. Insect pests of farm, garden and orchard . ile the wing-covers are mottled as shown in Fig. 223, a. Itmay be distinguished from the pea-weevil by its longer thorax andby the two small teeth next to the large tooth at the tip of thethighs. Life History.—In the field the eggs aiv laid upon or are insertedin the bean-pod through holes made by the female or such open- * Bruchus obtectus Say. Family Bruchidoe. 310 INSECT PESTS OF FARM, GARDEN AND ORCHARD ings as are caused by its drying and splitting (Fig. 224, b, c). Inshelled beans the eggs are placed loosely among them or in theexit holes of t
. Insect pests of farm, garden and orchard . ile the wing-covers are mottled as shown in Fig. 223, a. Itmay be distinguished from the pea-weevil by its longer thorax andby the two small teeth next to the large tooth at the tip of thethighs. Life History.—In the field the eggs aiv laid upon or are insertedin the bean-pod through holes made by the female or such open- * Bruchus obtectus Say. Family Bruchidoe. 310 INSECT PESTS OF FARM, GARDEN AND ORCHARD ings as are caused by its drying and splitting (Fig. 224, b, c). Inshelled beans the eggs are placed loosely among them or in theexit holes of the beetles. The young larva hatching from the egghas long, slender legs, but with the first molt these are lost andwhen full grown it is a fat grul3 as shown in Fig. 223, b. The pupalstage is passed in an oval cell made by the larva within the have shown that the eggs hatch in from five days inthe hottest to twenty days in cooler weather; the larval stagerequires eleven to forty-two dajs, and the pupal stage five to eigh-. FiG. 224.—The bean-weevH; a, .side view of beetle; b, section of bean podshowing sHt for deposition of egg; c, part of inside of pod showing egg-mass inserted through slit—all enlarged. (After Riley and Chittenden,U. S. Dept. Agr.) teen days. Thus the whole life cycle will extend over a period offrom twenty-one to eighty clays, depending upon the season andlocality. Probably a out six generations occur annually in theDistrict of Columbia, and a less number further north. Unlike the pea-weevil, a large number of individuals w^illdevelop in a bean, as many as twenty-eight having beenf oundwithin a single seed. It will thus bereadily seen that the first out-door generation or any single indoor generation is capable ofexhausting seed and completely ruining it for food or planting orany other practical purpose, except perhaps as hog feed. The beetles begin to issue from beans in the field in a climate INSECTS INJURIOUS TO BEANS AND PEAS 311
Size: 1732px × 1442px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1915
