Fungicides

[Klause]

I believe the proliferation of crop disease is every bit as much if not way more a result of continuous cropping and environmental conditions than that of the advent of the use of fungicides.

But WTF does this uneducated Sandbox Farmer know?

Except it's prevalence is far greater here.


We farm with a focus on yield above all else.

It is going to be the one of us because it's tuning the soil into a dead medium.


An acre of healthy soil has 620ish tonnes of microbes and insects in it.

They have done plant health studies on "farmed" soil and found that number to be diminished to 40-50 Mt.


There's a book... Nature and properties of soil.... Everyone should be required to read it.

[seldomseen]

Crop rotation is your best defence and that doesn't mean wheat-canola year after year. Direct seeding is great when its dry but year after year of trash laying on top the soil is great for hot bed for fungus.

[Klause]

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4561232/ Microbial and enzymatic activity of soil contaminated with azoxystrobin

The use of fungicides in crop protection still effectively eliminates fungal pathogens of plants. However, fungicides may dissipate to various elements of the environment and cause irreversible changes. Considering this problem, the aim of the presented study was to evaluate changes in soil biological activity in response to contamination with azoxystrobin. The study was carried out in the laboratory on samples of sandy loam with a pH of 7.0 in 1 Mol KCl dm−3. Soil samples were treated with azoxystrobin in one of four doses: 0.075 (dose recommended by the manufacturer), 2.250, 11.25 and 22.50 mg kg−1 soil DM (dry matter of soil). The control soil sample did not contain fungicide. Bacteria were identified based on 16S rRNA gene sequencing, and fungi were identified by internal transcribed spacer (ITS) region sequencing. The study revealed that increased doses of azoxystrobin inhibited the growth of organotrophic bacteria, actinomycetes and fungi. The fungicide also caused changes in microbial biodiversity. The lowest values of the colony development (CD) index were recorded for fungi and the ecophysiological (EP) index for organotrophic bacteria. Azoxystrobin had an inhibitory effect on the activity of dehydrogenases, catalase, urease, acid phosphatase and alkaline phosphatase. Dehydrogenases were found to be most resistant to the effects of the fungicide, while alkaline phosphatase in the soil recovered the balance in the shortest time. Four species of bacteria from the genus Bacillus and two species of fungi from the genus Aphanoascus were isolated from the soil contaminated with the highest dose of azoxystrobin (22.50 mg kg−1).

Keywords: Azoxystrobin, Microorganisms, Biodiversity, Enzymes, Resistance, Identification of microorganisms
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Introduction
Pesticides are chemicals which play a major role in maintaining adequate quality of agricultural products by controlling plant pathogens. In addition, they are used in human and animal hygiene, in the protection of feed, food, natural raw materials and products made of them (Chatterjee et al. 2013). Primarily, the use of pesticides is aimed at controlling target organisms. Despite this fact, it is not possible to predict the environmental fate of pesticides. The widespread use, toxicity, mobility and persistence of pesticides may lead to their dissipation to all elements of the natural environment. Thus, the excessive use of pesticides is still a major problem affecting the quality of the natural environment, which is why more and more studies are being conducted to determine their effects on living organisms (Seiber and Kleinschmidt 2011; Wyszkowska and Kucharski 2004). The highest quantities of pesticides are accumulated in soil, which may cause changes in the terrestrial environment, often manifested by decreasing soil fertility. Studies on the presence of pesticides in soil and their impact on soil organisms are necessary because soil is most affected by contamination. Microbial activity of soil is used to assess the potential changes caused by these chemicals. Microbial response to contaminants dissipating to soil is prompt and thus can provide necessary information on environmental changes (Zhang et al. 2006). Due to the fact that plant protection products are potentially harmful to non-target organisms, there has been considerable interest in determining their impact on soil microorganisms and processes (Bending et al. 2007).

Azoxystrobin (methyl(E)-2-{2-[6-(2-cyanophenoxy)pyrimidin-4-yloxy]phenyl}-3-methoxyacrylate), a strobilurin-derived fungicide, is one of the most popular chemicals used for the control of fungal plant pathogens. It has a broad spectrum of systemic activity against pathogens by inhibiting mitochondrial respiration in the process of binding with cytochrome b complexes. The binding process blocks electron transport from cytochrome b to c, thus inhibiting the generation of energy through the oxidative phosphorylation necessary for cell growth, and finally causes the death of the pathogen (Bartlett et al. 2002). In the natural environment, azoxystrobin is degraded to azoxystrobin acid, which is much more water-soluble and prone to leaching in soils than its parent compound (Ghosh and Singh 2009). Rodrigues et al. (2013) reported that the half-life of azoxystrobin can range from 14 days to 6 months, depending on the microbiological and biochemical soil parameters. Microbial degradation of azoxystrobin is associated with the hydrolysis of the carboxylic ester bond in the parent compound (Katagi 2006). Therefore, microorganisms and enzymes have a significant role in the degradation of this active substance (Clinton et al. 2011).

The literature (Guo et al. 2015) provides limited information on the impact of azoxystrobin on microbial and biochemical activity in different types of soil. Considering this fact, the aim of our study was to determine the effect of azoxystrobin on the soil ecosystem by determining microbial counts, their biodiversity, enzymatic activity of soil, soil resistance and the soil resilience index. In the study, new microbial strains resistant to azoxystrobin were isolated.

Conclusions
Azoxystrobin has a harmful effect on soil microorganisms and their biodiversity, as well as enzymatic activity and resistance of soil. The microbial and biochemical soil indices identified in the study provided necessary information about soil quality and fertility. The calculated predicted environmental concentration (PEC) of azoxystrobin in soil confirms the fact that the use of this fungicide in contaminating doses creates a risk to living organisms. These findings suggest that azoxystrobin designed for the control of fungal diseases in crops and vegetables should be used carefully and according to the manufacturer’s recommendations. Its use in increased doses distorts the homeostasis of soil determined based on the activity of soil microorganisms, which can have a strong impact on plant growth and yield. Bacterial and fungal strains isolated from soil show the adaptability to contamination of soil with azoxystrobin but also with other strobilurin-derived substances. Because of their degrading potential, these microorganisms can be considered when developing strategies for the bioremediation of soils contaminated with pesticides.

[seldomseen]

There's beneficial that prey on the bad fungi... Plus sask didn't have a fusarium problem till heavy use of fungicide began.




Sask did not have a fusarium problem until it started raining more and everyone stopped working there straw down.
There was lots of fusarium here in 1993 after a terrible wet summer and I don't think there was any fungicides sprayed around here at that time.
It wasn't that long ago that Sask was 50% crop and 50% fallow. Most farm seeded into black dirt and there wasn't much crop disease.
No one had fusarium until the No Till Drill was invented so it must be the No Till Drill that caused the epidemic.

[furrowtickler]

All of you that keep spraying so many fungicides... Look at your soil under an electronic microscope before and a few days after.

The amount of beneficial soil bugs you are killing is mind numbing

There's beneficial that prey on the bad fungi... Plus sask didn't have a fusarium problem till heavy use of fungicide began.



I wish more farmers took unbiased soil biology education there would be a lot less money wssted.


Spray plane going in drizzle herfe this morning.

🎯 agree 100%

[Klause]

There's beneficial that prey on the bad fungi... Plus sask didn't have a fusarium problem till heavy use of fungicide began.




Sask did not have a fusarium problem until it started raining more and everyone stopped working there straw down.
There was lots of fusarium here in 1993 after a terrible wet summer and I don't think there was any fungicides sprayed around here at that time.
It wasn't that long ago that Sask was 50% crop and 50% fallow. Most farm seeded into black dirt and there wasn't much crop disease.
No one had fusarium until the No Till Drill was invented so it must be the No Till Drill that caused the epidemic.

Fusarium has been documented back to ancient Egypt.

Fusarium is also a catch-all for a bunch of similar diseases.

Humans fan and do get fusarium infections also.

[Guest]

All i know is that the guys that dont use fungicide will cut their canola a week
To 10 days earlier than the ones that do . That has to translate into quite a yield increase . Oil goes in last and that is the bushel weight . Their probably is better alternatives but we need something

[Braveheart]

Thankfully our business is still free enough we can do what we want. If we didn't spray fungicides here fusarium would make our wheat unsaleable in a year like this (warm and moist).

Re direct seeding, residue and fungus, the Red River Valley is plagued with fusarium as well and for years residue was burned and tillage is extensive. Innoculum is everywhere. Conditions in MB with warm and humidity promote fungal growth.

[SASKFARMER3]

Peas recovered a bit and look way better. Never ever will use viper.



Canola last year did the test and only applied on a section and some full sections half the field. Yea they drag on a bit longer but last year no measurable yield difference. This year more tests but I’m thinking no difference.



Last the HRS we will probably do half acres since a lot is past point and it’s been very little dew since Wednesday last week.

I’ll have results at harvest and grade.




Last year 100% hrs and peas and barley canola just a bit. Similar yield to neighbours some was higher but seeded later.

[seldomseen]

Your peas look super and quite a change from your earlier pics so I would wonder about root rot. Any time my peas had the stems pinched off they never recovered but that might be because it never dried up.

[farmaholic]

SF3, so are you saying you sprayed everything last year but won't spray everything this year? Are you overall drier this year than last year?

I will base my decision to spray on our conditions on our farm. This is definitely a different year than last year for us....as I explained earlier.

I have some dirt that sees wheat just about every second year. I have land that had epidemic fusarium infections on them. Rolly land with moist rich low spots. We were NEVER regular fungicide users in the past either...in fact I balked it! Until you get a durum crop decimated by fusarium, a canola crop that "ripens" prematurely and lodges because of sclerotinia stem rot. A lentil crop that has sclerotia bodies growing in white cotton like structures on their stems! And in some cases conditions that not even fungicides can overcome....even if applied twice, like they sometimes suggest!

Continuous cropping
Zero Till
High moisture environment
Pathogens
Hosts

No doubt the current farming methods have exasperated/exacerbate the potential problem.

If the market wouldn't punish us for a minute amount of fusarium in cereals...maybe I would fore go an application too. Mother Nature can take enough, then the market kicks you in the nuts too...

[SASKFARMER3]

We are way dryer than last year. Very little to no dew last week.

We’re just right like before the floods.

Last year all wheat barley and peas sprayed plus some canola.

I think we’re back to normal weather.