UW Extension, 2020
UW Extension, “Visual Guide to Corn Development,” Date Published: February 27, 2020, Date Accessed: April 16, 2020.
SUMMARY:
This guide to corn development hopes to make the stages easy to understand by using clear, annotated images that highlight the details of what is happening in the plant and potentially make the connection to sound management practices. Toss it in the glovebox and use it when scouting fields! The corn plants used were both greenhouse and field grown in south central Wisconsin using a 100–110 day relative maturity yellow dent hybrid with 20–21 leaves, silking at ~65 days after emergence and reaching maturity at ~60 days after silking. FULL TEXT
Esker and Proost, 2020
Paul Esker and Richard Proost, “What’s on your seed?,” University of Wisconsin Extension, 2020, Date accessed: 4/16/2020.
SUMMARY:
Seed treatments have been used for a number of years, mostly for protection against seedling diseases. However, there are a number of new seed treatments marketed for protection against a range of pests—including seedling diseases,
insects and nematodes—and even improving plant health.
The purpose of this publication is to take some of the confusion of seed treatments away, giving you a better understanding of what is on your seed. The list covers seed treatments registered in the state of Wisconsin for use on corn and/or soybean seed. The seed treatments are grouped by the number of active ingredients (1-4), treatment type (fungicide, insecticide, nematicide or plant growth regulator) and then alphabetically by the product trade name. The list is not based on efficacy of the seed treatments and is not an endorsement or criticism of one product over another. FULL TEXT
Ross et al., 2013
Ross, S. M., McManus, I. C., Harrison, V., & Mason, O.; “Neurobehavioral problems following low-level exposure to organophosphate pesticides: a systematic and meta-analytic review;” Critical Reviews in Toxicology, 2013, 43(1), 21-44; DOI: 10.3109/10408444.2012.738645.
ABSTRACT:
Meta-analysis was carried out to determine the neurotoxic effects of long-term exposure to low levels of organophosphates (OPs) in occupational settings. Concern about the effects of OPs on human health has been growing as they are increasingly used throughout the world for a variety of agricultural, industrial and domestic purposes. The neurotoxic effects of acute poisoning are well established but the possibility that low-level exposure causes ill health is controversial. It is important to get a clear answer to this question as more individuals are at risk of low-level exposure than acute poisoning. Although a number of reviews on this topic have been published in the past, authors have come to conflicting conclusions. To date, none of these reviews have attempted quantitative evaluation of study findings using meta-analysis. This paper reviews the available evidence concerning the neurotoxicity of low-level occupational exposure to OPs and goes on to report the results of a meta-analysis of 14 studies which fulfilled criteria for this type of statistical analysis (means and standard deviations of dependant variables reported). Data were assimilated from more than 1600 participants. The majority of well designed studies found a significant association between low-level exposure to OPs and impaired neurobehavioral function which is consistent, small to moderate in magnitude and concerned primarily with cognitive functions such as psychomotor speed, executive function, visuospatial ability, working and visual memory. Unresolved issues in the literature which should become the focus of further studies are highlighted and discussed. FULL TEXT
Heu et al., 2012
Heu, C., Elie-Caille, C., Mougey, V., Launay, S., & Nicod, L.; “A step further toward glyphosate-induced epidermal cell death: involvement of mitochondrial and oxidative mechanisms;” Environmental Toxicology and Pharmacology, 2012, 34(2), 144-153; DOI: 10.1016/j.etap.2012.02.010.
ABSTRACT:
A deregulation of programmed cell death mechanisms in human epidermis leads to skin pathologies. We previously showed that glyphosate, an extensively used herbicide, provoked cytotoxic effects on cultured human keratinocytes, affecting their antioxidant capacities and impairing morphological and functional cell characteristics. The aim of the present study, carried out on the human epidermal cell line HaCaT, was to examine the part of apoptosis plays in the cytotoxic effects of glyphosate and the intracellular mechanisms involved in the apoptotic events. We have conducted different incubation periods to reveal the specific events in glyphosate-induced cell death. We observed an increase in the number of early apoptotic cells at a low cytotoxicity level (15%), and then, a decrease, in favor of late apoptotic and necrotic cell rates for more severe cytotoxicity conditions. At the same time, we showed that the glyphosate-induced mitochondrial membrane potential disruption could be a cause of apoptosis in keratinocyte cultures. FULL TEXT
Rendon-von Osten et al., 2017
Rendon-von Osten, J., & Dzul-Caamal, R.; “Glyphosate Residues in Groundwater, Drinking Water and Urine of Subsistence Farmers from Intensive Agriculture Localities: A Survey in Hopelchen, Campeche, Mexico;” International Journal of Environmental Research and Public Health, 2017, 14(6); DOI: 10.3390/ijerph14060595.
ABSTRACT:
The use of pesticides in Mexican agriculture creates an interest in learning about the presence of these substances in different environmental matrices. Glyphosate (GLY) is an herbicide widely used in the state of Campeche, located in the Mayan zone in the western Yucatan peninsula. Despite the fact that GLY is considered a non-toxic pesticide to humans, its presence in water bodies through spillage, runoff, and leaching are a risk to human health or biota that inhabit these ecosystems. In the present study, glyphosate residues were determined in groundwater, bottled drinking water, and the urine of subsistence farmers from various localities of the Hopelchen municipality in Campeche. Determination of GLY was carried out using Enzyme-Linked Immunosorbent Assay (ELISA). The highest concentrations of GLY were observed in the groundwater (1.42 mug/L) of Ich-Ek and urine (0.47 mug/L) samples of subsistence farmers from the Francisco J. Mujica communities. The glyphosate concentrations in groundwater and bottled drinking water indicate an exposure and excessive use of glyphosate in these agricultural communities. This is one of the first studies that reports glyphosate concentration levels in human urine and bottled drinking water in Mexico and in the groundwater in the Yucatan Peninsula as part of a prospective pilot study, to which a follow-up will be performed to monitor this trend over time. FULL TEXT
Perry et al., 2019
Perry, M. J., Mandrioli, D., Belpoggi, F., Manservisi, F., Panzacchi, S., & Irwin, C.; “Historical evidence of glyphosate exposure from a US agricultural cohort;” Environmental Health, 2019, 18(1), 42; DOI: 10.1186/s12940-019-0474-6.
ABSTRACT:
In response to the recent review by Gillezeau et al., The evidence of human exposure to glyphosate: A review, Environmental Health 1/19/19, here we report additional glyphosate biomonitoring data from a repository of urine samples collected from United States farmers in 1997-98. To determine if glyphosate exposure could be identified historically, we examined urine samples from a biorepository of specimens collected from US dairy farmers between 1997 and 98. We compared samples from farmers who self-reported glyphosate application in the 8 h prior to sample collection to samples from farm applicators who did not report using glyphosate. Of 18 applicator samples tested, 39% showed detectable levels of glyphosate (mean concentration 4.04 mug/kg; range:1.3-12) compared to 0% detections among 17 non glyphosate applicator samples (p-value < 0.01). One of the applicator samples that tested positive for glyphosate also tested positive for AMPA. Concentrations of glyphosate were consistent with levels reported in the prior occupational biomonitoring studies reviewed by Gillezeau et al.Accurately detecting both glyphosate and AMPA in this small sample of Wisconsin farmers demonstrates a) glyphosate exposures among farmers were occurring 20 years ago, which was prior to the widespread planting of genetically engineered glyphosate tolerant crops first approved in 1996; and b) liquid chromatography tandem mass spectrometry (LC-MS/MS) can be used for sensitive characterization in cryopreserved urine samples. These data offer an important historical benchmark to which urinary levels from current and future biomonitoring studies can be compared. FULL TEXT
Bus, 2015
Bus, J. S.; “Analysis of Moms Across America report suggesting bioaccumulation of glyphosate in U.S. mother’s breast milk: Implausibility based on inconsistency with available body of glyphosate animal toxicokinetic, human biomonitoring, and physico-chemical data;” Regulatory Toxicology and Pharmacology, 2015, 73(3), 758-764; DOI: 10.1016/j.yrtph.2015.10.022.
ABSTRACT:
The non-peer-reviewed biomonitoring report published online by Moms Across America (MAA; Honeycutt and Rowlands, 2014) does not support the conclusion that glyphosate concentrations detected in a limited number of urine samples from women, men and children, or breast milk from nursing mothers, pose a health risk to the public, including nursing children. Systemically absorbed doses of glyphosate estimated from the MAA urine biomonitoring data and from other published biomonitoring studies indicate that daily glyphosate doses are substantially below health protective reference standards (ADIs; RfDs) established by regulatory agencies. The MAA report also suggested that detection of relatively high glyphosate concentrations in breast milk in 3 of 10 sampled women raised a concern for bioaccumulation in breast milk. However, the breast milk concentrations reported by MAA are highly implausible when considered in context to low daily systemic doses of glyphosate estimated from human urine biomonitoring data, and also are inconsistent with animal toxicokinetic data demonstrating no evidence of retention in tissues or milk after single- or multiple-dose glyphosate treatment. In addition, toxicokinetic studies in lactating goats have shown that glyphosate does not partition into milk at concentrations greater than blood, and that only a very small percentage of the total administered dose (<0.03%) is ultimately excreted into milk. The toxicokinetic studies also indicate that human glyphosate exposures estimated from urine biomonitoring fall thousands-of-fold short of external doses capable of producing blood concentrations sufficient to result in the breast milk concentrations described in the MAA report. Finally, in contrast to highly lipophilic compounds with bioaccumulation potential in breast milk, the physico-chemical properties of glyphosate indicate that it is highly hydrophilic (ionized) at physiological pH and unlikely to preferentially distribute into breast milk. FULL TEXT
Hall et al., 1989
Hall, J. Christopher, Deschamps, Raymond J. A., & Krieg, Kim K.; “Immunoassays for the detection of 2,4-D and picloram in river water and urine;” Journal of Agricultural and Food Chemistry, 1989, 37(4), 981-984; DOI: 10.1021/jf00088a035.
ABSTRACT:
Immunoassays for 2,4-D [ (2,4-dichlorophenoxy)acetic acid] and picloram (4-amino-3,5,6-trichloro-2pyridinecarboxylic acid) detection were developed with polyclonal antibodies raised in New Zealand white rabbits. Concentrations of 2,4-D within the working range 100-10 000 and 50-10 0oO ng/mL could be quantitated with an indirect enzyme-linked immunosorbent assay (ELISA) and a radioimmunoassay (RIA) in river water and urine, respectively. Concentrations of picloram within the working range 50-5000 ng/mL also could be quantitated in river water and urine by RIA. Determinations using the immunoassays required no sample cleanup. Specificities of the antisera for structurally similar herbicides were low compared to 2,4-D or picloram. The RIA methods incorporated a novel radiolabel consisting of [3H]glycine covalently linked to the herbicide molecule. When compared to the ELISA, the RIA was a more simple, efficient, and rapid procedure, requiring fewer steps to complete the assay. The immunoassays would be suitable for herbicide quantitation in applicator exposure and environmental fate studies. FULL TEXT
Balderrama-Carmona et al., 2019
Balderrama-Carmona, A. P., Valenzuela-Rincon, M., Zamora-Alvarez, L. A., Adan-Bante, N. P., Leyva-Soto, L. A., Silva-Beltran, N. P., & Moran-Palacio, E. F.; “Herbicide biomonitoring in agricultural workers in Valle del Mayo, Sonora Mexico;” Environmental Science and Pollution Research International, 2019; DOI: 10.1007/s11356-019-07087-6.
ABSTRACT:
Valle del Mayo is an important agricultural area at the northwest of Mexico where up to 20,000 L of a mix composed of glyphosate and tordon is used in drains and canals. This study was carried out in order to evaluate the cellular damage caused by glyphosate, aminomethylphosphonic acid (AMPA), and picloram in agricultural workers. Biomonitoring was performed through the quantification of herbicides in urine using HPLC (high-performance liquid chromatography) to then evaluate the cellular damage in exposed people by means of an evaluation of micronuclei and cellular proliferation in lymphocyte cultures. The urine samples (n = 30) have shown a concentration of up to 10.25 mug/L of picloram and 2.23 mug/L of AMPA; no positive samples for glyphosate were reported. The calculation of the external dose reveals that agricultural workers ingest up to 146 mg/kg/day; however, this concentration does not surpass the limits that are allowed internationally. As for the results for the micronuclei test, 53% of the workers showed cellular damage, and the nuclear division index test reported that there was a significant difference (P < 0.05) between the exposed and the control population, which indicated that the exposure time to pesticides in the people of Valle del Mayo can induce alterations which can cause chronic damage. FULL TEXT
Singh et al., 2020
Singh, Simranjeet, Kumar, Vijay, Datta, Shivika, Wani, Abdul Basit, Dhanjal, Daljeet Singh, Romero, Romina, & Singh, Joginder; “Glyphosate uptake, translocation, resistance emergence in crops, analytical monitoring, toxicity and degradation: a review;” Environmental Chemistry Letters, 2020; DOI: 10.1007/s10311-020-00969-z.
ABSTRACT:
The herbicide glyphosate is widely used to control weeds in grain crops. The overuse of glyphosate has induced issues such as contamination of surface water, decreased soils fertility, adverse effects on soil microbiota and possible incorporation in food chains. Here we review biochemical, agricultural, microbiological and analytical aspects of glyphosate. We discuss uptake, translocation, toxicity, degradation, complexation behaviour, analytical monitoring techniques and resistance emergence in crops. We provide data of glyphosate toxicity on different ecosystems. Experiments reveal that excessive glyphosate use induces stress on crops and on non-target plants, and is toxic for mammalians, microorganisms and invertebrates. The long half-life period of glyphosate and its metabolites under different environmental conditions is a major concern. Development of analytical methods for the detection of glyphosate is important because glyphosate has no chromophoric or fluorophoric groups. FULL TEXT