Insect Resistance and Genetics

Biology and Management of Economically Important Lepidopteran Cereal Stem Borers in Africa

Cereals (maize, sorghum, millet, rice) are extremely important crops grown in Africa for human consumption. Of the various insect pests attacking cereal crops in Africa, lepidopteran stem borers are by far the most injurious. All 21 economically important stem borers of cultivated grasses in Africa are indigenous except Chilo partellus, which invaded the continent from India, and C. sacchariphagus, which has recently been found in sugarcane in Mozambique. C. partellus is competitively displacing indigenous stem borers in East and southern Africa. A parasitoid, Cotesia flavipes, was introduced from Pakistan for biological control of C. partellus and caused a 32-55% decrease in stem borer densities. This article is an attempt to summarize the status of knowledge about economically important cereal stem borers in Africa with emphasis on their distribution, pest status and yield losses, diapause, natural enemies, cultural control, host plant resistance, and biological control. Special attention is given to Busseola fusca and C. partellus, the most important pests of maize and grain sorghum.

Invasiveness, biology, ecology, and management of the fall armyworm, Spodoptera frugiperda

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Occurrence, biology, natural enemies and management of Tuta absoluta in Africa

International audience

A Review of the Biology and Control of Whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), with Special Reference to Biological Control Using Entomopathogenic Fungi

Whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), consists of genetically diverse species known to cause significant destruction in several crops around the world. Nymphs and adults of B. tabaci cause damage to plants during feeding, and they can act as a virus vector, thus causing significant yield loss to crops in the tropical and subtropical regions. Chemical pesticides are widely used to control B. tabaci due to their immediate action, but this approach has several drawbacks including food safety issues, insecticide resistance, environmental pollution, and the effect on non-target organisms. A biological control agent using entomopathogenic fungi (EPF) has therefore been developed as an alternative against the conventional use of chemical pesticides in an integrated pest management (IPM) system to effectively control B. tabaci. It is apparent from this review that species of hyphomycetes fungi are the most common EPF used to effectively control B. tabaci, with the second instar being the most susceptible stage of infection. Therefore, this review article focuses specifically on the control of B. tabaci with special emphasis on the use of EPF as biological control agents and their integration in IPM.

Comparative Biology of two Phycitid Moths, Plodia Interpunctella (Hubn.) and Ephestia Cautella (WLK.) on some Selected Food Media

The Biology and Ecology of Busseola fusea and Sesamia Species in South-Western Nigeria. I. Distribution and Population Studies

The distribution of maize stem borers, Busseola fusca Fuller, Sesamia calamistis Hampson, and S. penniseti Bowden, throughout south-western Nigeria was studied between November and December 1964. The maize-sample survey revealed that B. fusca was more abundant than S. calamistis. While B. fusca was prevalent in the southerly, more humid lowland rainforest zones, S. calamistis was generally distributed and was more prevalent in the dry savanna zones of the region. S. penniseti was not abundant and was very sparsely distributed. There was a marked difference in the position of egg masses on the maize plants. All egg masses of B. fusca were laid within 30 inches of the maize whorl, while S. calamistis egg masses were spread over greater distances from the whorl. This distribution appears to be associated with the larval habits of both B. fusea and S. calamistis. Larval populations studies revealed that in lbadan (and probably south-western Nigeria) there are 4 generations of B. fusca in maize per annum. There are 2 generations between April and July, 1 in September-October, and another in November. It is the larvae of the November generation which go into the dry-season diapause and which later give rise to the 1st-generation adults the following year. S. calamistis,, although not so numerous as B. fusca, was observed to breed throughout the year.