In a study in KwaZulu-Natal, South Africa high levels of parasitism of Busseola fusca pupae by the parasitoid Procerochasmias nigromaculatus (Cameron) (Ichneumonidae) were recorded. Up to 100% parasitism was recorded in the middle of the growing season, during February-March, and 80% during November, when borer larvae which had terminated diapause were parasitised after pupation. Larval parasitism mainly by Cotesia sesamiae, which was reared from about 87% of parasitised larvae, peaked at 75% during January. Despite the high parasitism levels by these parasitoids they did not prevent economically significant damage.

In addition the following parasitoids were also recorded from Busseola fusca in South Africa: the egg parasitoids Telenomus busseolae Gahan (Scelionidae) and Trichogrammatoidea lutea Girault (Trichogrammatidae); the larval parasitoids Aleiodes sp. (Braconidae), Bracon sesamiae Cameron (Braconidae), Chelonus curvimaculatus Cameron (Braconidae), Stenobracon (=Euvipio) sp. (Braconidae), Glyptapanteles maculitarsis (Cameron) (Braconidae), Habrobracon brevicornis (Wesmael) (Braconidae), Iphiaulax sp. (Braconidae), Palexorista sp. (Tachinidae), Paradrino halli Curran (Tachinidae), Sarcophaga sp. (Sarcophagidae), Temelucha sp. (Ichneumonidae) and Odontepyris transvaalensis (De Buysson) (Bethylidae); the pupal parasitoid Pediobius furvus Gahan (Eulophidae), and the hyperparasitoids Aphanogmus fijiensis (Ferrière) (Ceraphronidae) which attacks C. sesamiae cocoons, and Eurytoma braconidis Ferrière (Eurytomidae) which attacks Stenobracon sp. and H. brevicornis.

In the North-West Province of South Africa, peaks of up to 100% parasitism were recorded on Chilo partellus pupae every year in several consecutive growing seasons during the second part of January and the first part of February. The most abundant pupal parasitoids were the solitary Dentichasmias busseolae and the gregarious Pediobius furvus. Occasionally, Conomorium sp. (Pteromalidae), was also reared from field-collected pupae of Chilo partellus. Larval parasitoids were active throughout the growing season on maize and grain sorghum. Parasitism oscillated around 10% with occasional peaks of 20-30%. The most abundant larval parasitoid of Chilo partellus was Cotesia sesamiae. This parasitoid was active throughout the season and was reared from about 93% of all parasitised larvae. The hyperparasitoid, Aphanogmus fijiensis, was frequently reared from field-collected Cotesia sesamiae cocoons, sometimes reaching 50-100% parasitism in autumn. Other larval parasitoids that attacked C. partellus were Iphiaulax sp., the egg-larval parasitoids, Chelonus curvimaculatus, and Chelonus sp., Bracon sp., Norbanus sp. (Pteromalidae), Pristomerus sp. (Ichneumonidae) and Palexorista sp. (Tachinidae) The hyperparasite, Eurytoma sp., was reared from field collected cocoons of Iphiaulax sp. on several occasions. During winter, parasitism of diapausing C. partellus larvae was very low. Two parasitoids, C. sesamiae and Bracon sp. were observed to be active during winter. Three parasitoids, Chelonus curvimaculatus, Chelonus sp. and Pristomerus sp. diapaused in synchrony inside the larvae, and Iphiaulax sp. diapaused in its own cocoon inside the dry stalks.

All the above parasitoids are indigenous to Africa and their association with the exotic C. partellus is relatively new. These parasitoids usually develop on other indigenous Lepidoptera and they moved from their indigenous hosts to utilize C. partellus as a new alternative host. Although larval and pupal parasitoids are playing an important role in reducing the population levels of C. partellus, they are not able to reduce it to below economic damage levels. The parasitoids could not prevent the dispersal and subsequent wide distribution of C. partellus after its introduction into Africa.


The ant, Dorylus helvolus (L.) and the mouse, Mastomys natalensis (Smith) were found to be the dominant predators of stem borers in maize and grain sorghum in South Africa. Other predators in descending order of importance were Cardiophorinae larvae, the doryline ant Aenictus sp., larvae of Astylus atromaculatus Bl. (Coleoptera: Melyridae), tenebrionid larvae, larvae and adults of Heteronychus arator F., carabid larvae, staphylinids and Dermaptera.


Stem borer pathogens in southern Africa have received very little attention. High winter mortality of hibernating B. fusca larvae was recorded. As low activity by stem borer parasitoids was recorded in winter, this mortality could be partially attributed to pathogens. A microsporidium, Nosema partelli Walters & Kfir (Protozoa: Microsporidia: Nosematidae), was recorded in C. partellus in South Africa. In addition, a recent survey of pathogens conducted in South Africa revealed the following pathogens identified from cadavers of B. fusca: cytoplasmic polyhedrosis virus, granulosis virus, nuclear polyhedrosis virus, the entomopathogenic fungi Beauveria bassiana (Balsamo) (Fungi imperfecti) and Entomophthora sp. (Phycomycetes), the bacteria Serratia marcescens Bizio (gram-negative facultative anaerobic pathogen, non-sporeformer) and Bacillus thuringiensis Berliner (endospore-forming rods and cocci, obligate pathogen), and the microsporidium Nosema sp. From cadavers of C. partellus cytoplasmic polyhedrosis virus, entomopox virus, the fungi Beauveria bassiana, Entomophthora sp. and Aspergillus sp. (Fungi imperfecti) the bacteria Streptococcus sp. (gram-nagative cocci), Serratia maecescens and Bacillus thuringiensis and the microsporidium Nosema partelli were isolated.