M A R C H 2 0 1 8 24 POTATO GROWER significantly improved by fumiga- tion in MS and MR cultivars. However, fumigation did signifi- cantly improve total yield in 1/3 Verticillium resistant cultivars. In 2017 Verticillium wilt development was substantially higher compared to 2016. Because of the higher Verticillium wilt pressure, soil fumi- gation significantly increased yield in all moderately susceptible culti- vars and in moderately resistant Ranger Russet. Soil fumigation did not significantly increase yield in cultivars resistant to Verticillium except for Bannock Russet. This trial will be repeated for a third year in 2018. Dr. Gudmestad expects that this needs to be done for at least four or five years to obtain more definite results. Hosting Ability of Potato and Northern-grown Crops in Rotation with Potato for the Root-lesion Nematode, Pratylenchus penetrans was the topic of Dr. Guiping Yan, NDSU, who found that the popula- tion development of P. penetrans varies among varieties of potato and rotational crops. Red Norland was a very good host. Merlot, All Blue, Shepody and Atlantic were good hosts, while Lamoka was a minor host. The barley varieties Barley (Genesis, Pinnacle) and wheat vari- eties, (Glenn, Faller) were minor hosts. The soybean varieties (Barnes, Sheyenne) were good hosts. Of corn (DK-44-13) was a good host and (DK-43-48) was very good host. Dr. Guiping Yan concluded that P. penetrans is highly virulent and more potato varieties and rotational crops need to be evaluated. Dr. Carl Rosen, UMN, had his flight canceled due to inclement weather, but still managed to arrive on time braving road conditions. People in the audience appreciated his dedica- tion. The topic was the first and sec- ond year results of the Nitrogen Response and Soil Microbial Activity in Potato Cropping Systems as Affected by Fumigation. Dr. Rosen wanted to compare the effectiveness of two fumigants, Vapam and chloropicrin, on potato yield and quality and the potato response to nitrogen fertilizer application. He also characterized the effects of fumigation on microbial activity and nitrogen transformations. Soil health tests were used to determine microbial activity and evaluate fumigation effects on disease inci- dence. A “CO2 burst” is one of many indicators of soil health. Dr. Rosen used a newly commercialized test kit, Solvita®. Some of the find- ings were that fumigation with Vapam and chloropicrin resulted in a 50-60 cwt/A increase over the con- trols in 2016 and up to 100 cwt/A in 2017. Also, microbial activity was reduced with fumigation. CO2 burst The NPPGA Research Reporting Conference was well attended by growers and potato industry folks alike.