Development of a sequential sampling program for Frankliniella occidentalis Pergando (Thysanoptera) on strawberry in plastic tunnels in southern Italy
2000
Laudonia, S. ((Universita di Napoli Federico 2, Portici (Italie). Dipartimento di Entomologia e Zoologia Agraria)) | Pedata, P.A. | Viggiani, G.
Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is considered a key pest in tunnel-grown strawberries in southern Italy. We present data about the distribution of the population of WFT and develop a sequential sampling scheme based on Wald's procedure. The thrips population density was monitored in commercial plastic tunnels in two areas of Campania (southern Italy). The series of aggregated data were confronted with three theoretical distributions, i.e. normal, Poisson and negative binomial. Since for densities 1 thrips/flower the negative binomial distribution described better the pest population, we calculated the corresponding dispersion parameter (k). Single k's were used to calculate a common k (kc=1.56). We constructed a sequential chart under the condition of negative binomial distribution by choosing 7 and 15 thrips/flower as the tolerance and the intervention thresholds respectively. The maximum average sample number (ASN) required to obtain maximum allowable risks fixed at alpha=beta=0.05 is 11.1 flowers
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