Worms were in full force in Mid-South cotton fields this summer, but large-field test plots of Bollgard II required no oversprays for caterpillar control, according to Walt Mullins, Monsanto's cotton technical manager for Bollgard and Bollgard II.
Original Bollgard, which has been on the market for seven years, provided excellent control of tobacco budworms, but often required additional treatment for other worm pests, including the cotton bollworm.
Bollgard II contains two Bt proteins toxic to caterpillar pests, Cry 1 Ac and Cry 2 Ab, which Monsanto hopes will broaden control of caterpillar pests and manage resistance in Bt cotton. Original Bollgard had only one Bt protein, Cry 1 Ac.
“We've seen pressure from multiple species, bollworms and budworms, fall armyworms in our research and Southern armyworms in the coastal areas around Georgia and Alabama. We were looking for any type of breakthroughs in the cotton and found less than 1 percent,” Mullins said.
“Bollgard II held up extremely well. It's not perfect, but we have not seen a case this year in our experimental plots where a foliar application was required for Lepidopterous larvae. On the other hand, we do find an occasional larvae in the Bollgard II. From the standpoint of control, it looks excellent.”
EPA was expected to approve Bollgard II in September. “EPA is looking to register Bollgard II as part of their fiscal year 2002 plan. That ends on Oct. 15. So we're hopeful we'll have it registered by then,” Mullins said earlier this month.
Should approval come, there could be enough seed available to plant a limited amount of Bollgard II cotton varieties in 2003, according to Mullins. “We would like to spread the varieties out as much as we can to get as much experience as we can across the Cotton Belt.
Bollgard II technology “is likely to have a price premium” over original Bollgard, but, according to Mullins, the price has not been determined. “There's been a lot of money invested in it by Monsanto, and the company will look to recoup that.”
Bollgard II technology is expected to become available in Australia shortly after approval in the United States, however, it's not likely that Down Under cotton producers will have access to it until 2004 since they're already preparing to plant their 2003 cotton crops. Bollgard is called InGard in Australia.
Initially, refuge requirements for Bollgard II will not differ from those used for Bollgard, according to Mullins. “That way, there will be less confusion about how to do refuge plans. Once we get a lot of Bollgard II varieties available and get close to replacing Bollgard with Bollgard II, there will be other refuge options that we hope will be more desirable than they are today.”
Mullins' optimism is based on laboratory experiments in which Bollgard II toxins killed 100 percent of resistant Lepidopterous cultures.
“We also have a cooperative study in five states to determine where the bollworms flying in and out of these fields are coming from. We have a notion that a lot of bollworms in cotton fields grew up on something other than cotton. This means there is a lot of natural refuge around cotton fields. Just one year of data indicates that a lot of these moths are coming from somewhere other than the cotton, even in August and September.”