Novel rearing technique, developmental biology, fecundity and morphometrics of the brown cocoa mirid Sahlbergella singularis Haglund in Nigeria

The brown cocoa mirid, Sahlbergella singularis is the major insect pest of cocoa in Nigeria capable of causing up to 80% yield loss. This study described a new rearing technique for mass culture and aspects of the laboratory and field biology of the insect. The rearing technique involved two phases in which day old nymphs were collected from the field and transferred into the specially fabricated rearing chamber (300cm x 200cm x 240cm) made of plywood with installed temperature regulating unit of 22 - 240C and humidifier with Relative Humidity of 85 ± 5%. The insect was reared using this new technique. Adult gravid females from the growth chamber were then confined in the field on cocoa trees under natural conditions for the purpose of egg laying and thereafter pods containing eggs and emergents were plucked and taken into the rearing chambers for biological studies. Each life stage was collected, measured and described. The nymphal instars were clearly separated on the basis of the cast-off exuviae. The life cycle from egg to adult lasted an average of 41.1 days while the egg incubation period was 31.3% of the total developmental time. There were five nymphal instars with total mean duration of 27 days. There were significant differences in the body morphometrics of each of the life stages (P>0.05). The sex ratio of male to female was 1:1.03. The potential fecundity of S. singularis was 42.20 ± 4.96 from dissected gravid female whereas the mean actual fecundity from mated females was 37.90 ± 3.09. The breakthrough in the continuous cultures of S. singularis therefore makes homogenous populations of mirids to be available for intensive laboratory bioassays. Moreover, it facilitated indepth knowledge of the biology of the pest which is basic for the development of an efficient and ecologically sound management strategy. (Texte intégral)

Bibliographic Details

Main Authors:	Anikwe, J.C., Omoloye, A.A., Okelana, F.A., Babin, Régis
Format:	conference_item biblioteca
Language:	eng
Published:	Cocoa Producers' Alliance
Subjects:	H10 - Ravageurs des plantes, Theobroma cacao, Sahlbergella, Miridae, http://aims.fao.org/aos/agrovoc/c_7713, http://aims.fao.org/aos/agrovoc/c_6735, http://aims.fao.org/aos/agrovoc/c_12607, http://aims.fao.org/aos/agrovoc/c_5182,
Online Access:	http://agritrop.cirad.fr/554237/ http://agritrop.cirad.fr/554237/1/document_554237.pdf
Tags:	Add Tag No Tags, Be the first to tag this record!