. Cooperative economic insect report. Beneficial insects; Insect pests. - 15 - INSECTS NOT KNOWN TO OCCUR IN THE UNITED STATES BRAZILIAN COTTON BORER (Eutinobothrus brasiliensis (Hambleton)) Economic Importance: This weevil has been known as a pest in Brazil since 190 5, but in recent years it has become a major pest of cotton in that country. During the 1935-36 crop season in the State of Sao Paulo, it caused an estimated loss of about 30,000 tons. Early planted cotton is attacked first, infestations sometimes reaching 95 percent during the first three months of the season and plant mortality
. Cooperative economic insect report. Beneficial insects; Insect pests. - 15 - INSECTS NOT KNOWN TO OCCUR IN THE UNITED STATES BRAZILIAN COTTON BORER (Eutinobothrus brasiliensis (Hambleton)) Economic Importance: This weevil has been known as a pest in Brazil since 190 5, but in recent years it has become a major pest of cotton in that country. During the 1935-36 crop season in the State of Sao Paulo, it caused an estimated loss of about 30,000 tons. Early planted cotton is attacked first, infestations sometimes reaching 95 percent during the first three months of the season and plant mortality being estimated at 50 percent. A closely related species, Eutinobothrus gossypii (Pierce), occurs in Peru and Ecuador and attacks cotton in much the same manner as E. brasiliensis in Brazil. Distribution: Eastern Brazil and the Chaco of Argentina. Hosts: Occurs on cotton, okra, hibiscus, roselle, floss-silktree and numer- ous other species of malvaceous plants. Gossypium purpurascens is the species of cotton most severely attacked and G. trilobum the General Distribution of Eutinobothrus brasiliensis Life History and Habits: Adults overwinter in trash or malvaceous weeds, but true hibernation has not been observed and oviposition may continue throughout the year where conditions permit. Overwintered females appear in September and October in Sao Paulo and oviposit until April, females of subsequent generations lay eggs through the crop season and the winter. Each female will lay about 160 eggs. Eggs are laid singly, in small cavities beneath the surface of the stem or root, and occasionally in the boll. The lower portion of the stem is preferred. Eggs hatch in 5-18 days and larvae bore into the center of the stem or root, often killing the plant. In older plants, larvae are almost entirely confined to the area between the bark and woody tissue. Feeding galleries run in all directions, often encircling the plant and causing death. In heavily infested plants, eggs are la
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