Short communication: A predictive model for the time course of seedling emergence of Phalaris brachystachys (short-spiked canary grass) in wheat fields

Aim of study: A predictive model of the seedling emergence pattern of Phalaris brachystachys Link (short-spiked canary grass) was developed, aimed to contribute to support a more efficient management of this troublesome, competitive weed in winter cereal crops around its native Mediterranean range and in different areas of the world where it is introduced.Area of study: Southern (Andalusia) and northern Spain (Navarra).Material and methods: A model describing the emergence pattern of P. brachystachys in cereal fields based on accumulation of hydrothermal time in soil was developed and validated. For model development, cumulative emergence data were obtained in an experimental field, while an independent validation of the model was conducted with data collected in two commercial wheat fields from climatically contrasting regions of Spain.Main results: The relationship between cumulative emergence and cumulative hydrothermal time (CHT) was well described by a Logistic model. According to model predictions, 50% and 95% seedling emergence takes place at 108 and 160 CHT above base water potential for seed germination, respectively. The model accurately predicted the seedling emergence time course of P. brachystachys in the two commercial wheat fields (R2 ≥ 0.92).Research highlights: This model is a new tool that may be useful to improve the timing of control measures to maximize efficiency in reducing P. brachystachys infestations in cereal crops.Phalaris brachystachys Link (short-spiked canary grass) is a competitive weed that affects winter cereal crops around its native Mediterranean basin and in different areas of the world where it is introduced. The development of a predictive model of the seedling emergence pattern may contribute to support a more efficient management of this species. In this work, a model describing the emergence time course of P. brachystachys in cereal fields based on accumulation of hydrothermal time in soil was developed and validated. For model development, cumulative emergence data were obtained in an experimental field, while an independent validation of the model was conducted with data collected in two commercial wheat fields from climatically contrasting regions of Spain. The relationship between cumulative emergence and cumulative hydrothermal time (ΘCHTT) was well described by a Logistic model. According to model predictions, 50% and 95% seedling emergence takes place at 108 and 160 ΘCHTT above base water potential for seed