Efeito De Linhagens Com Características Morfológicas Mutantes Sobre O Bicudo E a Produção Do Algodoeiro

Abstract

RESUMO O presente trabalho objetivou avaliar linhagensde algodoeiro com características morfológicas mutantes quanto à infestação pelo bicudo Anthonomus grandis Boheman e suas produções. O experimento foi conduzido em campo, com a cultivar IAC-24 (testemunha), IAC-04/227 (planta vermelha) e IAC-04/489 (folha “okra”). A infestação foi avaliada contando os botões florais perfurados para a alimentação e oviposição do bicudo. A produção foi avaliada pelo do rendimento de algodão. A linhagem IAC-04/227 diferiu da cultivar IAC-24 e da linhagem IAC04/489 até 85 dias após a emergência das plântulas, apresentando menor porcentual de botões florais perfurados pelo bicudo. Este fato indica que a coloração vermelha das plantas é um caráter importante no manejo da resistência do algodoeiro ao bicudo. Não houve diferença significativa, entre os genótipos, para o rendimento de algodão, mas para a massa de 100 sementes, a cultivar IAC-24 diferiu da linhagem IAC-04/227, apresentando a maior média.

New Host Plants for Soybean Weevil, Rhyssomatus nigerrimus1, in Mexico

“…Similar feeding habits of adult Rhyssomatus subtilis Fiedler (Coleoptera: Curculionidae) on host weeds before soybean planting were reported in Argentina (Cazado et al 2013). In tropical areas, alternate plant hosts of Anthonomus grandis (Boheman) (Coleoptera: Curculionidae) are only for food and refuge, but not reproduction (Gabriel 2002). During sampling, R. nigerrimus adults were also observed feeding on flowers of H. rufa , S. halepense , R. cochinchinensis , E. colona , C. myosuroides , C. ciliata , Cynodon sp., L. camara , H. rovirosae , and P. erythrocarpa .…”

Fungal seed treatments of cotton affect boll weevil development

“…16 Depending on temperature and humidity, three to seven generations of boll weevils may occur during the cotton growing season. 17 Based on these estimates of fecundity and generation times, an initial population of 50 boll weevils at the beginning of the season could potentially yield 500 000 adults by harvest time. 18 Thus, plant damage and yield losses are proportionally related to weevil reproductive intensity.…”

“…The critical stage of cotton susceptibility to boll weevil is during peak reproductive development from about 40 to 90 days after germination. 17 Chemical insecticides continue to be the dominant control strategy in many agricultural systems despite constraints such as cost, insecticide resistance, and environmental and human health hazards. 20 This is particularly true for boll weevil control, which relies heavily on repeated insecticide applications to control adult weevils.…”

“…Adult longevity typically ranges from 20 to 40 days, during which females can oviposit ~100–300 eggs over their lifespan 16 . Depending on temperature and humidity, three to seven generations of boll weevils may occur during the cotton growing season 17 . Based on these estimates of fecundity and generation times, an initial population of 50 boll weevils at the beginning of the season could potentially yield 500 000 adults by harvest time 18 .…”

“…Consequently, plant traits reducing weevil reproduction can benefit yield maintenance. The critical stage of cotton susceptibility to boll weevil is during peak reproductive development from about 40 to 90 days after germination 17 …”