The HTA is worried that the extra costs caused by Defra outsourcing plant-health research could be charged to the horticulture industry.
Following the publication of Defra's Protecting Plant Health: A Plant Biosecurity Strategy for Great Britain and Tree Health Management Plan last month, HTA horticulture head Raoul Curtis-Machin said: "We have concerns about Defra looking to outsource a lot of the Food & Environment Research Agency's work.
"There's a cost-sharing question and costs might be offloaded onto industry. It's not clear whether they're talking about increasing costs after outsourcing but there could be cost implications."
However, he said post-ash dieback Defra has improved the speed and accessibility of its operations.
The HTA is "broadly in favour" of the documents, said Curtis-Machin, and he added that Defra has improved how it deals with pest and disease outbreaks in plane and sweet chestnut.
Documents Plant health strategy and plan
The biosecurity strategy sets out to "introduce management that will incentivise risk reduction" through a plant-health service that makes risk-based decisions; greater awareness of plant biosecurity; strengthened international regimes for safe movement of plant material; enhanced capability, capacity and collaboration in plant health; enhanced technology and scientific tools to enable better pest detection; a resilient environment with species choice, design and management approaches to better deal with pests; and a revised strategy with refined goals to ensure optimal delivery.
The tree plan provides an update on research into Chalara, Phytophthora and oak processionary moth. Chalara pathogen has been tested for sensitivity to 17 chemical pesticides with some success.
The report states that the five-year Phytophthora Research Programme (2009 to 2013) "has enhanced knowledge and understanding of P. ramorum and P. kernoviae."
On oak processionary moth (OPM), one approved biopesticide and two approved chemical treatments have been tested in field trials at outbreak sites against OPM, with no success reported yet.