Across the corn belt depending on time of year | Both refuge strategies (Seed Mix vs separate block refuges) have real issues.
Block refuges of non-gmo are better at producing beetles which are not exposed to the toxin and thereby can mate with potentially individuals who survived the toxin. However, there are two big issues. 1) farmers ignored the regulations because the sale personnel told the farmer the refuge idea was horsepucky and the product of a bunch of academics ivory tower ideas. and 2) Rootworm mate immediately upon emergence so there is little chance the susceptible individuals will enter into the gmo field to mate with the individuals exposed to the toxin.
Seed mixes: The number of refuge seeds is way to small to be effective (5% currently or 20% when there was only a single event) and the mixing of the non-gmo roots with the gmo roots provides a way for the rootworm larvae to first feed on the non toxic roots, grow to gain size and then the larger larvae can more effectively survive the dose of Bt in the gmo root.
Block refuge: More perfect refuge (scientifically) but imperfect deployment.
Seed Mix: Imperfect refuge but perfect deployment.
Bottom line: Refuges are too small. Soil insecticides had a greater than 50% refuge and no resistance. GMO had at best a 20% refuge but mostly a 5% refuge and we have resistance |
rootworm damage on CRW corn paid for by seed companies
