BioControl (1999) 44, 449-471
J. de Kraker, A. van Huis, J.C. van Lenteren, K.L. Heong and R. Rabbinge (1999)
Egg mortality of rice leaffolders Cnaphalocrocis medinalis and Marasmia patnalis in irrigated rice fields
BioControl 44 (4), 449-471
Abstract: Egg mortality of rice leaffolders Cnaphalocrocis medinalisand Marasmia patnalis was studied in unsprayed irrigated rice fields in Laguna Province, the Philippines. Mortalitywas assessed by field exposure of laboratory-laid eggsfor two days and by monitoring of field-laid eggs. Eggdisappearance, the major mortality factor, was low inthe first four weeks after transplanting and thenincreased. Egg parasitism by Trichogrammajaponicum was highest at the start of the crop anddecreased to a low level towards crop maturity.Non-hatching of eggs was of minor importance. Over thetotal duration of the egg stage, the averagedisappearance of exposed laboratory-laid eggs was40%, and of field-laid eggs 46%. Egg mortality dueto parasitism averaged 15% and 18%, respectively. Thepotential impact of egg parasitism is probably partlyobscured by the disappearance of parasitized eggs.Mortality rates were highly variable between eggcohorts, but with multiple regression analysis severalfactors were identified that statistically explaineda significant part of this variation. The resultssuggest that the predatory crickets Metiochevittaticollis and Anaxipha longipennis play amajor role in egg disappearance, and that eggparasitism is positively dependent on the overalldensity of host eggs of Trichogramma in thefield.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Joop C. van Lenteren, Arnold van Huis, Kong Luen Heong
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation
