Dear Sam Stone A microorganism is a microscopic organism which may exist in its single-celled form or a colony of cells. The predominant organisms in this group include bacteria (including PGPR), some fungi (including yeast), and green algae. The useful application of microbes can be accessed at:

https://en.wikipedia.org/wiki/Microorganism

The negative effects of bacteria and fungi include a long list of plant diseases. Some bacterial diseases are bacterial wilt of tomato, bacterial leaf blight of rice, citrus canker, black rot of Indian mustard and cabbage, cotton leaf spot, gumming disease of sugarcane, and the like:

https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/bacterial-diseases-of-plants

Thanks, AKC

It is very clear that microorganisms such as yeast are very useful in human food system wheras the huge number of microorganisms such bacterias can be cause of diseases for human and animals and plants. This is a huge science to deal.

Thank you!

Harmful microorganisms may be even when it depends on the habitat selected. It may be a benefit just on the habitat, an

intruder. Above all, microorgansism may be harmful when they are resistant pests, and above all when antibiotic is included. It is always recommended to use natural fertilisers.

They might be harmful when there is contamination. Sewage might help but it is difficult to say if it is treated. We can at least say it follows a standard. It might be harmful when it is difficult to control a process. We might be using bacteria but we can't control the processes with them. Agrobacterium causes infection, but we use it to control growth. The breakage of pyramids of biomass could be a way it may be harmful. A toxin or toxic bacteria might kill herd or cattle and this causes more troubles in the rest of the farming process, or even irrigation systems

I didnt read through all the contributions, but just like our guts need a healthy interflora or ecosystem of micro organisms so does the soil. One example of a destructive micro organism is Phytophthora a genus of plant-damaging oomycetes, whose member species are capable of causing enormous economic losses on crops worldwide, as well as environmental damage in natural ecosystems. And then you get Trichoderma which are fungi that form an anti virulant simbiotic relationship with plant roots to help defend the plant from infections. There will always be good microbes and bad ones, but in my experience in an artifical or clinical environment you stand more chance of losing to an undetectable, opportunistic viral or fungal infection. I will also draw your attention to beneficial nematodes like Steinernema sp which control larvae of destructive insects and or aid in composting organic matter. The case for microbes is far stronger for beneficial organisms than negative ones since most of the good guys control the bad guys. Jeyes Fluid used to be listed and widely used as a soil sterilant back in the day until the cost of killing all the good guys in the soil outweighed the benefits of killing the bad guys ( similar too the case for and against antibiotics).

Chapter Beneficial and Negative Impacts on Soil by the Reuse of Trea...

I advise you read the article through the link put here.

Thank you, Good Luck!

Dear Sam Stone as we know there r millions of microorganisms in soil and some r beneficial but some r harmful as it depends on habitat and around things. Many cause fatal diseases in plants while some work as natural trappers and some make the soil fertile for plants like Bacillus etc.

From the soil point of view and on a positive note micro-organisms help to breakdown the organic matter into materials for the uptake of plant growth

Saludos mis estimados.

Las micorrizas, son microorganismos benéficos y altamente utilizadas en diferentes tipos de cultivos, como resultado de la adopción de estos microorganismos, se han obtenido mayor cantidad de producción y es muy orgánico que también contribuye a garantizar una alimentación saludable. Sin duda, existen microorganismos patógenos que intervienen en los cultivos atacando constantemente, pero son tratables si se detentan a tiempo.

Los efectos negativos y positivos, se debe a una mala distribución de microorganismos, por ejemplo: si existen mayor cantidad de microorganismos patógenos, estos tratarán en primer lugar exterminar a la población de microorganismos benéficos, luego a la producción y viceversa.