With fast growing fungi on general media the dilution plates can grow so fast that the individual colonies become intermingled and indistinguishable. The use of surfactants restrict the growth many the colony count easier and allowing for better isolation of pure colonies. The use of these agents aid in the enumeration and the purification and the manipulation of the fungi.

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Good question

Paul Reed Hepperly Thank you sir. What do you think is the best surfactant that can be used for the same in case of Trichoderma viride

Dear Ravathi Dhanashar, The use of the agents might be effective. Workers with Trichoderma used to select strains with benzimidazole resistance to identify they and may their re isolation easier. The Trichoderma fungi seem to have association with humates and some workers use them in their media. In all these things you need to try things out and see what works for you. Earlier workers used dyes as colony restricters Rose Bengal was one which was commonly used. Good Luck and let us know your results. Sincerely, Paul

Dear Revathi Dhanashekar, If I was looking for a way to get smaller and more restricted colonies for later use I would test the Trichoderma with common sodium salt. I think this salt effect would be very reversible after retransferring the colonies. I also like the idea that it is not very toxic to work with. It also is look cost. Some thoughts. PRH

Paul Reed Hepperly How does common salt even play a role in colony restriction?? Hypotonic effect?

The salt creates an osmotic stress which could restrict the expansion of the colony. You would need to do a concentration to prove out its usefulness or not.

Paul Reed Hepperly yes, like you said we will need a concentration to colony restriction profile in order to test its effectiveness. Thank you for the input, Sir.

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Salts can be considered as restrictive factor of colony growth.

Paul Reed Hepperly. Thank you sir

which kind of salt would you recommend as colony restriction.

Sodium chloride common table salt should work fine.

Thank you Paul Reed Hepperly

I used Sorbose and it worked well. I need an easily available alternative because I cannot get Sorbose where I work now.

Dear Orji,

As Dr. Paul said, You can use pure Sodium Chloride (NaCl). Because it creates an osmotic stress which could restrict the growth of colony.

So, you can experience it and see the results. If the result is good, you can continue. But if the result is bad, you must immediately stop the experiment.

Kind regards.