scholarly journals Investigation of Seed Treatments for Management of Bacterial Leaf Spot of Lettuce

Plant Disease ◽  
2002 ◽  
Vol 86 (2) ◽  
pp. 151-155 ◽  
Author(s):  
Ken Pernezny ◽  
Russell Nagata ◽  
Richard N. Raid ◽  
Janice Collins ◽  
Amanda Carroll

Chemical seed treatments were evaluated for efficacy of disinfestation of lettuce seed that had been inoculated with Xanthomonas campestris pv. vitians. Three concentrations of each chemical were evaluated by treating seed lots for 5 or 15 min. In addition, the effects of each seed treatment on seed germination and early plant growth were examined by observing seed germination rates. Bacteria were not detected when seed were treated with 3 or 5% hydrogen peroxide for 5 or 15 min. Treatment of seed with 0.52% sodium hypochlorite was relatively ineffective at 5 and 15 min. When sodium hypochlorite was used at a 1% concentration for 15 min, the level of bacterial infestation was reduced to 2%. Suspensions of copper hydroxide plus mancozeb also reduced seedborne inoculum to ≤2%. Treatment of seed with copper hydroxide alone, benzoyl peroxide, or calcium peroxide did not reduce seed infestation levels significantly. Seed germination rates were 90% or greater for the majority of seed treatments tested in laboratory assays. Hydrogen peroxide treatments at a concentration of 5% reduced seed germination up to 28% compared with controls. However, no significant differences in germination were observed among control treatments (noninoculated, nontreated seed and inoculated, nontreated seed) and any of the chemical seed treatments when seed were sown in a pasteurized soil mix in the greenhouse.

Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 295-299 ◽  
Author(s):  
O. Carisse ◽  
A. Ouimet ◽  
V. Toussaint ◽  
V. Philion

As a part of a broader program for management of bacterial leaf spot, the effects of lettuce-seed treatments, greenhouse application of bactericides, and cultivars were evaluated. Seed artificially inoculated with Xanthomonas campestris pv. vitians was treated with bactericides or heat treated and evaluated for the incidence of contaminated seed and seed germination. Seed soaked in 1% sodium hypochlorite for 5 and 20 min had an incidence of contaminated seed of less than 10%. Dry-heat (1 h), hot-water (50°C, 2 h), and organic-acid treatments significantly reduced seed germination. Considering both the effects on incidence of contaminated seed and seed germination, the best treatments were soaking the seeds in 1% sodium hypochlorite for 5 or 20 min. Copper sulfate, alone or mixed with Zineb or Dithane, failed to control the disease and caused phytotoxicity. All of the other bactericides significantly reduced the severity of bacterial leaf spot. However, the differences among bactericide efficacy were too small to allow comparison between the different forms of copper used, as well as the effect of adding manganese and zinc (Dithane) or zinc alone (Zineb) to the copper product. Nevertheless, copper hydroxide alone, mixed with Zineb or mixed with Dithane, and basic copper sulfate reduced disease severity by 86.89, 78.67, 80.42, and 81.82%, respectively, without causing phytotoxicity. For the two years of cultivar evaluation, no significant difference in mean disease severity was observed among the cultivars. Based on disease incidence, the most susceptible cultivar was Bellagreen. Cvs. Ideal cos, Grand Teton, Great Lakes, Paris Island, Ithaca, and Optima showed intermediate susceptibility, and the least-susceptible cultivars were Waldmann's and Grand Rapids, both green-leaf type. There was no significant difference between the three romaine (cos) cultivars and between the two crisphead cultivars, but a significant difference was observed between the two butterhead types, Bellagreen and Optima, which had 80.04 and 48.01%, respectively, of their leaves diseased at the time of harvest.


2021 ◽  
Vol 10 (3) ◽  
pp. 206-210
Author(s):  
Bhut JB ◽  
◽  
Jethva DM ◽  
Naggana R ◽  
◽  
...  

Field experiment on evaluation of insecticidal seed treatments against white grub Holotrichia consanguinea Blachard infesting groundnut was conducted during kharif 2018 and 2019 at farmers field. The nine insecticides evaluated as seed treatment against white grub infesting groundnut, the lowest per cent plant morality and number of grub/m2 was observed in treatment of clothianidin 50 WDG @ 2 g a.i. /kg and imidacloprid 40 + fipronil 40 WG @ 3 g a.i. /kg. These treatments were produced 2329 and 2296 yield of pod, 3970 & 3780 kg/ha yield of halum, respectively. Increased in yield over control in these treatments was recorded 57.79 and 55.56 per cent in pod, 76.29 and 64.65 per cent in halum. Whereas avoidable yield loss recorded of these treatments was recorded 36.63 and 35.71 per cent in pod, 43.27 and 39.27 per cent in halum. However, the highest 1:28.32 NICRB was recorded in treatment of chlorpyriphos 20 EC @ 30 ml a.i. /kg. The NICRB of clothianidin 50 WDG @ 2 g a.i. /kg and imidacloprid 40 + fipronil 40 WG @ 3 g a.i. /kg were recorded 1:14.95 and 1:9.20, respectively. The evaluated insecticides had no adverse effect on seed germination


Author(s):  
Amit Kumar Tiwari ◽  
Prawal P.S. Verma ◽  
Dipender Kumar ◽  
Sonveer Singh ◽  
Rakesh Kumar ◽  
...  

Background: Sarpagandha is an indigenous medicinal herb of Indian continent. It has many medicinal properties. Due to increasing demand of Sarpagandha, its exploitation is increasing continuously but for lack of cultivation, this plant has been listed in endangered category. Commercially, it is propagated through seeds but the main barrier of seed propagation is its irregular and low germination. Hence, the current study was undertaken to study the effect of growing media and seed treatment methods on seed germination and seedling growth of Sarpagandha to eliminate the inhibitory effect of the hard stony endocarp.Methods: Seed germination and seedling growth experiments of Sarpagandha were carried out with following different seed treatments, T1 (Control), T2 (Water soaking for 24 hours), T3 (water soaking for 48 hours), T4 (Water soaking for 24 hours + cotton cloth wrapping for 24 hours), T5 (GA3 200 ppm), T6 (FYM treatment for 24 hours), T7 (FYM treatment for 48 hours), T8 (Hot water treatment) and T9 (Cow dung treatment for 24 hours). Experiment was laid out in CRD. The data recorded on the various parameters were analyzed at 5% level of significance by using ANOVA.Result: Results indicated highest germination percentage (51), lowest mortality percent (49), minimum days for initiation of germination (23), minimum days taken for germination completion (33), highest speed of germination (3.77), maximum vigour index (1441.44), highest root (11.27 cm) and highest shoot length (17 cm) in T5 (GA3 200 ppm) followed by T3 (water soaking for 48 hours). Indicating, T5 (GA3 200 ppm) to be best seed treatment for higher germination and subsequent seedling growth of Sarpagandha (Rauvolfia serpentine L.).


2018 ◽  
Vol 98 (3) ◽  
pp. 648-656
Author(s):  
A.P. Friesen ◽  
R.L. Conner ◽  
D.E. Robinson ◽  
W.R. Barton ◽  
S. Chatterton ◽  
...  

Halo blight, caused by Pseudomonas syringae pv. phaseolicola, is a seed-borne disease of dry bean (Phaseolus vulgaris L.) that lowers seed quality and yield. Over 2 yr, laboratory and field studies were conducted to evaluate the effect of microwave radiation on two market classes: navy (‘Envoy’) and white kidney (‘GTS 402’) bean. In the laboratory, seed germination and vigour decreased up to 15% after 40 s of microwave exposure, where <7% decrease was observed during 0–30 s. Disease plating showed no correlation between pathogen colonization of the seed and microwave radiation, as incidence of pathogen colonization was low across all exposure times. In field trials in Morden and Winkler, MB, microwave radiation was tested alone and in combination with copper hydroxide 53.8% and pyraclostrobin + fluxapyroxad + metalaxyl. Seed treatment with copper hydroxide slightly decreased the incidence of halo blight but had little impact on seed pick, hundred-seed weight, yield, or return on investment. Pyraclostrobin + fluxapyroxad + metalaxyl seed treatment had no effect on any of these parameters. Microwave radiation lowered seed emergence by up to 9% but did not reduce disease incidence and severity or increase yield or return of investment when applied alone or in combination with a chemical treatment.


2020 ◽  
Vol 11 (1) ◽  
pp. 60-66
Author(s):  
A. I. Bozhkov ◽  
M. K. Kovalova ◽  
Z. A. Azeez ◽  
А. V. Goltvjansky

The importance of studying pre-sowing seed treatment lies in the possibility of regulating the rate of seed germination, the intensity of their growth and obtaining root exudates in biotechnology. The effect of three pre-sowing treatment methods was examined (control – washing with running water; the first method – washing with 0.05% sodium permanganate solution; the second method – 30 se­conds in 70% ethyl alcohol (C2H5OH) and 30 minutes in 5% sodium hypochlorite (NaOCl); the third method – 5 minutes in 70% C2H5OH and 40 minutes in 5% NaOCl) on the growth rate, germination rate, excretion rate of seeds of wheat and peas and composition (of protein, carbohydrate, amino acid content) of root exudates from the first to the third day of growth in order to obtain root exudates. It was revealed that the same pre-sowing treatment of wheat and pea seeds has a different effect on the rate and variability of seedling growth from the first to the third day, as well as on the qualitative and quantitative composition of root exudates. It was shown that pre-sowing treatment of wheat and pea seeds for 5 minutes with 70% ethanol followed by treatment with sodium hypochlorite (a “hard” treatment method) accelerates seedling growth and seed germination. This method of treatment reduces the intensity of excretion of root exudates and composition in wheat, but it increases the intensity of excretion in peas. The discovered effects can be explained by hormesis. Additionally, the third method of pre-sowing seed treatment can be used in root technologies for obtaining root exudates.


Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2397
Author(s):  
Marco Pepe ◽  
Mohsen Hesami ◽  
Andrew Maxwell Phineas Jones

In vitro seed germination is a useful tool for developing a variety of biotechnologies, but cannabis has presented some challenges in uniformity and germination time, presumably due to the disinfection procedure. Disinfection and subsequent growth are influenced by many factors, such as media pH, temperature, as well as the types and levels of contaminants and disinfectants, which contribute independently and dynamically to system complexity and nonlinearity. Hence, artificial intelligence models are well suited to model and optimize this dynamic system. The current study was aimed to evaluate the effect of different types and concentrations of disinfectants (sodium hypochlorite, hydrogen peroxide) and immersion times on contamination frequency using the generalized regression neural network (GRNN), a powerful artificial neural network (ANN). The GRNN model had high prediction performance (R2 > 0.91) in both training and testing. Moreover, a genetic algorithm (GA) was subjected to the GRNN to find the optimal type and level of disinfectants and immersion time to determine the best methods for contamination reduction. According to the optimization process, 4.6% sodium hypochlorite along with 0.008% hydrogen peroxide for 16.81 min would result in the best outcomes. The results of a validation experiment demonstrated that this protocol resulted in 0% contamination as predicted, but germination rates were low and sporadic. However, using this sterilization protocol in combination with the scarification of in vitro cannabis seed (seed tip removal) resulted in 0% contamination and 100% seed germination within one week.


2014 ◽  
Vol 21 (2) ◽  
pp. 309-326 ◽  
Author(s):  
Dorota Szopińska

Abstract The decrease of seed quality during storage is strongly associated with damage caused by free radicals. Some compounds of natural origin, known due to their antioxidative and antifungal properties, may be potentially used in organic production for seed treatment as an alternative to pesticides. The aim of the experiment was to study an ability of hydrogen peroxide and organic acid to improve germination, vigour and health of non-deteriorated and deteriorated zinnia seeds. Two seed samples, cv. Illumination and Orys, varying in initial infestation with fungi were tested. For deterioration seeds were kept at 30°C and 80% RH for 30 days. Seed quality tests were performed before and after deterioration for controls and seeds soaked in 3.0% hydrogen peroxide solution and in 1.0 and 5.0% solutions of ascorbic and lactic acids for 10, 30 and 60 min. The controls were untreated seeds, seeds soaked in 0.2% solution of Kaptan zawiesinowy 50 WP for 30 min and seeds soaked in distilled water for 10, 30 and 60 min. Treating zinnia seeds with organic acids more significantly affected seed germination and health after deterioration than before, and improvement of germination capacity was usually correlated with decrease of the percentage of abnormal diseased seedlings. Deterioration had no influence on mean germination time, whereas in particular cases treating seeds with hydrogen peroxide and organic acids negatively affected this parameter. After deterioration regardless of treatment increased number of seeds free from fungi. Lactic acid followed by hydrogen peroxide and ascorbic acid effectively limited growth of A. alternata, A. zinnia and Fusarium spp. on zinnia seeds, however at higher concentration negatively affected seed germination and vigour. Moreover, treating seeds with hydrogen peroxide and organic acids many a time increased seeds infestation with B. cinerea.


Author(s):  
M. S. Teodoro ◽  
M. C. S. Alves ◽  
M. N. Lacerda ◽  
L. M. S. Araújo

<p>O presente trabalho foi desenvolvido em condições de casa de vegetação situada em Parnaíba-PI, município onde predominam altas temperaturas. Objetivou-se avaliar a germinação de diferentes lotes de sementes de alface antes e após a embebição em solução de hipoclorito de sódio (NaCIO). O delineamento experimental foi em blocos casualisados, com os tratamentos dispostos em arranjo fatorial 2 x 7 (duas variáveis como pré-germinativos: com imersão em NaClO e sem imersão em NaClO, e sete cultivares de alface), com quatro repetições. As variáveis analisadas foram: Primeira contagem do teste de germinação (PCG), Teste de germinação (TG) e Índice de velocidade de germinação (IVG). Analisando-se os dados obtidos, verificou-se que independente da presença ou ausência do tratamento pré-germinativo, a cultivar T6 foi a que apresentou os melhores resultados para as variáveis analisadas. Exceto T2, todas as outras cultivares que receberam tratamento com hipoclorito de sódio (NaClO) obtiveram resultados expressivos, em comparação com as que não receberam esse tratamento, entretanto, a germinação de todos os lotes foi inferior ao estabelecido para comercialização de sementes de alface, com recomendações acima de 80%. </p><p align="center"><strong><em>Influence of NaClO on lettuce seed germination in Parnaíba-PI</em></strong></p><p><strong>Abstract</strong><strong>: </strong>The present study aimed to evaluate, under conditions of a greenhouse located in Parnaiba, PI, where high temperatures and after soaking in solution of sodium hypochlorite (NaCIO), the germination of seeds of seven cultivars of lettuce. The experimental design was of randomized blocks, with treatments arranged in factorial arrangement 2 x 7 (two variables as pré-germinativos: with NaClO and immersion without immersion in NaClO, and seven cultivars of lettuce), with four replicates. The seeds were subjected to the following determinations: First germination test score (PCG), germination test (TG) and germination speed Index (IVG). Analyzing the data obtained, it was found that regardless of the presence or absence of treatment pre-germinative, cultivating T6 was presented the best results for the variables analyzed. Except for T2, all other cultivars that received treatment with sodium hypochlorite (NaClO) achieved significant results, compared to those who did not receive this treatment, however, the germination of all batches was lower than that established for commercialization of seeds of lettuce, with recommendations above 80.</p>


2005 ◽  
Vol 23 (1) ◽  
pp. 4-8 ◽  
Author(s):  
Tyler L. Burgess ◽  
Frank A. Blazich ◽  
David L. Nash ◽  
Betsy Randall-Schadel

Abstract Seeds of southern seaoats (Uniola paniculata L.) were removed from storage at 4C (39F) and treated with the following selected surface disinfestants, fungicides, or combinations of these chemicals: nontreated (control), 1.3% sodium hypochlorite [NaOCl (chlorine bleach)], 2.6% sodium hypochlorite, RTU® (12.6% thiram + 0.34% thiabendazole), RTU®-PCNB (24% pentachloronitrobenzene), 1.3% sodium hypochlorite and RTU®, 2.6% sodium hypochlorite and RTU®, 1.3% sodium hypochlorite and RTU®-PCNB, or 2.6% sodium hypochlorite and RTU®-PCNB. Following treatment, seeds were germinated at an 8/16 hr thermoperiod of 35/20C (95/68F). The seed treatments and germination thermoperiod utilized were based on three preliminary trials that investigated the influence of selected surface disinfestants, fungicides, and temperature on seed germination of the species. Germination was recorded every 3 days for 30 days. Seed treatment was highly significant (P = 0.0001) for both total percentage germination and total percentage of decayed seeds. Germination of nontreated seeds was 45%, and four treatments resulted in germination &gt; 80% [RTU®-PCNB (81%), 2.6% sodium hypochlorite and RTU® (83%), 1.3% sodium hypochlorite and RTU® (87%), and 1.3% sodium hypochlorite and RTU®-PCNB (89%)]. A subsequent experiment investigated the effects of the aforementioned treatments with the exception of 1.3% sodium hypochlorite and RTU®, both used alone, on initial seedling growth of the species. Following treatment, seeds were sown in containers filled with a peat-based medium and the containers placed in a growth chamber maintained at an 8/16 hr thermoperiod of 35/20C (95/68F) with long day conditions. Emergence data were recorded every 3 days for 45 days. After 45 days, the study was terminated and additional data recorded to include plant height (height of main stem), leaf number, length and width of the two longest leaves, and top and root dry weights. Surface disinfestant, fungicide, and combination treatments were highly significant (P = 0.0004). Percentage emergence of nontreated seeds was 35% and five of the seven treatments resulted in emergence ≥ 75% [2.6% sodium hypochlorite (75%), 1.3% sodium hypochlorite and RTU® (75%), 1.3% sodium hypochlorite and RTU®-PCNB (76%), 2.6% sodium hypochlorite and RTU®-PCNB (81%), and 2.6% sodium hypochlorite and RTU® (83%)] with negligible effects on seedling growth. There were significant treatment differences regarding some of the variables used to evaluate seedling growth. In most cases these differences were due to seedlings from nontreated seeds having lower values for each measured variable than values for the same variables from treated seeds. Results of both experiments demonstrate the potential value of chemical seed treatment during production of seedling transplants of U. paniculata.


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