In high summer and autumn the beautiful orb webs of the Garden Spider, Araneus diadematus, can be found strung across paths, between shrubs and even in front of doors. This one is living on my fan trained pear tree clearly a great hunting ground for the insects attracted to the ripe fruits.
A large and distinctively marked spider found in a wide range of habitats wherever the habitat can provide supports for its large and conspicuous orb web, such as all types of woodland, scrub and other vegetation, hedgerows and roadside verges, buildings (sometimes inside) and gardens, as well as heathland, quarries and cliff-faces. It spins large orb webs up to 40 cm across at heights of between 1.5 m and 2.5 m in shrubs and tall herbaceous vegetation. Both sexes are mature in late summer and autumn, females surviving through to late autumn. It takes two years for the young spiderlings to reach maturity in Britain, and immatures may be found throughout the year.
During the night the industrious spider spins its silk and weaves it into a web ready for the following day. The distinctive white cross mark on the abdomen has given rise to the alternative names of ‘Cross spider’ and ‘Diadem spider’. Colours vary and include sandy brown, fox-red and almost black.
Adult female grow to 15mm (body length), and males to 9mm. They are commonly seen between June and November when the first frosts kill them off. Garden spiders are found in Europe and much of Asia across to Japan. They are now also found in parts of North America.
You can also see gymnosporangium sabinae or pear rust growing on the pear leaves.
Like many rust diseases, G. sabinae requires two different hosts to complete its life cycle from year to year. Juniper is the winter host and pear is the most common summer host. Spores (called aeciospores) are produced from the fungal lantern-shaped growths which protrude from the blisters on the underside of the pear leaf which become airborne and infect junipers. This fungus overwinters in swellings or galls on infected twigs and branches of susceptible juniper plants. In the spring after a rain or heavy dew, the galls on the juniper produce tiny dark horn-like growths that become covered with an orange-brown gelatinous mass called telia.
The corresponding stage on the pear trees is known as aecia. The telia and aecia release wind borne resting or hibernating spores (called teliospores and aeciospores) capable of infecting susceptible pear leaves and Juniper respectively. Spores produced from the fungus-induced swellings on juniper stems can be infectious up to 6 km.
The disease causes a yellow-orange spot that turns bright red on leaves of pear trees. The disease can be particularly damaging on pear, resulting in complete defoliation and crop loss if not treated. The fungus feeds on the living cells of the host plant and is not capable of surviving on dead plant material, and so must either alternate with a different host or produce resting spores to pass the dormant season.
Amazing birth of a whole nest of spiders in my garden. I found this egg sac hidden between the pear tree leaves. The mum was hiding behind, and they had only been hatched a few days.
