The Pamphlet Collection of Sir Robert Stout: Volume 14
The flea, in reality a winged beetle, passes the winter in the perfect state under clods, tufts of grasses, or weeds near the hop plants, or on the outsides of hop plantations. In early spring, directly the bines are ready to tie, they come up from the ground near the plant-centres, or fly from their retreats at a distance, and at once begin to eat and fret the leaves. Pairing takes place and eggs are laid under the leaves as well as on the smaller bines. Only one egg is laid daily by a female, so that these insects are not very prolific. In about eight or nine days larvæ, little white maggots, with six pectoral feet are hatched from the eggs, and immediately burrow in the leaves and feed upon their tissues. In about a week they become chrysalids, and in due time the perfect beetles appear again, and the life stages are repeated. Breeding goes on thus in favourable circumstances until September. It is alleged that the flea deposits eggs within the hop cones, and that the larvæ mining the strigs, or stems, cause the decay and disintegration of the bracts. This has not been quite determined, but it seems very probable that the serious damage to hop cones, which has increased so much within the last 10 years, may be caused by fleas, together with another insect which is described further on.