NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665
October 7, 1999
The level of sugarbeet root maggot pressure continues to be a concern for producers in the northern end of the Red River Valley. In fact, producers raising sugarbeets in an area stretching from Minto north to Cavalier will likely need to make dual insecticide treatments next year to keep the root maggot in check, says a researcher with North Dakota State University.
"There were some areas this year in the northern end of the valley where insecticides didn't perform as well as hoped for," says Mark Boetel, extension sugarbeet entomologist and Integrated Pest Management (IPM) specialist at NDSU. "I have a feeling that the amount of rain after planting, coupled with the sandier soils in that area, resulted in reduced levels of insecticide material in the target zone. The high root maggot infestation levels that existed in some fields may have been more severe than what the remaining insecticide material could adequately control."
Boetel expects heavy insect pressure in that area again next year because so many maggots survived the insecticide applications this year. But, he says, the data compiled thus far don't indicate an insecticide-resistance problem.
"As of right now, I would strongly encourage dual insecticide applications in those hot-spot areas, but conditions between now and peak fly activity next year will determine an individual producer's ultimate strategy," Boetel says. "The factors involved in next year's pest-management strategies for sugarbeet root maggot will be a focus of discussion during the winter meetings."
Sugarbeet root maggot populations have been building in the northern end of the valley during recent years, despite the region having experienced a dramatic change in precipitation patterns--from drought in the late 1980s to flooding in the late 1990s. Boetel says, "The sugarbeet root maggot has been a much-studied insect that still demands a lot of research. There may be other environmental conditions we really don't know about that have been helping the populations build."
Meanwhile, a breeding team including plant scientists from the USDA Agricultural Research Service in Fargo and NDSU entomologists have developed two sugarbeet lines, F1015 and F1016, which are resistant to the root maggot. In trials, researchers rated root maggot damage on a zero-to-nine scale, with zero representing no visible scars from maggot feeding. Based on that rating system, F1015 and F1016 exhibit substantially less damage than any of the commercial hybrids, says Larry Campbell, the USDA-ARS sugarbeet breeder in Fargo.
The sugar content of both F1015 and F1016 were lower than typical commercial hybrids in the trials, Campbell says. Root yields for F1015 ranged from 75 percent to 80 percent of the yields of commercial hybrids that had been treated with insecticide to control the sugarbeet root maggot. The roots yields of F1016 ranged from 60 percent to 80 percent of the yields of commercial hybrids receiving insecticide treatments.
"Both maggot-resistant lines provide sources from which commercial breeders can develop agronomically acceptable material with resistance to the sugarbeet root maggot," Campbell says. "Seed of the maggot-resistant lines has been distributed to commercial breeders, and they are incorporating resistance into their elite lines."
Transgenic technology allows for the introduction of genes from other organisms into sugarbeet chromosomes to produce features such as insect or herbicide resistance. The result is genetically modified (GM) sugarbeets. Because the Environmental Protection Agency is re-evaluating organophosphate and carbamate pesticides--the only chemistries currently registered for sugarbeet root maggot control--transgenic technology may provide sugarbeet growers with another option. Yet despite the benefits, Boetel hopes that sugarbeet producers will use transgenic technology selectively.
"What I wouldn't want to see is the entire Red River Valley covered with the same type of transgenic insecticidal sugarbeets," Boetel says.
Opposition to transgenic technology currently is high among consumers in the European Union. Some analysts speculate that this resistance will drop only when GM crops begin offering consumer benefits. If so, a long-term effort under way in the Netherlands may produce a sugarbeet hybrid that consumers will support. Boetel says researchers there have successfully transferred a gene from a Jerusalem artichoke into the sugarbeet. The gene expresses itself by causing the plant to produce a zero-calorie sweetener instead of sugar.
"Although it will be a few years before this technology is available in commercial hybrids, I think it has potential to be a real economic boost for our beet producers," Boetel says.
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Sources: Mark Boetel (701) 231-7901
Larry G. Campbell (701) 239-1350
Editor: Dean Hulse (701) 231-6136
