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The Pamphlet Collection of Sir Robert Stout: Volume 14

The Wireworm. Elater lineatus. Linn. Agriotes segetis. Westwood

page 26

The Wireworm. Elater lineatus. Linn. Agriotes segetis. Westwood.

Fig. VII.

Fig. VII.

1, Length, and breadth across wings of perfect insect; 2, mag.; 3, larva; 4, mag.

The wireworm, the larva of the Elater lineatus, of the order Coleoptera, division Herrieomes, family Elateridæ, is an universal crop destroyer, and may fairly be held to be the first and foremost insect enemy of farmers and gardeners. It has already been described in the first part of this series of Reports as greatly injuring hop plants. It is even more injurious to corn crops of all descriptions as well as to grasses.

There are several species which also feed upon the roots and stems of corn plants and grasses, among other crops, but the wireworm proper, the arch enemy, the typical destroyer of the race is the Elater lineatus, known also as Elater segetis and Agriotes segetis. Its larva is larger than that of other species and is well known to all cultivators as long, yellow, and tough-skinned, almost as tough as wire, from which its familiar name is derived. This insect is known in America, Germany, and indeed in all Continental countries.

Upon light soils it is usually more abundant and destructive, though in some seasons it has been most troublesome in the Fens of Lincolnshire and in the clay soils of Essex. In the friable chalk soil in certain districts of Wilts, Dorset, Hants, and East Kent corn and other crops often suffer severely from its ravages.

The attacks of wireworms are always more frequent and serious in districts where clover leys form a part of crop rotation, and especially where these remain down two or more years, also where sainfoin is grown, in which case the land usually remains laid page 27 down from two to five years. It often happens that wheat after sainfoin ley ploughed and pressed in the ordinary manner loses plant disastrously and yields but little corn. To take an instance in East Kent in 1882. Ten acres of land after sainfoin were sown with wheat in October. Even before Christmas, as the weather was mild, it was noticed that the plant was getting thin and that it got small by degrees and beautifully less, and it was finally reduced to less than half a plant, the other having been eaten by wireworms. After this crop trifolium was taken and cut for horses and cattle. Turnips followed and were very much damaged by wireworms, so that the farmer estimated his losses upon this field in the two years at over 90l.

Oat plants suffer even worse than wheat plants, because the wireworm works more actively in the spring when oats are sown, so that the plants have less chance to grow away from them. Large bare places may be seen in many oat fields particularly in light land counties in almost every season, in which upon examination wireworms may be seen at work in numbers. Barley plants are also very liable to receive injuries from wireworm. Curtis relates that a certain farmer employed boys to pick wireworms from an infested barley field, and that 18,000 were collected on 1½ acres.

In short, in England, Scotland, and Ireland the wireworm is a continual source of harm to corn crops of all descriptions. This insect also does much mischief in pasture land and meadows, often undiscovered and unsuspected. The finer grasses especially are chosen, and their stems and root crowns are bored into and eaten away by the wireworms. In the case of newly sown grasses very much and irreparable damage is caused. Failure of grass seeds to take and form pastures in due time is more often occasioned by these larvæ than is dreamed of. Many complaints have been made of mischief to beans. It appears that the wireworms attack these directly the seed has become soft and has commenced to send forth radicles and plumules. The mode of procedure of these wireworms is to fix their heads into the soft parts of the stem just at its junction with the crown, and with their horny jaws to bite away the tissues so that the stem dies, being bitten through and through, or so much bitten that the sap circulation is arrested.