How to control aphids in your garden
Aphid cause leaf curl, wilting, stunting of shoot growth, and delay in production of flowers and fruit, general decline in plant health. Some aphids also carry plant diseases, they transmit in the feeding process.
How to control aphids : While there are some insects that will eat aphids (ladybugs and parasitic wasps), by the time you notice an aphid infestation, it's probably too late to try to introduce aphid predators in the hopes of controlling the aphids.
Controlling aphids is actually easy, though somewhat time consuming. A sharp stream of water will knock the little buggers off the plant, although a hose nozzle may be too strong - especially for tender plants like peas.
Another effective alternative is insecticidal soap. The soap washes off the aphid’s protective waxy coating and causes dehydration, thus killing the insect. Insecticidal soap spray is economical, nontoxic, and environmentally safe both indoors and in the garden.
From : tennzen