Herbicide—Pathogen Interactions and Mycoherbicides as Alternative Strategies for Weed Control

Altman, Jack; Neate, Stephen M.; Rovira, Albert

doi:10.1021/bk-1990-0439.ch013

Cited by 25 publications

(25 citation statements)

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“…However, cell adhesion and bio®lm formation are essential in immobilized cell bioreactors for the ecient entrapment of the biocatalyst (Casey et al, 2000;Lele et al, 1996). In agriculture, the adhesion of microbes is also essential for ecient biological control of insect pest species (Sosa-Gomez et al, 1998) and weeds (Altman et al, 1990). In medicine and dentistry, the adhesion of bacteria and yeast to human tissue is an initial step in the onset of infection.…”

Section: Introductionmentioning

confidence: 99%

The measurement of Bacillus mycoides spore adhesion using atomic force microscopy, simple counting methods, and a spinning disk technique

Bowen

Fenton

Lovitt

et al. 2002

Biotech & Bioengineering

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An atomic force microscope has been used to study the adhesion of Bacillus mycoides spores to a hydrophilic glass surface and a hydrophobic-coated glass surface. AFM images of spores attached to the hydrophobic-coated mica surface allowed the measurement of spore dimensions in an aqueous environment without desiccation. The spore exosporium was observed to be flexible and to promote the adhesion of the spore by increasing the area of spore contact with the surface. Results from counting procedures using light microscopy matched the density of spores observed on the hydrophobic-coated glass surface with AFM. However, no spores were observed on the hydrophilic glass surface with AFM, a consequence of the weaker adhesion of the spores at this surface. AFM was also used to quantify directly the interactions of B. mycoides spores at the two surfaces in an aqueous environment. The measurements used "spore probes" constructed by immobilizing a single spore at the apex of a tipless AFM cantilever. The data showed that stretching and sequential bond breaking occurred as the spores were retracted from the hydrophilic glass surface. The greatest spore adhesion was measured at the hydrophobic-coated glass surface. An attractive force on the spores was measured as the spores approached the hydrophobic-coated surface. At the hydrophilic glass surface, only repulsive forces were measured during the approach of the spores. The AFM force measurements were in qualitative agreement with the results of a hydrodynamic shear adhesion assay that used a spinning disk technique. Quantitatively, AFM measurements of adhesive force were up to 4 x 10(3) times larger than the estimates made using the spinning disk data. This is a consequence of the different types of forces applied to the spore in the different adhesion assays. AFM has provided some unique insights into the interactions of spores with surfaces. No other instrument can make such direct measurements for single microbiological cells.

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Section: Introductionmentioning

confidence: 99%

The measurement of Bacillus mycoides spore adhesion using atomic force microscopy, simple counting methods, and a spinning disk technique

Bowen

Fenton

Lovitt

et al. 2002

Biotech & Bioengineering

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“…The interactions between various herbicides and plant pathogens (Altman et al 1990;Smith 1991;Hoagland 1996), herbicide induction of microbial invasion of plant roots (Greaves & Sargent 1986), and the interactions of sublethal herbicide doses on root pathogens (Lévesque & Rahe 1992) have been reviewed. One of the earliest reports indicating that herbicides could block resistance to pathogens was the increased infection of an incompatible race of Phytophthora megasperma Drechs.…”

Section: Resultsmentioning

confidence: 99%

Interaction of a bioherbicide and glyphosate for controlling hemp sesbania in glyphosate‐resistant soybean

Boyette

Hoagland

Weaver³

2008

Weed Biology and Management

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The bioherbicidal fungus, Colletotrichum truncatum (Schwein.) Andrus & Moore, was tested at different inoculum concentrations alone and in combination with, prior to or following treatment with different rates of glyphosate (N-[phosphonomethyl]glycine) (Roundup Ultra) for the control of hemp sesbania (Sesbania exaltata [Raf.] Rydb. ex A.W. Hill) in Roundup Ready soybean field plots. Colletotrichum truncatum and glyphosate were applied in all pair-wise combinations of 0, 1.25, 2.5, 5.0, and 10.0 ¥ 10 6 spores mL -1 (i.e. 3.125, 6.25, 12.5, and 25 ¥ 10 11 spores ha -1 ), and 0.15, 0.30, 0.60, and 1.2 kg ha -1 , respectively. Weed control and disease incidence were enhanced at the two lowest fungal and herbicidal rates when the fungal spores were applied after glyphosate treatment.The application of the fungus in combination with or prior to glyphosate application at 0.30 kg ha -1 resulted in reduced disease incidence and weed control regardless of the inoculum's concentration. At the highest glyphosate rates, the weeds were controlled by the herbicide alone.These results suggest that it might be possible to utilize additive or synergistic herbicide and pathogen interactions to enhance hemp sesbania control.

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“…2). Synergism of chemical herbicides with fungal biocontrol agents have been tested with the intention of increasing the disease severity of the mycoherbicides (Altman et al 1990;Prasad 1994). Synergistic activity of chemical herbicides with fungal biocontrol agents has been found to enhance their mycoherbicidal potential.…”

Section: In Vivo Pot Assays Of the Bioherbicide Formulation(s)mentioning

confidence: 99%

Assessment of Phytotoxic Spent Broth and Spores of Alternaria Alternata (LC#508) As a Formulation with Enhanced Mycoherbicidal Activity to Control Lantana Camara

Saxena¹,

Pandey²

2009

Journal of Plant Protection Research

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Enhanced social concern towards the ill effects of synthetic agrochemicals, their residual toxicity and resistance development in the target pests created a necessity of exploration of alternatives. Fungal biocontrol agents have been used as herbicides over two decades and research continues to enhance their efficacy comparable to synthetic herbicides. Combinations of synthetic herbicides with the fungal biocontrol agents was an approach adopted to enhance mycoherbicidal activity but had limited acceptance due to negative effects of their synthetic components. Hence a necessity for development of the formulations having least toxicity or being benign to non-target organisms was felt. The present study brings forth a new dimension of holistic and ecofriendly bioherbicidal formulations comprising of crude phytotoxins and spores of Alternaria alternata LC# 508 which enhances outstandingly its mycoherbicidal potential. Spent broth of Alternaria alternata (LC#508) exhibited toxic activity to its spores (autotoxicity) at a concentration of 50µg/ml which was used for developing five formulations FN1 to FN5. Formulations No. 5 was the best of all the formulations when evaluated by pot trails compared to control and other formulations. Disease onset and mortality was observed in 3.5 days and 5 days respectively in case of formulation No 5 (50 µg of crude spent broth + 1x 10 6 spores/ml) when compared to spore spray alone. Thus the formulation of crude spent broth and fungal spores could be developed as a cost effective and efficacious bioherbicide formulation when compared to the spores alone.

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Herbicide—Pathogen Interactions and Mycoherbicides as Alternative Strategies for Weed Control

Cited by 25 publications

References 0 publications

The measurement of Bacillus mycoides spore adhesion using atomic force microscopy, simple counting methods, and a spinning disk technique

The measurement of Bacillus mycoides spore adhesion using atomic force microscopy, simple counting methods, and a spinning disk technique

Interaction of a bioherbicide and glyphosate for controlling hemp sesbania in glyphosate‐resistant soybean

Assessment of Phytotoxic Spent Broth and Spores of Alternaria Alternata (LC#508) As a Formulation with Enhanced Mycoherbicidal Activity to Control Lantana Camara

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