Using waste-based growing media can increase problems with certain pests on protected crops, according to latest research.
A project by the University of Warwick and ADAS presented at this year's BOPP technical seminar showed that growing media containing wood fibre and green compost can lead to greater insect populations.
Media containing wood fibre support better population development of sciarid flies, while green compost products support shore flies.
Senior research scientist Dr Dave Chandler, who led the project, said: "We now have evidence that wood fibre and green compost have a negative impact. There will be costs for growers in controlling fly populations.
"We will have to develop additives to the growing media to solve the problem or look at using alternatives. We have evidence to go to Defra and say there is going to be a cost and that it will be borne by growers."
He added that more research and development funding was needed to solve the problem.
Consultant Susie Holmes maintained that the findings would be a problem for those involved in propagation.
"If people are growing outside it is not such an issue. But in certain sectors and crop types there will be a problem, mainly those grown in tunnels in more humid conditions where there is a big sciarid problem anyway.
"As a result of this research we know this is something we have to look out for. At the moment we know how things behave, but with different growing media all these things could change and we need to be aware of that. We need help with research funding and that's what growers are hoping for."
Research project - Key findings
- Media containing wood fibre and green compost are more attractive to sciarid flies.
- Media containing wood fibre support better population development of sciarid flies.
- Media containing green compost support better population development of shore flies.