A garden syringe or engine, with a cap on the pipe full of very minute holes, will wash away these disagreeable visitors very quickly. You must bring the pipe close to the plant, and pump hard, so as to have considerable force on, and the plant, however badly infested, will soon be cleared, without receiving any injury. Afterwards rake the earth under the trees, and kill the insects that have been dislodged, or many will recover and climb up the stems of the plants. Aphides may also be cleared by means of tobacco smoke, but after this has been applied the plant should be well syringed.