Insects of Wild Rice in Minnesota

Abstract

Little information is available concerning the insect pests of wild rice. Jenks ( 1901) stated that caterpillars were serious pests of wild rice in the Rainy River area, and he referred also to the rice water weevil (Lissorhoptrus simplex). Moyle (1944) reported that "armyworms (Agrotis sp.)" occasionally injured wild rice by feeding on the kernels. Authors of this publication* have never observed armyworms causing this type injury, and believe that Moyle was referring to the wild riceworm, Apamea apamiformis (Guenee), which, currently, is the most important insect pest of wild rice. In the late 1950s, the riceworm was reported to be a pest of wild rice in Canada (Hammond, 1957, 1958, 1959). MacKay and Rockbume (1958) described the life history of the riceworm on wild rice in Canada and reported extensive injury to the seeds by the larvae. In 1960, the riceworm was reported to be a serious pest of wild rice in commercial paddies near Zim, Minnesota. Young larvae ate out the kernels and older larvae bored in the plants. Furthermore, the rice worm was a nuisance because larvae were flailed out with the rice at harvest (personal communication from Richard Swartz, October 4, 1960). Melvin (1966) published observations on insects attacking wild rice in Manitoba, and he concluded that the two most common pests were the riceworm and the rice stalk borer, Chilo plejadellus Zinc ken. He outlined the life history of the rice stalk borer and recovered the parasite, Chelonus knabi Vier. from the stalk borer larvae. However, he believed that parasites were not important in controlling stalk borers. As a result of recent increased acreages of wild rice grown in commercial paddies, there was a demand for additional knowledge concerning insect pests and how to control them. The present studies were begun in 1970, funded by the Minnesota Agricultural Experiment Station in cooperation with the Departments of Agronomy and Plant Genetics, Plant Pathology, Soil Science, and Agricultural Engineering.