The Pamphlet Collection of Sir Robert Stout: Volume 14
The roots and stocks of hop plants, forming plant-centres or "hills," remain in the ground for many years, and consist of congeries of interlaced fibres, affording succulent food for the larvae, and convenient shelter for the eggs and larvae of insects. Though without doubt many of them would be affected and decreased by application of caustic and disagreeable substances dug in round the plant-centres, there are some which would page 21 escape; still it would be desirable, after a very bad attack of jumpers, to "open round" the plant-centres, that is, to clear away the earth from them, leaving a trench round the fibrous stocks, which would lie exposed during the winter. Planters adopted this course formerly after a visitation of mould or mildew to let the air in and to destroy the germs or spores of the fungus. Caustic substances could then be put close to the stocks, as lime, lime ashes, soot, nitrate of soda, sulphate of ammonia. Dressings of sand, sawdust, wood ashes, or finely triturated earth, with which paraffin oil should be mixed, might be sprinkled all round the stocks with very much advantage. Opening in the manner described would be very effective, but if this could not be done the soil all round the stocks should be well dug and pulverised as early as possible directly after the poles had been set up, and caustic substances put on before the digging operation.