Evaluation of commercially available herbicides for weed control in cassava

A trial was conducted in 2008/09 at Chitedze (31o 59' S; 33o 38' E) and Chitala (13o 40' S; 34o 15' E) Research stations in Malawi to evaluate commercially available pre-emergent herbicides for weed control in cassava (Manihot esculenta Crantz). Four herbicides, Bullet (chloroacetanilide, dimethanamid, triazine), Harness 90 EC (chloroacetanilide), Codal Gold 412-5 EC (prometryn and S-metolachlor) and Metalachlor 960 EC (S-metolachlor; acetamide), were evaluated with and without follow up hand-hoe weeding (check). Panicum maximum, Elusine indica, Rottboellia chochinchinensis and Setaria pumila were the common narrow-leaved weeds while Commelina benghalensis, Bidens pilosa, Nicandra physalodes and Acanthospermum hispidum were the common broad leaved weeds. Herbicide application did not affect crop establishment but significantly (P<0.001) reduced early weed growth by 74.8 to 91.2 % at Chitedze and 53.7 to 97.9 % at Chitala. Bullet was more effective in early weed control (2.8 weeds m-2 at Chitedze and 0.0 weeds m-2 at Chitala) than the other herbicides (38.7 weeds m-2 at Chitedze and 8.8 weeds m-2 at Chitala) and resulted in root yields (12.3 t ha-1 at Chitedze and 18.4 t ha-1 at Chitala) and returns (MK238,844.00 ha-1 at Chitedze and MK360,779.00 ha-1 at Chitala) comparable to or higher than hand weeding (root yield of 10.6 t ha-1 at Chitedze and 16.3 t ha-1 at Chitala and returns of MK2 0 1 , 4 3 8 . 0 0 h a - 1 a t Ch i t e d z e a n d MK310,448.00 ha-1 at Chitala) and other treatments (root yield of 2.2-13.1 t ha-1 at Chitedze and 1.3-23.6 t ha-1 at Chitala and returns of MK44,000.00 to MK249,078 at Chitedze and MK26,000.00 to MK465,100 ha-1 at Chitala), making it a potential alternative to hand hoe weeding in cassava

Effect of cassava leaf harvesting on root yield and quality

Cassava leaves are increasingly becoming an important source of nutrition for both human beings and livestock. A study was conducted at Chitedze Research Station, Malawi, to determine the effects of leaf harvesting on root yield and quality from 2003/04 to 2005/06 season. Two cassava varieties were used which included Mbundumali, a sweet variety with low potential for cyanogenic glucosides and widely grown by farmers; and Silira (TMS 60142B) an improved variety which is bitter, originated from IITA in tissue culture form and has high potential for cyanogenic glucosides. The experiment was laid out in a 2 x 3 x 2 factorial design in randomized complete block design replicated three times. Leaves were harvested using two methods of de-topping and ratooning while the leaves from the control were harvested at root harvest. Two fertilizer levels were used of which 92kg N per hectare were applied to some treatments and zero N to the others. Results indicated that leaf harvesting regardless of type of method used reduced cassava root yield, size, and dry matter content significantly (P<0.001). Ratooning method of cassava leaf harvesting produced the highest leaf biomass of about 25.0 tons fresh weight per hectare followed by de-topping (22 tons/ha) and control (9.0 ton/ha). An inverse relationship was observed whereby the more leaves were produced the less the root yield between. Mbundumali variety which has vigorous growth habits produced more leaf biomass and was least affected by leaf harvesting on root yield and dry matter content also

Cassava and sweetpotato yield assessment in Malawi

Cassava (Manihot esculenta Crantz) and sweetpotato (Ipomoea batatas Lam) are important food and cash crops in Malawi. However, key information regarding varieties grown, sources of planting materials, post-harvest handling, utilisation and tuber yields is lacking. A study was, therefore, conducted to source this information. Farmers grow mostly local varieties of cassava with own gardens as the main source of planting materials. Several varieties of sweetpotato are grown with Kenya (SPN/O, bred in Tanzania) as the most popular. Sprouts from previous season\'s gardens are the main source of planting materials. Cassava and sweetpotato are grown for food and cash. However, in some area cassava stems are used for fuel wood. Most farmers do not store fresh cassava roots but process them into makaka, kanyakaska and kadonoska, or sell them fresh. Processing for sweetpotato is limited to boiling and roasting. Most farmers store sweetpotato, but this is constrained by the sweetpotato weevil damage and rotting. Root yield ranged from 13.1 to 31.4 t ha-1 for cassava, and 10.2 to 14.0 t ha-1 for sweetpotato. Except for Nkhata Bay, the yields of both crops were much lower than from research stations. Unavailability of acceptable improved varieties, high incidence of pests and diseases, and poor cultural practices are the main causes of low yields in the targeted areasLe manioc (Manihot esculenta Crantz) et la patate douce (Ipomoea batatas Lam) sont des importants aliments et plantes génératrices de ressources en Malawi. Cependant, l\'information clé concernant les variétés plantées, les sources de matériels de plantation, les manœuvres post-récoltes, l\'utilisation et les rendements de tubercules manque. Une étude était alors conduite pour approvisionner cette information. Les fermiers cultivent souvent les variétés locales de manioc avec comme source principale de matériels de plantation leurs propres champs. Plusieurs variétés de patate douce sont cultivées au Kenya (SPN/O, conditionnée en Tanzanie) comme le plus populaire. Les germes des champs de saison précédente sont la source principale de matériels de plantation. Le manioc et patate douce sont cultivés pour la nourriture et l\'argent. Cependant, dans certaines aires les tiges de manioc sont utilisées pour le bois de chauffe. La plus part des fermiers n\'entreposent pas les racines de manioc frais mais transforment les en makaka, kanyakaska et kadonoska, ou les vendent frais. La transformation de la patate douce est limitée à l\'ébullition et au rôtissage. La plus part des fermiers entreposent la patate douce, mais ceci est gêné par les dégâts et les avaries des charançons. Les rendements de racines ont variés de 13.1 a 13.4 t ha-1 pour la patate douce. A l\'exception de laurier Nkhata, les rendements des toutes les deux cultures étaient plus bas que ceux des stations de recherche. La non disponibilité des variétés améliorées acceptables, l\'incidence élevée des pestes et maladies, et les pauvres pratiques culturales sont les causes principales de faibles rendements dans les aires visées

Economic losses experienced by smallscale farmers in Malawi due to cassava brown streak virus disease

Cassava is an important root crop in Malawi. It is the second most important food crop after maize. It is grown throughout the country as a food security crop, sack/cash crop, and as a staple food crop along the Lake Malawi. Is is a staple for over 39 % of the country&rsquo;s population. Farmers are not benefiting as much as they might from cassava because they are faced with a number of constraints. These include: - inherent low yielding and late maturing local cultivars - pests and diseases prevalent in the country - low promotion of good cultural practices. The major pests and diseases of cassava in Malawi are, cassava mosaic virus disease (CMD), cassava bacterial blight (CBB), cassava brown streak virus disease (CBSD), cassava green mite (CGM), cassava mealy bug (CM) and termites. The objective of this study was to determine the economic impact of CBSD on the farmers in Malawi where the disease is prevalent. The paper makes the following recommendations: - the cassava research organisations should mount urgent awareness campaigns of the disease and its management for both extension agents and farmers - the cassava research organisations should establish effective collaboration with the extension system on matters of proper cassava husbandry to effectively and efficiently control the disease - they should additionally carry out local collection exercises for cultivars that show CBSD disease resistance in the high disease pressure areas - there is an urgent need for cassava research and extension organisations to multiply cultivars and promising clones that have shown multiple disease resistance and that are widely accepted by farmers for distribution in the heavily affected areas - in collaboration with entrepreneurs, these organisations need to develop and strengthen sustainable seed multiplication and distribution systems as a way of assuring the provision of clean planting material

CH92/082 and TME 6 cassava clones officially released for farmer growing in Malawi

Cassava clones CH92/082, TME 6 and BA95/070 were evaluated against Mbundumali, Phoso, Mulola and Sauti as checks. These clones were evaluated at Makoka, Mkondezi, Baka and Kasinthula Research Stations that represented different agro ecologies and in Mzuzu ADD under farmers' conditions. The objective of cassava improvement programme in Malawi is to develop cassava varieties that are: high yielding per unit area of land; tolerant to major diseases (cassava mosaic disease and cassava brown streak disease) and pests (cassava green mite and cassava mealy bug), adaptable to local environmental conditions and acceptable by end-users

Contribution of SARRNET to food security in the SADC region

The Southern Africa Root Crops Research Netwrok (SARRNET), in collaboration with national research programmes in Southern Africa Development Community (SADC ) have made considerable impact in the SADC region in terms of promoting cassava (Manihot esculenta) and sweetpotato (Ipomea batatus) production and commercialization. Area under cassava and sweetpotato production has increased tremendously in some SADC countries since mid 1990s. This is attributable to research work on germplasm development where about 51 improved cassava and sweetpotato varieties have been released and made available to farmers through the accelerated plant material multiplication and distribution programmes that took place in at least 10 of the 14 SADC countries. SARRNET has also made great impacts in skill development and knowledge in root crops research for development in the SADC region through funding post graduate/graduate studies, short-term training courses, workshops and symposia. In its second phase which started in 1999, SARRNET shifted its strategy with more emphasis on market oriented research for development by promoting cassava and sweetpotato commercialization in the region. This has made these crops to play a significant role in the economic growth of the SADC countries. This paper presents the contribution of SARRNET on cassava and sweetpotato germplasm development, seed multiplication and distribution, cassava commercialisation, post harvest technologies, training, information and technology exchangeLe réseau de recherche du sud de l'Afrique en racines des plantes (SARRNET), en collaboration avec les programmes de recherche national des communautés de développement du sud de l'Afrique (SADC) ont rapporté des impacts considérables dans la région du SADC en termes de promotion de production de manioc (Manihot esculenta) et de patate douce (Ipomea batatus) et de commercialisation. Les aires sous production de manioc et patate douce ont énormément augmenté dans certains pays de SADC depuis mi 1990. Ceci est attribué au travail de recherche sur le développement du germplasme ou environ 51 variétés de manioc et patate douce améliorées ont été larguées et disponibilisées aux fermiers a travers les programmes accélérées de l'usine de distribution et de multiplication des matériels qui se sont tenu dans au moins 10 de 14 pays de SADC. SARRNET a aussi fait des grands impacts dans le développement d'habileté et de connaissance dans la recherche en racines des plantes pour le développement dans la région de SADC a travers des fonds d'études post graduat et de graduat, des cours de formation à court terme, séminaires et symposiums. Dans sa seconde phase qui a commencé en 1999, SARRNET a orienté sa stratégie avec plus d'insistance sur la recherche orientée au marché pour le développement par la promotion de la commercialisation du manioc et de la patate douce dans la région. Ceci a amené ces cultures à jouer un rôle significatif dans la croissance économique des pays de SADC. Cet article présente la contribution de SARRNET sur le développement de germplasme du manioc et de la patate douce, la multiplication et distribution des semences, la commercialisation du manioc, les technologies de post culture, la formation, l'échange de l'information et de la technologie