Abstract:

The biology, host specificity and impact of Dichrorampha odorata (Lepidoptera: Tortricidae), a potential biological control agent of Chromolaena odorata (Asteraceae)

N Dube1, C Zachariades1,3 , M Whitwell2

1Agricultural Research Council, Plant Protection Research Institute,
Private Bag X6006, Hilton, 3245, South Africa
2Department of Agriculture, and Environment Affairs,Private Bag X9059, Pietermaritzburg, 3200, South Africa
3School of Biological and Conservation Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa

Chromolaena odorata (Asteraceae) is a shrub native to South and Central America which has invaded a wide variety of ecosystems, including protected areas in KwaZulu-Natal. Because it is so damaging and expensive to control through conventional means, it has been targeted for biological control. Among other biological control agents, Dichrorampha odorata (Lepidoptera: Tortricidae), a moth whose larvae bore into the shoot tips of C. odorata, and thereby stop growth of the stems, has also been considered recently. This study was aimed at determining if D. odorata is a suitable candidate to complement two leaf-feeding biocontrol agents that are already established on C. odorata in KwaZulu-Natal. Laboratory trials were set up to determine (i) biology: adult fecundity, fertility and longevity, and immature developmental stages, (ii) host specificity: larval no-choice trials, and (iii) impact. Host-specificity tests indicate that D. odorata is highly specific to C. odorata. The moth is multivoltine, scatters its eggs along the veins of the leaves of the host plant and has a high rate of increase, which should facilitate a rapid population build-up and spread once released as a biocontrol agent in the field in South Africa.  A decrease in plant height and therefore competitiveness, and flower reduction, caused by D. odorata may contribute to the success of biological control of C. odorata.

Presentation Topic

The biology, host specificity and impact of Dichrorampha odorata (Lepidoptera: Tortricidae), a potential biological control agent of Chromolaena odorata (Asteraceae)

 

Contact Ms Dube:

Agricultural Research Council, Plant Protection Research Institute, Private Bag X6006, Hilton, 3245, South Africa

 

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