Buen día, desde mi punto de vista es posible distinguirlos. Fusarium presenta un crecimiento blanquecino a una tonalidad rosada en el medio de cultivo mientras Colletotrichum al madurar en el medio empieza a desarrollar pequeños puntos oscuros que son sus acérvulos. Aunque en el microscopio son totalmente distintos ya que Fusarium presenta microconidas (ovales) y macroconidias (segmentadas) y Colletotrichum son conidias de una célula. Cuidado!! una especie de Colletotrichum presenta conidias curvadas parecidas a Fusarium pero verificar segmentación y presencia de microconidias.

I highly recommend the Hanlin keys. They are the best for identification of Asco's. Here is a link to the combined keys. I own all of his keys. Highly recommend. https://www.amazon.com/Combined-Keys-Illustrated-Genera-Ascomycetes/dp/089054199X

Emerson Omar Herrera sir could you please rewrite your answer in English and thank you for your consideration for my question.

@Jonathan-Hulse thank you sir.

I only do identify these two genera and distinguish between them by examining diseased plant material. The differences between these fungi are:

1. Fusarium spp. are hyphomycete fungi, i.e. the spores are borne on stalks (conidiophores), while those produced by Colletotrichum spp. are produced by an acervulus, i.e. a cushion-like structure partially embedded in the plant tissue.

2. Fusarium spp. conidia (spores) are of two types

a) Micro Conidia: which are small, elongate, hyaline spores and in my opinion not the best used for identification and

b) macro conidia, which are septate, falcate to lunate (banana- to boomerang- shaped) hyaline spores

Conidia formed by Colletotrichum spp. are mostly cylindrical elongate. They are also hyaline or subhyaline and one-celled (no septation present). There are also several species of Colletotrichum, which do produce falcate or lunate conidia. However, those are also not septate. Another thing you may find with some Colletotrichum spp. is the presence of setae, which are hair-like structures of generally a dark coloration.

On morphological and cultural basis, we can identify upto genus level. There are more than 100 species of Fusarium and more than 50 of Colletotrichum. In my research I observed that Fusarium culture showed Fusaric acid in the form of drops after 14 days . Such drops never observed on Colletotrichum culture. For primary identification morphological and cultural characters are based but for final identity molecular characterization is best solution. Now a days morphological chacters are not enough for publication of paper in high quality journals. Other things that Fusarium is mainly root rot pathogen while Colletotrichum is leaf pathogen.

Dr. Purushottam Khetri Ramteke thank you so much sir for your kind suggestion and your consideration.

Harald Grieb thank you so much sir for your kind suggestion and your consideration.

Jonathan Hulse thank you sir for your suggestion.

Good morning, from my point of view it is possible to distinguish them. Fusarium shows a whitish to pinkish growth in the culture, when Colletotrichum maturing in the culture, begins to develop small dark spots that are its acorn. Although in the microscope they are totally different since Fusarium presents microconids (oval) and macroconidia (segmented) and Colletotrichum are conidia of one cell. Careful!! one species of Colletotrichum are curved conidia similar to Fusarium but verify segmentation and the presence of microconidia.

http://website.nbm-mnb.ca/mycologywebpages/Moulds/Fusarium.html

https://scialert.net/fulltext/?doi=ajppaj.2018.7.15

Dear, Shilpa,

Greetings and nice day.

I think it's easily to differentiate between Fusarium and Colletotrichum.

Fusarium spp. belong to the Class: Hyphomycetes , their spores are borne on conidiophores on sporodochia, while Colletotrichum spp. belong to Class: Coelomycetes which produce their conidia on an acervulus.

Also the fungus Fusarium spp. produce three types of conidia, they are microconidia, macroconidia and chlamydospores with one, two, three or more cells , while the fungus Colletotrichum produce one type of conidia with one cell.

The microconidia in Fusarium are spindle, elongated, spherical, tear like or ovoid shaped with one or two cells. Macrocondia are sickle shaped, falcate shaped or lunate shaped with 3-9 cells according to species and some times with foot cell. Chlamydospores are one or more thick cells which were terminal or intercellular. While, Colletotrichum spp. have one type of conidia which were non septate elongated cylindrical conidia.

Good question, all the best

Fusarium spp. like F. oxysporum, F. solani, F. equiseti etc. cause root rot, seed decay, crown rot damping off (mostly, root system), while Colletotrichum spp. i.e. C. falcatum causes red rot for sugarcane foliar system.

Yehya A. Salih Thank you so much sir for your detail information. I would like to add one more question, sir while working in the lab it's becomes very difficult for us, whether they are septate or non septate because we don't have advanced type of microscope, and we still found difficulties to distinguish microconidia. Could you please provide any refence publication or book for further study. And again Thank you sir for your consideration.

I support the explanation given by Prof.Dr.Yehya A Salih regarding the differentiation of Fusarium and Colletotrichum based on microscopic morphology.

We have published two research papers on the etiologic role of Fusarium solani in ocular disorders of animals.

The culture of most Colletotrichum spp. has typical Aesculus (yellowish) and the culture is also flat however, the culture Fusarium is mostly cottonlike and fluffy. Fusarium spp. has different colour of culture range from whitish, pinkish, and yellowish. With microscopic differences, Fusarium has both microconidia and macroconidia (boatlike). Colletotrichum spp. has single cell cconidia. With Fusarium spp. the macrocondia is always septated but Colletotrichum is not.

Dear, Shilpa Devcota,

Greetings sir. I am so sorry for the delay, because I did not see your message before this time.

The simple compound microscope with a power of 100, 400 and 1000 X can shows microconidia and macroconidia of the fungus Fusarium with a power of 400X easily.

You can depend on the reference named "The Fusarium laboratory manual" By: Leslie, J. F. and Summerell, B. A. (2006) to distinguish and identify Fusarium species.

The macroconidia of Fusarium are septate with 2-5 transverse septa. some times the septa are more. In Fuarium equiseti the macroconidia are long, while some other species are having short and stout macroconidia.

@Yehya A. Salih Thank you sir.

You are most welcome dear Shilpa Devkota.

With cordial greetings.

Be safe and healthy.

I attach the above reference that I mentioned it yesterday (The Fusarium Laboratory Manual) to use it as a key for identification and diagnosis the Fusarium species. It will be useful.

With best regards.

Also, you can see other reference about Fusarium which titled "Introduction to Fusarium taxonomy" By Tatiana Gagkaeva.

I attach it too. It may be useful.

My dear Shilpa,

Please take a look at the the attached reference which titled "Illustrated genera of imperfect fungi" By: Barnett and Hunter. I see it's very important reference for identification imperfect fungi (Deuteromycota) such as Fusarium and Colletotrichum etc.

I hope it will be helpful.

With my warm regards.

Yehya A. Salih Thank you so much sir for your warm consideration and suggestion. I will go through the link.

Shilpa Devkota

You are always welcome dear Shilpa.

You must know that the above references are not links but they are as pdfs. So, you can download them directly. I keep them in my library and send them to you as pdf.

Take care of your health.