Development and validation of binomial sampling plans for estimating leafmine density of Liriomyza trifolii (Diptera: Agromyzidae) in greenhouse tomatoes

Abstract

The dynamics of leafmines developed by Liriomyza trifolii (Burgess) larvae in greenhouse tomatoes were studied in Korea during [2003][2004] in order to construct and validate binomial sampling plans. An empirical P T -m model, expressed as: ln(m)ϭaϩb ln[Ϫln(1ϪP T )], was used to relate between the proportion of infested leaves (P T ) and mean densities (m) at tally thresholds (T, the minimum number of leafmines present before a leaf is considered infested) of 1, 2, 3, 4 and 5 mines per leaf. To ensure the consistent selection of sample units, a sequence of reference pictures, with various levels of leafmine formation, was measured in advance by image analysis. The mines Ͻ0.4 cm 2 in area were excluded from counting in the greenhouses. There were no significant relationships between the total numbers of leafmines and individual mine areas. The binomial sampling plans were validated using resampling simulations with seven independent data sets. In an estimation of the density, the sampling precision (SE/mean) was found to increase with higher Ts; however, there were negligible improvements in the precision with TՆ3 mines per leaf. Using Tϭ3, over a wide range of mine densities, as few as 30 samples were necessary to achieve a precision of 0.30. In comparing binomial models with Tϭ3 and 5, using seven independent data, the model with Tϭ3 was a robust and relatively unbiased predictor of the mean density, whereas the Tϭ5 model was generally biased towards over-prediction of the mean density. The binomial sampling plans presented here should permit rapid estimation of the mine density and enhance development for a damage assessment program in greenhouse tomatoes.

A Binomial Sampling Plans for Aphis gossypii (Hemiptera: Aphididae) in Greenhouse Cultivation of Cucumbers

“…2). This finding is consistent with those of previous studies (Cho et al, 1998;Lee et al, 2005;Salguero Navas et al, 1994;). This is likely because sample size has little effect on the estimation of the variance term (Jones, 1994) and the MSE is the largest variance component (Binns et al, 2000).…”

“…In the binomial sampling method, pest densities are estimated on the ratio of infested sampling unit greater than a tally threshold, so abnormally high densities would have a negligible effect on the results. Selection of a proper tally threshold in binomial sampling can reduce the variability and bias of the estimated mean, and use of sequential classification can yield acceptable error rates and average sample sizes (Cho et al, 2000;Lee et al, 2005;Nyrop and Binns, 1991;Song, 2003).…”

Temperature-dependent development of Diglyphus isaea (Hymenoptera: Eulophidae) on Liriomyza sativae (Diptera: Agromyzidae) on cucumber

“…Agromyzid leafminers occur worldwide and are economically important pest of many agricultural crops (Kaspi and Parrella 2005;Lee et al 2005;Hondo et al 2006). Vegetable leafminer, Liriomyza sativae Blanchard is a major pest of a wide variety of vegetables and ornamental crops throughout the world (Parrella 1983;Reitz and Trumble 2002).…”

A Novel Method for Estimating Soybean Herbivory in Western Corn Rootworm (Coleoptera: Chrysomelidae)

“…Table 3. Soybean herbivory percentages measured by two naïve system users in blind assays of three 25-beetle samples containing different percentages of soybean-feeding and negative control western corn rootworm females Digital image analysis techniques have been used for a variety of past entomological studies; in particular, thresholds have been used to separate leaf tissue damaged by insect herbivory from healthy (background) tissue (James and Newcombe 2000;Lee et al 2005). However, threshold analysis of the dark green abdominal coloration that results from soybean foliar feeding is a more complex problem.…”