M. Kenis, D. Cugala

Prospects for the biological control of the groundnut leaf miner, Aproaerema modicella, in Africa.

Abstract:

The groundnut leaf miner, Aproaerema modicella, is a pest of groundnut and soybean in South and southeast Asia that has recently invaded Africa. It was first found in Uganda in 1998 and is now recorded in Mozambique, Malawi, Democratic Republic of Congo and South Africa. In all African countries where A. modicella has been found, the pest has reached outbreak densities and severe yield losses have been observed on groundnut. In this paper, we review the natural enemies of A. modicella in Asia and evaluate their potential for biological control in Africa. The main natural enemies of A. modicella in Asia are parasitoids. Over 30 primary parasitoid species have been recorded with mean parasitism rates fluctuating between 20 and 50% and peak parasitism reaching 53-91%. The most often cited parasitoids belong to the genera Goniozus (Hym.: Bethylidae), Apanteles, Bracon, Chelonus and Avga (Hym.: Braconidae), Brachymeria (Hym.: Chalcididae), and Stenomesius, Sympiesis and Tetrastichus (Hym.: Eulophidae). Predators and pathogens have been poorly studied. A. modicella is a promising target for classical biological control using natural enemies from Asia. Damage levels are, on average, higher in Africa than in Asia, where parasitoids and possibly predators and pathogens, probably play an important role in the natural control of the pest. However, surveys are needed in Asia to better study natural enemies of A. modicella before selecting the most suitable agents. Until now, most studies on natural enemies were carried out in India, where A. modicella is considered a serious pest. New surveys should focus on other regions, where the moth causes little damage and very little is known on its natural enemy complex.