Advantage of the quadratic regression equation for estimating probit 9 by methyl bromide treatment to citrus infested by the Mexican fruit fly Diptera: Tephritidae 230

Seven concentrations of methyl bromide (MB) were evaluated for mortalities of immature stages of Mexican fruit fly, Anastrepha ludens (Loew), in grapefruit (Citrus grandis) and analyzed by linear probit and the curvilinear quadratic regressions for estimated doses which provide quarantine security of probit 9. The quadratic regressions fit the data better than the probit regression as determined by the Coefficient of Determination. The 95% confidence interval was narrower and less variable for the quadratic than for the probit regression. The curvilinear regression indicates that lower doses of MB can be used to achieve quarantine security than does the linear regression. Lower doses reduce the cost and time required to treat batches of fruit as well as environmental concerns.