Relationship Between Population Density of Citrus Rust Mite (Acari: Eriophyidae) and Damage to ‘Hamlin’ Orange Fruit

Abstract

Six studies were conducted to quantify the relationship between fruit surface damage of ‘Hamlin’ orange, Citrus sinensis , and population denisty of the citrus rust mite, Phyllocoptruta oleivora (Ashmead). Over time, the damage rate per mite-day increased in sigmoid fashion mainlyas a result of a sigmoid increase in cumulative mite-days. The sigmoid increase in cumulative mite-days resulted from the single-peaked, more or less symmetrically shaped mite population growth. Increasing fruit maturity increased susceptibility to mite feeding. This was indicated by a decline in mite-days required to cause a given percentage of surface damage as fruit maturity increased. Tree age and grove location did not seem to have obvious effect on the general trend in damage rate. A mathematical model was developed to describe the relationship between cumulative damage and cumulative mite-days. The model could be used to predict fruit surface damage based on mite population data.