Economic entomology for the farmer Economic entomology for the farmer and the fruit grower, and for use as a text-book in agricultural schools and colleges; economicentomolo00smit Year: 1906 372 AN ECONOMIC ENTOMOLOGY. Fig. 428. tion of the body around the edge of the leaf or twig while feed- ing. This is quite a characteristic peculiarity, and there is rarely excuse for mistaking the larva of a saw-fly for that of a Lepidop- teron, even without counting the prolegs. Many of these larvae are injurious to cultivated plants, and some of them are known to farmers as 'slugs' or 'worms;' for insta
Economic entomology for the farmer Economic entomology for the farmer and the fruit grower, and for use as a text-book in agricultural schools and colleges; economicentomolo00smit Year: 1906 372 AN ECONOMIC ENTOMOLOGY. Fig. 428. tion of the body around the edge of the leaf or twig while feed- ing. This is quite a characteristic peculiarity, and there is rarely excuse for mistaking the larva of a saw-fly for that of a Lepidop- teron, even without counting the prolegs. Many of these larvae are injurious to cultivated plants, and some of them are known to farmers as 'slugs' or 'worms;' for instance, we have the 'currant-worm,' the 'grape-slug,' the 'rose-slug,' and the ' pear-slug.' When these larvae are full-grown they form thin, tough, parchment-like cocoons, in which they change to pupae, sometimes on the plant on which they feed, sometimes a little below the surface of the ground. Perhaps none of the members of this family are better known than the 'currant-worm,' or 'slug,' Nematus ribesii, which is an imported insect, and annually does great injury where its food plant is raised on a large scale. The flies, which are easily dis- tinguishable by a rather deep yellow body, may be seen sitting upon the foliage, or flying about heavily as soon as the leaves of the currants are toler- ably well developed in spring, and we may, even at that time, find on the under sides, arranged along the veins, series of little white eggs laid by them. The larvae soon make their appearance and feed ravenously, frequently stripping a bush completely in the course of a few days. I have seen rows of currants covering an acre or more almost entirely devoid of leaves and the fruit hang- ing to bare twigs. There are two or three broods in the course of a season, depending upon latitude, the latter rarely as abundant as the first and second, and practically not nearly so destructive. The larva is green, dotted with black, and nearly an inch in length. On pears we frequently note a very dar
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