Sequential sampling plan for corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), in corn fields on the south coast of Puerto Rico

Abstract

The corn earworm, Helicoverpa zea (Boddie), is the major insect pest of corn, Zea mays L., in Puerto Rico. The objective of this study was to design a sequential sampling plan with fixed precision levels for H. zea (Boddie) in corn fields on the south coast of Puerto Rico. For determining the presence (= 1) or absence (= 0) of H. zea eggs, 25 corn plants were randomly sampled from December 2003 to March 2004. Data were analyzed by using the beta binomial distribution. Critical density levels of 0.10 and 0.08 infested plants, before and after the emergence of ear silks, were used for Iwao's and converging lines formulae. A converging line sampling plan is recommended because it selected a smaller average sample size. This plan can be used to make cost effective control decisions on field corn in Puerto Rico.