Wow, Jean-François, this sounds very ambitious!

I think this idea is fascinating and should be looked at in more detail by people working on pest-control. However, as you mentioned, these guys prefer other fungi over the pathogens, don't they. How would you then make them feed on pathogenic fungi, when they have the choice to preferentially feed on others?

Cheers,

Martin

Dear Jean Francois,

I do not have experience in such field. Please contact my collegue Gloria Innocenti, Bologna University in Research Gate. She has published some articles about the interaction between plant pathogenic fungi and collembola

Sincerely

Roberta

First, a reply to Martin Zimmer. No, Martin, I never said that P. alba preferred other strains than pathogenic ones, In fact I never tested these strains over non-pathogenic ones. You are right, if it is the case, then it would be highly improbable that they could clean a culture from its pathogens. This must be tested before any allegation of a new method of biological control. In reply to Roberta, I found several very interesting papers by Gloria Innocenti. She established experimentally the impact of another collembolan on plant-pathogen interactions:

https://www.researchgate.net/publication/225534248

I am sure that these animals will be used in routine in a near future...

Article Effects of Collembola on plant-pathogenic fungus interaction...

Ah, OK, Jean-François - I understood:

"This species exhibited clear preferences for some strains but was able to feed and reproduce on the majority of them, including the well-known pathogenic fungi Verticillium dahliae"

in this direction. If this is not the case, I would think that, yes, one can!

I think that the idea of using springtails for the biological control of pathogenic fungi is more for greenhouses and hydroponics because they are most often devoid of soil fauna. In fields, where there are already abundant and diversified soil animal communities, bringing fungal-eating springtails will not change anything.

This sounds promising. I tested nematodes in relation to suppressive effects in agricultural soils, but there was no relation found. It could be as you said above that other organisms dominate the ecosystem. However, in hydroponics hyphal feeding nematodes could be an additional method.

How would the colembola survive in hydroponics when there are no pathogens to eat?

Excellent remark from Michael: what if no longer pathogenic fungi to eat? I cannot answer in a straightforward manner, but I think that there will be always some microfungal development, even if invisible to our eyes. No matter these fungi are saprophagous or plant parasites, they will be browsed by P. alba (or other Pseudosinella species). The only exception is in the use of fungicides, but the method I suggest is an alternative to the use of pesticides. Anyhow the population size of P. alba will be controlled by fungal availability.

I'm not up to date with hydroponics, but I think there are some approaches with mycorhizza. This could possibly be worth a combined approach where high abundance of P. alba could be maintained via food supply from the mycorhizza.

However, a usual problem with ecological control methods is unspecific feeding behavior. If the springtails do not "prefer" the pathogens higher abundant other fungi will diminish the control effect. It would be interesting to know more about the specific feeding behavior of Pseudosinella alba.

Yes, Michael, you are right, this is a current problem in biological control, when there is no specitificity in foraging behaviour of the purported "favourable" species. According to my observations, P.alba was able to feed on V. dahliae and V. lecanii, but these were not the preferred fungal strains (see my paper, unfortunately in French, cited in my first message, at least put a glance to Table 1, page 295). Other studies have shown that, above some density, some collembolan species may be detrimental to mycorrhizal fungi. These equilibria are subtle, and difficult to manage, I know...

I managed to have a look on your paper now. As far as i understood you observed the reduction of mycelia due to P. alba when fungi were in pure culture. is that right?

It would be interesting to see the preferences of P. alba when it can actively choose between different fungi. I think this would give a clearer figure on their preferences. Reduction of mycelia in this experiment (again: if I understood it right) would be largely time dependent. hence, depending on factors like digestability, cell wall strength,... but also nutritional value --> less is needed. However, it would not necessarily reflect the choice of food in an ecosystem.

If P. alba does not reject the pathogens when other fungi are present it should have a pathogen reducing effect if the ration of preferences between the fungi, the population density of colembola and the growth rate of pathogen mycelia are in ballance.

It would be also interesting to research influences of P. alba on sporebuilding capacity and pathogenicity of pathogens. That could be further interesting interactions that could be utilized.

Everything is right in your answer. My (old) observations were just a starting point for further experiments, but researches were discontinued. This is another story. Do not hesitate to grasp the subject if you are interested...

Dear Jean-François,

I was wondering the same thing about Folsomia candida, and I posted a message on ReasearchGate about "Why collembola are not considered as bio control agents". I'm currently opening my own company to supply these organisms as bio-control agents, but the thing is that I don't really know the true potential of these invertebrates.

I've also started a project to collect and rear organisms of interest in ecotoxicology (and biocontrol) to supply labs that can't afford cultures.

However, I truly think that collembola have a potential for bio-control as well as for increasing soil quality, via feces (N/P/K) and soil poration. Is it possible to discuss about that (in french :) via e-mail?

Regards,

Pierre

Bonjour Pierre,

Votre idée est passionnante. J'espère vivement que vous rencontrerez le succès espéré. Bien sûr, nous pouvons échanger via le webmail. Mon adresse est [email protected]. N'hésitez pas à me poser toutes les questions que vous voudrez. Je suis en retraite mais toujours disposé à aider...

Bien cordialement,

JF PONGE

This is an old research question - I read articles about Collembola potentially (only potentially) controlling take-all Gaumannomyces, when starting my PhD in 1982!  The PhD was about them grazing on mycorrhizal fungi (to summarise 3 years hard work in 1 sentence: probably not much if at all!).  I do know of just one successful instance of Collembola controlling pathogenic fungi - it was an entomologist who reared phasmids (stick insects), and found that the eggs decayed from mould in his vivarium.  He introduced a culture of Folsomia candida and the fungus problem disappeared!  This is the only truly successful case I know.  It doesn't help that Collembola are choosy about their fungal foods, and will simply not eat some mycelia.

Yes, I agree, the fact that they prefer some fungi (and even some strains) against others is a huge problem: will they feed on pathogenic fungi if more attractive species are present in the environment? I do not find any satisfactory solution except if we saturate the cultural soil with a species in the absence of any predators and competitors, provided the growing population will not shift to plant roots once fungal resources have been overconsumed. The example you cite in your message seems of this kind, no?

I can see no hope of using Collembola to replace fungicides for field crops, but Pierre's idea of selling defined Collembola stock cultures might have mileage.  Folsomia candida is specified as a test organism in EU legislation AFAIK, as well as being a proven egg-saver.

Sure, not for field crops, I never dreamed of that, but this could be a potential tool for deterring pathogenic fungi from hydroponic cultures or even household cultures, more generally all controlled cultures where a high level of air moisture and heat favour fungal development. If this could avoid the use of fungicides or sterile conditions (voracious of energy), this would be highly beneficial to mankind, and nature...

I am also interested in this issue. Based on my observations (not published yet), I can assume that Collembola (specifically Folsomia candida) can feed on some fungi species and at the same time can transfer fungal hyphae on their skin. Therefore on the one hand Collembola can potentially suppress plant diseases and on the other hand can act as vectors of them. The question is which action is more important.

Yes Iwona, you are right. Collembola ensures both functions: they control mycoflora (including pathogenic strains), by feeding on hyphae, and they allow fungal dispersal by carrying propagules on their skin (and thus they also contribute to infestations). At the moment, we do not know what is their net effect on fungal diseases...

Interesting discussion about springtails, I can see that they have not been able to reach certain conclusions, due to the variability of the results, but this gives us the general idea of ​​the importance of soil microfauna in the development and balance of an ecosystem.

I am also interested in the feeding on pathogenic fungi by Collembola. Quite many study reported that pathogenic fungi played an important role in plant-soil negative feedbacks by affecting the advantage of dominant species, and thereby the diversity of plant community. Despite lots of reports about Collembola feeding on pathogenic fungi, surprisingly only one publication tried to consider the role of Collembola in plant-soil negative feedbacks (as I know).

Dear Zhipeng,

Yes, this is surprising to see that practically nobody tried to use these animals in the biological control of pathogenic fungi. There is here a quite open research subject. However, being retired for more than 11 years I cannot perform that target. My colleague Sandrine Salmon intends to work in this direction. If you are interested you can contact her ([email protected]) from my part. Best regards. JF PONGE

Dear Prof. Ponge,

Thank you very much for your reply. Indeed, this is a very open and interesting subject. Thanks a lot for sharing the information with me.

Best regards

Zhipeng

In our recently published meta-analysis, we summarized results of 21 quantitative studies that evaluated the effect of soil fauna (Collembola, Acari, Oligochaeta, Nematoda) on the abundance and pathogenicity of Fusarium fungi. Main conclusions about Collembola and pathogenic Fusarium species: 1) Fusarium fungi are 1.7 times (95% CI, 1.4–2.0) more preferable as food source compared to other tested soil fungi for collembolans, 2) Overall, soil fauna diminish the abundance of Fusarium fungi in experimental systems by 20.0% (95% CI, 9.9–30.1).

Article Trophic interactions between Fusarium species and soil fauna...

Many thanks for this paper: it is a promising field of research, indeed...

Our lab found that pathogenic fungi could indeed affect the reproductive rate and numbers of f. candida. But we're not sure exactly how they relate to each other. So I think your idea make sense and that would be a good research topic😀

@Xin Zhang