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The Pamphlet Collection of Sir Robert Stout: Volume 14

The Hop Fly. Aphis humuli

page 8

The Hop Fly. Aphis humuli.

Fig. I.

Fig. I.

1 & 2. Winged female Aphis; 3 & 4, larvæ; or lice, nat. size and mag.

This is a species of the large tribe Aphidin œ, of the genus Phorodon, thus distinguished because its species have toothed frontal tubercles, most developed according to Mr. Buckton, in the wingless viviparous females. Very many of the cultivated and wild plants of this country are infested with peculiar species of aphides, which in some seasons favourable for their development and increase are infinitely destructive. Rose growers know how often these flowers are spoiled by the rose aphis. Fruit producers often suffer much from the species which attack currant bushes, plum, damson, and peach trees. The lime tree, whose blossoms are delightfully fragrant, is constantly so beset by the Pterocallis tili œ that it is unpleasant to sit under its shade on account of the showers of honey dew that fall from the legions of insects on its leaves.

The losses to hop planters occasioned by the hop aphis have been almost incalculable. Hop plants have been liable to its attacks for at least 200 years. It appears from records of these attacks, "black blights," that they have been of more frequent occurrence during the last 50 years. It would be difficult to give accurate estimates of the. losses to hop planters and to the whole community caused by the ravages of aphides. In the last serious blight in 1882, not a hop was picked in many important hop-growing parishes, and it was estimated that the whole produce of the hop land in England, 65,619 acres in 1882, did not exceed 114,832 cwts., or an average yield of 1¾ cwts. per acre. The annual average yield of the English plantations is about 7 cwts. per acre, or a total yield of 459,333 cwts. upon the acreage of 1882, which at 7l. 7s. per cwt., the average price of English hops, taking the 20 years previous to 1882, would represent a total value of 3,370,177l. The picking of an average crop of hops upon the acreage of 1882* would cost page 9 from 350,000l. to 380,000l., whereas the cost of picking the crop of 1882 did not amount to more than 155,000l.; so that the labourers who depend upon the hop picking suffered considerably.

* The hop acreage in 1884 had increased to 69,258 acres.