Side Effects Of Herbicides Research Articles

Commercial glyphosate-based herbicides effects on springtails (Collembola) differ from those of their respective active ingredients and vary with soil organic matter content

Glyphosate-based herbicides (GBH) are currently the most widely used agrochemicals for weed control. Environmental risk assessments (ERA) on nontarget organisms mostly consider the active ingredients (AIs) of these herbicides, while much less is known on effects of commercial GBH formulations that are actually applied in the field. Moreover, it is largely unknown to what extent different soil characteristics alter potential side effects of herbicides. We conducted a greenhouse experiment growing a model weed population of Amaranthus retroflexus in arable field soil with either 3.0 or 4.1% soil organic matter (SOM) content and treated these weeds either with GBHs (Roundup LB Plus, Touchdown Quattro, Roundup PowerFlex) or their respective AIs (isopropylammonium, diammonium or potassium salts of glyphosate) at recommended dosages. Control pots were mechanically weeded. Nontarget effects were assessed on the surface activity of the springtail species Sminthurinus niger (pitfall trapping) and litter decomposition in the soil (teabag approach). Both GBHs and AIs increased the surface activity of springtails compared to control pots; springtail activity was higher under GBHs than under corresponding AIs. Stimulation of springtail activity was much higher in soil with higher SOM content than with low SOM content (significant treatment x SOM interaction). Litter decomposition was unaffected by GBHs, AIs or SOM levels. We suggest that ERAs for pesticides should be performed with actually applied herbicides rather than only on AIs and should also consider influences of different soil properties.

Ammonium glufosinate and triazine herbicides have side effects on soil microorganisms and pathogens

Goal. Analysis and synthesis of research results regarding the beneficial and negative side effects of ammonium glufosinate and thiazine herbicides on microorganisms. Methods. System-analytical, abstract-logical, empirical. Results. Information on the side effects of herbicides with the content of the active substance glufosinate ammonium and derivatives of thiazine herbicides is given. One of the side effects of herbicides that attracts attention is their biological activity. The biological activity of herbicides goes beyond the effects on target organisms and, thus, herbicides can influence the plant-pathogen interaction through their effect on the causative agent or on the surrounding soil microorganisms, including symbiotic relationships. As a side effect, both a decrease and an increase in diseases caused by phytopathogens that affect leaves, stems or roots are established. However, in some cases, the results obtained in in vitro experiments differed from the results obtained in field conditions in vivo or on a host plant. The phenomenon of the manifestation of side effects of herbicides was first discovered in the early 1940s and began to be studied in more detail since 1960. Conclusions. Generalized information about the history, studies of the side effects of herbicides on different cultures and in different conditions in the world. It is important that such effects are not fully studied, and these mechanisms attract the attention of scientists for their further research. Future studies are planned to be carried out using high-precision methods, such as chip-based technologies, to study all the mechanisms involved in the pathogen-plant interaction, which are modulated by herbicides. This trilateral relationship today is studied as a molecular and biochemical cross-linkage between a plant and a pathogen, a plant and a herbicide, as well as a pathogen and a herbicide. Active studies by foreign scientists of the side effects of herbicides show that in Ukraine, as an agrarian state, it is necessary to purposefully investigate the effect of herbicides on soil microorganisms and pathogens to optimize the use of plant protection products in agricultural production.

Influence of Propazine and Chlorthal Dimethyl on Mycorrhizal Development in Pinus radiata Seedlings

In an investigation into the side effects of herbicides on mycorrhizal formation in Pinus radiata nurseries, propazine and chlorthal dimethyl were added at concentrations that approximated to normal (2.20 and 1.88 g a.I-1L) and half-normal (1.10 and 0.94 g a.i.-1L) field application rates respectively to P. Radiata seedlings growing in terra cotta pots. A humus-rich, surface soil from a 40-year-old P. radiata plantation was used as mycorrhizal inoculum. Root length, mycorrhizal numbers and type, and seedling growth were assessed and a histological examination of bulk mycorrhizal samples was carried out. Propazine applied at both dosage rates and chlorthal dimethyl at the higher rate significantly sup- pressed root growth during the first 3 months and mycorrhizal formation during both the early and later stages of growth. However, neither herbicide affected shoot growth after 3 months and both increased shoot growth at the end of 6 months. Two mycorrhizal types were identified, a white-coloured, heavily dichotomised ectomycorrhiza with a thick mantle and a reddish-coloured, weakly dichotomous ectendomycorrhiza. The roots of chlorthal dimethyl treated seedlings strongly suppressed intracellular penetration in the ectendomycorrhiza, producing an unusual association with only a Hartig net, which was similar to that seen in senescing associations and some long roots of conifers. The ratio of white to red mycorrhizal numbers was highest in the untreated controls and was reduced by both herbicides. Both herbicides appeared to effect mycorrhizal formation through their influence on root morpho- genesis and host physiology.