Severe crop damage to GMO Monsanto BT corn from rootworms which have developed resistance to BT has prompted the EPA to issue a memo to Monsanto demanding a remedial action plan that includes using conventional pesticides, crop rotation and GMO crop free refuges. Because GMO corn, and Roundup used on it, accounts for 41% of Monsanto's profits, Monsanto's stock price plunged on the news. Monsanto continues to claim that there is no scientific evidence of developing resistance despite EPA's memo and multiple EPA confirmed reports from multiple states.
The EPA has determined that resistance to Monsanto's BT genetically modified corn appears to be evolving in the rootworm population. Monsanto appears to have not expected such rapid failure of this GMO crop, which was just introduced in 2003, to control rootworms. EPA has determined that Monsanto's response to performance failures it cannot explain are inadequate.
Monsanto reported that high rootworm pressure was typically the result of continuous-corn plantings that built up CRW population densities over time and used this reasoning as a justification to use a GTED threshold level of 1.5. The BPPD IRM Team notes that continuous planting of corn with Cry3Bb1 without rotation also leads to greater selection pressure. Hence, unexpected pest damage in such Cry3Bb1 fields with agronomic practices as described by Monsanto should be reason for concern and has a greater probability to be due to resistance evolution in that population. Therefore, the BPPD IRM Team maintains that a threshold level of 1.0 for a single toxin PIP is a more appropriate trigger to initiate adult collections.
Monsanto stated that they had been working with Dr. Ostlie in MN to understand the greater than expected root damage observed in Cry3Bb1 corn during the late corn growing season in 2009. The BPPD IRM Team interprets this to mean that Monsanto is unsure of the reasons for Bt failure and notes that this is an example of instance where collections should have occurred the following year (despite lower damage levels or population numbers). If growers ‘bombed’ adults in fall 2009 or used IPM approaches to manage their fields, it should be expected that population densities and subsequent root damage were lower in 2010. However, resistance genes could still be in these populations, which is the reason why adult collections should be made once unexplained performance failures have occurred.
A Monsanto representative said that a very small percentage of its GMO corn has been damaged by the resistant worms, and recommended using an another GMO corn product with 2 types of BT, but EPA challenged the effectiveness of Monsanto's recommendation. The EPA suspects that if one type of BT fails, the other type is also likely to fail.
Less than 0.2 percent of the acres planted with Monsanto’s Bt corn were affected by unexpected rootworm damage this year, Quarles said. Farmers with root damage in their fields should consider changing practices to “stay ahead of this insect,” Monsanto said in a statement. That could include rotating corn with soybeans or using a product such as Monsanto’s SmartStax corn, which kills rootworms with two types of Bt, the company said.
The EPA's report concludes that Monsanto is not adequately monitoring the development of resistance and has inadequate plans to deal with resistance once it develops.
EXECUTIVE SUMMARY
The BPPD IRM Team concludes that Cry3Bb1 resistance is suspected in at least some portions of four states in which “unexpected damage” reports originated (IA, IL, MN, and NE) and recommends that the Cry3Bb1 remedial action plan be implemented for “suspected resistance”. The BPPD IRM Team’s conclusions are based on multiple documented cases of unexpected “severe” corn rootworm damage to Cry3Bb1 fields
(Gassmann et al. 2011a; Gray 2011a, c) and other undocumented reports from corn entomologists. The 2009 resistance monitoring data for Cry3Bb1 showed that field-collected populations (collected from Illinois, Iowa, and Nebraska) were less susceptible to the toxin than the laboratory reference colony. In 2009, every field-collected population had a higher EC50 and LC50 than the laboratory control, in some cases by an order of magnitude.
Sampling was conducted in three states (Nebraska, Illinois, and Iowa); the BPPD IRM Team recommends that Colorado, South Dakota, Minnesota, and western Wisconsin be included in future monitoring based on the registrant’s reported Cry3Bb1 performance inquiries. After reviewing Monsanto’s overall resistance monitoring strategy for Cry3Bb1 (including responses to previous Agency reviews), the BPPD IRM Team concludes that the registrant’s current resistance monitoring program (as proposed) is inadequate and likely to miss early resistance events. This is due to a sampling trigger (> 1.5 NIS) in fields with unexpected damage that is too high (and may miss potentially resistant populations) and a sampling regime that collects beetles too far (1-2 miles away) from problem fields.
Can Monsanto be trusted with GMO technology?