Observatree at Ladybower Reservoir

On one of the first warm and sunny days of spring, the Midlands based volunteers headed out to Ladybower Reservoir, just outside Sheffield, with Plant pathologist Charles Lane from Fera Science Ltd to explore the beautiful ancient woodlands of the area.

Ladybower Reservoir was completed during the second world war and famously used as the location for the Dam Busters to practise their bombing raids. Surrounding the reservoirs, plantations were developed, mainly of spruce (Sitka and Norway), larch and other conifers; but there are also some areas of beech and other broadleaf species.

The hunt for signs and symptoms of pests and diseases started in earnest, we had barely cleaned and sterilised our boots before we saw symptoms of ash dieback, which now sadly is very common across this region.  As we finally got out of the car park, we were interested to see dieback on the young hawthorn foliage. Initially, we thought this could be symptoms of a bacterial canker (Erwinia amylovora) that affects other rosaceous plants, commonly called fire blight disease. However, on closer examination we could see white powdery growth on the upper leaf typical of powdery mildew. This is a very common problem on hawthorn, although quite early in the year to see the symptoms of leaf blackening, contortion, and tip dieback. Although unsightly, it is unlikely to cause long-term damage to these plants.

Continuing on to the ancient woodland, we started to inspect the rhododendron for signs of Phytophthora diseases. We saw no typical symptoms (water soaked brown/black leaf spots at the tip and extending up the mid rib); but discrete black leaf spots of a common fungal infection (Colletotrichum).  As our minds were focussed on Phytophthora, we encountered a small patch of holly to check for symptoms (black water-soaked stems at ground level) Phytophthora ilicis.  We all agreed there was no symptoms and gave it a clean bill of health.

As we headed up towards the maturing spruce plantation, we were drawn to several trees close to the path with signs of resin bleeding.  As we looked closer, they seem to be not just restricted to one tree but in a small cluster. Signs of bleeding occurred up in the main stem and typically was seen below the side branches which was the first suggestion this could be symptoms of great spruce bark beetle (GSBB), one of the Observatree Priority pests and diseases.  There were prolific translucent ‘runny’ liquid bleeds as well as dried up white bleeds.  As we started to look closer and down to ground level, we could see signs of the resin tubes, which is another typical symptom of GSBB. Paul Gill as the local volunteer took all the necessary pictures and grid references, and reported it to Tree Alert and received the following response:

"Thank you for your enquiry and for taking an interest in tree health. I have added your enquiry to our plant health database here at Forest Research.  I would agree with that this is most likely Dendroctonus micans."

Fellow volunteers Sue Quick and John Pitcairn commented ‘a fantastic day due to the interaction and sharing of expertise within the group; we would highly recommend a visit to this site’. 

For further information see on Ladybower nature reserve go to: https://www.derbyshirewildlifetrust.org.uk/nature-reserves/ladybower-wood.