Another notable weather event affecting production was a series of severe hailstorms in mid-August, which is extremely rare. Hail events are normally in June-July. Three devastating storms occurred within a 4-day period, two of which occurred less than 12 hours apart (Figure 1). The damage from these storms was centered in the Platte Valley extending from Morrill to Bridgeport.

Bacterial diseases were particularly problematic to those field of sunflowers, corn and beans that were not completely destroyed by the hail. This report will summarize some of the major and/or unusual disease occurrences encountered during 2019 for sugar beets, dry beans and other relatively new pulse crops, sunflowers, and other minor specialty crops, as well as some reports from wheat and corn.

Root rot diseases of sugar beets in general were about average in 2019, due to scattered, localized water availability. Rhizoctonia was seen first in late June in some areas (Figure 2).

However, we continued to evaluate the integration of multiple methods for optimal management of Rhizoctonia root and crown rot, as it is the most important and consistently damaging disease in Nebraska. The dry rot canker disease was again documented from several fields near Bridgeport in the older growing areas of the valley. This is a root rot disease that is very unique in being caused by a distinct species of Rhizoctonia, referred to as binucleate.

It is likely that Cercospora leaf spot would have been particularly problematic due to the very wet, conditions with high night temperatures in July. In fact, we found young lesions on lower leaves (Figure 3), providing evidence of infection within research plots at the Panhandle REC very early – July 15.

This is very rare. The hailstorm removed most of the foliage in August, so Cercospora was not a problem after this point. However, yield reductions were seen as a result of the storms. The plants were not killed, but were producing new leaves in September when they should have been concentrating on developing sucrose into the roots.

Cowpea is another new crop that shows promise for producers in Nebraska. We are still learning how to grow it, but to date we have identified several bacterial diseases that also appear to be the same (wilt, common blight) ones that affect dry beans. However, this also is a question that we are now addressing with greenhouse testing. Root diseases (Figure 4) are also seen sporadically in low incidences within fields, but are not of any concern at this time.

However, they are being characterized and tested for pathogenicity and virulence against dry beans, which will likely be a major rotational crop throughout the state. It is also interesting to note that in the last two years, we have found both white mold and Phomopsis stem canker in our cowpea research plots. When published, both will be new reports for these diseases in North America, but the actual impact on economic production is unknown at present.

Interest in chickpea production in Nebraska continues, so we will still to conduct industry field trials for new and more efficient fungicides for managing Ascochyta blight. This is a serious and widespread fungal disease which is our major yield-limiting factor. We also continue to collaborate with Carlos Urrea in the development of new disease resistant cultivars adapted for western Nebraska. Several breeding lines and cultivars with high levels of resistance have been released with more expected in the new few years. 2019 was a particularly bad year for A. blight, and high levels of the disease were seen wherever the crop was grown due to the cool, wet conditions (Figure 5).

Sunflowers in the valley were severely damaged by the multiple hailstorms.

Several fields were completely stripped of leaves (Figure 6), resulting in early senescence and death of plants. Our field plots yielded practically nothing as the seed never filled properly due to the storms occurring right after blooming began. It is also notable to mention that very little disease was observed from those fields that did not suffer from the storms. We assisted in the conduction of another survey in cooperation of the National Sunflower Association and discovered that 5 randomly selected fields from Kimball, Banner, and Box Butte Counties were relatively free of any disease. This is extremely rare based on past surveys and I have no explanation for this.

I also went back to the same field in Kimball County from which the Orobanche (broom rape) infestations were documented 5 years ago. Broom rape is a parasitic plant that infects roots, and it was found occurring on sunflowers within a commercial, production crop back in 2014. This field has not had sunflowers grown since that time but is in a wheat-fallow rotational system. It appeared that the wheat crop was grown in 2018 and fallowed in 2019, but some of the wheat had been left unharvested in the field in patches with wild sunflowers. Within those patches the Orobanche plants were readily found wherever wild sunflowers had grown (Figure 7). This a very interesting project that will continue to be investigated in the future.

Another new potentially profitable crop for western Nebraska is mint, grown for the oil. Both spearmint and peppermint varieties/breeding lines are currently being evaluated by Dipak Santra, the alternative crops breeder, at the Panhandle REC in small research plots. A rust disease was observed again this year as it was in 2018, likely due to the cool and moist environment (Figure 8).

Curiously, it was again seen only on specific spearmint entries, but not throughout the entire study. We will continue to monitor the plots of this perennial crop for studying the pathogen’s life cycle and spore stages this winter and into next spring. This is a new finding since the idea for growing the crop in this region is also in the experimental stages.