Biopesticide Formulations Research Articles

Essential Oils as a Source of Ecofriendly Insecticides for Drosophila suzukii (Diptera: Drosophilidae) and Their Potential Non-Target Effects.

The spotted wing drosophila (Drosophila suzukii) is one of the main invasive pests of small fruits in the world. Thus, 19 essential oils (EOs) were selected to analyze the effects through toxicity and repellency on oviposition and D. suzukii adults. In addition, their lethal and sublethal effects on the pupal endoparasitoid Trichopria anastrephae were evaluated. The EOs of C. flexuosus and Mentha spp. had the highest toxicity observed in the topical application bioassay for D. suzukii. In contrast, the EOs of C. verum, C. citratus QT citratus, and C. winterianus showed the highest toxicity in the ingestion bioassay for D. suzukii. The dry residues of C. verum and C. citratus QT citratus reduced the oviposition of D. suzukii. In the repellency bioassays, the 19 EOs analyzed repelled ≅ 90% of the D. suzukii females. All EOs evaluated using the LC90 values of the products provided mortality of less than 20% of T. anastrephae adults and did not cause a reduction in the parasitism of surviving T. anastrephae females. We conclude that the EOs evaluated have the potential to be used in the management of D. suzukii. They can also serve as selective active ingredients for the formulation and synthesis of new biopesticides.

Entomopathogenic fungi as biological control agents of Dactylopius opuntiae (Hemiptera: Dactylopiidae) under laboratory and greenhouse conditions

The cactus Opuntia ficus-indica L. is widly cultivated in Morocco and has a very an important economic role as a source of food, livestock feed and not forgetting that it is considered to be an income for people in rural communities. This crop is subject to the attack of a serious insect pest, the Dactylopius opuntiae (Cockerell), which sucks the sap from the plant causing huge production losses since its introduction to the country in 2014. The present study investigated the entomopathogenic effect of six fungal isolates {Beauveria bassiana [HASS; RFSL10; SPT 011(a)]; Akanthomyces lecanii [RFSLV; SPT R 215] and Cordyceps farinosa [SPSBI4]} for controlling of both nymphs and adult females of D. opuntiae in laboratory and greenhouse bioassays. Under laboratory conditions, the highest mortality of female D. opuntiae was registered by B. bassiana strain HASS at 108 conidia ml−1 with 100%, followed by B. bassiana strain RFSL10, A. lecanii RFSLV, and C. farinosa SPSBI4 isolates with 98%, respectively, 10 days after treatments. Similarly, the highest level of nymph mortality (100%) was recorded by B. bassiana RFSL10 and HASS isolates at 108 conidia ml1, respectively, 4 and 5 days after application. Under greenhouse conditions, B. bassiana (HASS and RFSL10) and A. lecanii (RFSLV) isolates sprayed alone expressed a higher toxicity on nymphs with 75, 68.5 and 58%, respectively, 12 days after treatments. However, no significant difference was observed in adult female's mortality between different fungal isolates, where B. bassiana (HASS) at 108 conidia ml−1 presented a moderate mortality rate with 55%, 12 days after application. In fact, the combination of black soap (60 g/L) with B. bassiana HASS and RFSL10 and A. lecanii (RFSLV) isolates at 108 conidia ml−1 caused the highest toxic activity on D. opuntiae adult females, with 70.5, 68.75 and 67.65%, respectively. These findings showed that entomopathogenic fungi are promising for developing a biopesticide formulation for the management of D. opuntiae as an adequate and safe alternative to chemical pesticides.

Interview with Dr Minshad Ansari, Founder and CEO of Bionema Ltd

Bionema is a leading UK biopesticide technology developer. We create chemical-free, pest management solutions for the horticulture, turf & amenity, landscaping, and forestry sectors. We have more than 30 years' experience in research, development, and the commercialisation of biopesticides. The company was founded in 2012 by Dr Minshad Ansari, a former academic who had already worked at research institutions across India, Belgium, and the UK. He joined Swansea University in 2005 and started working on the development of biopesticides for the control of insect pests in the horticulture and forestry sectors. When he visited growers and farmers, he was often asked about pest control methods that did not require the extensive use of chemical solutions. These queries made him investigate the development of non-toxic, natural methods of pest control that would reduce the need for chemical use. Once Dr Ansari developed his thinking around biopesticide alternatives, he set up Bionema in 2012 a spinout from Swansea University. The focus of Bionema's research was the development and commercialisation of naturally occurring microorganisms for crop protection against pests and diseases thereby reducing the use of synthetic pesticides, enhancing food security, and increasing crop yields. The company established its headquarters at the Institute of Life Science at Swansea University in the UK. In 2017, Bionema made a breakthrough discovery in the development of NemaTrident, a tri-component patented solution, and the conception of the microencapsulation formulation delivery system in 2018 for foliar challenges. Shortly afterwards, Dr Ansari raised £680,000 equity investment and received £1.1 million in grant funding from Innovate UK and the Welsh Government which was used for the development and commercialisation of UniSporeG, a unique fungal bioinsecticide for weevil control in soft fruits. Innovation in biopesticide formulations is a core objective for Bionema, enabling the company to commercialise multiple product lines and to generate a pipeline of advanced and early-stage products that include beneficial nematicides, bioinsecticides, compatible surfactants and delivery platforms. Bionema has also developed a robust patent portfolio and collected a library of more than a hundred commercially viable microorganisms for pipeline candidates.

Bovine pancreatic trypsin inhibitor and soybean Kunitz trypsin inhibitor: Differential effects on proteases and larval development of the soybean pest Anticarsia gemmatalis (Lepidoptera: Noctuidae)

Pest management is challenged with resistant herbivores and problems regarding human health and environmental issues. Indeed, the greatest challenge to modern agriculture is to protect crops from pests and still maintain environmental quality. This study aimed to analyze by in silico, in vitro, and in vivo approaches to the feasibility of using the inhibitory protein extracted from mammals – Bovine Pancreatic Trypsin Inhibitor (BPTI) as a potential inhibitor of digestive trypsins from the pest Anticarsia gemmatalis and comparing the results with the host-plant inhibitor – Soybean Kunitz Trypsin Inhibitor (SKTI). BPTI and SKTI interacts with A. gemmatalis trypsin-like enzyme competitively, through hydrogen and hydrophobic bonds. A. gemmatalis larvae exposed to BPTI did not show two common adaptative mechanisms i.e., proteolytic degradation and overproduction of proteases, presenting highly reduced trypsin-like activity. On the other hand, SKTI-fed larvae did not show reduced trypsin-like activity, presenting overproduction of proteases and SKTI digestion. In addition, the larval survival was reduced by BPTI similarly to SKTI, and additionally caused a decrease in pupal weight. The non-plant protease inhibitor BPTI presents intriguing element to compose biopesticide formulations to help decrease the use of conventional refractory pesticides into integrated pest management programs.

RNA Interference-Mediated Knockdown of Bombyx mori Haemocyte-Specific Cathepsin L (Cat L)-Like Cysteine Protease Gene Increases Bacillus thuringiensis kurstaki Toxicity and Reproduction in Insect Cadavers.

The silkworm’s Cat L-like gene, which encodes a lysosomal cathepsin L-like cysteine protease, is thought to be part of the insect’s innate immunity via an as-yet-undetermined mechanism. Assuming that the primary function of Cat L-like is microbial degradation in mature phagosomes, we hypothesise that the suppression of the Cat L-like gene expression would increase Bacillus thuringiensis (Bt) bacteraemia and toxicity in knockdown insects. Here, we performed a functional analysis of Cat L-like in larvae that were fed mulberry leaves contaminated with a commercial biopesticide formulation based on Bt kurstaki (Btk) (i.e., Dipel) to investigate its role in insect defence against a known entomopathogen. Exposure to sublethal doses of Dipel resulted in overexpression of the Cat L-like gene in insect haemolymph 24 and 48 h after exposure. RNA interference (RNAi)-mediated suppression of Cat L-like expression significantly increased the toxicity of Dipel to exposed larvae. Moreover, Btk replication was higher in RNAi insects, suggesting that Cat L-like cathepsin may be involved in a bacterial killing mechanism of haemocytes. Finally, our results confirm that Cat L-like protease is part of the antimicrobial defence of insects and suggest that it could be used as a target to increase the insecticidal efficacy of Bt-based biopesticides.

Foliar application of natural products reduces population of two-spotted spider mite, Tetranychus urticae Koch on parthenocarpic cucumber (Cucumis sativus L.) under protected environment

The indigenously prepared natural products namely; cow urine, Darekastra, fermented buttermilk, Panchgavya, Tamarlassi, vermiwash and biopesticide formulations i.e. Azadirachtin 0.15 EC and Eupatorium 5 EC possessing acaricidal activity were evaluated for their bioefficacy against Tetranychus urticae and their effects on cucumber fruit yield under protected environment. After 85 days of transplanting, preventive spray of bioacaricides, vermiwash (15.36 mites/leaf) and Darekastra (16.22 mites/leaf) resulted into lower mite population per leaf whereas curative spray of Darekastra significantly reduced mite population levels (112.53 mites/leaf). The effect of bioacaricide application in the form of spray was also quantified in terms of cucumber fruit yield. The bioacaricides applied as preventive sprays enhanced the cucumber fruit yield. High fruit yield was observed after preventive spray of bioacaricides viz. Tamarlassi (1660.67 g/plant), vermiwash (1656.50 g/plant) and Darekastra (1626.0 g/plant). As curative spray, Darekastra resulted into high fruit yield (1446.33 g/plant). Among the biopesticide checks, Azadirachtin 0.15 EC performed best in managing mite population levels and enhancing the fruit yield under both management measures.

PHYTOCHEMICAL SCREENING AND PESTICIDAL EFFICACY OF PHYTOECDYSTEROID FRACTION OF A FERN PITYROGRAMMA CALOMELANOS (L.) LINK AGAINST SPODOPTERA LITURA (FABRICIUS.)

Lepidopteran insect pests voraciously feed the vegetable crops and causes yield loss every year. Chemical insecticides widely used to control the destructive pest incidence which heavily affects the beneficial and non-target organisms and in the mean time, pests developed resistance. Biopesticides are being developed to minimize these ill effects. Plants synthesize secondary metabolites to prevent from biotic and abiotic stresses. More than 27 families of pteridophyta (ferns) are reported with phytoecdysteroids (PEs). PEs are analogues of insect moulting hormone and acts as insect growth regulators (IGRs). The present study aimed to isolate the phytoecdysteroid fraction from the fern, Pityrogramma calomelanos, preliminary screening of phytochemicals using standard protocols including UV-Visible spectrophotometric analysis and survival, growth and developmental periods of Spodoptera litura treated with phytoecdysteroid fraction. Steroids and phenolic compounds were present in the fraction and six prominent peaks were recorded between the wavelength of 200-800nm. Spodoptera litura larvae treated with phytoecdysteroid fraction showed maximum larval mortality (68%) in 2000ppm (LC50 = 1473ppm; F = 48.65; p = 0.049). Pupation, pupal weight and adult emergence were decreased in higher concentrations. Pupal mortality was relatively high in treated group than control (2.04%). Larvae treated with minimal concentrations exhibited developmental deformities includes larval - pupal, pupal -adult intermediates, deformed pupae, ecdysial failure, adultoids, early/late developmental periods and it may due to the interaction of phytoecdysteroid fraction to the insect endocrine system. Therefore, phytoecdysteroid mediated biopesticide formulation could be the better alternative to commercial chemical insecticides under IPM programme.

Determination of 52 hidden chemical pesticides in biopesticide products by GC-MS/MS and LC-MS/MS

Addition of chemical pesticides in biopesticides are expected to be common, due to effect of pest control during plant protection. These hidden chemical pesticides may cause various food safety problems if consumed. The purpose of our study was to develop a method to determine 52 hidden chemical pesticides in three formulation biopesticide products. Optimizations of different parameters, such as the instrument analysis condition for target, the extraction, and the composition of clean-up materials were carried out. The developed method used acetonitrile as an extraction solvent for all biopesticide formulations. The composition of adsorbents was based on QuEChERS, called QuSEL which was a needle filter head, containing PSA, GCB, and MgSO4. Fifty-two chemical pesticides residues were then analyzed by GC-MS/MS and LC-MS/MS. The present results showed good linearity by correlation coefficients of more than 0.99 for all analyses. The LOQ ranged from 5.0 to 20.0 μg kg−1. Recoveries of 32 chemical pesticides ranged from 71.9% to 118.4% at the spiked level of 10, 50, and 100 μg kg−1, and 20 chemical pesticides ranged from 75.3% to 119.8% at the spiked level of 5, 25, and 50 μg kg−1. The developed method was applied for biopesticide products, and 9 samples were positive in 20 samples.

Potential biocontrol mechanisms of Bacillus sp. TSO2 against Bipolaris sorokiniana, spot blotch in wheat

<p class="Default"><em>Bipolaris sorokiniana </em>is a pathogen of cereals such as wheat and barley, causing root rot, leaf blight, seedling blight, and spot blotch. This phytopathogen causes a considerable reduction in cereal yield of up to 85%. Thus, sustainable alternatives to the application of synthetic fungicides are determinants for the control of phytopathogens, such as the application of biological control agents. This study aims to identify the potential biocontrol mechanisms of the bacterial strain TSO2 by sequencing, annotation, and mining its genome. The draft genome of strain TSO2 was sequenced through the Illumina Miseq platform and presented 4,242,212 bp, 43.9% G+C content, 300,069 bp N50, 5 L50, 47 contigs, 96 RNAs, and 4,432 predicted coding DNA sequences. Besides, the presence of 86 CDS of agricultural importance involved in virulence, disease, defense, iron acquisition, and secondary and phosphate metabolisms was detected. On the other hand, seven putative secondary metabolite gene clusters involved in biocontrol activity were identified in the genome of strain TSO2. <em>Bacillus </em>sp. TSO2 contains a great number of biosynthetic gene clusters which supports its biocontrol activity against phytopathogenic fungi. Thus, this strain needs to be further studied as a potential bioactive ingredient for the biopesticide formulation due to its high potential as a biological control agent.</p>

DEVELOPMENT OF KARANJ OIL AND CASTOR OIL NANOEMULSIONS AND ITS ENCAPSULATION INTO BEADS FOR CONTROLLED RELEASE LARVICIDAL ACTIVITY

Karanjin and Ricinoleic acid, found in Karanj oil and Castor oil respectively exhibited medicinal and pesticidal properties. Karanj oil and Castor oil has low aqueous solubility, high photo sensitivity which restrict its application for the control of agricultural pests. The present study highlights development of Karanj oil and Castor oil nanoemulsions and its encapsulation into Calcium alginate beads for control release application. The encapsulated beads were characterized by various physicochemical properties such as size, encapsulation efficiency, release kinetics and stability. The beads exhibited a nearly spherical shape and are nonporous in nature. FTIR spectral studies revealed the absence of chemical interactions between active ingredients and crosslinking agent. The encapsulated Karanj oil and Castor oil nanoemulsions showed the potential for controlled release of Karanjin and Ricinoleic acid. The encapsulated beads of Karanj oil and Castor oil nanoemulsions were tested for larvicidal activity and proved to be effective against variety of mosquito species. The advantages of these biopesticidal formulations appear to be an excellent alternative to conventional pesticides.

Recommendations for Effective and Sustainable Regulation of Biopesticides in Nigeria

The global trend towards increased demand for organic food, greener environments, and the integration of biological control agents into pest management strategies has greatly enhanced the need for biopesticides. Biopesticides are made from micro-organisms or other natural substances and are, hence, generally environmentally friendly. However, despite their great potential—and in part due to regulatory challenges—relatively few biopesticides have been registered and commercialised in Nigeria compared to other African countries, such as South Africa and Kenya. Biological active agents are so diverse that applying the same safety standards to all of them is almost impossible. A comparative review of risk assessment processes of Nigeria’s biopesticide regulations with other developing African countries (South Africa and Kenya) and developed regions (the European Union and the United States of America) was conducted. Prolonged field testing, lack of bridged risk assessments, and technical checklists were identified as key factors hampering the research and development of biopesticides in Nigeria. Suitable amendments to the existing regulations guiding biopesticide formulation and utilisation in Nigeria are recommended. Risk assessment matrices for microbial and biochemical pesticides and a scientific/technical checklist have also been developed. It is apparent that harmonisation and data exchange among countries in the region could enhance the advancement of scientific and technical knowledge for sustainable regulation of, and cross-border trade in, biopesticides.

Draft genome sequence of Bacillus sp. strain FSQ1, a biological control agent against white mold in common bean (Phaseolus vulgaris L.).

Bacillus sp. strain FSQ1 was isolated from the common bean (Phaseolus vulgaris L.). The genome of this strain presented 3,598,499bp; 43.0% G+C content; 925,913bp N50; 2 L50; 33 contigs; 97 RNAs and 3,908 predicted coding DNA sequences (CDS) distributed in 315 subsystems. Based on genome mining, the biological control activity of strains FSQ1 could be associated with the biosynthesis of rhizocticin A and bacillibactin. Thus, this strain is a promising active ingredient for the formulation of biopesticides.

Efficacy of virus based biopesticide formulation against gram pod borer, Helicoverpa armigera in chickpea

Efficacy of virus based biopesticide formulation against gram pod borer, Helicoverpa armigera in chickpea

Natural Coinfection between Novel Species of Baculoviruses in Spodoptera ornithogalli Larvae.

Spodoptera ornithogalli (Guenée) (Lepidoptera: Noctuidae) is an important pest in different crops of economic relevance in America. For its control, strategies that include chemicals are usually used; so, the description of entomopathogens would be very useful for the formulation of biopesticides. In this regard, two different baculoviruses affecting S. ornithogalli were isolated in Colombia, with one of them being an NPV and the other a GV. Ultrastructural, molecular, and biological characterization showed that both isolates possess the 38 core genes and are novel species in Baculoviridae, named as Spodoptera ornithogalli nucleopolyhedrovirus (SporNPV) and Spodoptera ornithogalli granulovirus (SporGV). The bioassays carried out in larvae of S. ornithogalli and S. frugiperda showed infectivity in both hosts but being higher in the first. In addition, it was observed that SporGV potentiates the insecticidal action of SporNPV (maximum value in ratio 2.5:97.5). Both viruses are individually infective but coexist in nature, producing mixed infections with a synergistic effect that improves the performance of the NPV and enables the transmission of the GV, which presents a slowly killing phenotype.

Bioengineering of neem nano-formulation with adjuvant for better adhesion over applied surface to give long term insect control

Although safe and eco-friendly botanical pesticides have been intensively promoted to combat pest attacks in agriculture, but their stability and efficacies remain an issue for their wide acceptability as sustained and effective approaches. The purpose of this work was to develop stable neem oil based nano-emulsion (NE) formulation with enhanced activity employing suitable bio-inspired adjuvant. So, Neem NEs (with and without) natural adjuvants (Cymbopogon citratus and Prosopis juliflora) in different concentrations were prepared and quality parameters dictating kinetic stability, acidity/alkalinity, viscosity, droplet size, zeta potential, surface tension, stability and compatibility were monitored using Viscometer, Zetasizer, Surface Tensiometer, High Performance Liquid Chromatography (HPLC) and Fourier Transform Infrared Spectroscopy (FTIR). Nano-emulsion biosynthesis optimization studies suggested that slightly acidic (5.9–6.5) NE is kinetically stable with no phase separation; creaming or crystallization may be due to botanical adjuvant (lemongrass oil). Findings proved that Prosopis juliflora, acted as bio-polymeric adjuvant to stabilize NE by increasing Brownian motion and weakening the attractive forces with smaller droplets (25–50 nm), low zeta potential (−30 mV) and poly-dispersive index (<0.3). Botanical adjuvant (30%) based NE with optimum viscosity (98.8cPs) can give long term storage stability and improved adhesiveness and wetting with reduced surface tension and contact angle. FT-IR analysis assured azadirachtin’s stability and compatibility with adjuvant. With negligible degradation (1.42%) and higher half-life (t1/2) of 492.95 days, natural adjuvant based NE is substantially stable formulation, may be due to presence of glycosidic and phenolics compounds. Neem 20NE (with 30% adjuvant) exhibited remarkable insecticidal activity (91.24%) against whitefly (Bemisia tabaci G.) in brinjal (Solanum melongena) as evidenced by in-vivo assay. Results thus obtained suggest, bio-pesticide formulation may be used as safer alternative to chemical pesticides to minimize pesticide residues and presence of natural adjuvant may improves the stability and efficacy of biopesticides for safe crop protection in organic agriculture and Integrated Pest Management.

Development of biopesticide and biostimulant formulations for good agricultural practices in greenhouse cucumber cultivation

Development of biopesticide and biostimulant formulations for good agricultural practices in greenhouse cucumber cultivation

Biopesticide production using Bacillus thuringiensis kurstaki by valorization of starch industry wastewater and effluent from aerobic, anaerobic digestion

Unconventional alternatives such as aerobic and anaerobic effluent from starch industry contain essential nutrients for Btk active ingredient synthesis. Effluent from starch industry is rich in carbon and nitrogen and can replace expensive feedstock used during the fermentation process. The main objective of this study was to achieve a biopesticide formulation from starch industry wastewater (SIW) with high entomotoxicity (UI/ml) of larvae comparable to Foray 76B, which is a commercial biopesticide. Bacillus thuringiensis var kurstaki HD1 (Btk) strain was cultivated and sub-cultured to aerobic, anaerobic digested effluent and SIW. Pre-treatment was carried on these different substrates to enhance the residual carbon required for Btk growth and delta endotoxin synthesis. After 48 hours of fermentation, cells count and delta-endotoxin were determined. A biopesticide formulation containing fermented broth and adjuvants was fed to larvae to determine larvae mortality. Btk cell growth and sporulation profile in SIW media displayed a high total cell count and viable spores compared to btk growth in anaerobic or aerobic media after 48h fermentation. The maximum endotoxin concentration in the SIW medium was 435μg/mL, whereas, in anaerobic and aerobic effluent, the maximum concentrations were at 161 μg/mL and 136 μg/mL, respectively. When acidic treatment was performed at pH 2 for these substrates, entomotoxicity obtained from aerobic and anaerobic biopesticide formulations displayed significantly higher entomoxicity than the untreated ones. The entomotoxicity of SIW treated at pH 2 was equivalent to the standard Foray 76B which is 20,000 IU/μL. Anaerobic and aerobic effluent did not contain enough total organic carbon to augment Btk growth and entomotoxicity. Substrates pre-treated at pH 2 provided significant organic matter for Btk growth and resulted in larval mortality equivalent to the com ercial biopesticide Foray 76B.

PESTICIDES AND INDIAN AGRICULTURE- A REVIEW

Globally more than half of the pesticides are utilized in Asia. India stands 12th in pesticide use globally and 3rd in Asia after China and Turkey. In present study, the data of different types of pesticides, pesticide use pattern and detailed pesticide consumption of the India and world were collected, organized and summarized. Agriculture is the most important sector of the Indian economy providing employment and livelihood to nearly 70% of the total population. And pesticides are an integral part of modern agriculture. Insecticides, fungicides and herbicides are commonly used for pest control in agriculture. However, insecticides form the highest share in total pesticide use in India. India share only1% of the global pesticide use. India has utilized around 58160 tonnes of pesticide in 2018. Per hectare application rate of pesticide was 0.31 kg in 2017. Despite a low per hectare use of pesticides in India, their injudicious use has led to the presence of residues in both biotic and abiotic sections of the environment. The advance research and development in the field of bio-pesticides applications greatly reduce the environmental pollution caused by the chemical synthetic insecticides residues and promotes sustainable development of agriculture. In India numerous bio-pesticides presently being developed may be exceptional replacements to chemical pesticides. There are many eco-friendly plant based and microbial bio-pesticides available in the market. Bio-pesticides consumption is only 8% in India. For sustainable agricultural development and to protect environment from adverse effect of chemical pesticides, formulation and utilization of bio-pesticides should be prompted.

Characterization of physiological properties of bacteria isolates TM4 and BNt8 in biopesticide formulas

Some physiological characteristics can be used to determine the antagonistic ability of a bacterium, was the ability of bacteria to produce extracellular enzymes (chitinase, proteases, and cellulose), hydrogen cyanide (HCN), phosphate solvents, and fluorescence activities. The aim of the study was to examine the physiological characteristics of bacterial isolates TM4 and BNt8 biopesticide formulations. The experiment was conducted at the Plant Pathology Laboratory and greenhouse of Indonesian Cereals Research Institute at Maros South Sulawesi. The results showed that the two isolates tested for physiological characteristics using specific media had chitinolytic, proteolytic, cellulolytic, phosphate and potassium activity. This result was seen from the formation of a clear zone. Based on the results of in vitro tests using a completely randomized design, it was found that the two bacterial isolates tested were able to inhibit the growth of R. solani pathogen with inhibitory levels by TM4 isolates ranging from 13-26% and inhibition of BNt8 isolates around 11-38% respectively. The percentage of bacterial inhibition on PDA media was higher than on media PDA and PDA + TSA. From the field test on maize plants, it was found that the two bacterial isolates tested could significantly increase plant growth.

In vitro screening of 65 mycotoxins for insecticidal potential.

The economic losses and threats to human and animal health caused by insects and the pathogens transmitted by them require effective and environmentally-friendly methods of controlling them. One such group of natural biocontrol agents which may be used as biopesticides is that of the entomopathogenic fungi and their toxic secondary metabolites (mycotoxins). The present in vitro work examined the insecticidal potential of 65 commercially-available mycotoxins against the insect Sf-9 cell line. Mammalian Caco-2 and THP-1 cell lines served as reference controls to select insecticidal mycotoxins harmless to mammalian cells. All tested mycotoxins significantly reduced the in vitro proliferation of the Sf-9 cells and evoked morphological changes. Ten of the mycotoxins found to strongly inhibit Sf-9 proliferation also had moderate or no effect on Caco-2 cells. The THP-1 cells were highly resistant to the tested mycotoxins: doses 103 times higher were needed to affect viability and morphology (1 μg/ml for THP-1 versus 1 ng/ml for Sf-9 and Caco-2). Nine mycotoxins significantly decreased Sf-9 cell proliferation with minor effects on mammalian cells: cyclosporins B and D, cytochalasin E, gliotoxin, HC toxin, paxilline, penitrem A, stachybotrylactam and verruculogen. These may be good candidates for future biopesticide formulations.