Six sweetpotato breeding lines, ‘NASPOT 1 (‘Namulonge Sweetpotato 1 ), ‘NASPOT 2 , ‘NASPOT 3 , ‘NASPOT 4 , ‘NASPOT 5 , and ‘NASPOT 6 , were approved for release by the Ugandan Plant Variety Release Committee in Feb. 1999. This is the second lot of sweetpotato cultivars to be officially released by the sweetpotato program in Uganda, the first being released in 1995 (Mwanga et al.,2001). All six cultivars have good storage root shapes, high dry matter content, excellent consumer acceptance (Tables 1 and 2), moderate to high levels of field resistance to sweetpotato virus disease (SPVD), and high storage root yields compared to the average national root yield of 4 t·ha (International Potato Center, 1999). The release of these six cultivars provides consumers and farmers with improved quality sweetpotatoes of white, yellow, and orange flesh color.

Trapping experiments were carried out in Uganda with decyl (E)-2-butenoate and dodecyl (E)-2-butenoate, previously identified as components of the female sex pheromones of the African species of sweetpotato weevil, Cylas puncticollis and C. brunneus, respectively. In four on-station trials of season-long mass-trapping of both species of weevil in 0.5ha sweetpotato plots with 100 jerry can trapsha−1 (50traps for each species placed alternately), populations of male weevils were reduced by up to 89%, compared to un-trapped control plots. However, no differences in tuber infestation levels were recorded between mass-trapped and untreated control plots, and no differences in the proportions of female weevils that were mated were observed.

A trial was carried out in Uganda for the control of sweetpotato weevils, Cylas puncticollis and C. brunneus, by mating-disruption using the synthetic sex pheromone of C. brunneus formulated in PVC resin dispensers. Almost no C. brunneus males were caught in pheromone traps in the treatment plot, whereas catches in the control plot ranged up to 30 weevils per trap over each two-night monitoring period. Suppression of C. puncticollis catches was weaker. Mating of C. puncticollis was significantly suppressed on one sample date, 18 weeks after planting, but not on two subsequent occasions, at 19 and 33 weeks. Yields of roots in the two plots were similar, but root infestation was lower in the plot treated with pheromone on four out of five sample harvest dates, from 17 to 36 weeks after planting.

Studies were carried out in the field at Serere Agricultural and Animal Production Research Institute (SAARI), Eastern Uganda, to establish whether the existing sweetpotato germplasm in Uganda has cultivars resistant to the sweetpotato weevils, Cylas spp. The trials were conducted during the two growing seasons of 1997. Root size was the only sweetpotato rooting characteristic that significantly influenced tuber infestation (P=0.009) and damage (P=0.049). Root size was positively correlated to tuber infestation by Cylas spp. (Y=0.0456x + 21.206; R2 = 0.2731) and negatively correlated to damage by Cylas weevils (Y=-0.027x + 29.684, R2=0.1647). A laboratory study demonstrated the effect of temperature on oviposition, survival and developement of Cylas puncticollis (Boheman). The variety 'Tanzania' that was used as the susceptible check registered the highest weevil emergence under both wet and dry weather conditions while varieties 'Kasira' and 'Akere-Ikokolak' registered the least emergence of adult C. puncticollis. These results indicate that the latter two varieties posses considerable levels of resistance to sweetpotato weevils. Key Words: Germplasm, resistance, sweetpotato weevils, Uganda (African Crop Science Journal 2001 9(1): 165-174)

Bwanjule', 'New Kawogo', 'Tanzania', and 'Wagabolige' are superior Ugandan farmers' cultivars selected from a collection of 380 landrace accessions assembled at Namulonge Agricultural and Animal Production Research Institute (NAARI) in 1987 and subsequently evaluated in trials at NAARI and elsewhere in Uganda.Pedigrees of these landrace cultivars are not known, but they are assumed to be chance seedlings selected by farmers.On the basis of numbers of landrace cultivars, and the adaptation of these cultivars to local conditions, including diseases and pests, eastern Africa is considered to be a secondary center of sweetpotato genetic diversity.'Sowola', designated NIS/90/389a during testing, is a seedling selection from the sweetpotato breeding program at NAARI, and was selected from bulked seed from a polycross of 18 parents made from 1989 to 1990.The progenitors in this polycross block were popular farmers' cultivars from various parts of Uganda as follows: 'Odeyo cani', 'Bwom dege', and 'Cwara opoko', from Gulu District; 'Tanzania', from Soroti District; 'Siliki', 'Mpaeifumbiro', and 'Wagabolige', from Jinja District; 'Katalaako', from Iganga District; 'Tororo 1', 'Tororo 2', and 'Tororo 3', from Tororo District; 'Nylon', 'Bugerere', 'Sukali', and 'Mwezigumu' from Nakasongola District; and 'Nantongo', 'Kawogo', and 'Mwezigumu' from Mpigi District.Because of the open-pollinated and bulk nature of the seed population, the pedigree of 'Sowola' is not known.At the time of official release, 'Bwanjule' and 'Wagabolige' were of localized importance in their areas of original collection in Uganda, and 'New Kawogo' and 'Tanzania' were already widely grown by Ugandan farmers.'New Kawogo' is the predominant cultivar grown in the tall grassland agroecological zone near Kampala.'Tanzania' is a commercially important cultivar widely grown in the drier northeastern districts of Kumi and Soroti.On the basis of morphological characteristics,

The species range, activity and relative abundance of parasitoids attacking the sweetpotato butterfly, Acraea acerata Hew. (Lepidoptera: Nymphalidae) in Uganda was investigated. Samples of eggs and larvae of the sweetpotato butterfly were collected from some of the major sweetpotato growing districts of Uganda to identify the range of parasitoids in the country. Monthly surveys to collect samples of caterpillars from selected sites were also carried out to evaluate percentage parasitism over time. The collected samples were reared in the laboratory for parasitoid emergence. Results showed that the sweetpotato butterfly is attacked by three larval parasitoid species in Uganda, namely, Meteorus sp. (AKW), Charops sp. (AKW) and Caricelia normula Wyatt. No parasitoids emerged from eggs, indicating an absence of egg parasitoids. Charops sp. was the most abundant parasitoid species at all sites, Meteorus sp. had moderate occurrence, while C. normula was the least abundant. Percentage parasitism was found to be rather low to afford significant control on its own. Nevertheless, long term impact of parasitoids is important in moderating pest population dynamics. It is, therefore, important to conserve the native natural enemies by avoiding over use of insecticides. Key Words: Acraea acerata, biological control, Caricelia normula, Charops sp., Meteorus sp., natural enemies, percentage parasitism, parasitoids, Uganda (African Crop Science Journal 2001 9(1): 157-164)

The sweetpotato butterfly, Acraea acerata Hew. (Lepidoptera: Nymphalidae) is known to extensively defoliate the sweetpotato crop, especially during the dry season, and this leads to significant foliage yield reductions. However, storage root yield losses due to the defoliation have not been adequately quantified. Artificial defoliation studies were undertaken at Namulonge in central Uganda, to estimate the effect of frequency and timing of defoliation on the agronomic performance of sweetpotato (Ipomoea batatus). Results showed that defoliation had no effect on shoot survival. Single quality defoliations had little effect on storage root yield but repeated defoliations significantly (P

The biology of two African sweetpotato weevil species, Cylas pitncticollis and C. bninnens (Fabricius) (Coleoptera: Apionidae), was studied in laboratory experiments carried out at 27 ±1°C, 45 ±5% RH, and a 12 h photophase. Cylns pinicticollis females lived longer than C. brunneus (141 ±10 and 92 ±12 days respectively), developed faster (egg to adult 20-28 days, and 32-41 days respectively) and had a lower oviposition rate (1.10±0.04 and 1.53 ±0.06 eggs per female per day respectively). The total egg production per female (average 101), sex ratio (1:1) and proportion of eggs surviving to adulthood (average 89%) were similar for both species. The intrinsic rate of increase was higher for C. pnncticoUis (0.553 per 10-day period compared to 0.521 for C. brunneus). Under field conditions C. bhmneiis will benefit from its higher oviposition rate during periods of favourable conditions for sweet potato weevils, like dry spells which expose tubers for egg laying. Cylns pitncticollis will benefit from its longer longevity during less favourable conditions, as females can survive extended periods when no oviposition sites are available and then resume egg laying when conditions improve. Key Words: sweetpotato weevil, Cylas pnncticollis, Cylas brunneus, Ipomoca batatas, biology, Kenya

Trapping experiments were carried out in Uganda and Indonesia with decyl (E)-2-butenoate and dodecyl (E)-2-butenoate, previously identified as components of the female sex pheromones of the African species of sweetpotato weevil, Cylas puncticollis and C. brunneus, respectively. In Uganda, decyl (E)-2-butenoate attracted only C. puncticollis males, but dodecyl (E)-2-butenoate attracted males of both C. brunneus and C. puncticollis. Catches of C. puncticollis with both compounds were higher when they were dispensed from polyethylene vials rather than rubber septa, while dodecyl (E)-2-butenoate dispensed from rubber septa gave higher catches of C. brunneus and was more selective for this species. Release rates of the two compounds from the two types of dispenser were measured in the laboratory and possible explanations for differences in dispenser performance considered. Lures containing decyl (E)-2-butenoate were as attactive to male C. puncticollis as 10 live virgin female C. puncticollis weevils, but lures containing dodecyl (E)-2-butenoate were not always as attractive to male C. brunneus as the conspecific virgin female weevils. Dose–response relationships with the synthetic pheromones varied between repeat experiments and with the type of dispenser. Addition of dodecyl (E)-2-butenoate to decyl (E)-2-butenoate either did not affect or increased catches of C. puncticollis males, but adding 1% or more of decyl (E)-2-butenoate to dodecyl (E)-2-butenoate significantly reduced attractiveness to C. brunneus. Traps baited with synthetic lures captured male C. brunneus weevils mostly early in the evening while the majority of male C. puncticollis were trapped between 01:00 hr and 03:00 hr. This clear temporal separation of activity of males of the two species helps to ensure species specificity of mating in these sympatric species. In Indonesia, dodecyl (E)-2-butenoate but not decyl (E)-2-butenoate attracted C. formicarius males, but this attractiveness was less than 0.4% that of the pheromone of C. formicarius, (Z)-3-dodecenyl (E)-2-butenoate.

The biology of two African sweetpotato weevil species, Cylas puncticollis and C. brunneus (Fabricius) (Coleoptera: Apionidae), was studied in laboratory experiments carried out at 27 ± 1°C, 45 ± 5% RH, and a 12 h photophase. Cylas puncticollis females lived longer than C. brunneus (141 ± 10 and 92±12 days respectively), developed faster (egg to adult 20–28 days, and 32–41 days respectively) and had a lower oviposition rate (1.10 ± 0.04 and 1.53 ± 0.06 eggs per female per day respectively). The total egg production per female (average 101), sex ratio (1:1) and proportion of eggs surviving to adulthood (average 89%) were similar for both species. The intrinsic rate of increase was higher for C. puncticollis (0.553 per 10-day period compared to 0.521 for C. brunneus). Under field conditions C. brunneus will benefit from its higher oviposition rate during periods of favourable conditions for sweet potato weevils, like dry spells which expose tubers for egg laying. Cylas puncticollis will benefit from its longer longevity during less favourable conditions, as females can survive extended periods when no oviposition sites are available and then resume egg laying when conditions improve.

Experiments were carried out in Uganda to optimise pheromone traps for the African sweetpotato weevil species, Cylas puncticollis Bohe. and C. brunneus F. (Coleoptera: Apionidae). Various designs of funnel, water and sticky traps were compared and a 5-l plastic jerry can trap was the most appropriate design for effectiveness and practicability. A solution of Omo detergent in water was found to be the most effective trapping agent. Fewer weevils were caught in red traps than in yellow, white, green or blue traps. Catches of C. puncticollis increased when the trap was raised above crop height, but catches of C. brunneus were unaffected. When marked weevils were dropped onto the trap, 36% of C. puncticollis and 23% of C. brunneus were captured, and, of weevils placed in the trap, 88% and 92%, respectively, of the two species remained overnight. Lures for the two species showed no significant loss in attractiveness after 8 weeks in the field, and chemical analysis showed 19% of the C. puncticollis pheromone and 72% of the C. brunneus pheromone remaining after this time. Summarizing, the following trap is presently recommended for monitoring/controlling African Cylas species: a 5-l plastic jerry can trap of any colour with rectangular openings of Il x 5 and 6 x 5 cm positioned 15 cm above the crop canopy, filled with 0.5 l Omo solution(l g/l l water), with 0.1 mg lures to be replaced every 8 weeks.

The sweetpotato butterfly ( Acraea acerata Hew.) is an important defoliating insect pest of sweetpotato in Eastern Africa. Data on distribution, biology and yield loss are presented. Control strategies such as handpicking, chemical control, host-plant resistance, cultural control and biological control are discussed.

Traditionally, in Uganda most farmers growing sweetpotato practise in-ground storage combined with piecemeal harvesting. Several times during the growing period, between 3 and 7–12 months after planting, large roots are removed from individual plants and small roots are allowed to remain in the ground to enlarge further. The overall aim of the practice is to maintain a supply of roots in the ground for the longest possible period. In a series of four trials, once-over harvests at different intervals after planting and a simulated piecemeal harvesting treatment are compared for yield and quality losses caused by sweetpotato weevils (Cylas puncticollis and C. brunneus). For the once-over harvests, the percentage of damaged roots increased linearly the longer the harvest was delayed. Losses ranged between 3% at a harvest 3.5 months after planting (MAP) and 73% at 9.5 MAP. The total yield and undamaged yield for the piecemeal harvesting treatments were comparable to the yields at the optimum harvest times for once-over harvesting at 6–7.5 MAP. The results indicate that piecemeal harvesting is a practice with a controlling effect on sweetpotato weevil infestation.

Sweetpotato weevils (Cyias puncticollis (Bohe.) and C. brunneus (Fabr.) Coleoptera: Apionidae) are the most important insect pests in South Nyanza, Kenya's principal sweetpotato-growing district. A pest of secondary importance is the sweetpotato butterfly (Acraea acerata (Hew.) Lepidoptera: Nymphalidae). Cultural central is currently the most promising component of an integrated pest management strategy for subsistence sweetpotato farmers in Kenya A survey of farmers' cultural practices in South Nyanza suggests that crop protection workers should concentrate their research and extension efforts on crop sanitation and the avoidance of adjacent planting of successive crops. The life cycle and behaviour of the sweetpotato weevils end butterfly should be explained to farmers, so that they better understand the insects' modes of dispersal and thus see the need for sanitation and adjacent planting.

During the past decade, interest in sweetpotato in Sub-Saharan Africa (SSA) has been expanding, the number of projects utilizing sweetpotato increasing, and the demand for training development practitioners and farmers subsequently rising as well.Sweetpotato scientists at the International Potato Center and national research centres often receive these requests and frequently hold 1-3 day training sessions, drawing on whatever training materials they have or can quickly pull together.The inadequacy of this approach has been quite apparent, but resources to address the problem were not available until now.The funding of the Reaching Agents of Change (RAC) project in 2011 has changed the situation.Jointly implemented by the International Potato Center (CIP) and Helen Keller International (HKI), RAC seeks to empower advocates for orange-fleshed sweetpotato (OFSP) to successfully raise awareness about OFSP and mobilize resources for OFSP projects.RAC also seeks to build the capacity of public sector extension and non-governmental organizational personnel to effectively implement those projects funded to promote the dissemination and appropriate use of vitamin A rich, orange-fleshed sweetpotato.The goal is to see sustained capacity for training senior extension personnel about the latest developments in sweetpotato production and utilization in each of the major sub-regions of SSA: Eastern and Central Africa, Southern Africa, and West Africa.Hence, CIP has identified a local institution to work with in Mozambique, Tanzania, and Nigeria to host an annual course entitled: Everything You Ever Wanted to Know about Sweetpotato.During the first cycle of this course, CIP scientists worked closely with national scientists in implementing the course.During the second cycle, the national scientists will lead the training activities and course management with backstopping from CIP personnel.During the third cycle, national scientists will organise and conduct the course with just financial support from the project.In subsequent years, we hope that the course will have become fully self-sufficient on a cost recovery basis.