Ag Engineering/Agronomy, Central Iowa and BioCentury Research Farms
Anyone who has tried to count the entire number of aphids on a single plant when populations are high can appreciate the need for a more time-efficient method of estimating aphid densities. One of the treatments in this study was designed to evaluate the speed scouting system developed at the University of Minnesota. (For more information see www.soybeans.umn.edu/crop/insects/aphid/aphi d_sampling.htm.). The speed scouting technique is a binary system in which a plant receives a score of either a ‘+’(more than 40 aphids/plant) or a ‘-’(fewer than 40 aphids/plant). Using this system, there is never any need to count more than 40 aphids/plant. After accessing a number of plants(either + or -), a decision is made based on a sequential plant sampling. Under heavy aphid populations, this technique results in significantly fewer aphids being counted as compared with the 250 aphids/plant threshold.
Iowa State University
Johnson, Kevin D., "Scouting Recommendations for Soybean Aphid Aphis glycines Management" (2006). Iowa State Research Farm Progress Reports. 1022.