Occurrence, biology, natural enemies and management of Tuta absoluta in Africa
Entomologia Generalis · 2018
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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.
First Report of Outbreaks of the Fall Armyworm Spodoptera frugiperda (J E Smith) (Lepidoptera, Noctuidae), a New Alien Invasive Pest in West and Central Africa
The fall armyworm Spodoptera frugiperda is a prime noctuid pest of maize on the American continents where it has remained confined despite occasional interceptions by European quarantine services in recent years. The pest has currently become a new invasive species in West and Central Africa where outbreaks were recorded for the first time in early 2016. The presence of at least two distinct haplotypes within samples collected on maize in Nigeria and São Tomé suggests multiple introductions into the African continent. Implications of this new threat to the maize crop in tropical Africa are briefly discussed.
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.