The impact of Amaranthus palmeri on Gossypium hirsutum
Amaranthus palmeri (Amaranthaceae - EPPO A2 List) is a dioecious summer annual species native to North America. In the EPPO region it is present in several countries with both established and transient populations. In Türkiye A. palmeri is an invasive alien plant and can invade summer crops. In other regions, A. palmeri is reported to decrease cotton yield by up to 50 %. This could be a concern for Türkiye as in some years, cotton (Gossypium hirsutum) planting has been delayed due to excessive spring rainfall. Late sowing conditions could favour A. palmeri emergence and stimulate early competition. A study was conducted to assess if A. palmeri reduces cotton growth and yield in early and late emerging crops. A. palmeri and cotton were grown in pots under two regimes (1) early: sowing seed of both seed together, and (2) late: sowing A. palmeri with cotton at 4–6 leaf stage. Three different A. palmeri densities 1, 2 and 4 seeds per pot were used. Field experiments were also conducted to assess early A. palmeri competition with cotton. Pot experiments showed that early competition caused a greater decrease in cotton height and dry weights compared to late competition. The field experiments showed cotton height, node number, boll number and yield significantly decreased with increasing A. palmeri densities. These results show that A. palmeri has the potential to cause negative impacts on cotton in Türkiye and management strategies should be implemented.
Sources
Erbaş F, Doğan MN, Türkseven SG, Ongun AR, Tunali SP (2024) Competition of Palmer amaranth at different densities with cotton in Turkey. Weed Research 65(2), e70007. https://doi.org/10.1111/wre.70007