When pea pods are opened, some of the peas will be damaged and have dark excrement near them. Inside infested peas you will find a tiny light grey to brown caterpillar.
You can use row cover (garden fleece) to prevent egg laying by adults if pea moths are a serious problem. Early planting also can help peas escape damage. In most areas natural predators help to keep this pest under control. Flat-podded mange-tout peas are less affected compared to shell peas.
Check plants regularly as soon as they begin to bloom, and pick off affected pods. Little can be done once the adult moths have laid their eggs on pea plants.
In large plantings, pheromone traps are often used to monitor this pest.