Fire blight is a highly infectious disease caused by the bacteria Erwinia amylovoro. A relatively new disease in Europe, it is thought that it was imported on a shipment of apples from the USA into northern Europe in the 1950's.
It was first spotted in Ireland in Dublin on a Cotoneaster plant in Dublin in 1986 and we have been on the lookout for it ever since.
Our climate, unfortunately, is perfect for the Fire blight disease. The mildness of our winters and the plentiful rain is exactly what it needs to spread.
The plants that it infects are, Cotoneaster, Apples, Pears, Rowan and Hawthorn and should they be infected there is nothing that can be done. The plants must be destroyed to prevent the spread.
Should the plants not be destroyed they will eventually wither and die regardless but will have more time to pass on the infection to other plants in the area.
Fire blight is spread by wind/rain, passing animals or using tools that have not been disinfected.
The symptoms to watch out for are as follows;
- Cankers on twigs and trunk that ooze a light brown colour and is sticky to the touch.
- Wilting of new growth that can have a grey/silver sheen.
-Large areas of dead bark.
-Brown wilting of leaf edges and new shoot edges which give it a burnt look (it's namesake)
We are quite good here in Ireland at controlling any outbreaks that we do get but the problem is that we keep on importing it.
It comes in mostly on shipments of Whitethorn hedging which is a host plant for the disease. In 2023 we imported over one million Whitethorn/Hawthorn plants so the risk is huge.
The potential destruction this poses is substantial. it's not just garden apples we have to worry about but entire hedgerows and habitats for all our native birds and insects. The crop threat is also vast as Fire blight has been known to decimate acres of apple and pear trees.
Our native Rowans or Ash trees are still reeling from Ash dieback disease so Fire blight is really the last thing they needed.
If you are planting fruit crops there are resistant varieties you can plant (resistant not immune) for example the 'Freedom' apple tree was specifically bred to resist any canker causing diseases. 'Warren' is a disease resistant pear but, again, these are resistant and certainly not immune.
It is worth mentioning also that Cherry, Plum, and Greengage trees are NOT affected by Fire blight so if you do have these you are not to worry (well there's other diseases that do affect them but not Fire blight).
The main way that we can prevent Fire blight is to be vigilant. If you think you have Fire blight in your garden don't just destroy it or try and treat it yourself, report it. If you spot a line of roadside hedgerow that looks like it has it, report it.
You can do this by emailing plantsandpests@agriculture.gov.ie and should it turn out to be a case it can then get registered and dealt with properly.
