Table 2.

PBWRA of a hypothetical insect resistant and herbicide tolerant GM cotton, and relevant comparators

Land use	Plant	Rating
Impact question: could the plant affect the health of animals and/or people?
Nature reserve	Non-GM cotton	Low. Cotton contains compounds that may be toxic if ingested in large quantities. However, most native animals find it unpalatable
	GM cotton	Medium? In addition to the above, GM cotton may kill insects that consume it due to toxicity from the insect resistance gene. There is uncertainty about whether any of these insects are desirable for nature conservation in a nature reserve land use
Irrigated/dryland agriculture	Non-GM cotton	Low. Cotton contains compounds that may be toxic if ingested in large quantities. However, cotton products are treated to remove toxins before human consumption, and stock are only fed cotton in safe quantities. Cotton is usually treated with pesticides to kill insects. In an agricultural setting these insects are not considered desirable
	GM cotton	Low. Similar to non-GM cotton. The pesticide compounds expressed in GM cotton would not kill a larger range of insects than standard pesticides (chemical or organic) applied to cotton
Invasiveness question: what is the plant’s ability to survive to reproduction despite herbivory or pathogenesis?
Nature reserve	Non-GM cotton	Low. Cotton seedlings and young plants are susceptible to insect herbivory as well as disease and pathogens
	GM cotton	Medium? Although the statement above applies to GM cotton, the GM insect resistance trait potentially reduces herbivory of seedlings and young plants by some insects
Irrigated/dryland agriculture	Non-GM cotton	Low. Cotton seedlings and young plants are susceptible to insect herbivory as well as disease and pathogens. Agricultural areas may be treated with chemicals such as pesticides or fungicides to reduce pest or pathogen pressure
	GM cotton	Medium? Although the statements above apply to GM cotton, the GM insect resistance trait potentially reduces herbivory of seedlings and young plants by some insects
Invasiveness question: what is the plant’s tolerance to average weed management practices in the land use?
Nature reserve	Non-GM cotton	High. In some nature conservation areas there are weed management practices, but these do not specifically target cotton. In other nature conservation areas no weed management is conducted
	GM cotton	High? As above. If weed management in nature conservation areas involves broad use of the specific herbicide that the GM cotton is tolerant to, the survival of GM cotton could potentially be increased
Irrigated/dryland agriculture	Non-GM cotton	Low. Cotton volunteers are typically controlled by mechanical methods such as mulching and root cutting and/or the application of appropriate herbicides
	GM cotton	Medium? Although GM cotton tolerates a certain herbicide, farmers who have planted GM cotton are unlikely to attempt to use this herbicide to control cotton volunteers in a subsequent crop. If there has been inadvertent gene flow from a GM cotton crop to another cotton crop, the volunteers from the other cotton crop could potentially survive standard herbicide application

Only impact or invasiveness questions where the GM cotton differs from its parent species are listed