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Lepidopteran stemborers are amongst the most important insect pests of maize, sorghum and sugarcane in sub-Saharan Africa. With the exception of Chilo partellus (Swinhoe), which was accidentally introduced into Africa, the other stemborer pests are indigenous to the continent and have co-evolved with native grasses and sedges. In addition to pest species, wild habitats harbour diverse non-economic stemborer species, some of which are new to science. However, the diversity and distribution of both non-economic and pest species of stemborer are currently mostly unknown in Botswana. Accordingly, country-wide surveys were conducted during 2014/15 and 2015/16 austral summer to determine species diversity and distribution in cultivated and wild host plants of stemborers in Botswana. A total of 1597 stemborer larvae and 228 pupae were collected, constituting 63.1 and 36.9 larvae and 84.8 and 15.2% pupae from cultivated versus wild habitats, respectively. In addition to C. partellus, Sesamia calamistis Hampson and Eldana saccharina Walkerwhich were previously reported, 12 more stemborer species were recorded for the first time in Botswana, including nine undescribed species. These species were from the Sciomesa, Sesamia and Conicofrontia genera and Tortricidae and Pyralidae families. Fourteen wild host and two cultivated host plant species of stemborers were recorded. Chilo partellus was most abundant (89.5%) in cultivated habitats whilst E. saccharina (33.6%) was most abundant in wild habitats. Stemborer species diversity was higher in wild habitats than cultivated. Current results highlight the significance of wild, especially wetland habitats for ecological functions and conservation of lepidopteran stemborer biodiversity.

Lepidopteran stem-borers in Africa are attacked by diverse natural enemies in natural and cultivated environments. Field surveys of stem-borer natural enemies and associated host plants were conducted during the austral summers of 2014/15 and 2015/16 on natural and cultivated habitats across Botswana to determine their diversity and relative abundance. In cultivated habitats, the most common parasitoids of larvae were Cotesia flavipes Cameron, C. sesamiae (Cameron), and of pupae, Pediobius furvus Gahan and Gambroides nimbipennis Seyrig. In natural habitats, the larval parasitoids Chelonus curvimaculatus Cameron and Goniozus indicus Ashmead were recorded, along with the pupal parasitoid, Dentichasmias busseolae Heinrich. Furthermore, the predatory ants Linepithema humile Mayr, Crematogaster peringueyi Emery and Aenictus species were recorded in both cultivated and natural habitats. The major cultivated plants hosting stem-borers and related natural enemies were maize, sorghum, sweet sorghum, and the major wild plants were Echinochloa pyramidalis, Typha latifolia, Schoenopkctus corymbosus and Cyperus dives. Chilo partellus Swinhoe and Sesamia spp. were the major hosts for parasitoids, with C. partellus predominating in cultivated habitats and Sesamia jansei Tams & Bowden in natural habitats. Larval parasitism ranged from 2.1 to 34.7% and 3.3 to 14.3% in cultivated and natural habitats respectively, whereas pupal parasitism ranged from 6.1 to 10.6% and 6.7 to 9.1%, respectively. Parasitoid percentage abundance ranged from 1.1 to 41.6% and 4.8 to 38.1% in cultivated and natural habitats respectively, with C. flavipes dominating in cultivated and C. curvimaculatus in natural habitats. Our results show that cultivated and natural environments in Botswana harbor a diverse natural enemy community worthy of conserving for stem-borer biological control.

Participatory, mixed-methods research was conducted to study the role of sugarcane in small-scale sugarcane farmers’ livelihoods in the Noodsberg area, KwaZulu-Natal. Thirty-five farmers were visited at their homes and data was collected through semi-structured interviews, participatory sketch mapping, matrix scoring activities and informal field-based discussions. Results indicated that sugarcane was a key livelihood resource providing employment and income, and it generated more income than any other single agricultural enterprise. It was considered the most important crop in most households, even though it was grown within a diverse agricultural system including maize, beans, taro (amadumbe) and potatoes. Considering the important role of sugarcane as a cash crop in farmers’ livelihoods, further development of land to sugarcane in the Noodsberg area will continue to reduce poverty and improve the livelihoods of farmers.Keywords: farming systems, food security, poverty, rural development, small-scale growers, sugarcane.

Surveys to investigate the distribution and abundance of stem borers in natural habitats were conducted in February 2006 and January-February 2007. The surveys included eastern, northern and central parts of South Africa as well as three localities in Lesotho. During the surveys, Eldana saccharina Walker was recovered from three new localities in inland South Africa and two new indigenous hosts, Phragmites australis Cav. and Panicum maximum Jacq. from Boskop in the North-West Province and Oribi Gorge in KwaZulu-Natal respectively. Populations of E. saccharina in different parts of Africa are known for their differences in larval feeding behaviours, host plant choice and natural enemies. It is important to understand the origin of the newly recovered population for prevention of incursion and efficient management in case it invades crops. Molecular analysis indicated that the populations recovered in these new locations and from the new host plants are part of the southern African population of E. saccharina. With change in climate, and disturbance in wetlands the insect is expected in the future to be more abundant and problematic in inland areas of southern Africa.