Herald van der Knaap on ASPERELLO T34 Biocontrol

For many years, Herald has been cultivating Merlice tomatoes on his 3.3ha nursery at Zwartendijk, in Monster. He also operates a second site with his nephew on the Bospolder, in Honselersdijk.

In 2017, Biobest advisor Marvin Koot first told Herald about successful trials of the biological fungicide ASPERELLO in ornamentals. More specifically, he explained how the beneficial fungus Trichoderma asperellum T34 helped to protect plants from soil-borne fungal diseases such as Pythium.

Standard application now

Until then, Herald's team had used various chemical products to control Pythium. "Since using ASPERELLO through the entire growing season, we no longer have this problem - it has become part of our standard procedure."

According to Herald, ASPERELLO is easy to use. "We inject it into the main line of our drip irrigation system via a tank - situated after the sand and fine filters. It's important to apply ASPERELLO after the filters, so it reaches the roots efficiently," he says. 

The tank is situated after the sand and fine filters so growers can inject products directly into the main line.

Adequate establishment of beneficial fungus

Herald fills the 100-litre tank twice. Each time he adds 1.75kg of ASPERELLO - totalling 3.5kg for 3.3ha.

"It's important the product doesn't remain in the drip system at night, as this may harm the fungus and can cause clogging," explains Marvin Koot. "The product needs to be out of the lines by the end of the day, so the fungus can establish adequately around the roots. For some time after application, it is important to avoid certain incompatible chemicals that may harm the beneficial fungus."

ASPERELLO contributes to healthy roots

The earlier, the better

Biobest advises early use of this biological product - ideally at the propagation stage.

"The earlier the fungus colonises the root, the less chance of infection with Pythium spp. and/or Fusarium spp," explains Marvin. "Growers only need to apply it four times per year to achieve year-round protection. After the application at the propagator, the grower should apply when filling the slabs."

"I am convinced of the efficacy of ASPERELLO as we no longer suffer any losses due to Pythium. It also means we are applying fewer chemicals. What's more, we are seeing more spontaneous crop growth. With all these benefits, we will certainly continue to use ASPERELLO in the future."

Source: HortiBiz