Database of weed species under specific herbicide management

This database summarizes the results of weed monitoring in a long-term field trial with various herbicide applications. The experiment was established in 2009 in the experimental area of the Crop research Institute in Prague - Ruzyně with the aim of the evaluation the efficacy of different frequently used selective herbicides and their impact on weed species diversity. Database of weed species will contribute to the realization of the project´s goal to identify appropriate and inappropriate pesticides from the point of the view of their impact on the non-target organisms and to create recommendations for users of these products. These will lead to a reduction of risks for biodiversity and the protection of non-target organisms.

The first part of the experiment took place between 2013 and 2016. The trial area was split into 20 randomised plots with 5 different herbicide treatments in 4 replications. Herbicide treatments differed in the herbicide target – only dicots and dicots + annual grasses; and in intensity of weed control – narrower spectrum and broader spectrum (Table 1). The area of each plot was 100 m2 and the 10 by 10 m plots were separated from field boundaries and from each other by 2 m on all sides in order to eliminate interaction between plots. Herbicides were applied post emergency in spring from the tillering crop stage to the beginning of stem elongation (BBCH 21–31) by the Agrio-Napa 12 sprayer. A sequence of winter wheat and winter barley was grown in the experimental field. Weed species composition and weed density were assessed from 2013 to 2016. Weed data was recorded in spring at the 4 to 6-leaf crop stage before herbicide application and 4 weeks after herbicide application. Individual plants in each plot were counted in five 0.25 m2 random sampling squares (0.5m by 0.5m) and densities of these five squares were averaged and converted to 1m2 samples. Weed species were identified at the species level whenever possible and some species, such as Vicia spp. L., were identified at genus level. Botanical nomenclature followed Kubát et al. (2002). More detailed methodology and the results of the experiment are described in Mayerová et al. (2018).

Herbicide application was discontinued from 2016-2023 and restored in spring 2024, but replaced by a different mode to match the goal of the new project. Only two of the originally 5 herbicides were selected: syntetic auxine MCPA, which replaced 2,4-D, and sulfonylurea chlorulfuron (Glean 75 PX). Before herbicide application in 2024, weed species were evaluated using the same method as in previous years. The list of weed species evaluated at the end of the first part of the experiment in 2016 and the list of species after 7 years in 2024 without herbicide application form the first part of the database. The second part of the database consists of a list of weed species in 2024 before and after herbicide application. The database will be gradually supplemented in the following years.

Table 1. Summary of the herbicides and active ingredients used in the trial 2013-2016. Classification Group by Herbicide Resistance Action Committee (HRAC).

herbicide

dose

formulation

active ingredient

content of a.i.

HRAC group

target weeds

Esteron

0.8 l/ha

EC

2,4 - D

600 g/l

O

dicot, narrower spectrum

Esteron

Glean 75 PX

0.8 l/ha

15 g/ha

EC

WG

2,4 - D

chlorsulfuron

600 g/l

750g/l

O

B

annual grasses + dicot,

narrower spectrum

Mustang Forte

1 l/ha

SE

aminopyralid

2,4 - D

florasulam

10g/l

180g/l

5g/l

O

O

B

dicot

broader spectrum

Huricane

200 g/ha

WG

aminopyralid

florasulam

pyroxsulam

50g/l

25g/l

50g/l

O

B

B

annual grasses + dicot, broader spectrum

Untreated

control

Mayerová M., Mikulka J., Soukup J. (2018): Effects of selective herbicide treatment on weed community in cereal crop rotation. Plant Soil Environ., 64: 413–420.