• WordNet 3.6
    • n jointworm larva of chalcid flies injurious to the straw of wheat and other grains
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Webster's Revised Unabridged Dictionary
    • n Jointworm (Zoöl) The larva of a small, hymenopterous fly (Eurytoma hordei), which is found in gall-like swellings on the stalks of wheat, usually at or just above the first joint. In some parts of America it does great damage to the crop.
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Century Dictionary and Cyclopedia
    • n jointworm A jointed worm; an intestinal worm of the genus Tænia; a tapeworm. See cut under Tænia.
    • n jointworm The larva of a chalcid hymenopterous parasite of the genus Isosoma, as I. hordei, which is very destructive to crops of barley, wheat, and rye in the United States. The eggs are laid in the stems of these cereals, and the larvæ feed in slight enlargements near the Joints. There is only one annual generation, and the insect winters in the stubble in both the pupal and adult states. All the species of Isosoma are phytophagous or plant-feeding, and work like I. hordei upon the stalks of various grasses and cereals. These worms are of small size, one tenth to one fifth of an inch long. They attack the crop when it is a foot or less in height, checking the growth, causing the green leaves to turn yellow, and making knots on the stem. The rye joint-worm is the larva of I. secalis; the wheat joint-worm, that of I. tritici; both of these are merely varieties of I. hordei, which is morefully called barley joint-worm. See Isosoma.
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