Static Bug - this colourful bug was on a nettle in a roadside verge. It is the pupa of a Harlequin Ladybird which, any day now, will hatch into a Harlequin ladybird. This introduced species is very much like our native ladybird but almost twice the size and coming in much more variety of pattern. They were introduced from America to control/eat aphids, but being larger and more voracious, are out-competing our native species and so are a cause of their decline. They also predate our native ones, which doesn't help their popularity!
Sick Horse Chestnut seedling - these odd patches on the leaves of this young tree are caused by the horse chestnut leaf mining moth laying its eggs on the leaves and the developing grub burrowing into the leaves and eating them from the inside, living between the layers of the leaf. It causes early leaf drop, in late summer, and although will possibly weaken the tree in the long term, most of the damage is done after the main growth spurt has been made in the spring. There can be three or four generations of moth before winter, the latest ones pupate overwinter in the dead leaves and emerge as moths in the spring to continue the cycle. Similar leaf miners attack Holly too.
Cotton Wool on hedgerows - this is Woolly Aphid, which like all aphids suck the plant sap, though this one is different in that it attacks through the bark rather than soft tissue. It hides underneath a protective fluffy waxy coat which looks a bit like a mould. Infestations soon proliferate and the young overwinter hidden in bark crevices and cracks, to emerge in the spring and start a new colony. Adults appear after a few years, with wings, to fly off and infect other trees. Where aphids are, other diseases often follow, infiltrating the plants through the wounds caused by the insect, cankers especially.
Lumpy brown warts - this is brown scale insect on hazel. There are lots of different types of scale insects, all of which are sap sucking and can weaken plants if the infestation is bad. The outer hard shell protects the inner soft body. Adults are not mobile but young scale that hatch from under the shell in July will move to leaf undersides before moving back to sites on the stems in autumn. Some scale insects produce a sticky 'honeydew' which drops onto foliage below and acts as host to a black sooty mould - this is often seen on Bay and Camellias and is usually the first indication that there is a scale infestation.
Knobbly Acorns - acorns have started dropping from the oaks now, but some of them look lumpy and deformed, as in the photo. This is due to a little wasp called the Knopper Gall Wasp which lays its eggs in the oak buds, the grubs emerge and cause these weird growths - Knopper Galls. They live inside the tissue until the acorn falls off the tree. The grub emerges as a wasp in spring and the whole cycle repeats itself. Acorns infected by the Knopper Wasp won't grow into oak trees, but since the acorn crop is usually quite generous, it doesn't really matter. Before the 1960s, there were no Knopper Wasps in the UK, they possibly arrived from the continent on the wind!
Odd wizened fruit on plum/damson/bullace - this is known as 'Pocket Plum'. A fungal infection of plum which causes some of the undeveloped fruit to wither and go pale. When opened they have no stone/seed in side - hence the 'pocket'. Apart from diminishing the crop, no lasting damage is done to the tree.
Great big limbs have fallen off some of the oaks trees. This one in Norfolk is at least 200yrs old. 'Summer Drop' is well known to tree surgeons and happens when the tree is under stress, made worse by being in full leaf. Major work required!
This bright scarlet and black, active and fast beetle with a canny way of dropping off the leaf just when you're about to catch it, is the Lily Beetle. Plus a black sticky mess that hides its grub. Leaf damage is caused by the grub eating the leaf, leaving a paper-like skeleton behind. The black stuff is frass or excrement from the grub and is horribly unsightly. It also falls off and can land on the flowers and buds. On the whole, lilies are weakened by a bad attack and will grow less well the following year. Flower stems cannot be used in arrangements without stripping the damaged leaves. It has been noticed on the Snakeshead Lilies (Fritillarias) in the meadow part of the garden which is worrying for our rare native wildflower species.
Black spots with fine yellow edges on Sycamore leaves, and occasionally Norway and Silver Maple. These are caused by a fungus, Rhytisma acerinum, but apart from being unsightly, don't do any real damage. It used to be thought that in highly polluted areas, the fungus didn't survive, but this is now thought not to be the case. Control is by clearing up the dead leaves in the autumn since spores over-winter in the leaf litter and infect new leaves in the spring. In built up urban areas, leaves are more likely to be swept and tidied up and so less infection occurred - hence the theory about pollution.
This rather coarse, brown hair-ball mass attached to the stem of a Dog Rose is know as a Robin's Pincushion. It's made by a small gall wasp laying her eggs in the growing tip of the shoot. The eggs hatch into larvae that feed on the shoot causing a proliferation or gall. The larvae continue to develop inside the gall until autumn when they pupate, overwinter, and hatch out as adults in the late spring for the whole cycle to start again. The 'Robin' part of the name refers to the folklore sprite/elf Robin Goodfellow, not the bird!