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The COM–Poisson distribution is a two-parameter generalization of the Poisson distribution that can deal with under-, equi- and overdispersed count data. Unfortunately, its location parameter does not correspond to the expectation, which complicates the parameter interpretation. In this article, we propose a straightforward reparametrization of the COM–Poisson distribution based on an approximation to the expectation. Estimation and inference are done using the likelihood paradigm. Simulation studies show that the maximum likelihood estimators are unbiased and consistent for both regression and dispersion parameters. In addition, the nature of the deviance surfaces suggests that these parameters are also orthogonal for most of the parameter space, which is advantageous for interpretation, inference and computational efficiency. Study of the distribution's properties, through a consideration of dispersion, zero-inflation and heavy tail indexes, together with the results of data analyses show the flexibility over standard approaches. The computational routines and datasets are available in the supplementary material. [ABSTRACT FROM AUTHOR]

The frequency of strains ofMonilinia fructicolathat are resistant to the demethylation inhibiting fungicide tebuconazole in Brazil was determined by three methods. The first involved testing 295 isolates for relative growth under a discriminatory dose of 0.3 µg mL−1. The second and the third methods involved testing 120 isolates for the effective concentration for 50% population inhibition (EC50); one method employed the discriminatory dose of 0.3 µg mL−1and the other method utilized the baseline dose of 0.046 µg mL−1to separate the strains based on sensitivity. The frequencies of resistance among the isolates based on the three methods were determined by measuring mycelial growth in fungicide-amended media. The shifts inM. fructicolasensitivities were determined by comparing the EC50density distributions of the baseline (2000–2004, n=31), intermediate (2005–2008, n=88), and current (2009–2011, n=120) isolate populations. The frequency of resistance to tebuconazole varied according to the assessment method; the resistance frequencies were 18.3% for the relative growth method, 40% for the baseline EC50method, and 8.33% for the EC50method segregated by the dose of 0.3 µg mL−1. The application of the EC50method involving the discriminatory dose of 0.3 µg mL−1revealed a decrease in the frequency of resistant genotypes. However, the baseline EC50method is recommended for future resistance surveys because this method was originally used to determine the mean sensitivity prior to the use of tebuconazole in Brazil. Additionally, a shift of the current population toward sensitivity was observed compared with the intermediate population. Finally, São Paulo was found to be the state with the highest EC50values (0.186 µg mL−1) compared with Paraná (0.053 µg mL−1) and Rio Grande do Sul (0.026 µg mL−1). These results suggest that the build-up of fungicide resistance inMonilinia fructicolahas been prevented by the use of anti-resistance strategies in the main peach production areas of Brazil; however, additional studies are required to demonstrate how resistance instability and fitness are affecting isolate sensitivity. [ABSTRACT FROM AUTHOR]

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