Plant diseases caused by phytopathogenic fungi can lead to huge losses in the agricultural fields and therefore remain a continuous threat to the global food security. Chemical-based fungicides ...contributed significantly in securing crop production. However, indiscriminate application of fungicides has led to increased chemical resistance and potential risks to human health and environment. Thus, there is an urgent need for searching for new bioactive natural products and developing them into new biopesticides. Fungal endophytes, microorganisms that reside in the fresh tissues of living plants, are regarded as untapped sources of novel natural products for exploitation in agriculture and/or medicine. Chemical examination of endophytic fungi has yielded enormous antifungal natural products with potential use in the development of biopesticides. This review summarizes a total of 132 antifungal metabolites isolated from fungal endophytes in the past two decades. The emphasis is on the unique chemical diversity of these metabolic products, together with their relevant antifungal properties. Moreover, some "star molecules," such as griseofulvin and trichothecene, as well as their synthetic derivatives that possess high potential as candidates of new natural fungicides, are also presented herein.
The increase in the world population has generated an important need for both quality and quantity agricultural products, which has led to a significant surge in the use of chemical pesticides to ...fight crop diseases. Consumers, however, have become very concerned in recent years over the side effects of chemical fungicides on human health and the environment. As a result, research into alternative solutions to protect crops has been imposed and attracted wide attention from researchers worldwide. Among these alternatives, biological controls through beneficial microorganisms have gained considerable importance, whilst several biological control agents (BCAs) have been screened, among them
,
,
,
,
,
,
, and certain yeasts. At present, biopesticide products have been developed and marketed either to fight leaf diseases, root diseases, or fruit storage diseases. However, no positive correlation has been observed between the number of screened BCAs and available marketed products. Therefore, this review emphasizes the development of biofungicides products from screening to marketing and the problems that hinder their development. Finally, particular attention was given to the gaps observed in this sector and factors that hamper its development, particularly in terms of efficacy and legislation procedures.
Laboratory experiments were conducted to evaluate the effect of some commercially available biopesticidal formulations, such as Bacillus thuringiensis var. kurstaki (2g/l), Bacillus sphaericus(2g/l), ...Beauveria bassiana (5g/l), Metarhizium anisopliae (5g/l), Lecanicillium lecanii (5g/l) on the Temperature Tolerant strain of Trichogramma chilonis (TTT). Two sets of experiments were conducted, in the first experiment, all the test biopesticides were sprayed on the egg cards prepared from Corcyra cephalonica eggs (pre-release situation) and percent parasitisation and adult emergence were recorded; in the second one, test bio pesticides were sprayed on the parasitized cards (post release situation) and adult emergence was recorded. The results revealed that percent parasitisation and adult emergence from treated cards in both the experiments are on par with the untreated control, hence they are considered safe and can be used along with TTT.
Abstract
Background
To manage the cabbage butterfly,
Pieris
brassicae
(L.) (Lepidoptera: Pieridae), it is not wise to use insecticides on leafy vegetables which are eaten mostly fresh. During the ...past decades, the efforts to manage the pest, through chemical insecticides have raised serious health. Investigations were carried out to isolate naturally occurring GVs (PbGV) as a potent biopesticide against
P.
brassicae
and to explore their efficacy with the application of phagostimulants.
Results
Among the four naturally occurring isolates obtained from Northwestern Himalayas, Sudhmahadev isolate was found to be the most promising based on virulence and speed of kill against all the instars tested in the laboratory, showing the natural incidence of PbGV infection in field conditions. In concentration and time–response bioassay, all the isolates of
P.
brassicae
Granulosis virus were found high virulent against second instar larvae of cabbage butterfly. Therefore, for enhanced efficacy of PBGV, its combined application with phagostimulants (
Lepidium
sativum
+ Teepol + jaggery) or sticker (Teepol + jaggery), applied in field trials, resulted into greater mortality of larval instars than the single one. Overall, the results indicated that the introduction of a more isolates PBGV strain into populations of
P.
brassicae
could be of vital importance for eco-friendly suppression of this pest globally with the combination of phagostimulants. The application virus alone with the pre-standardized concentration of 1 × 10
12
OBs/ha did not reduce the larval population density to the desirable extent in the greenhouse chamber and therefore was not included in field experiments. Overall, the most promising treatments in reducing the larval population of the pest were PbGV + Teepol +
B.
thuringiensis
(93.49 and 91.39%) and PbGV + Teepol +
L.
sativum
(88.79 and 86.97%) over control in both greenhouse and field trials, respectively.
Conclusions
In this study, the native isolates of PbGV from different target locations to test their efficacy against different instars of
P.
brassicae
were explored. Using native PBGV isolates with phagostimulant combinations played an important role for regulating the pest effectively. These phagostimulants not only protected the OBs from degradation in the presence of sunlight but also increased the speed of killing. The biocontrol potential of PbGV in both laboratory and field conditions indicated that baculoviruses are sustainable alternative to chemical insecticides.
In Mexico, cacao production is endangered by pathogenic fungi, such as Phytophthora spp. and Moniliophthora rorei, that cause black pod rot and moniliasis, respectively. In this study the biocontrol ...agent Paenibacillus sp. NMA1017 was tested in cacao fields against the previous diseases. The treatments applied were shade management, inoculation of the bacterial strain with or without an adherent, and use of chemical control. The statistical analysis showed that the incidence of black pod rot in tagged cacao trees diminished when the bacterium was applied (reduction of 44.24 to 19.11%). The same result was observed with moniliasis when the pods were tagged (reduction of 66.6 to 27%). The use of Paenibacillus sp. NMA1017 with an integrated management might be a solution to cacao diseases and to having a sustainable production of cacao in Mexico.
Aims
This study aimed to evaluate the potential applicability of
Anabaena variabilis
SCAU30 as a biofertilizer and biopesticide in rice fields.
Methods
The effects of
A. variabilis
SCAU30 inoculation ...on disease severity, plant growth, rice yield, and soil nutrients were investigated by microchamber, micro-area, and field experiments. The nitrogen fixation ability was estimated by acetylene reduction activity. Hormones were analyzed using liquid chromatography-tandem mass spectrometry.
Results
In microchamber experiments, the control efficacies of
A. variabilis
SCAU30 against rice sheath blight and bacterial blight were 62.3 ± 8.9% and 45.3 ± 5.6%, respectively. The cell extracts of
A. variabilis
SCAU30 exhibited high antagonistic effects on corresponding pathogens, whereas volatile compounds only showed inhibition on
Xanthomonas oryzae
. The results of pond experiments showed that inoculation with
A. variabilis
SCAU30 could promote the growth of rice plants, increase yield, control diseases, and decrease chemical nitrogen fertilizer input. Moreover, in field experiments, the combined treatment of
A. variabilis
SCAU30 and 50% topdressing fertilizer increased rice yields by 13.9%–22% compared with the conventional fertilizer treatment. This potentially represents economic gains of 26,753 ~ 38,987 Chinese Yuan ha
−1
season
−1
if sold as a green food.
Conclusions
The present study suggests that
A. variabilis
SCAU30 may act as a fertilizer and pesticide in developing green rice in South China.
Lettuce crop is an important horticultural crop of several Mediterranean countries, including Italy. The Italian region which is a major producer of lettuce crops is Apulia, where this crop is ...cultivated in open fields an in greenhouses. Since several microbial pathogens are responsible for important diseases found on lettuce produced in greenhouses, in this study, the experimental activities focused on the most severe fungal soilborne pathogens, i.e., Sclerotinia sclerotiorum and Athelia rolfsii. Their control is often performed with fungicides which cause public concern over the environment and human health. The main aims of this study were to determine the biocontrol efficacy of a Streptomyces strain in vitro and in vivo conditions on lettuce seedlings against Athelia rolfsii and Sclerotinia sclerotiorum as severe fungal soilborne pathogens through the application of its vegetative propagules and putative bioactive crude extracts via filtrate culture. The results obtained confirm a significant effectiveness of CARA17 strain to control the severity of both fungal soilborne pathogens during two different experiments: when it is used as vegetative propagules and as a culture filtrate containing putative bioactive metabolites in vitro and in vivo conditions. These preliminary results demonstrated that the actinomycetes CARA17 strain is valid as a biocontrol agent (BCA) against both the severe phytopathogens used in this study. The biocontrol action performed from the CARA17 strain is clearly and mainly due to the putative bioactive crude extracts produced, but further studies are necessary to identify which metabolites (polyphenols, terpenes, fatty acids, etc.) are produced from this Streptomyces strain.
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•31 microbial-based bioproducts currently registered in South Africa under Act 36 of 1947.•New guidelines for registration of biopesticides published in 2015.•4 locally manufactured ...mycoinsecticides containing Beauveria bassiana (Hypocreales).•1 locally manufactured product containing Cryptophlebia leucotreta granulovirus.•11 endemic Steinernema spp. and 2 endemic Heterorhabditis spp. described to date.
Invertebrate pests pose a significant threat to food security on the African continent. In response, South Africa has become one of the largest importers of chemical pesticides in sub-Saharan Africa, with several hundred active ingredients registered. To address the over-reliance on such chemicals, the South African Department of Agriculture, Forestry and Fisheries (DAFF) has eliminated or restricted several pesticides since the late 1970s. The recent launch of the South African National Bio-Economy Strategy and establishment of the South African Bioproducts Organisation (SABO), together with new guidelines for registration of biopesticides in 2015, also support this endeavour. Concurrently, entomopathogen-related research and bioproduct development has increased over the past decade. Currently, 31 products (seven manufactured locally) are registered under the Fertilizers, Farm Feeds, Agricultural Remedies and Stock Remedies Act 36 of 1947. Commercially important microbes include Beauveria bassiana (Cordycipitaceae), Metarhizium anisopliae (Clavicipitaceae), Cydia pomonella granulovirus, Cryptophlebia leucotreta granulovirus, Helicoverpa armigera nucleopolyhedrovirus (Baculoviridae) and Bacillus thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai (Bacillaceae). Both parasitic and entomopathogenic nematodes (EPNs) show potential for development as bioinsecticides with one commercial EPN product, based on Heterorhabditis bacteriophora (Heterorhabditidae), registered under the Act. Rapid scientific progression, supported by a favourable legislative environment, should facilitate further advances in microbial control of phytophagous invertebrate pests in South Africa.
Paenibacillus polymyxa is a plant-growth promoting rhizobacterium that could be exploited as an environmentally friendlier alternative to chemical fertilizers and pesticides. Various strains have ...been isolated that can benefit agriculture through antimicrobial activity, nitrogen fixation, phosphate solubilization, plant hormone production, or lignocellulose degradation. However, no single strain has yet been identified in which all of these advantageous traits have been confirmed.
P. polymyxa CR1 was isolated from degrading corn roots from southern Ontario, Canada. It was shown to possess in vitro antagonistic activities against the common plant pathogens Phytophthora sojae P6497 (oomycete), Rhizoctonia solani 1809 (basidiomycete fungus), Cylindrocarpon destructans 2062 (ascomycete fungus), Pseudomonas syringae DC3000 (bacterium), and Xanthomonas campestris 93-1 (bacterium), as well as Bacillus cereus (bacterium), an agent of food-borne illness. P. polymyxa CR1 enhanced growth of maize, potato, cucumber, Arabidopsis, and tomato plants; utilized atmospheric nitrogen and insoluble phosphorus; produced the phytohormone indole-3-acetic acid (IAA); and degraded and utilized the major components of lignocellulose (lignin, cellulose, and hemicellulose).
P. polymyxa CR1 has multiple beneficial traits that are relevant to sustainable agriculture and the bio-economy. This strain could be developed for field application in order to control pathogens, promote plant growth, and degrade crop residues after harvest.
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