@article{nyankanga_olanya_ojiambo_wien_honeycutt_kirk_2011, title={Validation of tuber blight (Phytophthora infestans) prediction model}, volume={30}, ISSN={["1873-6904"]}, DOI={10.1016/j.cropro.2010.11.019}, abstractNote={Potato tuber blight caused by Phytophthora infestans accounts for significant losses of tubers in storage. Despite research on infection and management of tuber blight, there is paucity of information on the prediction of the occurrence tuber blight or modelling of tuber infection by P. infestans under field conditions. A tuber blight prediction model was developed in New York in experiments conducted using cultivars Allegany, NY101, and Katahdin in 1998 and 1999. This model was validated using data collected from the potato cultivar Snowden in field experiments in Laingsburg, Michigan from 2000 to 2009. In both New York and Michigan experiments, disease was initiated by artificial inoculation of cultivars with a US-8 isolate of P. infestans. Mean leaf area affected ranged from 0 to 94% at New York, and 0 to 93% at Michigan. At New York and Michigan, mean tuber blight incidences ranged from 1 to 40% and 0 to 15%, respectively. In the validation of the model using data collected at Laingsburg, Michigan, the model correctly predicted tuber blight incidence in 7 out of 9 years. Comparison of observed with predicted values indicated that slopes of the regression line between observed and predicted germination and infection data were not significantly different (P > 0.3547). Correlation coefficient between observed and predicted values was high (r2 > 0.65) and the coefficient of variation of the residuals of error was about 12%. Although inoculum availability is assumed in the model, incorporation of relationships of inoculum density, propagule survival in soil, and tuber blight incidence would greatly improve the prediction of tuber blight under field conditions.}, number={5}, journal={CROP PROTECTION}, publisher={Elsevier BV}, author={Nyankanga, R. O. and Olanya, O. M. and Ojiambo, P. S. and Wien, H. C. and Honeycutt, C. W. and Kirk, W. W.}, year={2011}, month={May}, pages={547–553} }
 @article{olanya_campbell_1990, title={ANALYSIS OF EPIDEMICS OF LEPTOSPHAERULINA LEAF SPOTS ON ALFALFA AND WHITE CLOVER IN TIME AND SPACE}, volume={80}, ISSN={["0031-949X"]}, DOI={10.1094/Phyto-80-1341}, abstractNote={The spatial and temporal development of leaf spots on alfalfa (Medicago sativa Arc') and Ladino-type white clover (Trifolium repens Regal') caused by Leptosphaerulina trifolii were monitored during spring 1987, fall 1987, and spring 1988. In spring 1987, disease gradients developed from diseased alfalfa to both alfalfa and white clover; little disease developed on either host in plots with diseased clover at the focus. In fall 1987 and spring 1988, disease developed from alfalfa or clover on both hosts (...)}, number={12}, journal={PHYTOPATHOLOGY}, author={OLANYA, OM and CAMPBELL, CL}, year={1990}, month={Dec}, pages={1341–1347} }
 @article{olanya_campbell_1990, title={ISOLATE CHARACTERISTICS AND EPIDEMIC COMPONENTS OF LEPTOSPHAERULINA LEAF SPOTS ON ALFALFA AND WHITE CLOVER}, volume={80}, ISSN={["0031-949X"]}, DOI={10.1094/Phyto-80-1278}, abstractNote={Isolates of Leptosphaerulina spp. from alfalfa (Medicago sativa) and white clover (Trifolium repens) were compared for growth rate on V-8 juice medium at 12-28 C, colony characteristics, production of pseudothecia, ascospore morphology, and pathogenicity on alfalfa and white clover. Optimum growth rate occurred at 20-24 C. Isolates from white clover generally had slower, restricted growth with irregular colony margins on agar medium, whereas isolates from alfalfa generally grew rapidly with regular colony margins (...)}, number={12}, journal={PHYTOPATHOLOGY}, author={OLANYA, OM and CAMPBELL, CL}, year={1990}, month={Dec}, pages={1278–1282} }