Seasonal distribution and migrations of Agrotis ipsilon (Hufnagel) (Lepidoptera, Noctuidae)

The larva of the near-cosmopolitan noctuid moth Agrotis ipsi/on (Hufnagel) (-A. ypsilon, Rhyacia ypsi/on (Rott.), R. ypsilon (Warren), Scotia ipsilon (Rott.)) is popularly known as the greasy cutworm in Asia and North America, the dark sword grass in Britain, and the black cutworm in Europe. The name 'cutworm' reflects. its feeding habit of cutting off plant seedlings at the base of the stem, and the adjectives 'greasy' or 'black' describe its greasy, earthy-brown, blackish or grey-green appearance which is due to its black head, numerous dark tubercles, and dorsal longitudinal dark stripes and lateral pale ones. The greasy cutworm can be of very considerable economic importance, not only because of its prolific and often localized breeding but also because its nocturnal feeding habits often cause outbreaks to escape notice until a late stage. The sudden appearances of A. ipsilon, often in large numbers, and its seasonal disappearances, especially in India, the Celebes, Egypt and the Middle East, caused this pest to be recognized as a migrant about half a century ago. The present author has attempted to obtain additional circumstantial biogeographical evidence of major seasonal redistributions of populations on a world-wide basis, particularly over continental land masses and remote islands. This has been done by plotting historical records, obtained from museum specimens, light-traps and the scientific literature, on monthly distribution maps. This type of analysis has previously been undertaken for the armyworm moth, Spodoptera exempta (Walk.), in Africa (Betts, Haggis & Odiyo 1968), and for the Desert Locust, Schistocerca gregaria (Forsk.), throughout its vast distribution area in Africa, the Middle East and south-west Asia (Waloff 1946; Donnelly 1947; Davies 1952; Fortescue-Foulkes 1953). A further aim is to attempt an interpretation of the role of seasonal changes in the distribution of A. ipsilon as a natural means of adaptation

Digestibility and metabolizable energy of selected tropical feedstuffs estimated by in vitro and prediction equations

In vivo determination of digestible organic matter (dOM) and metabolisable energy (ME) concentrations of feeds is laborious and expensive, whereas analysis of their nutrient contents is routinely performed. Prediction equations based on the chemical composition of feeds can be a compromise. This study compared dOM and ME estimates of tropical feeds derived from selected equations (Yan and Agnew, 2004; Stergiadis et al., 2015a; Stergiadis et al., 2015b; AFRC, 1993) with those determined by the in vitro gas production method (Menke and Steingass, 1988). Samples of supplement feedstuffs (n = 12) and the herbaceous and ligneous vegetation on native pastures (n = 12) were collected in Lower Nyando, Kenya, over two seasons of one year. Samples were analysed for dry matter (DM; in % of fresh matter), crude ash, crude protein, ether extract, neutral and acid detergent fiber (NDF, ADF) (all in % of DM). Gross energy was determined by calorimetry. Nutrient concentrations varied across all samples with 8.5 – 87.9% DM, 5.2 – 16.8% crude ash, 36.7 – 74.1% NDF, 25.5 – 39.4% ADF, 3.2 – 14.2% crude protein, and 0.6 – 4.5% ether extract. The gross energy, in vitro dOM, and ME concentrations were 14.5 – 18.8 MJ/kg DM, 26.3 – 54.5%, and 3.8 – 8.4 MJ/kg DM, respectively. Compared with the in vitro method, all nutrient-based equations overestimated dOM (P 0.5). Nutrient-based equations do not sufficiently account for differences in nutrient availability, an aspect better simulated in vitro. Further development and/or validation of nutrient-based equations might be needed to more accurately predict dOM and ME of tropical feeds. AFRC. 1993. Wallingford: CAB International. Stergiadis et al. 2015a. J Dairy Sci, 98(5), 3257–3273 Stergiadis et al 2015b. Brit J Nutr, 113(10), 1571–1584. Yan and Agnew. 2004. J Anim Sci., 82, 1367–1379

Calculation of new enteric methane emission factors for small ruminants in western Kenya highlights the heterogeneity of smallholder production systems

Context: African livestock play a critical role in food security and the wider economy, while accounting for >70% of African agricultural greenhouse gas emissions. Accurate estimates of greenhouse gas emissions from livestock are required for inventory purposes and to assess the efficacy of mitigation measures. While there is an increasing number of studies assessing methane (CH$_{4}$) emissions of cattle, little attention has been paid to small ruminants (SR). Aims: Enteric CH$_{4}$ emissions were assessed from 1345 SR in three counties of western Kenya to develop more accurate emission factors (EF) for enteric CH$_{4}$ from sheep and goats. Methods: Using on-farm animal activity data, feed samples were also analysed to produce estimates of feed digestibility by season and region. The combined data were also used to estimate daily CH$_{4}$ production by season, location and class of animal to produce new EF for annual enteric CH$_{4}$ production of SR. Key results: Mean dry-matter digestibility of the feed basket was in the range of 58–64%, depending on region and season (~10% greater than Tier I estimates). EF were similar for sheep (4.4 vs 5 kg CH$_{4}$/year), but lower for goats (3.7 vs 5 kg CH$_{4}$/year) than those given for SR in developing countries in Intergovernmental Panel on Climate Change (Tier I) estimates. Conclusions: Published estimates of EF for SR range widely across Africa. In smallholder systems in western Kenya, SR appear to be managed differently from cattle, and EF appear to be driven by different management considerations. Implications: The findings highlighted the heterogenous nature of SR enteric emissions in East Africa, but also suggested that emissions from SR are quantitatively less important than other estimates suggest compared with cattle

Soybean farm-saved seed viability and vigor as influenced by agro-ecological conditions of Meru South Sub-County, Kenya

Objective: The experiment was conducted with the aim of assessing the soybean farm-saved seed viability and vigor as influenced by agro-ecological conditions of Meru South Sub-County, Kenya.Methodology and results: Within one month of harvest, soybean farm-saved-seed was randomly sampled from 30 households in February 2013 from areas representative of agro-ecological zones Upper Midlands II (Ann. Mean temp. (18.2-20.60C); Upper Midlands III (19.2-20.60C; Lower Midlands III (20.9-22.90C) and Lower Midlands IV (21-240C). Standard germination, electrical conductivity and moisture content tests were done according to ISTA rules (2007). Analysis of Variance was done using SAS (9.2) and means separated using LSD. Results revealed that seed moisture was lowest in the warmer LM4 (6.3%) than in the cooler LM3 (8%); UM3 (8.4%) and UM2 (10%). In addition, soybean seed from the cooler agro-ecologies - UM2 (94%), UM3 (86.6%) and LM3 (99.5%) had significantly higher germination than seed from the lower warmer LM4 (57%). Similarly, seed vigor was highest in the cooler UM2 (41.7 C/cm/g), UM3 (45.8C/cm/g) and LM3 (31.6C/cm/g) as shown by reduced seed leachates; indicative of better integrity of seed membranes than seed from the warmer LM4 (79.1C/cm/g). In addition, there was a strong negative correlation between electrical conductivity and germination, showing a faster deterioration due to leakage of electrolytes.Conclusions and applications of findings: The soybean farm-saved seed germination and vigor were significantly influenced by agro-ecological conditions. Considering that seed moisture content in the lower warmer agro-ecologies was significantly lower than those from higher cooler agro-ecologies the observed seed deterioration was attributable to the higher temperatures characteristic of lower altitudes agro-ecologies. Therefore, since the farm saved seed viability and vigor was better retained in the cooler higher agroecological zones (UM2, UM3 and LM3) of Meru South Sub-County, farmers should source better quality soybean seed from these areas. The results validate the need for ecological zoning of suitable areas for the production of high quality soybean seed in Kenya.Keywords: soybean farm-saved seed, agro-ecological zones, seed germination and vigo

Village Baseline Study: Site Analysis Report for Albertine Rift – Hoima, Uganda

The village baseline study of Kibaire village in the CCAFS benchmark site Hoima in Uganda took place from 13 to 16 July 2011. Forests are exploited at unsustainable levels in Kibaire but deforestation does not appear to be a serious threat because the tree population is still relatively high. Most of the forests have been leased to private individuals as part of the privatisation policy being implemented in Uganda. Wetlands are also increasingly subjected to overexploitation and pollution from brewing and other activities. Farming at both subsistence and commercial level is increasing at the expense of forests. Community access to forest resources is restricted. Participants identified 29 organisations working in the community, two-third of them operating from outside the locality. Participants said that they did have plenty of food in the village, and women expressed that they had never had a food crisis. Nonetheless, half of the organisations men and women identified were involved in some form of food security related activity, and notably food availability. Less than one-third of the organisations addressed natural resources management, and most of them were from outside the community. Organisations are the most significant source of information on agriculture. Farmers also get information through the many radio stations in the area that air many programs in local languages