Some Highlights in Plant Pathology in the United States

Weeds are one of the main limiting factors in crop production, causing billions of dollars in annual global losses through degraded agricultural and silvicultural productivity. Weeds also reduce access to land and water, impair aesthetics, and disrupt human activities and well-being. The number of positions devoted to weed science teaching, research, and extension at 76 land-grant institutions across the United States and its territories was determined and compared with that for plant pathology and entomology. The number of classes and graduate students in these disciplines at those institutions was also determined. There are more than four times as many entomologists and more than three times as many plant pathologists as weed scientists at land-grant institutions. There are approximately five times as many graduate students currently in entomology and almost three times as many in plant pathology compared with weed science. There are approximately five times as many entomology and two and a half times as many plant pathology undergraduate classes compared with weed science classes. These differences increase when graduate courses are considered. Most land-grant universities have either none or few graduate classes in weed science. There are more than six times as many graduate entomology courses and more than five times as many plant pathology courses compared with weed science graduate classes. There are no departments devoted solely to weed science, whereas entomology and plant pathology departments are both common. Most universities have little to no faculty assigned to ornamental, fruit, aquatic, or forestry weed control. Number of faculty assigned to vegetable, turf, non-crop, ecology, and basic/laboratory studies in weed science are also limited. Additional university resources are needed if weed science research, teaching, and extension efforts are to meet the priority needs for the management of weeds in the agricultural, natural resources, and urban ecosystems.

Download Full-text

The Status of Weed Science at Universities and Experiment Stations in the Northeastern United States

Weed Technology ◽

10.1614/wt-03-253r1 ◽

2004 ◽

Vol 18 (4) ◽

pp. 1150-1156 ◽

Cited By ~ 6

Author(s):

Jeffrey F. Derr

Keyword(s):

United States ◽

Plant Pathology ◽

Weed Management ◽

Crop Production ◽

Science Research ◽

The United States ◽

Northeastern United States ◽

Weed Ecology ◽

Weed Science ◽

The Status

Weed science is an important component of pest management. Weeds cause approximately 12% loss in United States crop production, reduce crop quality, poison livestock, and adversely affect human health, recreation, and transportation. Herbicides comprise approximately 65% of pesticide expenditures, whereas insecticides and fungicides each comprise less than 20%. The total effect of weeds, including crop losses and costs of control, in the United States was estimated in 1994 to be $20 billion annually. A survey was prepared and mailed to weed scientists at universities and experiment stations in the northeastern United States to determine the number of faculty positions and course offerings devoted to weed science. There are approximately five times as many entomologists and more than three times as many plant pathologists as weed scientists at universities in the northeast. There are more than six times as many graduate students currently in entomology and more than four times as many in plant pathology compared with weed science. Few undergraduate courses in weed science are taught, and most universities have no graduate classes in weed science. There are almost seven times as many undergraduate entomology courses and more than twice as many plant pathology courses as weed science classes in this region. There are more than 17 times as many graduate entomology courses and more than 15 times as many plant pathology courses compared with weed science graduate classes. There are no departments devoted solely to weed science in the northeast, whereas entomology and plant pathology departments are both common. Most universities have little to no faculty assigned to aquatic, forestry, noncrop weed control, weed ecology, or laboratory trials, and numbers assigned to agronomic and horticultural crop weed management are limited. Additional university resources are needed if weed science research, teaching, and extension efforts are to meet the priority needs in weed management.

Download Full-text

First Report of Leaf and Stem Rust Caused by Puccinia sherardiana on Sphaeralcea grossulariaefolia in North America and S. munroana in Wyoming

Plant Disease ◽

10.1094/pdis.1998.82.7.831a ◽

1998 ◽

Vol 82 (7) ◽

pp. 831-831

Author(s):

S. C. Briere ◽

G. D. Franc

Keyword(s):

United States ◽

Plant Pathology ◽

Relative Humidity ◽

Plant Material ◽

The United States ◽

Diseased Plant ◽

Pathology Laboratory ◽

Natural Lighting ◽

Foliar Symptoms ◽

Plastic Bags

Diseased samples of globe mallow, Sphaeralcea grossulariaefolia and S. munroana, were submitted by an ornamental seed producer in Wyoming to our Extension Plant Pathology Laboratory in July 1997. Dark brown, amphigenous telia surrounded by chlorotic halos were present on both foliage and stems. Mean teliospore dimensions observed were 30.8 × 44.8 μm. The teliospores germinated readily on water agar at 20°C and formed basidiospores within 24 h. Aecia and uredinia were not found. Based on characteristics mentioned above, this fungus was identified as Puccinia sherardiana Körn (1). This microcyclic rust was previously described on 12 other Sphaeralcea spp. plus other plant species in the Malvaceae family (1,2). Stem and foliar symptoms were reproduced in a greenhouse on 8-week-old plants of S. grossulariaefolia and S. munroana. These plants were inoculated with teliospores removed from the original diseased plant material. Immediately after inoculation, plants were misted and placed in plastic bags and incubated for 36 h at 100% relative humidity and 20°C. Plants continued growth with natural lighting and with day and night temperatures of 20 and 15°C, respectively. Symptoms developed within 12 days with initial telia rupturing the host epidermis 13 days after inoculation. Telia were examined microscopically to complete Koch's postulates. References: (1) J. C. Arthur. Manual of Plant Rusts in United States and Canada. Hafner Pub., 1962. (2) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. American Phytopatholical Society, St. Paul, MN, 1989.

Download Full-text

Groundnut Ringspot Virus in Florida

EDIS ◽

10.32473/edis-pp282-2011 ◽

2011 ◽

Vol 2011 (8) ◽

Author(s):

Eugene McAvoy ◽

Scott Adkins ◽

Craig Webster ◽

Charles Mellinger ◽

Loren Horsman ◽

...

Keyword(s):

United States ◽

Plant Pathology ◽

Host Range ◽

Disease Transmission ◽

The United States ◽

South Florida ◽

Ringspot Virus ◽

Tomato Plants ◽

Fact Sheet ◽

Stages Of Growth

Groundnut ringspot virus was recently identified in tomatoes in South Florida — the first report in the United States. It can infect tomato plants at all stages of growth and lead to unmarketable fruits or plant death. This 4-page fact sheet shares what is known about the symptoms, host range, disease transmission, and management. Written by Eugene McAvoy, Scott Adkins, Craig Webster, Charles Mellinger, Loren Horsman, Galen Frantz, Stuart Reitz, and Shouan Zhang, and published by the UF Department of Plant Pathology, July 2011.

Download Full-text