Estimating the impact on maize production by the weed Parthenium hysterophorus in Pakistan

Abstract

Abstract Parthenium hysterophorus L. (Asteraceae) is an aggressive annual herbaceous weed which causes severe yield losses on a global scale. However, the precise impact of this weed in several countries is not yet known. To assess the impact of P. hysterophorus on maize crop losses in Pakistan, a 2 year field experiment was carried out at the CABI Rawalpindi campus in 2019 and 2020. Yield was measured on maize plants planted along with different densities (0, 1, 2, 4, 8, and 16 plants per m2) of P. hysterophorus. The trial was laid in a randomized complete block design with five replicates per density each year. The highest maize seed yield was obtained in weed-free plots (4256.5 ± 118 kg ha−1), while maize yield at weed infestation levels of 1, 2, 4, 8 and 16 plants m−2 was reduced by 14, 22, 29, 38 and 46%, respectively, compared to weed free plots. In the light of these findings, to reduce yield losses to non-significant levels it is proposed to reduce P. hysterophorus densities below 2 plants per m2 in maize fields.

Keywords

• Allelopathy
• Competition
• Yield loss
• Weed
• Maize