Integrated Study Underway For Sugarbeet Diseases, Insect Control
By Lois Kerr

A group of scientists representing several agencies and organizations have combined their efforts in the search to find new, integrated approaches to fighting old diseases and insects that affect sugarbeets. Stefan Jaronski, research entomologist at Sidney’s ARS, along with MSU plant pathologists Barry Jacobsen and Nina Zidack; entomologist Mark Botel from NDSU; and Larry Campbell, USDA/Fargo, have developed a close partnership in researching insect pests and diseases in sugarbeets. Dr. Robert Lartey, research plant pathologist with the Sidney ARS will join this research as he develops his new biocontrols of Cercospora.

Sidney’s Stefan Jaronski explains that this coordinated research takes a different approach from the more traditional methods of research. “We’re trying to develop a biologically based system to control root maggots and other insects, as well as diseases found in sugarbeets,” he remarks. “Traditionally, scientists develop a chemical or other control without considering any other needs. It’s like developing a Phillip’s screwdriver without considering all the other types of screws on the market.”

He adds, “We’re trying to develop a multi-use system that fits all the needs, like a screwdriver with multiple heads.”

Barry Jacobsen, MSU plant pathologist, explains that this program evolved because of the recent loss of some insecticides. “The program was born out of the potential loss of many root maggot insecticides through the EPA,” he comments. “The root maggot problem is major, as is Cercospora and Rhyzoctonia. We want to build a stable, cost effective system for growers that integrates biological controls for insects and diseases in conjunction with contemporary controls.”

Jacobsen points out that this year growers in the MonDak region have found several field failures with Benlate fungicide, used for Cercospora control. “The fungi have become resistant in these fields,” he explains. “Growers have lost another category of fungicides, so the development of new tools is critical.”

Both men expect to see the development of fungi and other microbes to control insect pests, coupled with breeding more resistant beet varieties, producing better chemicals, and using induced systemic resistance. “Plants can have biochemical resistance that can be induced by a kind of vaccination,” Jaronski says.

“We need to integrate all our information, including the use of resistant beet varieties which can in itself save growers one or two sprayings each season,” adds Jacobsen.

Jaronski’s efforts in this integrated program will focus on the development of a fungus to control root maggots. Other team members currently work to develop microbes that will control diseases, as well as continue their biological systems controls studies, and work to breed better beet varieties with increased resistance. “We want to develop a system so growers have a full tool box and know how to use all the tools within the box,” Jaronski remarks.

Jaronski explains how specialized fungi will work in root maggot control. “The spores of the fungi infect the insects,” he states. “I call it an infectious mine field of fungus. If the spores are put at the base of the plant, newly hatched maggots have to crawl through these spores to reach the plant. Insects contact the spores, become infected, and die.”
He continues, “These fungi act as “fatal athlete’s foot” for the insects. The spores attach to the maggots and bore through the skin within 12 to 24 hours. Once inside, the spores grow throughout the insects’ bodies and will kill them within three to five days. Insects feel sick before dying, so they will slow or stop feeding a day or so after infection.”

Jaronski points out that these specialized fungi attack only the targeted insects, making these fungi very safe for humans and the environment. “These fungi are specific to the insect,” he emphasizes. “These fungi are so safe that they can be used in the home garden market.”

Both Jaronski and Jacobsen stress that this research keeps the economics for growers in mind at all times. “We conduct our research keeping in mind the economics for growers. We’re doing things in such a way that growers can afford to do this,” Jaronski notes. “The end results of this research cannot be more expensive than existing controls. We are keeping the growers in mind and looking at this research from a grower’s perspective.”

Jacobsen concurs, and adds, “We look at this situation the way a grower does. Growers have to take information from all over and integrate this information for one crop. We try to do the same thing, by incorporating the known knowledge about insects, diseases, resistant varieties, biological systems and pesticides, and using all these methods to come up with an integrated, affordable system of control.”

Both men caution that it will take approximately five years to obtain concrete research results. “This is not a quick fix,” Jaronski warns. “It will be a good five years before we can transfer organisms, rates and recommendations to growers and industry. A lot of our research over the next three to five years will look at how the different tools integrate and combine, a factor not often considered in research until now.”

Jacobsen gives an example of why researchers must look at and evaluate all tools at the same time. “For instance, this year we have a full field label for the use of Quadris. However, Quadris is toxic to Stefan’s (Jaronski) microbe,” Jacobsen explains. “We need to research ways to get around this. This whole approach develops an integrated approach for sugarbeet growers in ways that make it stable, more economical, and more environmentally friendly.”

Outside funding agencies have recognized the importance of this research. The Western Regional Integrated Pest Management Program and the USDA’s National Research Initiative have both awarded grants for the continuation of this coordinated research. “Both programs fund less than 20% of all the grant proposals they receive, so to get funding from both of them makes me feel good about the quality of the science,” Jacobsen remarks.

Jaronski adds, “The relevance of this program has been recognized by outside sources through the awarding of these grants. I take comfort in this because these are very competitive grant programs, and to receive funding from both agencies is significant and tells me that our approach is on the right track. This is exciting. It isn’t often that we are in a position to look at the overall picture.”