Biologia e manejo de Chalcodermus bicolor Fiedler (Col.: Curculionidae: Molytinae), em plantios de eucalipto / Biology and management of Chalcodermus bicolor Fiedler (Col.: Curculionidae: Molytinae), in eucalypt plantations

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

27/07/2011

RESUMO

This work deals to the biology and pest management aspects of the “Eucalypt-trimmer”, a new leaf beetle in the Brazilian eucalypt plantations. Works were developed under lab conditions (Temperature = 25.29 0.20C; RH = 78.26 0.94%; photophase: scotophase = 10:14 hours). Insects were collected from cloned eucalypt in the Mucuri and Caravelas counties, Bahia State, Brazil, during November/2010 to February/2011 period. Females laid eggs, oblong shaped, smooth, membranous and translucent white- yellowish, 2.030.06 mm long and 1.00.04 mm wide; 4 to 5 days of incubation time. Larvae were 2.16 0.05 mm, 3.11 0.07 mm and 5.5 0.15 mm long for the first, second and third instars, respectively. As a full grown larva, the insect leave the main shoot tip, where it developed, and drop down to the soil for pupation. Each larva built a chamber at 1.1cm deep in the soil, where it develops to a pupa. Eulophidae Westwood, 1929 and Pteromalidae Dalman, 1820 were killing larvae, and may useful as natural enemies in the biological control of this pest, under plantation conditions. The parasitoid Pseudosecodes Girault, 1915 is recorded for the first time as a natural enemy of this pest in the Neotropical Region. Young pupa was white-yellowish, dark becoming at final stage. Male differs from female by an protuberance located at the final portion of the female abdomen. Male pupae were 6.45 0.61 mm long and 2.13 0.11 mm wide; female pupae were 6.23 0.68 mm long and 2.25 0.17 mm wide. Pupal period ranged from 7 to 12 days. The adult remained for a period of 4 to 8 days in the pupal chamber before its emergence to the soil surface. Sex ratio was 1.52 males for each female. The sexual difference was verified, as well, by the absence of pre-mucro on the hind and medium legs in males. At laboratory, adults had tanatose, but did not copulate. After three months past from the insect attack to young plantations of Eucalyptus urophylla vs. E. grandis, damage resulted in significant difference for height and xvi diameter of the trees, and trunk malformation. As a maximum, we found seven pruned shoots per tree. Females pruned more side shoots than main shoots. “Hand collection” technique presented control efficiency by 23.90%. Neonicotinoid insecticides used to evaluate the curative effect were efficient at lower dose of imidacloprid (Confidor 700WG) (100g/ha). As a preventative test, we obtained 100% mortality of larvae with lower dosages of insecticides (Actara, Confidor and Mospilan). Such basic information about the biology of the eucalypt-trimmer will help to improve integrated management strategies for this new Brazilian pest in the eucalypt plantations.

ASSUNTO(S)

entomologia e malacologia de parasitos e vetores entomologia florestal besouro desfolhador podador-do-eucalipto forest entomology beetle defoliator eucalypt-trimmer

ACESSO AO ARTIGO

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