One miner growers do not want to save
posted on May 16, 2011 8:29am
Miners have been in the news a lot lately. They’ve been stuck below ground. They’ve been rescued. They’ve been all over television and newspapers. Basically, we have miner fever. One tiny miner, however, isn’t garnering any applause. Instead, it is causing trouble for Michigan’s asparagus growers. Fortunately, researchers at Michigan State University (MSU) are out to find a way to stop it in its tracks.
Zsofia Szendrei is an assistant professor in the MSU Department of Entomology and MSU Extension Specialist. As part of a research project funded through Project GREEEN (Generating Research and Extension to meet Economic and Environmental Needs), she is working with an entomology graduate student to study the asparagus miner and better ways to control it in Michigan asparagus fields.
Asparagus miner, so named for its ability to tunnel through asparagus stems and cause “mines,” is one of the top insect pests in asparagus – a $15 million industry in the state, which harvests 25 million pounds annually. While the tunnels created are a problem, the bigger issue is that the tunnels
make the plant more vulnerable to disease. Since the miner is protected during the early stages of growth thanks to being inside the asparagus stem, current registered insecticides are ineffective at controlling it. Additionally, non-chemical control methods have never been developed for this species.
“The asparagus industry came to me and said ‘These are our problems. Can you help us?’” Szendrei explained. “They asked me to look at an integrated management approach.”
Based on recommendations from growers, Szendrei moved forward with a project titled “Development and delivery of a sustainable asparagus miner management program in Michigan.” Working with Rob Morrison, a graduate student in her laboratory, the pair set off to develop a degree-day model for the asparagus miner.
“Degree-day models draw a connection between temperature and insect development,” Szendrei said. “This model would allow growers to predict the best timing of miner management tactics in the field. The ultimate goal is to provide farmers with decision-making tools, in order to maximize their profits while minimizing management input and environmental costs.”
The ability to monitor and sample the number of asparagus miners present in the field is another important aspect for making informed decisions about pest management. The use of traps can monitor insect abundance in the crop field. The more species- specific the trap is, the easier it is to identify and count the insects caught in it. Traps can be baited to improve the chances of only catching the insects of interest. As part of his dissertation, Morrison focuses on looking at how volatile chemicals produced by the plant can be utilized in these baits to monitor adult miner numbers in the field. Chemicals emitted by asparagus plants may provide cues for the miners to locate food sources in the field. If researchers understand what chemicals are present, they may be able to incorporate them into baits to attract miners. Similarly, volatile compounds can also be produced by the asparagus miners, which may be used as signals by other asparagus miners in mate finding or by insects that prey on them.
One of the more exciting parts of the study, according to Szendrei, is their work looking at biological control agents of the asparagus
“No one has looked at biological control of asparagus miner in Michigan, or anywhere in the United States for that matter,” she said. “We’re identifying parasitoids, as well as looking at how we can make biological control more effective. For example, by providing floral resources, we hope to encourage parasitoids to come and stay near the asparagus miner.”
While the research is still ongoing, Szendrei is optimistic about the outcomes and is eager to give praise to the individuals and groups working on the project.
“This is an exciting project because of two main reasons: it is both an interesting research topic and the findings will be important for growers. This makes it more meaningful for a graduate student like Rob, because he feels engaged both in the research and the outreach component of the project,” she said.
She also gives thanks to Norm Myers, senior MSU Extension educator in western Michigan, who helped in setting up the field experiments.
“He put me in touch with growers, helped us locate asparagus farms and checked our traps sometimes. He has been an indispensable part of this project.”
Results from the project so far are available in a fact sheet titled “Asparagus Miner” available through the MSU Extension Bookstore.