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David Langston

Dr. David Langston received his B.S. in Agronomy and M. Ag. in Crop Science from North Carolina State University in 1990 and 1995, respectively. He received his Ph.D. degree in Plant Pathology from Virginia Polytechnic Institute & State University in 1998. He was hired as an Assistant Professor at the University of Georgia-Tifton Campus in 1998. He was promoted to Associate Professor and Professor at the University of Georgia in 2004 and 2010, respectively. In 2014 he was hired as the Director of Virginia Tech's Tidewater Agricultural Research and Extension Center in Suffolk, VA and Professor of Plant Pathology.

He has received over 20 state, regional and national awards, which includes 10 extension bulletins that received national awards. Two of his award-winning publications were “An Alternative Fumigation System to Replace Methyl Bromide” and “Diseases and Conditions of Vegetables in Georgia”. The first is a DVD video outlining the Georgia 3-Way fumigation system for replacing methyl bromide. Hundreds of these videos have been disseminated in Georgia and elsewhere since 2007. This video has been instrumental in helping growers through the transition from using methyl bromide to alternatives while sustaining economic viability. The second publication was co-authored by David Langston and Glenn Beard and was published as a for-sale publication by the University of Georgia. This is a unique educational tool that incorporates images of diseases, nutritional problems, herbicide damage and insect damage, and is designed to fit in one’s pocket. Hundreds of these have been sold over the years. Dr. Langston has authored or co-authored 135 Extension Publications, 52 Refereed Journal Articles, 111 Technical Publications, 29 popular articles, 40 newsletter articles and 75 disease alerts for a total of 442 publications.

Other duties for which Dr. Langston was responsible in Georgia included the diagnosing and delivering recommendations on all commercial vegetable samples sent to the diagnostic clinics in Tifton or Athens. He has diagnosed and given recommendations on over 4,500 physical samples in his career and 853 distance diagnostics samples through digital imaging since the year 2000. Langston currently supports the diagnostic clinics of Virginia Tech.

Dr. Langston had no formal research appointment at the University of Georgia, but actively supported the activities of his research counterparts and maintained a productive and well-supported applied research program. He maintained cooperative relationships with many researchers and extension personnel in Georgia as well as other states. These partnerships led to over $2 million in competitive grants and approximately half of the 52 refereed journal articles he has published. Much of Dr. Langston’s applied research focused on integration of new fungicide/bactericide chemistries into existing disease management programs. He conducted 30-50 replicated field trials annually to evaluate new products. Dr. Langston published efficacy tables in the Georgia Pest Control Handbook based on his results. These efficacy tables were also used in the North Carolina Ag. Chemicals Manual and the Vegetable Crop Guidelines for the Southeastern United States. The quality of Dr. Langston’s research in this area is evident by support received from industry, continued requests for evaluations, and his involvement in product development and registration discussions and regional and national industry sponsored meetings.

Dr. Langston focused his research programs on the most significant disease problems that vegetable growers face, such as methyl bromide alternatives for nematode and disease management; fungicide resistance management of Didymella bryoniae (causal agent of gummy stem blight; epidemiology and control of bacterial spot of pepper caused by Xanthomonas campestris pv. vesicatoria. He supported research counterpart towards management of Phytophthora crown and fruit of vegetables, caused by Phytophthora capsici. He collaborated with weed scientists to determine which alternative fumigants controlled weeds, diseases, and nematodes while maintaining acceptable yields and economic returns. The ‘Georgia 3-Way System’ has been the result of this work and was supported by two CSREES Methyl Bromide Transitions Grants. Over 50% of Georgia's vegetable growers are now using the Georgia 3-Way system. He also worked with new non-fumigant nematicides to offer better options for multiple crop plasticulture. His graduate student presented a paper on this topic at the APS Southern Division meeting and placed third out of 35 students in the competition.

Georgia is ranked in the top two watermelon-producing states annually with a farm gate value averaging $100 - $150 million. Dr. Langston’s watermelon research efforts have been part of the reason for that ranking. He focused much of his efforts on GSB Gummy stem blight (GSB), the most destructive disease of watermelon in the southeastern U.S. He developed fungicide recommendations for suppressing losses to GSB that minimized development of fungicide resistant strains. Dr. Langston has been at the forefront in this area working with strobilurin resistance and resistance to carboxamides. He documented field resistance to these fungicides which was later confirmed in lab assays conducted by Dr. Katherine Stevenson. They secured funding for this work from the National Watermelon Growers Assoc., Georgia Watermelon Growers Assoc., and the Georgia Fruit and Vegetable Growers Assoc. These grants supported initial data which was used to support a Crisis Exemption for the use of difenoconazole (Inspire) for suppression of GSB in Georgia as well as a multi-state USDA/CSREES Crops at Risk Grant that was funded to study the epidemiology of GSB and how it affects the spread of fungicide resistance. This work led to five refereed journal articles. Initially Dr. Langston had no formal teaching appointment but near the end of his time at Georgia, he became the back bone and essentially the graduate coordinator for the Master of Plant Protection and Pest Management degree offered at the Tifton Campus. Although the PPM degree had long been offered at UGA, Dr. Langston helped build it considerably and probably brought more students in to the program during his short tenure at the helm than in all the previous years combined. In addition, Dr. Langston has taught Integrated Pest Management 2006-2011, Clinical Plant Pathology 2004-2014, Pesticides and Transgenic Crops 2006-2014, and Diagnosis and Management of Plant Disease 2011-2014. He served on the committees of 15 graduate students, five of which he was the student's advisor.

Since 2014, Dr. Langston has overseen the operation of Virginia Tech’s Tidewater Agricultural Research and Extension Center in Suffolk where he also continues to conduct applied research and deliver Extension programming in vegetable disease control. His current focus in Virginia is to provide nematode diagnostic and management information to growers and Extension agents.

His considerable service to APS has included editor of Fungicide and Nematicide Tests for 3 years and a section editor for Plant Disease Management Reports for 5 years. He chaired the APS Chemical Control Committee in 2002, was President of the APS Southern Division in 2010, and received the Southern Division Outstanding Plant Pathologist Award in 2016.