First Report of Amaranthus palmeri S. Wats. in Cotton, Maize and Sorghum in Greece and Problems with Its Management

Panagiotis Kanatas,Ilias Travlos,Vyronas Dellaportas,Alexandros Tataridas

doi:10.3390/agronomy11091721

Panagiotis Kanatas, Ilias Travlos + Show 2 more

Open Access

https://doi.org/10.3390/agronomy11091721

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Journal: Agronomy	Publication Date: Aug 28, 2021
Citations: 10	License type: CC BY 4.0

Affiliation: University of Patras, Agricultural University of Athens

Abstract

Amaranthus palmeri S. Wats., or commonly Palmer amaranth, is an invasive plant species that has invaded many countries worldwide and causes significant yield losses to annual spring crops. Palmer amaranth biotypes were detected in maize and sorghum fields in Western Greece and cotton fields in Central Greece in 2020. The infestations were recorded both inside the crops and in the margins of the fields, indicating that Palmer amaranth could be characterized as an invasive weed for these regions and, thus, must be urgently managed. Four biotypes were screened for resistance to 2,4-D and nicosulfuron by using NDVI, canopy cover, photochemical efficiency, plant height and fresh weight values. All biotypes showed resistance to nicosulfuron. Resistance cases to important herbicides (i.e., ALS and synthetic auxins) in spring crops, such as maize and cotton, indicate that management could become even more challenging if farmers do not adopt integrated strategies and tools to manage this weed. The eradication of Palmer amaranth plants is imperative, since it has yet to be dispersed in several agricultural areas of Greece. Palmer amaranth is recommended to be enlisted as quarantine pest for regulation in Greece.

Highlights

Field monitoring was conducted in June and July 2020 in maize and sorghum fields in Vonitsa region, Western Greece, and cotton fields in Domokos region, Central Greece (Table 2), to identify Palmer amaranth infestations after reports from farmers on failed herbicide applications against an unknown weed
Several studies have shown that Palmer amaranth seeds can be dispersed via farm equipment, such as cotton gins, contaminated seed mixes and manure, and this could probably be the case in Greece as well [9,10]
Palmer amaranth has been reported for the first time in maize, sorghum and cotton fields in Greece

Summary

Introduction

Wats.) belongs to the Amaranthaceae family and is a C4 dioicous plant species. It is mainly wind-pollinated and demonstrates high fecundity with up to 600,000 seeds per plant being recorded [1]. Redroot pigweed (Amaranthus retroflexus L.) is another species of genus Amaranthus that is common in Greece and looks similar to Palmer amaranth in the first vegetative growth stages, making the identification a major challenge. Both species present a high variability in the fields. The biology and ecology of A. palmeri have been reviewed and are thoroughly presented in the pest risk analysis for Palmer amaranth, generated by EPPO, and the review of Ward et al (2013) [1]

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