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.