The government was "asleep on the job" when it should have been tackling the spread of ash dieback in the UK, shadow environment secretary Mary Creagh has said.
Having summoned Environment Minister David Heath to the Commons to answer an urgent question on the subject on 29 October 2012, Ms Creagh warned of the "biggest threat to British trees since 25 million trees were killed by Dutch elm disease 30 years ago".
The government has banned imports of ash trees as part of an attempt to halt the spread of the Chalara fraxinea fungus, which has infected 90% of ash trees in Denmark and has been found in East Anglia.
"We welcome the ban, but the question on everybody's lips is: 'Why did it take so long?'" Ms Creagh said.
The disease had been found last February at a nursery in Buckinghamshire.
"Why did ministers sit back, cross their fingers and wait until the disease was found in the wild in June?" the Labour frontbencher asked.
"After the forest sell-off fiasco, this incompetent government has been asleep on the job with ash dieback," she continued.
"Like Nero, ministers fiddled, and now it is our forests that will burn."
But the minister responded: "There's a sad predictability that when we have a serious condition which we are trying to deal with as a country, which could have enormous potential consequences, the first thing that the honourable lady thinks of is 'how can we blame the government?' rather than dealing with the disease."
Ministers had acted "straight away" to tackle the spread of the disease, he told MPs, imposing the ban on imports "well before the start of the main UK planting season".
Before that, a voluntary moratorium on imports had been "well observed", Mr Heath added.
But he warned that tracking the disease was "an enormous task, involving well over 1,000 sites, and it's on-going".
He questioned Ms Creagh's grasp of the subject: "What she might not understand is that is an airborne disease - it is likely to have been carried, on the air, on the wind, over the channel."
100,000 trees have already destroyed in the UK in an attempt to curb the spread of the disease, he told MPs.
Green Party MP Caroline Lucas called on the government to reverse the 25% cuts to the Forestry Commission's budget.
But Mr Heath told MPs that the resources available for plant health and tree health had not been cut.