Design and use of a simulation model to evaluate germplasm for antibiotic resistance to the greenhouse whitefly (Trialeurodes vaporariorum) and the sweetpotato whitefly (Bemisia tabaci)

Abstract

AbstractSARAH (Software for the Assessment of antibiotic Resistance to Aleyrodidae in Host plants) is a deterministic simulation model of whitefly population growth based on whitefly life‐history components determined on individual plants. The life‐history components recorded were oviposition rate, adult survival, pre‐adult survival, developmental period, and sex ratio. The simulation model serves as a tool to combine these components and to obtain a single criterion for (antibiotic) resistance. The criterion used was the decrease in simulated intrinsic population growth rate, rs, relative the rs value determined on a susceptible control genotype. This model‐based evaluation method was tested using the greenhouse whitefly, Trialeurodes vaporariorum Westwood, on tomato and the sweetpotato whitefly, Bemisia tabaci Gennadius, on tomato, eggplant, collard, and pepper.To study its consistency over time, the evaluation method was repeated six times for T. vaporariorum on a susceptible and a resistant tomato cultivar. Simulated intrinsic population growth rate was more consistent in indicating resistance than any of the individual life‐history components. Of ten L. hirsutum accessions tested for resistance to T. vaporariorum, three exhibited rs values that were significantly lower than those for the susceptible control. In addition, on these ten L. hirsutum accessions, a significant positive correlation was observed between rs and sex ratio (# females/# males).Four host plant species (tomato, collard, eggplant, and pepper) were evaluated for resistance to B. tabaci. All life‐history components and rs values varied among host species, while a negative rs value was observed for B. tabaci on pepper.A high correlation was found between results from a sensitivity analysis of SARAH and results from a sensitivity analysis of a validated whitefly population simulation model by Yano et al. (1989a). Significant correlations were found for the relationships between oviposition rate, adult survival, or pre‐adult survival and rs, indicating that none of these life‐history components can be omitted from the test procedure. This model‐based evaluation method offers a standardized way to quantify levels of antibiotic resistance to whiteflies and will enhance efficiency in breeding programs.