Evaluation of Italian ryegrass seed dispersal prior to and at wheat harvest in Kentucky

Abstract

AbstractHarvest weed seed control is a potential option to control herbicide‐resistant Italian ryegrass [Lolium perenne spp. multiflorum (Lam.) Husn.] in Kentucky's soft red winter wheat (Triticum aestivum L.). The use of harvest weed seed control to manage Italian ryegrass seed is only a viable option if Italian ryegrass seed is retained on the seed head up to wheat harvest and can successfully enter the combine at harvest. Italian ryegrass seed retention samples collected from eight wheat fields prior to harvest in 2020 and 2021 showed that 1,070 Italian ryegrass seeds ft−2 remained on the heads, whereas only 138 seeds ft−2 were found on the soil surface. In 2020, no differences were found in the amount of Italian ryegrass seed shattered at the combine's header compared with seed in the combine's grain tank or seed located within the chaff discharged from the combine. In contrast, in 2021 there was less seed shattered at the combine's header than the amount of Italian ryegrass seed found in the grain tank and in the chaff. Across both years, significantly fewer seeds were shattered at the combine's header than the number of seeds that successfully entered into the combine. Overall, this research confirmed that harvest weed seed control may be a viable option for the management of Italian ryegrass in Kentucky's soft red winter wheat.