Presence-absence sequential sampling for Panonychus ulmi (Koch) and Tetranychus urticae Koch, on nectarines varo Armking

René Vargas M.1 y Fernando Rodríguez A.1

A binomial sequential sampling plan was elaborated,· as a practical and economical form for rapid control decision of mite populations in nectarines. With the advantages of the enumerative sequential sampling, relative to rapidity and efectivity, the binomial sequential. method incorporates aditional time saving, as no individual mites have to be counted. Instead, presence or absence of them is registe red and related with percentage of infestation and densities of mites. The Taylor's Power Law fits the data well. A tentative control decision threshold is proposed for the mites. The validation of the method, using field data, showed a time economy close to 90%, compared to conventional sampling with a fixed sample size.

1 Subestación Experimental Control Biológico La Cruz (INlA), Casilla 3, La Cruz, Chile.