Effects of planting date, irrigation and rain on infection, disease severity and pod discoloration caused by Alternaria alternata (Fr.) Keissler in bean (Phaseolus vulgaris L.)

1993 ◽  
Vol 73 (1) ◽  
pp. 315-321
Author(s):  
J. C. Tu

Black-pod disease of bean, caused by Alternaria alternata, was shown to be more severe on early-seeded than on late-seeded crops. This contradicts an earlier view that early spring planting could reduce this disease. Beans should be planted late, harvested soon after maturity and dried rapidly. Overhead irrigation during the growing season reduced the establishment of epiphytic populations on the leaves and consequently reduced the incidence of infestation. After bean plants matured, epiphytic Alternaria began to grow on the pods when they came in contact with rain or dew. Key words: Bean, Alternaria black pod, planting date, irrigation, rain

1985 ◽  
Vol 65 (4) ◽  
pp. 913-919 ◽  
Author(s):  
J. C. TU

During the growing season Alternaria alternata was isolated from leaves of many weed species commonly found in or around a bean (Phaseolus vulgaris L.) field. The fungus was also found on bean plants at all stages of growth. Population densities of A. alternata on the leaves of bean plants grown from surface-sterilized and non-sterilized seeds were similar. Population densities of A. alternata on the leaves of weeds and beans increaased as the growing season advanced. The increase in the population of A. alternata was correlated with natural senescence of leaf tissues. Sugars and ninhydrin positive substances (NPS) in the leaf wash increased with plant age. At a given growth stage, the concentration of sugars and NPS found in leaf washes of cultivars susceptible to A. alternata were higher than those tolerant to it.Key words: Bean (field), Alternaria alternata


1982 ◽  
Vol 62 (2) ◽  
pp. 277-284 ◽  
Author(s):  
J. C. TU

Alternaria alternata (Fr.) Keissler was identified as the cause of the black pod disease and greyish discoloration of the seed coat of white beans (Phaseolus vulgaris L.). The severity of pod discoloration varied from dark grey flecks or stipples to dark grey patches which later coalesced. Seeds from severely affected pods often showed varying degrees of discoloration, which persisted through processing. Benomyl and chlorothalonil sprays, used to control white mold (Sclerotinia sclerotiorum), significantly increased the incidence of discoloration. In vitro, A. alternata was insensitive to both fungicides. There was more black pod disease and seed-coat discoloration in the early maturing cultivar Seafarer, than in the late-maturing cultivar Fleetwood.


1992 ◽  
Vol 27 (2) ◽  
pp. 143-153 ◽  
Author(s):  
Harry Bottenberg ◽  
Michael E. Irwin

Rhopalosiphum maidis (Fitch) dominated the aerial aphid plankton in bean (Phaseolus vulgaris L.) monocultures and mixed cultures of bean with corn (Zea mays L.) in Illinois. It was also the most common species landing on bean plants in this study during the summer of 1987. More flight activity was recorded in the monocultures than in the mixtures. More R. maidis flew at the top of the bean canopy than at the level of the corn canopy. Densely planted corn rows suppressed flight activity more than did sparsely planted rows. Plots that were planted early had lower aphid catches over the same time than did plots planted 13 and 24 days later. Aphid flight activity was negatively correlated with ground cover, corn barrier height, and corn barrier density. Aphid landing activity was not affected by planting date or corn row density but was negatively and significantly correlated with ground cover. Stepwise regression analysis revealed that ground cover was more important than barrier height and barrier density in suppressing flight and landing activity of R. maidis.


1989 ◽  
Vol 69 (3) ◽  
pp. 695-699 ◽  
Author(s):  
R. M. N. KUCEY

Dinitrogen fixation with field bean (Phaseolus vulgaris L. 'GN1140') and pea (Pisum sativum L. 'Trapper') over the growing season under field conditions was determined using 15N isotope dilution methods. Levels of N2 fixation were low during the early part of the growing season for both bean and pea, and increased later in the growing season. At physiological maturity, GN1140 fixed over 91 kg N ha−1, contributing between 60 and 90% of the N in the bean plants. Pea fixed 117 kg N ha−1, which constituted a maximum of 57% of the pea plant N. More N was contained in the bean and pea pods than was fixed over the growing season. Key words: Bean (field), pea, Phaseolus vulgaris, Pisum sativum, 15N dilution


2012 ◽  
Vol 10 (3) ◽  
pp. 254-257
Author(s):  
Erwin Aragon ◽  
Claudia Rivera ◽  
Helena Korpelainen ◽  
Aldo Rojas ◽  
Paula Elomaa ◽  
...  

A total of 60 farmers' cacao accessions (Theobroma cacao L.) from Nicaragua were investigated using microsatellite markers to reveal their genetic composition and to identify potentially resistant genotypes against the black pod disease caused by Phytophthora palmivora. These accessions were compared with 21 breeders' accessions maintained locally, two Criollo accessions from Costa Rica and two accessions from Ecuador. The analyses showed a low level of differentiation among groups of farmers' accessions (FST = 0.06) and that six Nicaraguan accessions were genetically closely related to the two Criollo accessions used as a reference. In addition, seven distinct genotypes were found to have allelic composition that may indicate linkage to resistance alleles, thus being potential parental lines in future breeding programmes.


Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Marcelo H. Jorge ◽  
Sara E. Sweeten ◽  
Michael C. True ◽  
Samuel R. Freeze ◽  
Michael J. Cherry ◽  
...  

Abstract Background Understanding the effects of disturbance events, land cover, and weather on wildlife activity is fundamental to wildlife management. Currently, in North America, bats are of high conservation concern due to white-nose syndrome and wind-energy development impact, but the role of fire as a potential additional stressor has received less focus. Although limited, the vast majority of research on bats and fire in the southeastern United States has been conducted during the growing season, thereby creating data gaps for bats in the region relative to overwintering conditions, particularly for non-hibernating species. The longleaf pine (Pinus palustris Mill.) ecosystem is an archetypal fire-mediated ecosystem that has been the focus of landscape-level restoration in the Southeast. Although historically fires predominately occurred during the growing season in these systems, dormant-season fire is more widely utilized for easier application and control as a means of habitat management in the region. To assess the impacts of fire and environmental factors on bat activity on Camp Blanding Joint Training Center (CB) in northern Florida, USA, we deployed 34 acoustic detectors across CB and recorded data from 26 February to 3 April 2019, and from 10 December 2019 to 14 January 2020. Results We identified eight bat species native to the region as present at CB. Bat activity was related to the proximity of mesic habitats as well as the presence of pine or deciduous forest types, depending on species morphology (i.e., body size, wing-loading, and echolocation call frequency). Activity for all bat species was influenced positively by either time since fire or mean fire return interval. Conclusion Overall, our results suggested that fire use provides a diverse landscape pattern at CB that maintains mesic, deciduous habitat within the larger pine forest matrix, thereby supporting the diverse bat community at CB during the dormant season and early spring.


1970 ◽  
Vol 48 (12) ◽  
pp. 2213-2217 ◽  
Author(s):  
B. Singh ◽  
D. K. Salunkhe

A solution containing 0.5 p.p.m. of atrazine, simazine, igran, or GS-14254 with 0.2% triton-B 1956 was applied to the foliage of 11-day-old seedlings of bush beans, Phaseolus vulgaris L. cultivar Tender-green, growing on vermiculite in a controlled environment. The activities of nitrate reductase, glutamic-pyruvic transaminase, α-amylase, starch phosphorylase, and adenosine triphosphatase were determined 5,10, and 20 days after treatment. In general, the activity of each of the five enzymes was stimulated by the treatment. The results suggest that protein increase following the application of.s-triazines to bean plants may stem in part from an enhanced rate of amino acid formation resulting from the induced increment in nitrate reductase and transaminase activity. The application of these chemicals also creates a metabolic condition favorable for greater use of carbohydrates needed for nitrate reduction and protein synthesis, and as a source of organic acid synthesis.


2007 ◽  
Vol 43 (4) ◽  
pp. 455-462 ◽  
Author(s):  
G. LOCKWOOD ◽  
F. OWUSU-ANSAH ◽  
Y. ADU-AMPOMAH

Broad sense heritabilities were estimated in three long-term cocoa clone trials in Ghana, with 20, 18 and 15 entries. They were 0.15, 0.05 and 0.15 for yield in pods per plant, and 0.26, 0.19 and 0.40 for incidence of ‘bad’ pods, mostly due to black pod disease, caused by infection with Phytophthora spp. The low heritability of single plant yield, which has been known for 80 years, has been widely overlooked in cocoa research and extension, compromising the success of clone selection programmes. The heritability of the incidence of black pod disease is high enough to justify mass selection where family level data are not available. The findings will be applied in a new large-scale programme in Ghana to select clones that are high yielding in the presence of P. megakarya.


1995 ◽  
Vol 73 (6) ◽  
pp. 937-942 ◽  
Author(s):  
Heather Sinton Gerling ◽  
Arthur W. Bailey ◽  
Walter D. Willms

The response of Festuca hallii (Vassey) Piper to time of burning was examined on the Festuca–Stipa grasslands of the Aspen Parklands at the University of Alberta Ranch located 150 km southeast of Edmonton, Alberta. Two defoliation treatments (burning and mowing) were examined on five dates in 1978 (8 April, 27 April, 1 June, 31 July, and 18 October), corresponding to different phenological stages of F. hallii. Burning and mowing reduced the standing crop of F. hallii produced in the first growing season after treatment, but tiller densities increased. Defoliation in early spring (8 April) had little effect on the standing crop; apparently the increase in tiller density compensated for the reduction in tiller length. Inflorescence density also increased following burning or mowing from 8 April to 1 June. Soil temperature (3 cm deep) on previously burned or mown sites was greater than on the control the year after treatment. Festuca hallii tolerates single burns at any time of the year, but early spring fires have the greatest benefits by increased tillering and standing crop. Key words: standing crop, tiller number, leaf length, litter, defoliation, mowing.


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