The hop-louse has other enemies besides the grower. These are the lady-birds (less prettily called “lady-bugs”), which feed greedily on the parasites, so that when the hop-grower sees plenty of them on a hop-vine he does not trouble to wash it. And there are other predaceous insects which tend to keep the hop-lice down. Cultivation and excessive production have resulted in putting, as it were, too heavy a task upon the natural enemies of the pest, whilst the more delicate but valuable varieties of hop cannot withstand the attacks of blight, which less valuable varieties would tolerate without fatal injury. Another complicated and difficult problem for the hop-grower is the “curing” of the hops when gathered. He has to arrange to grow a number of varieties which will not be all ready for picking at the same moment, so that the hop-pickers may be employed for some six weeks, and gather each kind at the exact time of ripeness. Then the gathered hops have to be “dried” and “cured.” In Germany (where the highest-priced hops are produced) small cultivators dry them in the sun, and they are “cured” by the purchaser, but in England they are dried in kilns (called “oasts” in Kent) near the hop-grounds. They are cured with sulphur fumes on the spot as soon as dried. The object of the drying and curing is quickly to get rid of the water, which forms 75 per cent. of the weight of the green flower-heads, but is reduced by drying to 10 per cent., and to destroy the “mould” (fungus) which may be present, and to keep the hops free from new access of mould by the slight deposit of sulphur fumes on their surface. The drying and fumigating require a great deal of skill, and a fine crop may be injured or even rendered worthless by want of care, rapidity, and judgment in treating the freshly gathered flower-cones. It is said that it takes years to acquire the art, and that skilled hop-curers are more difficult to obtain than formerly.