrostoma strain 94-44B, applied pre-emergence at 16 g a.i./ha, is evaluated to confirm its efficacy for season-long control of the following weeds: chickweed, broadleaf plantain, common ragweed, wild mustard and English daisy.

The outstanding product characterization and value information must be submitted to the PMRA by September 1, 2014.

Other Information

As these conditional registrations relate to a decision on which the public must be consulted, the PMRA will publish a consultation document when there is a proposed decision on the applications to convert the conditional registrations to full registrations or on applications to renew the conditional registrations, whichever occurs first.

The test data cited in Evaluation Report ERC2011-09, Phoma macrostoma strain 94-44B (i.e. the test data relevant in supporting the registration decision) will be made available for public inspection when the decision is made to convert the conditional registrations to full registrations or to renew the conditional registrations (following public consultation). If more information is required, please contact the PMRA's Pest Management Information Service.