Session VII Management of biotics stresses for sustainable intensification of root and tuber crops Lead lecture Bellotti, A. Crop- insect interaction using cassava as a model: The road ahead Oral presentation Alcazar, Jesus Plastic barriers control Andean potato weevils (Premnotrypes spp.): Large-scale testing of efficacy, economic and ecological evaluation and farmers’ perception Canedo, Verónica How do insecticides affect potato yield and ecosystem resilience to potato pest outbreaks? An ecological assessment from the central highlands of Peru Fontem, Dominic Impact of plant extracts and organic amendments on the growth of Ralstonia solanacearum and severity of potato bacterial wilt Oswald, Andreas Using rhizobacteria to improve productivity of potato Maharjan , Raneswor Pesticide use practices and awareness among potato growers in Nepal Perez, Wilmer Control of potato late blight with foliar application of phosphonate Kadian, Mohinder Early maturing late blight resistant potato varieties for cereal based system of sub-tropical Indo-Gangetic Plains Demo, Paul Performance of CIP-derived population B3 potato (Solanum tuberosum L.) clones under Malawi conditions Schaub, Birgit Phenology modeling and regional risk assessments for Tecia solanivora Andrade, Maria Need of breeding orange fleshed sweetpotato for drought prone regions – using Mozambique as drought prone test environments Attaluri, Sreekanth Performance of orange-fleshed sweetpotato genotypes in different agro-ecological regions of India Bechoff Aurélie Understanding losses of provitamin A after drying and storage of orange-fleshed sweetpotato (Ipomea batatas) Cuellar, Wilmer Molecular studies on the Sweetpotato virus disease (SPVD) Labarta Ricardo A. The introduction of the orange fleshed sweetpotato on the agricultural farming system of central Mozambique: the Opportunity cost of growing this nutritious crop Stevenson, Philip Reduced oviposition and feeding on the root surfaces of sweetpotato by Cylas puncticollis and C. brunneus caused by the presence of hexadecylesters of coumaric caffeic acid Cosio, Eric Fast analysis of maca bioactive compounds for ecotype characterization and export quality control Gonzales, Patricia Crop protection by volatile organic compounds from mashua: what we can learn from ancient agricultural techniques Posters Calvo, Pamela Microbiotic biodiversity and their functionality in roots and rhizosphere of potato plants Quiroz, Roberto Assessing Potato Yellow Vein Virus (PYVV) infection using remotely sensed data and multifractal analysis Manrique, Kurt Muña (sp. Minthostachis mollis) essential oil, as a natural alternative to control potato sprouting tested under different storage conditions Gamarra, Heydi Potato yellow vein virus: A model for emerging potato diseases and climate change Gamboa, Soledad Monitoring changes in Phytophthora populations in developing countries using microsatellites and the Phytophthora.exe database Schulte-Geldermann, Effect of suppressive composts and initial seed tuber infection on Elmar Rhizoctonia solani in organic potato production Kakuhenzire, Rogers Relationships among late blight epidemic descriptors and use of planting date as a disease escape strategy in the potato farming system of south western Uganda Gomez, Luis A PCR-RFLP assay for detection of Pythium myriotylum, the causal agent of cocoyam root rot disease Sharma, Kamal Molecular characterization of Colletotrichum gloeosporioides responsible for anthracnose of yam and cassava in Nigeria, and development a diagnostic PCR assay Maharjan , Rameswor Efficacy of botanicals against the potato tuber moth (Phthorimaea operculella) in Farmer's potato storerooms in Nepal and Bhutan Mujica, Norma Temperature-dependent development of three parasitoids of the leafminer fly Liriomyza huidobrensis Raymundo, Rubi Estimating potential impact of potato late blight resistant varieties in China with GIS Fuentes, Segundo Molecular variability of sweet potato feathery mottle virus and other potyviruses infecting sweet potato in Peru Fuentes, Segundo Bemisia afer sensu lato, a vector of sweet potato chlorotic stunt virus Korieocha, D.S Effect of time of herbicide application and sweetpotato morpho- typesmon the effectiveness of herbicide on weeds Korada , Rajasekhara Organic management of corm borer Haplosonyx chalybaeus (Hope) - A Rao Serious insect pest of colocasia in North Eastern India Picado, Ivania Phylogenetic analysis of Pythium myriotylum isolates from cocoyam and other host crops based on cytochrome oxidase I & II and -Tubulin gene sequences Sporleder, Marc ILCYM- Insect Life Cycle Modeling: Software for developing temperature-based insect phenology models with applications for regional and global pest risk assessments and mapping Kowalski, Britta Soluble chitosan applied as potato seed tuber treatment and foliar sprays under subtropical and temperate conditions-effect on yield parameters and disease incidence Plastic barriers control Andean potato weevils (Premnotrypes spp.): large-scale testing of efficacy, economic and ecological evaluation and farmers’ perception Jesús Alcázar and Jürgen Kroschel International Potato Center (CIP), Apartado 1558, Lima 12, Peru. [email protected] Abstract Andean potato weevils (Premnotrypes spp.) are key potato pests in the Andes. Insecticides are the most widely used control method employed by farmers. Recently, plastic barriers at field borders proved to stop the migration of flightless Andean potato weevil (Premnotrypes suturicallus) adults to potato fields and have been equally effective compared to farmers’ practice of using insecticides. The objectives of this study were to further validate the efficacy of this technology in two Andean villages with the participation of 40 farmers, to evaluate costs and environmental impact compared to insecticides, and to assess farmers´ perception and preparedness to use this technology. Plastic barriers effectively reduced Andean potato weevil damage by 65% and 70% in the two villages compared to farmers´ practice using 2 to 6 insecticide applications. Plastic barriers proved to be also effective to control other weevil species, such as P. solaniperda, P. latithorax and P. vorax in potato agroecologies of Peru, Bolivia and Ecuador. The use of plastic barriers resulted in an excellent investment with mean net benefits of US$147/ha and US$807/ha for farmers of the two villages. The environmental impact quotient (IEQ) was five times lower for the plastic barriers (32.86) compared to farmers’ practice (191.52) indicating the overall benefits of the technology to reduce the risks of insecticide applications for farmers, consumers and the environment. Farmers’ opinion was very positive with more than 90% of interviewed farmers considering plastic barriers as a very useful and easy-to-install control tool, and interested to further promote this technology among other farmers. Keywords: Potato, Integrated Pest management, Andean potato weevil, Premnotrypes suturicallus, physical control. Introduction Andean potato weevils (Premnotrypes spp.) are native in the Andean region and the most important pests of potato (Solanum spp.) at altitudes between 2,800 and 4,750 m. The species are widespread from Argentina to Venezuela covering a mountainous territory of a length of 5,000 km. The most severe crop damage is caused by larvae which feed on tubers and cause tuber infestations and losses of up to 100%, if no control measures are applied. Main control measures used by farmers are the application of hazardous insecticides (Ewell et al. 1990, Orozco et al. 2009). Adults of Andean potato weevils are flightless and hence migrate from previous years potato fields to new potato production sites. Recently, a new technology using physical barriers around potato fields have been successfully tested to control Andean potato weevil Premnotrypes suturicallus Kuschel (Kroschel et al. 2009). The objective of this study was to validate the plastic barrier technology with a large number of farmers in two Andean villages in comparison to farmers’ traditional practices of using several insecticide applications to control Andean potato weevil, and to study their economics and environmental impacts compared to insecticide applications. Additionally, we studied farmers’ perception about the use of plastic barriers in one Andean village, which was involved in the evaluation and use of the plastic barriers for several years. Materials and methods Large scale validation of the plastic barrier technology The study was carried out in the villages Ñuñunhuayo (3,800 m a.s.l., Department of Junin, Peru) and Aymara (3,900 m a;.s.l., Department of Huancavelica, Peru) with a participation of 20 farmers in each of the communities. Participating farmers established subplots in their potato fields of a size of 225 m2 (15 x 15 m), which were surrounded by a plastic barrier at the day of planting. The plastic was fixed on wooden stakes and installed 10 International Society for Tropical Root Crops (ISTRC) 3 cm below soil with a total height of 50 cm above soil as described in Kroschel et al. (2009). Except of the plastic to prepare the barriers all other inputs (seed, fertilizer) were provided by farmers. Further, farmers were equally responsible for all cultural labors (weeding, hilling). In the plastic barrier plots no insecticides were applied but fungicides Cymoxanil for controlling late blight (Phytophtora infestans Mont. De Bary), when considered appropriate. Potatoes grown outside of the plastic barriers received