Effect of sowing dates and fertilizer on the severity of stem borer (Busseola fusca Fuller, Lepidoptera: Noctuidae) on sorghum in Eritrea

AbstractThis study was conducted in the humid forest zone of Cameroon, in 2002 and 2003. The main objective was to investigate the effects of intercropping on infestation levels and parasitism of the noctuid maize stem borer Busseola fusca Fuller. Two trials were planted per year, one during the long and one during the short rainy season. Maize monocrops were compared with maize/legume or maize/cassava intercrops in two spatial arrangements: maize on alternate hills or in alternate rows. Spatial analyses showed that the stemborer egg batches were regularly dispersed in the maize monocrop and aggregated in the intercrops, as indicated by b, the index of dispersion of Taylor's power law. Depending on the crop association and planting pattern, intercrops reduced the percentage of plants with stem borer eggs by 47.4–58.4% and egg densities by 41.2–54.5% compared to monocropped maize. Consequently, larval densities were 44.4–61.5% lower in intercrops compared to monocrops. Intercropping maize with non-host plants did not affect larval parasitism. Up to two-fold higher levels of egg parasitism by scelionid Telenomus spp. were recorded in inter- compared to monocrops during the short rainy seasons of 2002 and 2003. No differences were found among the mixed cropping treatments and parasitism was lower during the long compared to the short rainy seasons. It was proposed that differences in levels of parasitism were due to density dependence effects rather than the effect of the presence of non-host plants in the system.

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Parasitoids of the African stem borer, Busseola fusca (Lepidoptera: Noctuidae), in South Africa

Bulletin of Entomological Research ◽

10.1017/s0007485300036105 ◽

1995 ◽

Vol 85 (3) ◽

pp. 369-377 ◽

Cited By ~ 37

Author(s):

Rami Kfir

Keyword(s):

South Africa ◽

Busseola Fusca ◽

Stem Borer ◽

Ratoon Crop ◽

Larval Parasitoids ◽

Larval Parasitoid ◽

Pupal Parasitoids ◽

Pupal Parasitism ◽

Lepidoptera Noctuidae ◽

Trichogrammatoidea Lutea

AbstractEighteen parasitoids were recorded from the African stem borer, Busseola fusca (Fuller), on maize and grain sorghum, in Delmas and Cedara, South Africa. In Delmas, larval parasitism on both crops fluctuated below 20% with occasional peaks of 40–60%. In Cedara, larval parasitoids were active throughout the season with peaks of 75% and 60% parasitism during January and March-April, respectively on the ratoon crop, and 20% in May on the crop. Pupal parasitism peaked in Cedara at 100% during February-March, and at 80% during November, when parasitoids attacked pupae that formed after B. fusca larvae had emerged from diapause and pupated. In Delmas activity by pupal parasitoids was negligible. The egg parasitoids, Telenomus busseolae Gahan (Hymenoptera: Scelionidae) and Trichogrammatoidea lutea Girault (Hymenoptera: Trichogrammatidae), were rare. The larval parasitoid, Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae), was active throughout the season and was by far the most abundant, emerging from about 90% of parasitized larvae. Its cocoons were often attacked by Aphanogmus fijiensis (Ferrière) (Hymenoptera: Ceraphronidae). Second in abundance among the larval parasitoids was Bracon sesamiae Cameron (Braconidae) whose cocoons were attacked in turn by Eurytoma braconidis Ferrière (Hymenoptera: Eurytomidae). Eurytoma braconidis was reared also from cocoons of Euvipio sp. and Aleiodes sp. (both Braconidae). All other larval parasitoids were rare. Procerochasmias nigromaculatus (Cameron) (Hymenoptera: Ichneumonidae) was the most abundant pupal parasitoid. Trichogrammatoidea lutea, Glyptapanteles maculitarsis (Cameron) (Braconidae) and Odontepyris transvaalensis (De Buysson) (Hymenoptera: Bethylidae) have not been recorded before from B. fusca. Some considerations and proposals for introductions of parasitoids into South Africa against B. fusca are discussed.

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