Bob Harveson - Extension Plant Pathologist, Panhandle Research and Extension Center

Bob Harveson

Faculty Bio

Sugar beet leaf with 3 very young, circular lesions induced by the CLS  pathogen, Cercospora betae.   If conditions are conducive, the disease can spread rapidly, even from this  small beginning.
Figure 1. Sugar beet leaf with three very young, circular lesions induced by the cercospora leaf spot pathogen, Cercospora betae. If conditions are conducive, the disease can spread rapidly, even from this small beginning.

Cercospora Leaf Spot Spotted in the Panhandle – Be Aware! July 15, 2019

On July 15 symptoms characteristic of cercospora leaf spot were observed on the lower leaves of sugar beets at the university’s Panhandle Research and Extension Center in Scottsbluff. While it is unusually early for this disease, growers are urged to scout their fields as fungicide applications may be necessary.

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Goss's Wilt of corn

Nebraska Plant Pathology: A Culture of New Diseases January 23, 2019

Though relatively small, UNL's Department of Plant Pathology has played a significant role in the discovery of many economically important plant diseases, including most recently, a new fungal pathogen causing Fusarium head blight of wheat. This article is from the 2019 Nebraska Crop Management Conference Proceedings.

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Specialty Crops Disease Update January 10, 2019

The occurrence and distribution of plant pathogens are long known to be strongly influenced by the environment. We see evidence of this concept every season on specialty crops in western Nebraska, and 2018 was no exception.

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Sunflower field at the High Plains Ag Lab

The Sunflower Pathology Working Group November 15, 2018

While diseases are one of the three biggest yield-limiting factors of sunflower production, there was little information on how to identify and manage them until university plant pathologists joined in a collaborative effort to conduct research and develop educational resources.

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Cowpea wilt
Figure 1. A two-year study of diseases in Nebraska cowpea, also known as black-eyed pea, found a wilt, similar to bacterial wilt in dry bean, to be most common. (Photos by Bob Harveson)

Cowpea Bacterial Wilt ― An Old Disease in a New Crop October 9, 2018

As growers in western Nebraska look at new pulse crops to integrate into their rotations, a UNL plant pathologist works to identify possible disease threats. Cowpea (black-eyed pea) is being studied now.

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Sunflower Rust
Figure 1. Cinnamon-colored uredial pustules (left) and dark, black telial pustules (right). These are the overwintering structures of rust. (Photos by Bob Harveson)

Sunflower Rust May be Problematic in 2018 — Be Aware! May 24, 2018

Unusually early findings of rust in volunteer sunflower in western Nebraska indicate the potential for a major outbreak much earlier than usual. Growers are encouraged to scout within the first few weeks of emergence and treat where necessary.

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Dry rot canker in sugarbeet
Figure 1. Surface tissues of the dry rot canker rhizoctonia disease first identified in sugarbeet in 1920 are marked by a distinctive series of concentric circles. (Photos by Bob Harveson)

Dry Rot Canker – Obscure, but Returning Rhizoctonia Disease May 23, 2018

Dry rot canker, one of several rhizoctonia diseaes of sugarbeet, has been relatively obscure since first being identified almost a century ago. New technologies, however, have helped to differentiate it from the more common Rhizoctonia root and crown rot disease.

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A typical wheat field in Nebraska early in the growing season.
Figure 1. A typical wheat field in Nebraska early in the growing season.

It's Time to Scout for Wheat Diseases April 19, 2018

With the predicted return to more normal temperatures, it's time to get into wheat fields and start scouting. Stripe rust has already been reported in southeastern Kansas and is expected to move northward. Included is a table of fungicide efficacy ratings for disease management in wheat.

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