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© 2004 Plant Management Network.
Accepted for publication 2 December 2004. Published 29 December 2004.

First Report of Western Bean Cutworm, Richia albicosta (Noctuidae) in Illinois and Missouri

David L. Dorhout and Marlin E. Rice, Department of Entomology, Iowa State University, Ames 50011

Corresponding author: David L. Dorhout. munch36@iastate.edu

Dorhout, D. L., and Rice, M. E. 2004. First report of western bean cutworm, Richia albicosta (Noctuidae) in Illinois and Missouri. Online. Crop Management doi:10.1094/CM-2004-1229-01-BR.

The western bean cutworm, Richia albicosta (Smith) (Lepidoptera: Noctuidae), is native to North America (1,2) and is an occasional pest of dry beans (Phaseolus spp.) and corn (Zea mays L.) (Fig. 1). One larva per corn plant at dent stage will reduce yields by approximately 3.7 bu/acre. Heavily infested corn may have 8 to 10 larvae per ear. Since the western bean cutworm was first described in 1887, it has slowly and steadily expanded its host range eastward from Arizona to southern Minnesota and central Iowa (1,3,4,5). Western bean cutworms were known to occur in western Iowa prior to 1970, but it was not until 2000 that an economically damaging population (i.e., exceeding the economic threshold) was found in field corn. Since then, it has become a recurring economic pest in western Iowa.

Fig. 1. A western bean cutworm moth.

In 2004, a pheromone trap network was established throughout eastern Iowa (Fig. 2) during July and August when the adult moths are present. The objective was to determine the eastern-most range of the western bean cutworm in the state. On July 12, a pheromone trap in Henry County (southeastern Iowa) captured six western bean cutworms. Subsequently, moths were caught at all Iowa locations where traps were located (Fig. 2). It was decided to expand the pheromone trapping into Illinois and Missouri since this insect has not previously been reported from these two states. Fourteen pheromone traps were placed approximately 25 miles apart on July 14 along a transect starting in Missouri (Harrison County) at exit 99 on Interstate 35, following U.S. Highway 136 into Illinois, north on U.S. Highway 67, then Interstate 74, and finally east on Illinois Highway 17, terminating in Henry County. Traps were constructed from unused gallon paint cans. They were placed next to corn fields, with the opening hung at grass height. Western bean cutworm pheromone (Scentry Biologicals, Inc., Billings, MT) was tied to the paint can handle using bailing wire and paper binder clips with the pheromone hanging approximately one inch above the can rim. Twenty-four ounces of a soapy water/anti-freeze mixture (4:1) were placed in the bottom of the can to kill and preserve any specimens captured. The traps were left in the field overnight and inspected the following day. The location of each trap was recorded using a handheld Pioneer global positioning system (Thales Navigation, Inc., Santa Clara, CA).

Fig. 2. The locations of pheromone traps in Iowa in 2004. Western bean cutworms were caught at all locations.

In Missouri, three western bean cutworms were found in three separate locations and five western bean cutworms were found at a single location in Illinois (Table 1). The captured western bean cutworms represent new state records for this species and represent a significant eastward expansion from its recent published historical distribution. It is important to note that the traps were operational for only one night and that a more comprehensive trapping effort may have been able to detect moths in the other counties. The eastern-most range of the western bean cutworm has not yet been established and should be done soon so that a record of its current distribution can be preserved for future study.

Table 1. Locations of pheromone traps used to capture western bean cutworms in 2004, and the number of moths caught.

In summary, the capture of western bean cutworms in Illinois and Missouri represents a significant eastward expansion of its previously known distribution range. The potential for economic damage to field corn from this insect now exists in these two states.

All captured moths are deposited in the Iowa State University, Department of Entomology Insect Collection as voucher specimens.

Acknowledgment

Thanks to Rich Pope for providing pheromone for this study.

Literature Cited

1. Blickenstaff, C. C. 1979. History and biology of the western bean cutworm in southern Idaho, 1942-1977. Univ. Idaho Agric. Exp. Stn. Bull. 592.

2. Hagen, A. F. 1976. A fourteen-year summary of light trap catches of the western bean cutworm, Loxagrotis albicosta (Smith) (Lepidoptera: Noctuidae). J. Kans. Entomol. Soc. 49:537-540.

3. Keith, D. L., Hill, R. E., and Tollefson, J. J. 1970. Survey and losses for western bean cutworm Loxagrotis albicosta (Smith), in Nebraska. Proc. North Cent. Branch Entomol. Soc. Am. 25:129-131.

4. O’Rourke, P. K., Hutchison, W. D. 2000. First report of the western bean cutworm, Richia albicosta (Smith) (Lepidoptera: Noctuidae), in Minnesota corn. J. Agric. Urban. Entomol. 17:213-217.

5. Rice, M. E. 2000. Western bean cutworm hits northwest Iowa. Integrated Crop Manage. IC-484 (22:163), Iowa State University Extension, Ames, IA.