scholarly journals Evidence for a Pythium sp. as a Chronic Yield Reducer in a Continuous Grain Sorghum Field

Plant Disease ◽  
2001 ◽  
Vol 85 (7) ◽  
pp. 780-784 ◽  
Author(s):  
M. A. Davis ◽  
W. W. Bockus

Pythium spp. have been reported to reduce stands and cause stalk rot of grain sorghum. Evidence is presented that it also can cause a serious seed and root rot in the field under a continuous grain sorghum production system. Experiments were conducted for 4 years in a field that had been cropped continuously to grain sorghum for at least 10 years. Effects of seed treatments with captan and metalaxyl on plant stands, early to mid-season plant vigor, and grain yields were evaluated. In five field experiments, seed treatment with metalaxyl (73 g a.i./100 kg) increased grain yields by an average of 24.0% compared with nontreated seed. In three out of four field experiments, seed treatment with metalaxyl increased grain yields by an average of 13.1% above seed treated with captan (73 g a.i./100 kg). The yield increases could not always be explained in terms of differences among treatments in plant stands or in visual estimates of the amount of top growth 26 to 72 days after sowing. Apparently, the Pythium sp. causes a chronic root and seed rot that has a significant negative effect on grain production without necessarily affecting stands or early to mid-season growth. P. ultimum var. ultimum was the fungus most commonly isolated from roots and seeds collected from the field. Tests for Koch's postulates conducted in a greenhouse verified it as the causal organism. In the greenhouse, treatment with metalaxyl protected seeds and roots from attack by P. ultimum var. ultimum for at least 28 days after planting.

2020 ◽  
Vol 34 (5) ◽  
pp. 699-703
Author(s):  
Jason K. Norsworthy ◽  
Jacob Richburg ◽  
Tom Barber ◽  
Trenton L. Roberts ◽  
Edward Gbur

AbstractAtrazine offers growers a reliable option to control a broad spectrum of weeds in grain sorghum production systems when applied PRE or POST. However, because of the extensive use of atrazine in grain sorghum and corn, it has been found in groundwater in the United States. Given this issue, field experiments were conducted in 2017 and 2018 in Fayetteville and Marianna, Arkansas, to explore the tolerance of grain sorghum to applications of assorted photosystem II (PSII)-inhibiting herbicides in combination with S-metolachlor (PRE and POST) or mesotrione (POST only) as atrazine replacements. All experiments were designed as a factorial, randomized complete block; the two factors were (1) PSII herbicide and (2) the herbicide added to create the mixture. The PSII herbicides were prometryn, ametryn, simazine, fluometuron, metribuzin, linuron, diuron, atrazine, and propazine. The second factor consisted of either no additional herbicide, S-metolachlor, or mesotrione; however, mesotrione was excluded in the PRE experiments. Crop injury estimates, height, and yield data were collected or calculated in both studies. In the PRE study, injury was less than 10% for all treatments except those containing simazine, which caused 11% injury 28 d after application (DAA). Averaged over PSII herbicide, S-metolachlor–containing treatments caused 7% injury at 14 and 28 DAA. Grain sorghum in atrazine-containing treatments yielded 97% of the nontreated. Grain sorghum receiving other herbicide treatments had significant yield loss due to crop injury, compared with atrazine-containing treatments. In the POST study, ametryn- and prometryn-containing treatments were more injurious than all other treatments 14 DAA. Grain sorghum yield in all POST treatments was comparable to atrazine, except prometryn plus mesotrione, which was 65% of the nontreated. More herbicides should be evaluated to find a comparable fit to atrazine when applied PRE in grain sorghum. However, when applied POST, diuron, fluometuron, linuron, metribuzin, propazine, and simazine have some potential to replace atrazine in terms of crop tolerance and should be further tested as part of a weed control program across a greater range of environments.


2009 ◽  
Vol 23 (1) ◽  
pp. 28-33 ◽  
Author(s):  
M. Joy M. Abit ◽  
Kassim Al-Khatib ◽  
David L. Regehr ◽  
Mitchell R. Tuinstra ◽  
Mark M. Claassen ◽  
...  

The selection of herbicide-resistant weeds in grain sorghum production has prompted researchers to explore alternative herbicides to prevent, delay, and manage herbicide-resistant weed biotypes. Greenhouse and field experiments were conducted to evaluate the differential response of sorghum hybrids to POST application of mesotrione. In a greenhouse experiment, 85 sorghum hybrids were treated with 0, 52, 105, 210, and 315 g ai/ha mesotrione when plants were at the three- to four-leaf collar stage. Sorghum response ranged from susceptible to tolerant sorghum hybrids. ‘Pioneer 84G62’, ‘Pioneer 85G01’, and ‘Triumph TR 438’ were the three most susceptible, whereas ‘Dekalb DKS35-70’, ‘Frontier F222E’, and ‘Asgrow Seneca’ were the three most tolerant hybrids. One week after treatment (WAT), the mesotrione rate causing 50% visible injury ranged from 121 to 184 and 64 to 91 g/ha in the most tolerant and susceptible hybrids, respectively. Mesotrione dose–response studies were conducted under field conditions on four sorghum hybrids. One WAT, injury symptoms were greater (up to 23%) in Pioneer 85G01 than in Asgrow Seneca (< 14%). However, all plants appeared normal by the end of the growing season. In addition, sorghum yields were not reduced by mesotrione treatments as verified by correlation coefficient analysis.


2012 ◽  
Vol 26 (1) ◽  
pp. 14-18 ◽  
Author(s):  
M. Joy M. Abit ◽  
Kassim Al-Khatib ◽  
Phillip W. Stahlman ◽  
Patrick W. Geier

Conventional grain sorghum is highly susceptible to POST grass control herbicides. Development of aryloxyphenoxypropionate-resistant grain sorghum could provide additional opportunities for POST herbicide grass control in grain sorghum. Field experiments were conducted at Hays and Manhattan, KS, to determine the effect of quizalofop rate and crop growth stage on injury and yield of aryloxyphenoxypropionate-resistant grain sorghum. Quizalofop was applied at 62, 124, 186, and 248 g ai ha−1at sorghum heights of 8 to 10, 15 to 25, and 30 to 38 cm, which corresponded to early POST (EPOST), mid-POST (MPOST), and late POST (LPOST) application timings, respectively. Grain sorghum injury ranged from 0 to 68% at 1 wk after treatment (WAT); by 4 WAT, plants generally recovered from injury. The EPOST and MPOST applications caused 9 to 68% and 2 to 48% injury, respectively, whereas injury from LPOST was 0 to 16%, depending on rate. Crop injury from quizalofop was more prominent at rates higher than the proposed use rate in grain sorghum of 62 g ha−1. Grain yields were similar in treated and nontreated plots; applications of quizalofop at different timings did not reduce yield except when applied MPOST at the Manhattan site.


2011 ◽  
Vol 34 (9) ◽  
pp. 1330-1340 ◽  
Author(s):  
Daniel W. Sweeney ◽  
Joseph L. Moyer ◽  
Douglas J. Jardine ◽  
David A. Whitney

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rabia Naz ◽  
Asghari Bano ◽  
Asia Nosheen ◽  
Humaira Yasmin ◽  
Rumana Keyani ◽  
...  

AbstractFusarium verticillioides is an important fungal pathogen of maize, causing stalk rot and severely affecting crop production. The aim of this study was to characterize the protective effects of formulations based on Jacaranda mimosifolia leaf extracts against F. verticillioides in maize. We compared different seed treatments comprising J. mimosifolia extracts, chemical fungicide (mefenoxam) and salicylic acid to modulate the defense system of maize host plants. Both aqueous and methanolic leaf extracts of J. mimosifolia (1.2% w/v) resulted in 96–97% inhibition of mycelial growth of F. verticillioides. While a full-dose (1.2%) extract of J. mimosifolia provided significant protective effects on maize plants compared to the inoculated control, a half-dose (0.6% w/v) application of J. mimosifolia in combination with half-strength mefenoxam was the most effective treatment in reducing stalk rot disease in pot and field experiments. The same seed treatment significantly upregulated the expression of genes in the leaves encoding chitinase, glucanase, lipid transfer protein, and pathogenesis-related proteins PR-1, PR-5 and PR-10, 72 h after inoculation. This treatment also induced the activities of peroxidase, polyphenol oxidase, protease, acid invertase, chitinase and phenylalanine ammonia lyase. We conclude that seed pre-treatment with J. mimosifolia extract with half-strength chemical mefenoxam is a promising approach for the management of stalk rot in maize.


Weed Science ◽  
1980 ◽  
Vol 28 (6) ◽  
pp. 699-704 ◽  
Author(s):  
M. E. Winkle ◽  
J. R. C. Leavitt ◽  
O. C. Burnside

R-25788 (N,N-diallyl-2,2-dichloroacetamide) and H-31866 [N-allyl-N-(3,3-dichloroallyl)dichloroacetamide] were more effective than CDAA (N,N-diallyl-2-chloroacetamide) in preventing yield reductions to corn (Zea maysL. ‘NB-611’) from alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide] or metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] in the greenhouse. A CGA-43089 [α-(cyanomethoximino)-benzacetonitrile] seed treatment (1.25 g/kg) was more effective than a R-25788 tank mix in preventing yield reductions to grain sorghum [Sorghum bicolor(L.) Moench ‘G-623 GBR’] from alachlor or metolachlor in the greenhouse. Absorption of14C-alachlor by sorghum seedlings grown in petri dishes, and absorption, translocation, and metabolism of14C-metolachlor by sorghum seedlings grown in soil, were not affected by CGA-43089 seed treatment. Forage sorghum [Sorghum bicolor(L.) Moench ‘Rox Orange’] was used to simulate shatter cane [Sorghum bicolor(L.) Moench] in field plots. In the absence of Rox Orange, alachlor and metolachlor reduced sorghum grain yields. This yield reduction was prevented by a CGA-43089 seed treatment, but not by a R-25788 tank mix with herbicides. In plots seeded with 10,000 Rox Orange seed/57 m2, grain yields of sorghum increased as alachlor or metolachlor plus CGA-43089 rates increased. There was no grain yield response to any herbicide treatment in plots seeded with 50,000 Rox Orange seed/57 m2.


2010 ◽  
Vol 9 (1) ◽  
pp. 1-9
Author(s):  
Daniel W. Sweeney ◽  
Douglas J. Jardine ◽  
Joseph L. Moyer ◽  
David A. Whitney

2017 ◽  
Vol 31 (6) ◽  
pp. 781-792 ◽  
Author(s):  
Thierry E. Besançon ◽  
Ronnie W. Heiniger ◽  
Randy Weisz ◽  
Wesley J. Everman

Weed control remains a major challenge for economically viable grain sorghum production in the southeastern United States due to crop sensitivity to weed competition during early growth stages. Field experiments were conducted in 2012 and 2013 to determine the effects of grain sorghum row spacing, population density, and herbicide programs on Palmer amaranth control, crop growth, and grain yield. Treatments included row spacings of 19, 38, and 76 cm; grain sorghum population densities of 99,000, 198,000, 297,000, and 396,000 plants ha−1; and three herbicide programs: (1) a nontreated control, (2)S-metolachlor at 1,410 g ai ha−1plus atrazine at 1,820 g ha−1PRE, and (3)S-metolachlor at 1,070 g ha−1plus atrazine at 1,380 g ha−1PRE followed by 2,4 D at 330 g ha−1POST. Palmer amaranth control benefited from the addition of a POST herbicide and from crop density ≥297,000 plants ha−1. Under weedy conditions, Palmer amaranth density was not affected by narrower row spacing or increased crop density, whereas its dry biomass was reduced by 33% with 19 and 38 compared to 76 cm rows, and by 43% with ≥297,000 vs 99,000 plants ha−1. Row spacing had no effect on light interception by the crop canopy. However, crop density influenced canopy closure with maximum light interception occurring one and a half weeks earlier for density ≥297,000 plants ha−1. Yield increased by 18% for 19 vs 38 and 76 cm rows, whereas grain crop density had no effect. Overall, these results indicate that the combination of row spacing≤30 cm and crop density ≥297,000 plants ha−1provided at least 97% Palmer amaranth control in the absence of POST application and reduced its biomass by 32% in nontreated plots compared to 76 cm row spacing and crop density≤198,000 plants ha−1.


2013 ◽  
Vol 27 (4) ◽  
pp. 664-670 ◽  
Author(s):  
Seshadri S. Reddy ◽  
Phillip W. Stahlman ◽  
Patrick W. Geier ◽  
Curtis R. Thompson ◽  
Randall S. Currie ◽  
...  

Field experiments were conducted in grain sorghum at five locations in Kansas in 2009 and 2010, to evaluate the efficacy and crop safety of early- to mid-POST (EMPOST) and late-POST (LPOST) applications of premixed pyrasulfotole and bromoxynil (PYRA&BROM) in tank mix combinations with atrazine or atrazine plus 2,4-D ester or dicamba compared to bromoxynil plus atrazine. PYRA&BROM at 244 or 300 g ai ha−1 plus atrazine at 560 g ai ha−1 applied EMPOST controlled pigweed species (Palmer amaranth, tumble pigweed, and redroot pigweed), kochia, velvetleaf, common sunflower, ivyleaf morningglory, and common lambsquarters 93% or greater. Puncturevine control among three locations ranged from 85 to 99%. Control of most weed species was not improved by increasing PYRA&BROM rate from 244 to 300 g ha−1 or by tank mixing 2,4-D or dicamba with PYRA&BROM plus atrazine. However, ivyleaf morningglory control was improved at the LPOST timing by adding 2,4-D or dicamba at 140 g ae ha−1. In no instance did any PYRA&BROM treatment provide greater weed control than bromoxynil plus atrazine at 281 + 560 g ha−1 when applied EMPOST, but in most instances PYRA&BROM treatments were more effective than bromoxynil plus atrazine when applied LPOST. Generally, PYRA&BROM treatments were more effective when applied EMPOST than LPOST, especially when 2,4-D or dicamba was added. PYRA&BROM plus atrazine treatments caused foliar bleaching in sorghum within 7 ± 3 d after treatment, but recovery was complete within 3 to 4 wk and grain yields were not reduced. Tank mixing dicamba with PYRA&BROM and atrazine occasionally reduced visible crop response compared to PYRA&BROM plus atrazine. Our results indicate that PYRA&BROM plus atrazine with or without 2,4-D or dicamba selectively controls several troublesome broadleaf weeds in grain sorghum. Foliar bleaching of sorghum leaves can occur but the symptoms are transient, and grain yields are not likely to be reduced.


2020 ◽  
Vol 4 (41) ◽  
pp. 35-43
Author(s):  
ALEKSEY A. VASIL’EV ◽  
◽  
ALEKSEY N. VASIL’EV ◽  
DMITRIY BUDNIKOV ◽  
ANTON SHARKO

The use of electrophysical influences for pre-sowing treatment of seeds is an effective way to increase their sowing quality. The use of these methods is limited by the fact that their implementation requires new technological equipment in grain processing lines. This problem is solved more easily when pre-sowing processing is performed using installations for active ventilation and grain drying. (Research purpose) The research purpose is in determining the possibility of using active ventilation units and ultra-high-frequency convective grain dryers for pre-sowing grain processing and to evaluating the effectiveness of such processing using computer modeling. (Materials and methods) It is necessary to ensure the uniformity of processing with external influence the seeds placed in a dense layer. Authors carried out pre-sowing treatment of seeds on real installations. Treated seeds were sown in experimental plots and the results of treatment were evaluated. (Results and discussion) The article presents graphs of changes in grain temperature and humidity during processing. To check the feasibility of pre-sowing treatment, authors performed modeling of air-heat and ultra-high-frequency convective seed treatment processes. Based on the results of field experiments, air-heat treatment stimulates the development of secondary plant roots, contributes to an intensive increase in the green mass of plants; ultra-high-frequency convective seed treatment allows increasing the number of productive stems in plants, the number of ears in one plant. (Conclusions) Technological equipment designed for drying and active ventilation of grain can be effectively used for pre-sowing seed processing. In the course of field experiments, it was revealed the possibility of controlling the structure of the crop using different types of external influence on seeds during their pre-sowing processing.


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