Priciples and possibilities of determining degrees of nematode control leading to maximum returns. I - Protection of one crop sown or planted soon after treatment


  • J. W. Seinhorst


Although methods to prevent crop losses caused by nematode attack have been investigated and practiced for many years the economics of nematode control and the factors governing it have not yet been analyzed to a great extent. As a result, several treatments are known that decrease nematode populations and increase crop yields, but there is no way of ascertaining, even theoretically, how much treatment is required in a given case to obtain the maximum return. It is quite possible that, even if a system was known for the calculation of treatments giving maximum returns, the necessary estimations of values of the various parameters would not be accurate enough to make practical use of it. However, only if a system is identified can values of parameters and their variation be investigated. Therefore, an attempt is made here to describe the quantitative relationships between nematode density, treatment and yield. Our knowledge of the relevant parameters and their estimation in practical cases is discussed.