Features
What Do Organic Growers Do About Pea Caterpillars?
One of the great joys of vegetable gardening is lying in the sun beside a row of peas and eating the fresh fruit from the pods. But sometimes this harmless pleasure is spoiled by the presence of a green-coloured caterpillar inside the pods.
In some years growing peas can be difficult. Even if the seeds survive the attentions of birds and mice there is still the danger of slugs, aphids, botrytis and mildew. But at least these problems can be seen, unlike the larvae of the pea moth which can live unnoticed inside the pods. So the first sign of trouble- pods full of caterpillars- often comes too late for us to do anything about it.
The pea moth lays its eggs from June to August. The eggs quickly hatch out and make for the pods which provide a ready-made safe house for them. If they are not removed during this short hatching out period - before they get inside the pods- then your crop will be ruined.
Timing
Pea seeds germinate at low temperatures. So if the condition of your soil allows the crop to be sown early in March or even February, then much of your crop could be harvested before the pest is fully active. Equally, by sowing a later, autumn maturing variety you might avoid the pest altoghter. However, damp autumn weather can bring its own set of problems such as a greater risk of mildew and botrytis.
Insecticides
Soft soap is the traditional solution. Not the modern kind but the old-fashioned green type which contains potassium carbonate, an effective and safe insecticide. Use about 10gms per litre of water.
Quassia, one of the commercially available 'safe' insecticides is another solution. Some organic gardeners mix these two together. The soap helps the quassia to stick to the foliage.
When to spray
The effectiveness of any treatment for the pea caterpillar is totally dependent on the timing of the application. The larvae must be caught before they reach the forming pods. So the crucial time to spray them is just after the crop begins to flower and the pods are beginning to form. As the larvae are difficult to see, the safest solution is to spray your crop regularily from the flowering stage until the pods are formed.
Prevention
Some gardeners claim that planting aromatic herbs, sage, rosemary, mint and thyme beside the crop will keep away flying pests. If the pea moth is a regular visitor to your garden then it would be worth finding out if this works for you. The increasing number of claims made by enthusiastic users of seaweed never cease to amaze me. Some users find that spraying plants with seaweed liquid makes them less attractive to egg laying pests. Perhaps the pests feel all at sea?
Gillian Westbrook has been appointed to the new position of
General Manager with IOFGA. Coming from a background in the regulatory area...
