If you're debating about what impatiens to plant in your yard, a recent study at the University of Illinois suggests that you go with Cajun Carmine, that is if you want fewer insects in your garden. Why some varieties of the popular bedding plant impatiens attract more thrips than others was one of the questions graduate student Katie Yu investigated.
"The fragrances given off by flowers are actually complex compounds known as plant volatiles, some of which cannot be detected by humans," Yu said. "Volatile compounds act as a language that they use to communicate and interact with the surrounding environment. It's a defense mechanism against herbivores and it's a means to attract pollinators. As of today, there have been over 1,000 plant volatiles reported. But, none have yet to be reported in impatiens."
Impatiens, one of the top-selling bedding plants in America, is very durable, relatively easy to grow and has wholesale sales exceeding over $170 million per year. Yu chose two the popular varieties Dazzler White and Cajun Carmine to study their resistance to the Western flower thrips.
Yu's initial research in greenhouses showed that Cajun Carmine had significantly less damage from thrips than Dazzler White. So she set out to prove the reason why, suspecting that impatiens may emit volatiles that attract the thrips.
Thrips are very tiny, sliver-like insects that are native to northwestern North America. They are a worldwide pest, causing problems in field crops and greenhouses. They are attracted to a wide range of host plants including impatiens, fuscia, hibiscus, chrysanthemum, begonias, ivy, petunias, and major food crops. They feed on the plants' leaves and petals and transmit devastating plant viruses.
For her research, Yu used a tiny glass apparatus shaped like the letter "Y."
The thrips are inserted one at a time into the base of the Y. When the thrip reaches the junction in the Y, it has the opportuni
|Contact: Debra Levey Larson|
University of Illinois College of Agricultural, Consumer and Environmental Sciences