Resistance to metalaxyl was detected at about the same time as the migrations occurred. Field experiments confirmed that metalaxyl alone has no effect on the new, resistant genotypes. Since resistance to metalaxyl was almost certainly introduced, there was nothing U.S. potato growers could have done to prevent its occurrence. Seed potatoes should be monitored for the new genotypes to limit their migration and fields containing them should not be sprayed with metalaxyl. A new test has been developed to screen geraniums for newly discovered viruses.
Geraniums are one of the most rapidly expanding ornamental garden crops in the United States.
Since geraniums are propagated mainly from cuttings, more than fifteen different viral diseases threaten their production and quality, severely reducing vegetative growth and plant and flower quality. Often mixed viral infections cause severe disease, causing confusion about the exact identity of the culprit. ARS scientists isolated two of the top four viruses from geraniums. After studying their biological, biochemical and serological properties, the scientists called them pelargonium line pattern virus and ringspot virus. Next, they developed a polyclonal antisera to these viruses and showed they can detect the viruses in infected geranium.