In the second and/or third cultivation of cucumbers the conditions during and after planting are often favorable for the development of Pythium. A degradation of Pythium results in plants falling out and a greatly reduced production of the plant. That is why Carbon Gold, together with cucumber specialist Roel Hanssen with Mertens, has set up practical tests in the 2018 growing season. "The goal was to demonstrate that with a one-time application of enriched biochar (Biology Blend) Trichoderma strains can develop strongly on stone wool cultivation", Cor-Jan van der Elzen with Carbon Gold shares.
In cucumber cultivation the use of Pythium pesticides is under pressure. This year, the authorization of, for example, AATerra has been extended and is allowed under strict rules in the Netherlands. The MRL values have also become stricter. "In the long run, it is important for cucumber cultivation that a strategy is developed in which cultivation is less dependent on the chemical pesticides. Trichoderma fungi are known to be able to protect the plant."
Test set-up
Carbon Gold has made a trial design in collaboration with Mertens and cucumber specialist Roel Hanssen. The aim is to prove that with the help of enriched biochar (Biology Blend) on a rock wool cultivation, especially Trichoderma species establish and develop well. The strong presence of Trichoderma on and around the root of the plant must form the basis for a healthy microbiological balance with Pythium.
Treatment of the young plants at the propagation company with 5 grams of Biology Blend per block. The seed in the plug hole has a spreading of Biology Blend, possibly in combination with Vermiculite. This treatment is applied for the three different plant dates.
The planting hole on the slab is covered with 55 grams of Biology Blend. This treatment is exclusively used for the planting of the first crop.
Perception and analysis
On 20 March 2018, the first samples were taken from roots under the block. In all samples no Trichoderma fungi and also no other plant pathogenic fungi were found.
On 15 May 2018 samples were again taken from the slabs. The analysis showed that a variety of fungi was present, and in addition to harmless Fusarium and Pythium species, also harmful ones. However also many Trichoderma fungi at the end of the first crop.
On 22 August 2018 samples were taken again at the end of the cultivation. In the untreated slabs hardly any Trichoderma fungi were present, but in the treated slabs Trichoderma fungi had a strong presence.
Untreated
Treated
In the second cultivation 1 x AAterra was applied two weeks after planting. Despite treatment, the Trichoderma fungi have developed strongly in the slab with the help of the Biochar. Pythium degradation was very limited. The plants rooted well and the plants grew strongly.
The conclusion is that the build-up of a strong Trichoderma population in the slab with enriched Biochar is very well possible. A treatment with Biology Blend is a good method to make the plant preventively more resilient, concludes Cor-Jan.
For more information: 
Carbon Gold
www.carbongold.com
info@carbongold.com
Cor-Jan van der Elzen
+31 (0)6 23 31 54 25
Mertens
www.mertens-groep.nl/nl
info@mertens-groep.nl
Roel Hanssen
+31 (0)6 51 82 31 02