White mold incidence, severity and lima bean (Phaseolus lunatus) yield response to fungicide application timing in the mid-Atlantic region of the United States

2021 ◽  
pp. 105890
Author(s):  
Habtamu B. Demissie ◽  
Bahram Momen ◽  
Kathryne L. Everts
Keyword(s):  
United States ◽  
Lima Bean ◽  
The United States ◽  
Phaseolus Lunatus ◽  
White Mold ◽  
Yield Response ◽  
Atlantic Region ◽  
Application Timing ◽  
Fungicide Application

scholarly journals Lima Bean Downy Mildew Epiphytotics Caused by New Physiological Races of Phytophthora phaseoli

Plant Disease ◽  
2008 ◽  
Vol 92 (5) ◽  
pp. 670-674 ◽  
Author(s):  
C. R. Davidson ◽  
T. A. Evans ◽  
R. P. Mulrooney ◽  
N. F. Gregory ◽  
R. B. Carroll ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Fragment Length Polymorphism ◽  
Lima Bean ◽  
The United States ◽  
Phaseolus Lunatus ◽  
Atlantic Region ◽  
Resistant Cultivars ◽  
Physiological Races ◽  
Phytophthora Spp ◽  
Physiological Race

Before 1995, race D of Phytophthora phaseoli, the causal agent of downy mildew on lima bean (Phaseolus lunatus), was the prevalent physiological race in the mid-Atlantic region of the United States. Since 1995, however, new physiological races of P. phaseoli have been responsible for downy mildew outbreaks in previously resistant cultivars in this region. Cultivar differential testing of 180 isolates of P. phaseoli collected between 1994 and 2005 from Delaware and the eastern shore of Maryland has confirmed the presence of two new physiological races. The detection of race E in 1995 and race F only 5 years later in 2000, plus the lack of resistant cultivars to manage the epiphytotics in lima bean, have led to millions of dollars of crop losses. Intra- and interspecific genetic variation of Phytophthora spp. and isolates were assessed using amplified fragment length polymorphism DNA fingerprinting. Primer groups EcoRI+AG and MseI+C distinguished P. phaseoli and P. capsici from P. infestans but did not distinguish among different races of P. phaseoli.

scholarly journals First Report of Downy Mildew of Lima Bean Caused by Phytophthora phaseoli in Virginia

Plant Disease ◽  
2011 ◽  
Vol 95 (1) ◽  
pp. 71-71
Author(s):  
S. L. Rideout ◽  
M. A. Hansen ◽  
N. F. Gregory ◽  
T. A. Evans
Keyword(s):  
United States ◽  
New Jersey ◽  
Downy Mildew ◽  
Morphometric Analysis ◽  
Lima Bean ◽  
The United States ◽  
Shoot Tips ◽  
Phaseolus Lunatus ◽  
Eastern United States ◽  
Eastern Shore

Delaware, the eastern shore of Maryland, and southern New Jersey have been the center of lima bean (Phaseolus lunatus L.) production in the eastern United States for nearly 50 years (1). Downy mildew has been the most important disease of lima bean in the humid eastern United States over that period. The causal agent of downy mildew, the oomycete pathogen Phytophthora phaseoli Thaxt., was first identified on lima bean in Connecticut in 1887 by Thaxter. Signs and symptoms of lima bean downy mildew include infection, necrosis and abscission of flowers, and shepherd's crooking of racemes, shoot tips, and petioles (1). Sporangia develop on shoot tips, petioles, pins (small pods), and pods in the field and on hypocotyls in-vitro. Since 2005, approximately 50% of the baby lima beans processed in the United States have been grown in Delaware and the eastern shore of Maryland. In 2008, commercial lima bean production began on the eastern shore of Virginia in Accomack County but no downy mildew was reported in that season. In 2009, approximately 1,825 ha in Accomack and Northampton counties were planted to baby lima bean. Weather conditions in 2009, including above average rainfall, were conducive for the development of downy mildew on the Delmarva Peninsula. Downy mildew was widespread in growers' fields in August and September in butter bean in southern New Jersey and baby lima bean in Sussex County, DE. In August 2009, a home gardener in Rappahannock, VA sent samples of infected lima bean pods from baby, Fordhook, and pole lima bean plants to the Virginia Tech Plant Disease Clinic in Blacksburg. On the basis of morphometric analysis, samples were determined microscopically to be infected by a Phytophthora sp. with rather uniform sporangia averaging 39 × 22 μm and short pedicels, diagnostic for P. phaseoli (1). On October 27, 2009, field scouts in Accomack County, VA identified two lima bean fields planted to cv. C-Elite-Select exhibiting moderate symptoms of downy mildew. Samples were brought to the Plant Diagnostic Clinic at the University of Delaware under USDA-APHIS permit and determined to be P. phaseoli based on morphometric analysis. Samples were inoculated onto a lima bean cultivar differential to determine pathogenicity to complete Koch's postulates and to determine their physiological race. Samples were inoculated onto lima bean cvs. 184-185 and C-Elite-Select, which are susceptible to race F and resistant to race E, Eastland and 8-78, which are susceptible to race E and resistant to race F, and Concentrated Fordhook, susceptible to all known races (1). Three pots containing five emerging seedlings each were inoculated with sporangia (approximately 103 per ml) prepared by soaking infected pods in 500 ml of sterile distilled water for 1 min with gentle agitation. Plants were placed in a Percival dew chamber with intermittent misting and set at 19. Infection and disease development were assessed daily and signs developed 7 days postinoculation in cvs. 184-85, C-Elite-Select, and Concentrated Fordhook, but not in Eastland and 8-78. Cultivar differential tests indicated that the isolates were P. phaseoli race F. Hypocotyls of infected plants were scraped, and isolations made on lima bean pod agar confirmed the presence of P. phaseoli. To our knowledge, this is the first time that downy mildew of lima bean has been reported in Virginia. Reference: (1) T.A. Evans et al. Plant Dis. 91:128, 2007.

Impacts of row spacing and fungicide timing on foliar disease, greenstem and yield in double cropped soybeans grown in the Chesapeake Bay region of the United States.

2021 ◽  
Author(s):  
Nathan Kleczewski ◽  
Andrew Kness ◽  
Alyssa Koehler
Keyword(s):  
United States ◽  
Chesapeake Bay ◽  
The United States ◽  
Row Spacing ◽  
Soybean Yield ◽  
Foliar Disease ◽  
Application Timing ◽  
Soybean Production ◽  
Fungicide Application ◽  
Foliar Fungicide

Double cropped soybeans are planted on approximately 1/3 of crop acres in the Chesapeake Bay region of the United States. Producers have asked if foliar fungicides are required to optimize yields in this region. We assessed the impacts of foliar fungicide application timing and row spacing on foliar disease, greenstem, and yield from 11 site years spanning 2017-2019. Foliar diseases only developed at rateable levels in one location. Fungicide application, regardless of timing, increased percent greenstem over non-treated controls. Fungicide application did not impact soybean yield. Yield was greater in 38.1 cm rows when compared to 19 cm rows. Our data do not support the use of foliar fungicides in double cropped soybean production in this region.

scholarly journals Enteric Viruses and Pepper Mild Mottle Virus Show Significant Correlation in Select Mid-Atlantic Agricultural Waters

2021 ◽  
Author(s):  
Brienna L. Anderson-Coughlin ◽  
Shani Craighead ◽  
Alyssa Kelly ◽  
Samantha Gartley ◽  
Adam Vanore ◽  
...  
Keyword(s):  
United States ◽  
Surface Waters ◽  
Irrigation Water ◽  
Water Samples ◽  
Enteric Viruses ◽  
The United States ◽  
Mottle Virus ◽  
Pepper Mild Mottle Virus ◽  
Atlantic Region ◽  
Viral Pathogen

Enteric viruses (EV) are the largest contributors to foodborne illness and outbreaks globally. Their ability to persist in the environment, coupled with the challenges experienced in environmental monitoring create a critical aperture through which agricultural crops may become contaminated. This study involved a seventeen-month investigation of select human enteric viruses and viral indicators in non-traditional irrigation water sources, surface and reclaimed waters, in the Mid-Atlantic region of the United States. Real-time quantitative PCR was used for detection of Aichi virus, hepatitis A virus, noroviruses GI and GII. Pepper mild mottle virus (PMMoV), a common viral indicator of human fecal contamination, was also evaluated along with atmospheric (air and water temperature, cloud cover, and precipitation 24 h, 7 d and 14 d prior to sample collection) and physicochemical (dissolved oxygen, pH, salinity and turbidity) data to determine if there were any association between EV and measured parameters. EV were detected more frequently in reclaimed waters (32%, n=22) than in surface waters (4%, n=49) similar to PMMoV detection frequency in surface (33%, n=42) and reclaimed (67%, n=21) water. Our data show a significant correlation between EV and PMMoV (R2=0.628; p<0.05) detection in reclaimed water samples, but not in surface waters (R2=0.476; p=0.78). Water salinity significantly affected the detection of both EV and PMMoV (p<0.05) as demonstrated by logistic regression analyses. These results provide relevant insights into the extent and degree of association between human enteric (pathogenic) viruses and water quality data in Mid-Atlantic surface and reclaimed waters as potential sources for agricultural irrigation. IMPORTANCE Microbiological analysis of agricultural waters is fundamental to ensure microbial food safety. The highly variable nature of non-traditional sources of irrigation water are particularly difficult to test for the presence of viruses. Multiple characteristics influence viral persistence in a water source as well as affect the recovery and detection methods which are employed. Testing for a suite of viruses in water samples is often too costly and labor intensive, making identification of suitable indicators for viral pathogen contamination necessary. The results from this study address two critical data gaps: enteric virus prevalence in surface and reclaimed waters of the Mid-Atlantic region of the United States and subsequent evaluation of physicochemical and atmospheric parameters used to inform the potential for use of indicators of viral contamination.

scholarly journals First Report of Phytophthora capsici Infecting Lima Bean (Phaseolus lunatus) in the Mid-Atlantic Region

Plant Disease ◽  
2002 ◽  
Vol 86 (9) ◽  
pp. 1049-1049 ◽  
Author(s):  
C. R. Davidson ◽  
R. B. Carroll ◽  
T. A. Evans ◽  
R. P. Mulrooney ◽  
S. H. Kim
Keyword(s):  
Phytophthora Capsici ◽  
Petri Dish ◽  
Lima Bean ◽  
Phaseolus Lunatus ◽  
Pathogenicity Test ◽  
Atlantic Region ◽  
Kent County ◽  
Original Field ◽  
Lima Beans ◽  
Stem Lesions

Lima beans are an important crop in Delaware and the Mid-Atlantic Region. In the summer of 2000, five commercial cultivars (3–28, 184–85, C-elite Sel, Butter Bean, and Jackson Wonder) of lima bean in Delaware, Maryland, and New Jersey were observed with white, appressed mycelia on infected pods that appeared distinctly different from signs of downy mildew infection caused by Phytophthora phaseoli. Isolations were made by placing diseased pods between layers of rye media (1). A fungus that produced white mycelia with sporangia was consistently isolated. All Phytophthora isolates from the infected pods were heterothallic, grew at 35°C, had as much as 100 μm long pedicles on varying shapes of caducous sporangia with tapering base and >2 papillae, and were identified as P. capsici (2). Initially, three surface-disinfected pods from cv. Early Thorogreen plants grown in the greenhouse were floated on 20 ml of sterile water in a petri dish, and each was inoculated with a disk of P. capsici. This was repeated for nine isolates obtained from lima bean. After incubation for 7 days at room temperature, all 27 pods were infected, and P. capsici was reisolated from all the pods. A pathogenicity test was performed on the same cultivars from which the original field isolates were collected. Three seedlings and two plants with mature pods were inoculated with a sporangial suspension of each of the nine isolates and placed in a dew chamber for 5 days at 20 to 25°C and 100% relative humidity. White mycelial growth was observed on seedlings and mature pods. One inoculated plant developed brown-to-black stem lesions with white mycelia. All pods on the mature plants showed appressed, white mycelia identical to that observed in the commercial lima bean fields. P. capsici was consistently reisolated from all inoculated plants. In 2000, most infected pods in infested fields were observed low in the plant canopy or touching the soil. However, in 2001, infected pods were mostly in the lower and mid-portion of the plants observed in baby lima bean fields in Kent County, DE. References: (1) C. E. Caten and J. L. Jinks. Can. J. Bot. 46:329, 1967. (2) D. C. Erwin and O. K. Ribeiro. Phytophthora capsici. Page 264 in: Phytophthora Diseases Worldwide. The American Phytopathological Society, St Paul, MN, 1996.

Palmer Amaranth (Amaranthus palmeri) Control by Glufosinate plus Fluometuron Applied Postemergence to WideStrike®Cotton

2013 ◽  
Vol 27 (2) ◽  
pp. 291-297 ◽  
Author(s):  
Kelly A. Barnett ◽  
A. Stanley Culpepper ◽  
Alan C. York ◽  
Lawrence E. Steckel
Keyword(s):  
United States ◽  
Weed Control ◽  
Acetolactate Synthase ◽  
The United States ◽  
Palmer Amaranth ◽  
Effective Control ◽  
Yield Response ◽  
Amaranthus Palmeri ◽  
Cotton Yield ◽  
Cotton Cultivar

Glyphosate-resistant (GR) weeds, especially GR Palmer amaranth, are very problematic for cotton growers in the Southeast and Midsouth regions of the United States. Glufosinate can control GR Palmer amaranth, and growers are transitioning to glufosinate-based systems. Palmer amaranth must be small for consistently effective control by glufosinate. Because this weed grows rapidly, growers are not always timely with applications. With widespread resistance to acetolactate synthase-inhibiting herbicides, growers have few herbicide options to mix with glufosinate to improve control of larger weeds. In a field study using a WideStrike®cotton cultivar, we evaluated fluometuron at 140 to 1,120 g ai ha−1mixed with the ammonium salt of glufosinate at 485 g ae ha−1for control of GR Palmer amaranth 13 and 26 cm tall. Standard PRE- and POST-directed herbicides were included in the systems. Glufosinate alone injured the WideStrike® cotton less than 10%. Fluometuron increased injury up to 25% but did not adversely affect yield. Glufosinate controlled 13-cm Palmer amaranth at least 90%, and there was no improvement in weed control nor a cotton yield response to fluometuron mixed with glufosinate. Palmer amaranth 26 cm tall was controlled only 59% by glufosinate. Fluometuron mixed with glufosinate increased control of the larger weeds up to 28% and there was a trend for greater yields. However, delaying applications until weeds were 26 cm reduced yield 22% relative to timely application. Our results suggest fluometuron mixed with glufosinate may be of some benefit when attempting to control large Palmer amaranth. However, mixing fluometuron with glufosinate is not a substitute for a timely glufosinate application.

State of the Estuaries in the Mid-Atlantic Region of the United States

1998 ◽  
pp. 269-284 ◽  
Author(s):  
J. F. Paul ◽  
C. J. Strobel ◽  
B. D. Melzian ◽  
J. A. Kiddon ◽  
J. S. Latimer ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Atlantic Region
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