April Bug of the month

Ladybirds on sage

Each month Jo, one of our garden team, explains a little more about the different pests, both good and bad, that affect the garden.

Ladybirds (coleoptera)

Spring is now here; the gloomy days of winter seem behind us and the garden is full of colour and the promise of things to come.  We have been busy in the garden getting ready for the season ahead, finishing off border clearing and getting areas mulched. During this time we have been seeing many ladybirds over wintering in the leaf and plant litter. These little beetles, which have benefited from a short mild winter, are now emerging into the sunshine and can be seen in large numbers roaming through the fresh new foliage.  So for April I thought Bug of the Month should be the lovely and highly beneficial Ladybird.

This number of ladybirds is a good sign for us and our fight against plant pests, particularly aphids, which are already staking their claim to the new young shoots and buds through the garden.  We do not spray any insecticides here so ladybirds are a very important element to our pest and disease management as it is a prolific eater of aphids, both in its larvae and beetle stage.

Lots of ladybirds on sage
Lots of ladybirds on sage
Lots of ladybirds on sage

The instinctive approach on seeing an aphid might be to spray with an insecticide; while this may see off your aphids it will also kill the ladybirds. The aphids will quickly bounce back; they are the master of quick reproduction producing up to 40 generations a year. The ladybirds however have a much longer life cycle often only producing one or two generations per year.  If we removed all the aphids there would be no food source and we could then loose the ladybirds and this would affect the natural balance within the garden.

The most common species of ladybird is the bright red 7-spot ladybird, but there are 46 different types in the UK, not all of them are red and spotty, they come in orange, yellow, brown and black.  Their bright colouring and patterns remind predators that they taste nasty; however, some birds like swifts and swallows, as well as some spiders and other insects can eat ladybirds.

The ladybird’s life cycle:

• In early spring ladybirds start to emerge from their winter snooze and look for food.
• In May they mate and lay their eggs. The eggs are yellow or orange and are stuck to the underside of leaves. A mature female can lay 500 eggs throughout summer.
• In early summer each egg hatches into a little grub called a larva, these alligator-like larvae are also predators, and greedily feed on the aphids. They are spiny and black with bright spots. 
• The larvae shed its skin several times as it grows. In about four weeks it hardens into a pupa which protects the new ladybird as it develops.
• In August, the mature ladybird emerges from the pupa. The older generation is starting to die off now.
• By November the new ladybirds are starting to look for a sheltered place to sleep for the winter, all before the lifecycle starts again.