The Pea And Bean Weevils. Sitona crinita. Oliv. Sitono, lineata. Linn.

Fig. XVIII.

1 and 2, Sitona crinita nat. size and mag.; 3 and 4, Sitona lineata nat. size and mag.

These are two species of weevils very destructive to pulse crops. Farmers and gardeners have constantly noticed that the leaves of pea and bean plants are full of holes and notches, and so much so as to affect their growth most materially in some seasons. These weevils cause this and are most dangerous when the plants are young, commencing their depredations in March, or as soon as the weather becomes spring like, they work until the end of July.

It is said that they do not attack the common pea that is grown principally for pigs and sheep, but this is not correct, for complaints have been made from several parts showing that these have not by any means escaped. From observation it is clear that they eat all kinds of peas readily, in field and garden, as well as Mazagan, tick, and broad beans. In some seasons, and when the seed is sown late, they fairly prevent the plants from starting, eating off the leaves directly they appear from the cotyledons. A large grower of peas for seed reported that in 1883 he sustained considerable losses by the onslaughts of the pea weevils, especially upon the Early Sunrise sort.

Clover is much destroyed by these weevils, as well as by a closely allied and almost identical species, known as Sitona puncticollis. The weevils eat the leaves, and the grubs or larvæ devour the roots of the clover. In 1883 there were many complaints made of clover dying in patches in various parts of England in October. It was thought at first this was due to clover sickness, or to a fungus. Upon close examination small maggots were page 61 found at the roots, which were living upon the juicy succulent parts. Again, in the early spring following, the mischief was continued. Trifolium incarnatum is also attacked frequently. Plant is lost quickly and mysteriously. It is said that the "worm" is in it. In Kent, in 1882, this happened in a large piece of trifolium sown upon wheat stubble without ploughing. After the plants had nearly all disappeared the cause of the loss was traced to the larvæ of the Sitonæ.