Hop-growers are constantly contending with these pests in the same way as other growers of crops have to contend with similar pests, but the hop-growers have the more difficult and delicate “patient” to steer through its diseases. The finest kinds of hops are not robust; it is a chance whether or no they will suffer from a wet and cold season, or other irregularity of climate, to such a degree as to fall ready victims to blight and mildew. Yet they pay better, provided the season is favourable, and so the grower risks planting the fine, delicate variety instead of being content with the more certain but smaller profits yielded by a more robust variety of hop. The hop-lice, or blight insects, are destroyed by washing with soft soap and quassia—a process requiring, even when a machine is used, a good deal of care and labour. Mildew and mould are destroyed and also prevented by dusting the hop-vines in hot summer weather with finely powdered sulphur. But both diseases can be combated by keeping the source of infection away from the hop-garden. The mould-fungus can be checked by burning all leaves and plants attacked by it within the hop-garden. If the infected leaves are left to rot they carry on the parasitic fungus to a new season. An interesting fact has been discovered about the hop-blight aphis (called by zoologists _Phorodon humuli_). It appears that the winter brood of this little insect (when the hop-vine has died down) deposit their eggs on the bark of the sloe (the wild plum), and also that any cultivated plum trees serve them for the same purpose. When the hop is dead they must of necessity get nourishment and shelter from the plum tree. Clearly, then, if you can keep all plum trees at a distance of half a mile from your hop-garden you will render it very difficult, if not impossible, for the blight aphis to carry on from season to season. It will rarely, if ever, travel half a mile, and not in any number. But hop-growers have not always the control of the cultivation for half a mile around their hop-fields, though large growers should be able to acquire it. The skilful grower even finds it useful to leave one or two plum trees in the hop-field, so as to attract the winter brood of the blight aphis to them, and then he falls upon the devastating but minute rascals with quassia and other poisons, and ensures their destruction. The increase of plum orchards in the neighbourhood of hop-gardens is probably a chief cause of the increased loss by hop-blight of late years in Kent.