Insect pests of farm, garden and orchard . e arc soon alldestroyed, and the leaves thereujx)!! soon wither, and the wholebeet shrivels and becomes spongy. This wilting of the leaves willfrequently, in fact, be the first thing to attract the attention of thebeet-grower. The actual injury to the crop will, of course, dependlargely upon the time when the attack of the aphis is made. If theplants are small they may be readih destroyed, while if they arepractically full grown the loss of the small rootlets will notmaterially affect them. * See Forbes and Hart, Bulletin 60, 111. Agr. Exp. Sta., and
Insect pests of farm, garden and orchard . e arc soon alldestroyed, and the leaves thereujx)!! soon wither, and the wholebeet shrivels and becomes spongy. This wilting of the leaves willfrequently, in fact, be the first thing to attract the attention of thebeet-grower. The actual injury to the crop will, of course, dependlargely upon the time when the attack of the aphis is made. If theplants are small they may be readih destroyed, while if they arepractically full grown the loss of the small rootlets will notmaterially affect them. * See Forbes and Hart, Bulletin 60, 111. Agr. Exp. Sta., and F. H. Chitten-den, Bulletin 43, n. s., Div. Ent., U. S. Dept. Pemphigus hetce Doane. Family Bulletin No. 42, Wash. Agr. Exp. Sta. 330 INSECTS INJURIOUS TO BEETS AND SPINACH 331 No sexual generation of this aphis has as yet been discoveredand no eggs have l^een seen, viviparous reproduction continuingthroughout the year except when the cold of the winter tempora-rily suspends the physiological activities of the species. The. Fig. 237.—The beet-aphis (Pemphigus beta Doane): o, winged female; b,wingless female; c, antenna of winged female. (After Doane.) winged females, appearing from time to time during the summerand fall, serve to distribute the species generally, new coloniesIjeing started wherever these females find lodgment and food. Indistricts liable to injury by this insect it seems inadvisable thatbeets should l^e the first crop on new land, or that ground should be continued in beets or in any otherroot-crop after the pest has made itsappearance in the field. y/F^^j^ ^y Another plant-louse, called the beet f^ 11 Yi^^^^^-^^^C ]-oot-apliis *, proved injurious to sugar- beets in Colorado in 1903. They werefound quite generally distributed inthe beet-fields in the vicinity ofRockyforcl and attacking the roots ofmany weeds. What seemed to be thisspecies was very abundant upon theroots of the common garden purslane,to which it was very injurious. Near* Tychea
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