Phenological Development of Waxy-Leaved Mustard (Boreava orientalis Jaub. and Spach.)

Waxy-leaved mustard (Boreava orientalis Jaub. and Spach.) is an invasive weed that has rapidly spread across wheat fields in the Kurdistan Province, Iran. The germination and phenology of this species were studied through a series of greenhouse and field experiments conducted from 2018 to 2020 to better understand its biology and support effective management strategies. We calculated the growing degree days (GDD) required for each growth stage of B. orientalis and related the calculations to the Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie (BBCH) scale. We also studied whether light affected germination. The results indicated that light significantly reduced germination. The base temperature for germination (4 °C) is identical to that of wheat, and the growth periods were largely similar. Consequently, the maturation of wheat and B. orientalis seeds co-occurred, leading to the dispersal of weed seeds during wheat harvest and increasing field infestation. Understanding the phenological development of B. orientalis provides a valuable basis for developing management strategies and implementing effective control measures to reduce field contamination and prevent further spread.