How many bushels per acre soybean yield loss can I expect for a given SCN egg population density (egg count)? In other words, what is the relationship between soybean yield loss in relation to the number of eggs per 100 cc of soil?
It is impossible to provide such precise information about the potential for yield loss because the amount of damage caused by SCN is very dependent on numerous interrelated factors including:
- SCN egg population density
- soil pH, texture, organic matter, and an assortment of other soil factors
- rainfall and temperature
- presence of other soil-borne soybean pathogens (such as Phytophthora, Fusarium, and the brown stem rot fungus, Phialophora, etc.)
- presence of insect pests (such as bean leaf beetle, spider mites, etc.) and weeds
Also, even if a yield-loss equation was available, the information generated from such an equation probably would not be very accurate because of errors related to soil sampling. The process of developing an effective SCN management program begins with collecting good soil samples that accurately represent the SCN population densities present in fields. Detailed information on the proper way to collect good soil samples can be found on the back of the ISU Plant Nematode Sample Submission Form (publication PD-32).