Sequential sampling plans for Colorado potato beetle (Coleoptera: Chrysomelidae) in eggplant

• Published in: Environmental entomology Vol. 27; no. 1
• Main Authors: Hamilton, G.C. (Cook College, Rutgers University, New Brunswick, NJ.), Lashomb, J.H, Arpaia, S, Chianese, R, Mayer, M
• Format: Journal Article
• Language: English
• Published: 01.02.1998
• Subjects: DENSIDAD DE LA POBLACION; DENSITE DE POPULATION; ECHANTILLONNAGE; LEPTINOTARSA DECEMLINEATA; METHODE STATISTIQUE; METODOS ESTADISTICOS; MUESTREO; NEW JERSEY; POPULATION DENSITY; SAMPLING; SOLANUM MELONGENA; STATISTICAL METHODS; TAYLOR POWER LAW
• ISSN: 0046-225X; 1938-2936
• DOI: 10.1093/ee/27.1.33

During a 4-yr period (1988-1991), Colorado potato beetle, Leptinotarsa decemlineata (Say), eggmass, larvae, and adult populations in 17 commercial eggplant, Solanum melongena L., fields were sampled twice weekly using a 100-plant fixed sampling program. Eggmass and combined adult/larvae (placed on an equivalent feeding basis) densities were determined. The Taylor power law was calculated for use in developing sequential estimation sampling plans. Two plans were created, 1 for eggmasses and 1 standardized for combined adults and larvae. Resampling for validation of sampling plans software was used to test each plan using 18 independently collected data sets from 2 eggplant fields during 1992. Each year, beetle densities ranged between 0.0 and 8.0 for eggmasses and between 0.0 and 55.0 for combined larvae/adults. Application of the Taylor power law to the data resulted in a significant linear relationship between the means and variances for each year and described aggregated sampling distributions for both eggmasses and combined adults/larvae. Based on the lack of significant differences in regression slopes between years, combined year values for the Taylor a and b (eggmasses, a = 1.74, b = 1.18; combined adults/larvae, a = 3.55, b = 1.56) were calculated and used to generate optimal sample sizes and critical stop lines. The simulations conducted to validate each sampling program resulted in mean precision levels for each data set tested that were lower than the precision level specified (D = 0.25). The simulations also showed a high degree of agreement between actual and estimated densities on all sampling occasions