Missouri Southern State University1, Biology, Joplin, MO 64801 Iowa State University2, Plant Pathology, Ames, IA 50011
The purpose of this study was to obtain quantitative data on the spatial spread of Bean pod mottle virus (BPMV) in soybean crops. Such information may aid in the development of more cost-effective, integrated methods to manage BPMV and its insect vector, the bean leaf beetle. This experiment was conducted by using a total of 15 field plots (five different treatments replicated three times). The five treatments were: 1) establishing a BPMV inoculated point source, 2) two foliar sprays of lambda-cyhalothrin (Warrior) insecticide, 3) a non-treated control, 4) a BPMV inoculated point source, plus two foliar sprays of lambda-cyhalothrin, and 5) a BPMV inoculated point source, plus an insecticide seed treatment. Treatments were arranged in a randomized complete block design to reduce bias. The dimensions of each plot were 6.1 meters x 10.7 meters, and plots were spaced at least 12.2 meters apart. Each sampled plot consisted of six rows, which were further subdivided into 150, 30-centimeter quadrats. Soybean leaf samples were collected from each quadrat beginning 8-10 days after planting. Sap samples from soybean leaves (quadrats) were obtained using a leaf roller press and the extracted sap was then tested for the presence of BPMV using an enzyme-linked immunosorbent assay (ELISA). BPMV was first detected in soybeans during the first sampling period (12 June). As of the fifth sampling, BPMV incidence ranged from 1.3% to 12%. Ordinary runs analysis indicated that the spatial pattern of BPMV incidence within the treatments was clustered.
[Abstract (DOC)]