Biopesticides are natural, biologically occurring compounds that are used to control various agricultural pests infesting plants in forests, gardens, farmlands, etc. There are different types of biopesticides that have been developed from various sources. This paper underscores the utility of biocontrol agents composed of microorganisms including bacteria, cyanobacteria, and microalgae, plant-based compounds, and recently applied RNAi-based technology. These techniques are described and suggestions are made for their application in modern agricultural practices for managing crop yield losses due to pest infestation. Biopesticides have several advantages over their chemical counterparts and are expected to occupy a large share of the market in the coming period.

An Overview of Some Biopesticides and Their Importance in Plant Protection for Commercial Acceptance

Infection of broad mites, Polyphagotarsonemus latus, by conidia of Beauveria bassiana, Hirsutella thompsonii, and Paecilomyces fumosoroseus conidia was investigated in the laboratory under controlled temperature and moisture conditions. Infection of P. latus by the fungus (LC50) was related positively to the 1.16 × 106 B. bassiana conidia per ml, 2.39 × 103 H. thompsonii conidia per ml, and 1.29 × 105 P. fumosoroseus conidia per ml. Mortality caused by B. bassiana occurred the fastest among densities fluctuating between 65 and 125 mites per leaf.The pathogens B. bassiana and P. fumosoroseus, adjuvants (oil and molasses), and the acaricide ABG6364, a microbial insecticide containing the Beta-exotoxin of Bacillus thuringiensis were evaluated for efficacy against P. latus in a greenhouse test. The B. bassiana treated plants had the greatest and most persistent effect on percentage mortality of total broad mites present per leaf (88 %) followed by the acaricide ABG6364. Use of adjuvants (oil and molasses) did not increase infection of P. latus.RésuméUne étude sur l’infection de Polyphagotarsonemus lotus par des conidies de Beauveria bassiana, Hirsutella thompsoni et P. fumosoroseus a été conduite en laboratoire dans des conditions de température et humidité contrÔlées. Une corrélation positive a été observée entre l’infection de P. lotus (LC50) et les traitements 1, 16 × 106 conidies/ml de B. bassiana, 2, 39 × 103 conidiés/ml de H. thompsonii et 1, 29 × 105 conidies /ml de P. fumosoroseus. Le taux de mortalité le plus rapide a été causé par B. bassiana au sein des populations de P. latus oscillant entre 65 et 125 individus par feuille. Les pathogènes B. bassiana et P. fumosoroseus, des adjuvants (huile et mélasse) et l’acaricide ABG6364 ont également été testés en serre en vue de déterminer leur efficacité contre P. lotus. L’effet le plus marqué et le plus persistant sur le taux de mortalité de P. latus (88 %) par feuille a été enregistré chez les plantes traitées au B. bassiana, suivies de celles traitées à l’acaricide ABG6364. Les adjuvants (huile et mélasse) n’ont pas fait augmenter la population de pathogènes.

Potential of fungi as biocontrol agents of Polyphagotarsonemus latus (Acari: Tarsonemidae) [Paecilomyces fumosoroseus]

Testing various biocontrol agents against the root-knot nematode (Meloidogyne incognita) in cucumber plants identifies a combination of Syncephalastrum racemosum and Paecilomyces lilacinus as being most effective

Recent advances in the biological control of citrus nematodes: A review

Paecilomyces variotii xylanase was, produced in stirred tank bioreactor with yield of 760 U/mL and purified using 70% ammonium sulfate precipitation and ultra-filtration causing 3.29-fold purification with 34.47% activity recovery. The enzyme purity was analyzed on sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) confirming its monomeric nature as single band at 32 KDa. Zymography showed xylan hydrolysis activity at the same band. The purified enzyme had optimum activity at 60 °C and pH 5.0. The pH stability range was 5–9 and the temperature stability was up 70 °C. Fe2+and Fe3+ exhibited inhibition of xylanase enzyme while Cu2+, Ca2+, Mg2+ and Mn2+ stimulated its activity. Mercaptoethanol stimulated its activity; however, Na2-EDTA and SDS inhibited its activity. The purified xylanase could hydrolyze beechwood xylan but not carboxymethyl cellulose (CMC), avicel or soluble starch. Paecilomyces variotii xylanase Km and Vmax for beechwood were determined to be 3.33 mg/mL and 5555 U/mg, respectively. The produced xylanase enzyme applied on beech xylan resulted in different types of XOS. The antioxidant activity of xylo-oligosaccharides increased from 15.22 to 70.57% when the extract concentration was increased from 0.1 to 1.5 mg/mL. The enzyme characteristics and kinetic parameters indicated its high efficiency in the hydrolysis of xylan and its potential effectiveness in lignocellulosic hydrolysis and other industrial application. It also suggests the potential of xylanase enzyme for production of XOS from biomass which are useful in food and pharmaceutical industries.

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Paecilomyces variotii xylanase production, purification and characterization with antioxidant xylo-oligosaccharides production

Incorporating beneficial microorganisms in crop production is the most promising strategy for maintaining agricultural productivity and reducing the use of inorganic fertilizers, herbicides, and pesticides. Numerous microorganisms have been described in the literature as biological control agents for pests and diseases, although some have not yet been commercialised due to their lack of viability or efficacy in different crops. Paecilomyces is a cosmopolitan fungus that is mainly known for its nematophagous capacity, but it has also been reported as an insect parasite and biological control agent of several fungi and phytopathogenic bacteria through different mechanisms of action. In addition, species of this genus have recently been described as biostimulants of plant growth and crop yield. This review includes all the information on the genus Paecilomyces as a biological control agent for pests and diseases. Its growth rate and high spore production rate in numerous substrates ensures the production of viable, affordable, and efficient commercial formulations for agricultural use.

https://www.mdpi.com/2223-7747/9/12/1746/pdf

Victoria Huertas

Papers

Paecilomyces and Its Importance in the Biological Control of Agricultural Pests and Diseases