Keeping up to date on the new pests, disorders and diseases is the best way to ensure the health of our trees, says Rick Milsom.
My first recollection of coming into contact with a tree-related pest was with the brown tail moth caterpillar. Ghastly, hairy little fellows, I used to see them years ago while I was in junior school, munching through various shrub beds, many of which were Rosaceous, which I obviously didn’t know at the time. We were told by the adults to keep away from them as they would give you a rash. I can remember picking up lackey moth caterpillars, but never brown tails, as I didn’t like the look of them.
In later years I came to know the brown tail moth caterpillar (or should I call it larvae, as I’m no longer a schoolboy) much better when I started work, and to my cost realised they do indeed give you a rash. I remember cutting a Cotoneaster hedge in a previous job which had a few of their empty nests in it. As with many of the hedge trimmers we had at that time, the blades were not overly sharp and it was difficult to achieve a nice finish on Cotoneaster due to its growth habit, so a few sweeps were required, which I can only assume served to send all the irritating hairs in the air and over me. Clever stuff , eh?
A slight irritation to the eyes at first, followed by an itchy neck and finally me looking like Mr Blobby, pink with red spots and an irritating rash, but a lesson learned and to this day I dislike brown tail moth.
One thing I did enjoy as part of exams I have taken in the past (with varying success) was the pest and disease aspect of arboriculture. It was important to keep up to date in preparation for the big day, as you could feel a right plum being questioned by an examiner and not knowing what to say, but equally as good if you did know. I think the format has changed now though.
These days it seems new pests and diseases are quite common. Some pests which could cause severe damage to our trees, like Asian long horn beetle, have been found here in the UK and are in the process of being eradicated, so it is more important than ever to be informed and keeping an eye on our tree stock.
Even in the last ten years or so a number of new diseases, disorders and pests have become established. Some I can think of just off the top of my head are:
● Horse chestnut leaf miner
● Horse chestnut bleeding canker
● Acute oak decline
● Chronic oak decline
● Ash dieback disease
● Various Phytophthoras
● Great spruce bark beetle
● Oak processionary moth
● Massaria disease of plane trees
● Red band needle blight
● Sweet chestnut blight
It’s a shame that the old tree damage alerts are no longer with us as they gave useful information on topical tree disorders and pests. A great source of information I have found is The Forestry Commission website, which advises on what to look for and what to do when you see it. If we are all aware of what’s out there or what may be coming we have a better chance of protecting our trees.
Starting out as an apprentice, Rick has worked in horticulture and arboriculture for 30 years, and is currently an arboricultural officer at Southend-on-Sea Borough Council.