Changes in weed infestation of spring barley depending on variable pluvio-thermal conditions

The aim of the study was to analyze segetal weeds present in spring barley against the background of changes in pluvio-thermal conditions observed over the last 20 years (1993–2012) at the Field Experimental Station of the Institute of Plant Protection – National Research Institute in Winna Góra, Poland. Based on the mean value of the Sielianinov hydrothermal coefficient for the three months of spring vegetation, i.e., April, May, and June, three classes of pluvio-thermal conditions (very dry, moderately dry, humid) were distinguished. The phytosociological stability of weed species analyzed during the study period was assessed and the Shannon–Wiener index of species diversity in the communities and the Simpson dominance index were calculated for segetal weeds present in spring barley.In the 20-year period analyzed, Chenopodium album and Viola arvensis exhibited the highest phytosociological stability and the highest abundance in the spring barley crop. Over the years analyzed, the dry spring vegetation periods were characterized by significant precipitation deficiency between late April and mid-June. In the years with favorable meteorological conditions, the weed species diversity measured by the Shannon–Wiener diversity index was higher than in the years with precipitation deficiency. In the very dry years, the species dominance index in the spring vegetation period was higher than in the wet years. The yield loss caused by weed infestation in the very dry years was higher by 6% as compared to moderately dry and wet years

Changes in weed infestation of spring barley depending on variable pluvio-thermal conditions

The aim of the study was to analyze segetal weeds present in spring barley against the background of changes in pluvio-thermal conditions observed over the last 20 years (1993–2012) at the Field Experimental Station of the Institute of Plant Protection – National Research Institute in Winna Góra, Poland. Based on the mean value of the Sielianinov hydrothermal coefficient for the three months of spring vegetation, i.e., April, May, and June, three classes of pluvio-thermal conditions (very dry, moderately dry, humid) were distinguished. The phytosociological stability of weed species analyzed during the study period was assessed and the Shannon–Wiener index of species diversity in the communities and the Simpson dominance index were calculated for segetal weeds present in spring barley. In the 20-year period analyzed, Chenopodium album and Viola arvensis exhibited the highest phytosociological stability and the highest abundance in the spring barley crop. Over the years analyzed, the dry spring vegetation periods were characterized by significant precipitation deficiency between late April and mid-June. In the years with favorable meteorological conditions, the weed species diversity measured by the Shannon–Wiener diversity index was higher than in the years with precipitation deficiency. In the very dry years, the species dominance index in the spring vegetation period was higher than in the wet years. The yield loss caused by weed infestation in the very dry years was higher by 6% as compared to moderately dry and wet years

Biotypes of scentless chamomile Matricaria maritima (L.) ssp. inodora (L.) Dostal and common poppy Papaver rhoeas (L.) resistant to tribenuron methyl, in Poland

Scentless chamomile Matricaria maritima (L.) ssp. inodora (L.) Dostal and common poppy Papaver rhoeas (L.) are species which very often infest winter cereal and winter rape crops. Inhibitors of acetolactate synthase (ALS) are commonly used for control of these weeds. The herbicides are characterised by a single site of action in the plant, which has an influence on selection of the weed population and may result in a rapid development of resistance. In 2012, five seed samples of scentless chamomile and five samples of common poppy were collected from five winter wheat crop fields in Żuławy Gdańskie where the weed species were very poorly controlled. Results of greenhouse experiments showed that two biotypes of scentless chamomile and common poppy were resistant to tribenuron methyl. It was not possible to control resistant biotypes even after use of tribenuron methyl at a dose four times higher than recommended in Poland, it is the first reported case of scentless chamomile and common poppy biotypes’ resistance to herbicides. It is not of economic importance but it does prove the growing problem of weed resistance in the country

Multiple resistance to acetolactate synthase (ALS)- and acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides in black-grass (Alopecurus myosuroides Huds.) populations from Poland

Alopecurus myosuroides seeds were sampled from 32 winter wheat fields from 2010 to 2014. Resistance to herbicides was detected in 17 A. myosuroides populations. In addition to single resistance to herbicides, cross-resistance and multiple resistance to acetolactate synthase (ALS)- and acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides were found. Application of sulfometuron and imazapyr was unable to control some of the resistant biotypes in this study. This result implies that resistance in these populations is due to a target site mechanism. The A. myosuroides biotypes resistant to ACCase-inhibiting herbicides varied in their responses to derivatives of aryloxy-phenoxy-propionic acid (FOPs), cyclohexanediones (DIMs) and phenylpyrazolines (DENs). Resistant biotypes of A. myosuroides that could not be controlled with fenoxaprop-P-ethyl (FOP) and pinoxaden (DEN) were controlled with clethodim (DIM)

How to search herbicide stress in plant system at molecular level?

Application of herbicides is connected with stress in plant system. Molecular signals of stress are of significant value. How to find them

Multiple resistance to acetolactate synthase (ALS)- and acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides in black-grass (Alopecurus myosuroides Huds.) populations from Poland

Alopecurus myosuroides seeds were sampled from 32 winter wheat fields from 2010 to 2014. Resistance to herbicides was detected in 17 A. myosuroides populations. In addition to single resistance to herbicides, cross-resistance and multiple resistance to acetolactate synthase (ALS)- and acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides were found. Application of sulfometuron and imazapyr was unable to control some of the resistant biotypes in this study. This result implies that resistance in these populations is due to a target site mechanism. The A. myosuroides biotypes resistant to ACCase-inhibiting herbicides varied in their responses to derivatives of aryloxy-phenoxy-propionic acid (FOPs), cyclohexanediones (DIMs) and phenylpyrazolines (DENs). Resistant biotypes of A. myosuroides that could not be controlled with fenoxaprop-P-ethyl (FOP) and pinoxaden (DEN) were controlled with clethodim (DIM)