Inhibition of oomycetes by the mixture of maleic acid and copper sulfate

Plant Disease ◽  
2021 ◽  
Author(s):  
Jehyeong Yeon ◽  
Ae Ran Park ◽  
Hang Thi Thu Nguyen ◽  
Hanna Gwak ◽  
Jiwon Kim ◽  
...  

After the discovery of the protective activity of Bordeaux mixture against plant disease caused by oomycetes, copper compounds have been used for over a century as a significant plant protection strategy. However, application of excessive copper can cause adverse effects through long-term heavy metal accumulation in soils. Therefore, it is necessary to develop new strategies to reduce or replace copper in pesticides based on organic and low-input farming systems. Organic acids are eco-friendly in nature. In this study, we tested the antifungal and anti-oomycete activity of maleic acid (MA) and copper sulfate (CS) against thirteen plant pathogens. Treatment of MA and CS mixture showed strong anti-oomycetes activity against Phytophthora cambivora, P. capsici and P. cinamomi. Moreover, the concentration of CS in the activated mixture of MA and CS was lower than that in the activated CS only, and the mixture showed synergy or partial synergy effects on the anti-oomycete activity. Application of a wettable powder formulation of MA and CS mixture (MCS 30WP; 26.67 % MA and 3.33 % CS) exhibited excellent protective activities in pot experiments with control values of 73 % Phytophthora blight on red pepper, 91 % damping-off on cucumber, and 84 % Pythium blight on creeping bentgrass, which are similar to those of the CS wettable powder formulation (6.67 % CS) containing two times the CS content in MCS 30WP. These observations suggest that the synergistic effect of the MA and CS combination is a sustainable alternative for effective management the destructive oomycete diseases.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marta Matuszewska ◽  
Tomasz Maciąg ◽  
Magdalena Rajewska ◽  
Aldona Wierzbicka ◽  
Sylwia Jafra

AbstractPseudomonas donghuensis P482 is a tomato rhizosphere isolate with the ability to inhibit growth of bacterial and fungal plant pathogens. Herein, we analysed the impact of the carbon source on the antibacterial activity of P482 and expression of the selected genes of three genomic regions in the P482 genome. These regions are involved in the synthesis of pyoverdine, 7-hydroxytropolone (7-HT) and an unknown compound (“cluster 17”) and are responsible for the antimicrobial activity of P482. We showed that the P482 mutants, defective in these regions, show variations and contrasting patterns of growth inhibition of the target pathogen under given nutritional conditions (with glucose or glycerol as a carbon source). We also selected and validated the reference genes for gene expression studies in P. donghuensis P482. Amongst ten candidate genes, we found gyrB, rpoD and mrdA the most stably expressed. Using selected reference genes in RT-qPCR, we assessed the expression of the genes of interest under minimal medium conditions with glucose or glycerol as carbon sources. Glycerol was shown to negatively affect the expression of genes necessary for 7-HT synthesis. The significance of this finding in the light of the role of nutrient (carbon) availability in biological plant protection is discussed.


Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2393
Author(s):  
Xiuping Wang ◽  
Fei Peng ◽  
Caihong Cheng ◽  
Lina Chen ◽  
Xuejuan Shi ◽  
...  

Plant pathogens constantly develop resistance to antimicrobial agents, and this poses great challenges to plant protection. Therefore, there is a pressing need to search for new antimicrobials. The combined use of antimicrobial agents with different antifungal mechanisms has been recognized as a promising approach to manage plant diseases. Graphene oxide (GO) is a newly emerging and highly promising antimicrobial agent against various plant pathogens in agricultural science. In this study, the inhibitory activity of GO combined with fungicides (Mancozeb, Cyproconazol and Difenoconazole) against Fusarium graminearum was investigated in vivo and in vitro. The results revealed that the combination of GO and fungicides has significant synergistic inhibitory effects on the mycelial growth, mycelial biomass and spore germination of F. graminearum relative to single fungicides. The magnitude of synergy was found to depend on the ratio of GO and fungicide in the composite. In field tests, GO–fungicides could significantly reduce the disease incidence and disease severity, exhibiting a significantly improved control efficacy on F. graminearum. The strong synergistic activity of GO with existing fungicides demonstrates the great application potential of GO in pest management.


2018 ◽  
Vol 56 (1) ◽  
pp. 581-610 ◽  
Author(s):  
Cristina Rosa ◽  
Yen-Wen Kuo ◽  
Hada Wuriyanghan ◽  
Bryce W. Falk

The origin of RNA interference (RNAi), the cell sentinel system widely shared among eukaryotes that recognizes RNAs and specifically degrades or prevents their translation in cells, is suggested to predate the last eukaryote common ancestor ( 138 ). Of particular relevance to plant pathology is that in plants, but also in some fungi, insects, and lower eukaryotes, RNAi is a primary and effective antiviral defense, and recent studies have revealed that small RNAs (sRNAs) involved in RNAi play important roles in other plant diseases, including those caused by cellular plant pathogens. Because of this, and because RNAi can be manipulated to interfere with the expression of endogenous genes in an intra- or interspecific manner, RNAi has been used as a tool in studies of gene function but also for plant protection. Here, we review the discovery of RNAi, canonical mechanisms, experimental and translational applications, and new RNA-based technologies of importance to plant pathology.


Plant Disease ◽  
2021 ◽  
Author(s):  
Li Wang ◽  
Tian Qian ◽  
Pei Zhou ◽  
Wenjun Zhao ◽  
Xianchao Sun

Clavibacter michiganensis subsp. michiganensis (Cmm), the cause of bacterial canker disease, is one of the most destructive pathogens in greenhouse and field tomato. The pathogen is now present in all main production areas of tomato and is quite widely distributed in the EPPO(European and Mediterranean Plant Protection Organization)region. The inspection and quarantine of the plant pathogens relies heavily on accurate detection tools. Primers and probes reported in previous studies do not distinguish the Cmm pathogen from other closely related subspecies of C. michiganensis, especially the non-pathogenic subspecies that were identified from tomato seeds recently. Here, we have developed a droplet digital polymerase chain reaction (ddPCR) method for the identification of this specific bacterium with primers/TaqMan probe set designed based on the pat-1 gene of Cmm. This new primers/probe set has been evaluated by qPCRthe real time PCR(qPCR) and ddPCR. The detection results suggest that the ddPCR method established in this study was highly specific for the target strains. The result showed the positive amplification for all 5 Cmm strains,and no amplification was observed for the other 43 tested bacteria, including the closely related C. michiganensis strains. The detection threshold of ddPCR was 10.8 CFU/mL for both pure Cmm cell suspensions and infected tomato seed, which was 100 times-fold more sensitive than that of the real-time PCR (qPCR ) performed using the same primers and probe. The data obtained suggest that our established ddPCR could detect Cmm even with low bacteria load, which could facilitate both Cmm inspection for pathogen quarantine and the routine pathogen detection for disease control of black canker in tomato.


Author(s):  
Wafaa Mokhtari ◽  
Mohamed Achouri ◽  
Abdellah Remah ◽  
Noureddine Chtaina ◽  
Hassan Boubaker

In this chapter, the authors introduce two research axes: Part A, nano-biosensors as ad-hoc technologies designed to meet plant diagnostic sensitivity and specificity needs at point of care, and Part B, the study of the interaction of drought and infection stresses in crops investigating bio-control potential antagonists in developing integrated approach (IPM) for disease control measures in crops system. The first part will be revising most used nano-biosensors in plant pathogens detection using different platforms in greenhouses, on-field, and during postharvest. A special focus will be on optical and voltametric immuno/DNA sensors application in plant protection. The last part will present case studies of using nanoparticles functionalized with antibody/DNA for detecting pathogenic Pseudomonas sp, mosaic viruses, Botrytis cinereal, and Fusarium mycotoxins (DON). The second part will be interpreting experimental results of a case study on evaluating bio-control efficacy of local Trichoderma spp. using root dips treatment in Fusarium solani-green beans pathosystem as a model.


Author(s):  
Deepti Malviya ◽  
Pramod Kumar Sahu ◽  
Udai B. Singh ◽  
Surinder Paul ◽  
Amrita Gupta ◽  
...  

Microorganisms area treasure in terms of theproduction of various bioactive compounds which are being explored in different arenas of applied sciences. In agriculture, microbes and their bioactive compounds are being utilized in growth promotion and health promotion withnutrient fortification and its acquisition. Exhaustive explorations are unraveling the vast diversity of microbialcompounds with their potential usage in solving multiferous problems incrop production. Lipopeptides are one of such microbial compounds which havestrong antimicrobial properties against different plant pathogens. These compounds are reported to be produced by bacteria, cyanobacteria, fungi, and few other microorganisms; however, genus Bacillus alone produces a majority of diverse lipopeptides. Lipopeptides are low molecular weight compounds which havemultiple industrial roles apart from being usedas biosurfactants and antimicrobials. In plant protection, lipopeptides have wide prospects owing totheirpore-forming ability in pathogens, siderophore activity, biofilm inhibition, and dislodging activity, preventing colonization bypathogens, antiviral activity, etc. Microbes with lipopeptides that haveall these actions are good biocontrol agents. Exploring these antimicrobial compounds could widen the vistasof biological pest control for existing and emerging plant pathogens. The broader diversity and strong antimicrobial behavior of lipopeptides could be a boon for dealing withcomplex pathosystems and controlling diseases of greater economic importance. Understanding which and how these compounds modulate the synthesis and production of defense-related biomolecules in the plants is a key question—the answer of whichneeds in-depth investigation. The present reviewprovides a comprehensive picture of important lipopeptides produced by plant microbiome, their isolation, characterization, mechanisms of disease control, behavior against phytopathogens to understand different aspects of antagonism, and potential prospects for future explorations as antimicrobial agents. Understanding and exploring the antimicrobial lipopeptides from bacteria and fungi could also open upan entire new arena of biopesticides for effective control of devastating plant diseases.


1979 ◽  
Vol 62 (6) ◽  
pp. 1220-1221
Author(s):  
Charles J Cohen ◽  
◽  
J B Audino ◽  
M Byrne ◽  
G S Grimes ◽  
...  

Abstract A collaborative study on the assay of Guthion (azinphos methyl) has been conducted by 10 laboratories. Data were obtained on a 2 Ib/gal. liquid concentrate and a 50% wettable powder formulation. The procedure specifies extraction and/or dilution followed by infrared absorbance measurement at 654 cm-1. The method has been adopted as official first action.


Weed Science ◽  
1982 ◽  
Vol 30 (4) ◽  
pp. 369-371
Author(s):  
Azmi Y. Shawa

Napropamide [2-(a-naphthoxy)N,N-diethylpropionamide] applied to cranberry (Vaccinium macrocarponAit.) as a granular or wettable powder formulation at 20 kg/ha in March 1978 controlled aster (Aster subspicatusNees) and birdsfoot trefoil (Lotus corniculatusL.) without any phytotoxicity to ‘McFarlin’ cranberry vines. Earlier application in February was ineffective, and late application in April injured the vines. Napropamide 10% granular applied at 14 kg/ha in March 1979 controlled aster 90% and birdsfoot trefoil 70%, and the 50% wettable powder formulation controlled aster 90% and birdsfoot trefoil 80%. Applications of granular napropamide at 12 kg/ha in March of 1979 or 1980 controlled both weeds 70%.


1979 ◽  
Vol 19 (101) ◽  
pp. 706 ◽  
Author(s):  
MH Campbell ◽  
AR Gilmour

Four experiments were carried out at Orange, New South Wales, in 1978 to test the effect of coating seeds with insecticides on their removal by seed harvesting ants (Pheidole sp.). Treated or untreated seeds of Phalaris aquatica were placed 10 cm from the entrance to an ant nest and the number of seeds taken by ants noted daily. Further experiments tested the effect of coating seeds with insecticides on the germination of P. aquatica and Medicago sativa and on the viability of rhizobia applied to the seed. Permethrin, at 1.50 and 2.25 g a.i. kg-1 seed and bendiocarb at 0.75, 1.50 and 2.25 g a.i. kg-1 seed significantly reduced the rate of removal of seed by ants when compared with the rate of removal of untreated seed. Ants removed untreated seed at > 150 seedsinest day-1 while treated seed was removed at an average of 5 seedslnest day-1 over a 14 day period. The wettable powder formulation of permethrin was as effective as the miscible oil formulation. The activity of ants from nests that took treated seed was reduced by the higher rates of bendiocarb, but not affected by permethrin and the low rate of bendiocarb when compared with the activity of ants from nests that took untreated seed. The miscible oil formulation of permethrin reduced the rate of germination of P. aquatica, but the wettable powder formulation of both permethrin and bendiocarb had no deleterious effect on germination. Neither permethrin nor bendiocarb had deleterious effects on the survival of Rhizobium meliloti or R. trifolii.


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