This is a ladybird larva. Not a bit like a ladybird, so don’t mistake it for a pest like an asparagus beetle (I’ve done that). Ladybirds, most people know, are excellent predators – eating aphids, mealybugs, scale insects, whiteflies, mites and other insects. Their larvae are even better. In the weeks it takes for them to develop, one larva can eat 500 aphids before pupating. The aphid (black and greenfly) are menaces – sucking the life out of beans and brassicas. A single cabbage aphid has the potential to produce 1,560,000,000,000,000,000,000,000,000 more aphids (I don’t know who counted them), though, for various reasons, this never happens. One of the reasons is, of course, the ladybird.
Even if your broad beans are sucked of life by aphids, don’t be tempted to use pesticides. They can make the problem worse. The pests will eventually adapt or become resistant to the chemicals and you might end up killing beneficial insects – such as ladybirds – as well. Chemicals also destroy the organisms in the soil that transform rotting material into food for your plants so that you need to rely increasingly on fertilisers and more pesticides. So, you need to encourage the good bugs by giving them the habitats and plants they like – basically plant a good variety of plants and leave wild patches. The plants will drop their leaves which provide places for ladybirds to overwinter. It’s essential to have nooks and crannies for ladybirds to lodge in so that they stay in the garden. If they find a good hibernation site their numbers will increase. Useful plants are ones that form basal rosettes, such as mulleins and evening primrose, umbellifers such as fennel, and plants with dense foliage such as brambles and ivy.
You can probably tell I have referred to A Book or two. One is called Pests by Charlie Ryrie and the other is Ladybirds, Natural Pest Control by Darren J Mann.
Cordwainers Garden 