Different LED Light Wavelengths and Photosynthetic Photon Flux Density Effect on Colletotrichum acutatum Growth

The study aimed to evaluate the effect of different photon flux density (PFD) and light-emitting diodes (LED) wavelengths on strawberry Colletotrichum acutatum growth characteristics. The C. acutatum growth characteristics under the blue 450 nm (B), green 530 nm (G), red 660 nm (R), far-red 735 nm (FR), and white 5700 K (W) LEDs at PFD 50, 100 and 200 μmol m−2 s−1 were evaluated. The effect on C. acutatum mycelial growth evaluated by daily measuring until five days after inoculation (DAI). The presence of conidia and size (width and length) evaluated after 5 DAI. The results showed that the highest inhibition of fungus growth was achieved after 1 DAI under B and G at 50 μmol m−2 s−1 PFD. Additionally, after 1–4 DAI under B at 200 μmol m−2 s−1 PFD. The lowest conidia width was under FR at 50 μmol m−2 s−1 PFD and length under FR at 100 μmol m−2 s−1 PFD. Various LED light wavelengths influenced differences in C. acutatum colonies color. In conclusion, different photosynthetic photon flux densities and wavelengths influence C. acutatum growth characteristics. The changes in C. acutatum morphological and phenotypical characteristics could be related to its ability to spread and infect plant tissues. This study’s findings could potentially help to manage C. acutatum by LEDs in controlled environment conditions.

Chemical composition and antifungal activity of oil extracted from leaves turmeric (Curcuma longa)

Turmeric rhizomes are commonly used in the culinary, pharmaceutical, herbal medicine, and beverage industries. On the contrary, turmeric leaves are underutilized. The aims of this study were to extract the essential oil from turmeric leaves, characterize the chemical composition of the oil, and determine its antifungal activities against aflatoxin-producing fungi. Steam distillation was used to extract the essential oil from turmeric leaves. The properties of the oil were identified using GC-MS. Antimicrobial activities against Aspergillus flavus and Aspergillus parasiticus were determined. Spores of the fungi were inoculated into potato dextrose agar plates supplemented with various quantities of turmeric leaves essential oil and incubated at 30°C for 7 days. The oil's primary constituents were α-phelandrene(46.70 %), followed by α-terpinolene (17.39 %), 1,8-cineole (8.78 %), benzene (4.24 %), and 2-β pinene (3.64 %). At low (<1%) concentrations, the oil delayed mycelia formation and at high concentrations it significantly inhibit fungal growth (at 1%) and completely inhibit colony formation (at 2%) Additionally, the result show that turmeric leaves oil can inhibited fungus growth at the lowest concentration (0.25 %) when compared to the control over a seven-day incubation period.

Antifungal activity of foliar extracts from Maytenus spp. on Cylindrocladium clavatum

The use of leaf extracts to reduce pesticide applications that harm the environment and cause environmental disorder can be an alternative to the control of fungi during propagation of eucalyptus. The experiment tested the effect of leaf extracts from two species of espinheira-santa on Cylindrocladium clavatum. The extraction of plant material was carried out through percolation at 28 °C for 7 days using column liquid chromatography with hexane, chloroform, and methanol as solvents. Evaluations of antifungal activity were performed with a fixed extract concentration of 2,000 mg L-1. The minimum inhibitory concentration of the extracts, sporulation, and control of C. clavatum in eucalyptus leaves were evaluated using concentrations of 500, 250, 125, and 100 mg L-1 after 5 and 15 days of incubation. The concentration of 500 mg L-1 of chloroform extract from leaves of M.ilicifolia and M.aquifolium resulted in a better control of Cylindrocladium clavatum. In the evaluation of sporulation, the crude and methanolic extracts obtained the best performances, with emphasis on the concentrations of 500 and 250 mg L-1, which resulted in the lowest number of spores. For the evaluation of the minimum inhibitory concentration, it was observed that the fungus is not 100% controlled, but that the greatest effect lies on the reduction of fungus growth. In the image tests with eucalyptus leaves, the crude extract resulted in the smallest lesion area at concentrations of 500 and 250 mg L-1. The extract was more effective when applied in its raw form and with greater concentration.

Basidiomycetes Are Particularly Sensitive to Bacterial Volatile Compounds: Mechanistic Insight Into the Case Study of Pseudomonas protegens Volatilome Against Heterobasidion abietinum

Volatile organic compounds (VOCs) play an important role in the communication among organisms, including plants, beneficial or pathogenic microbes, and pests. In vitro, we observed that the growth of seven out of eight Basidiomycete species tested was inhibited by the VOCs of the biocontrol agent Pseudomonas protegens strain CHA0. In the Ascomycota phylum, only some species were sensitive (e.g., Sclerotinia sclerotiorum, Botrytis cinerea, etc.) but others were resistant (e.g., Fusarium oxysporum f. sp. cubense, Verticillium dahliae, etc.). We further discovered that CHA0 as well as other ten beneficial or phytopathogenic bacterial strains were all able to inhibit Heterobasidion abietinum, which was used in this research as a model species. Moreover, such an inhibition occurred only when bacteria grew on media containing digested proteins like peptone or tryptone (e.g., Luria-Bertani agar or LBA). Also, the inhibition co-occurred with a pH increase of the agar medium where the fungus grew. Therefore, biogenic ammonia originating from protein degradation by bacteria was hypothesized to play a major role in fungus inhibition. Indeed, when tested as a synthetic compound, it was highly toxic to H. abietinum (effective concentration 50% or EC50 = 1.18 M; minimum inhibitory concentration or MIC = 2.14 M). Using gas chromatography coupled to mass spectrometry (GC/MS), eight VOCs were found specifically emitted by CHA0 grown on LBA compared to the bacterium grown on potato dextrose agar (PDA). Among them, two compounds were even more toxic than ammonia against H. abietinum: dimethyl trisulfide had EC50 = 0.02 M and MIC = 0.2 M, and 2-ethylhexanol had EC50 = 0.33 M and MIC = 0.77 M. The fungus growth inhibition was the result of severe cellular and sub-cellular alterations of hyphae occurring as early as 15 min of exposure to VOCs, as evidenced by transmission and scanning electron microscopy observations. Transcriptome reprogramming of H. abietinum induced by CHA0’s VOCs pointed out that detrimental effects occurred on ribosomes and protein synthesis while the cells tried to react by activating defense mechanisms, which required a lot of energy diverted from the growth and development (fitness cost).

Efficacy of Liquid Smoke Produced from Medang Wood (Cinnamomum sp.) against Schizophyllum commune

The efficacy of liquid smoke obtained from medang wood (Cinnamomum sp.)against Schizophyllum commune fungus was evaluated. This study aims to evaluate the antifungal properties of liquid smoke from medang against S. commune fungus. Potato Dextrose Agar (PDA) medium was used to determine the efficacy of the liquid smoke of medang wood on S. commune fungus growth. Three kinds of liquid smoke were obtained from the pyrolysis of medang wood at 370, 400, and 430°C. The efficacy of liquid smoke from medang wood for antifungal is a factorial 3 by 4 in a completely randomized design; the first factor was pyrolysis temperature of liquid smoke from medang (370, 400, and 430°C), and the second factor was the treatment of concentration of liquid smoke from medang wood (0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0%, v/v). The results showed that pyrolysis temperature affected liquid smoke from medang, and the concentration of liquid smoke was significantly different for inhibition of fungal growth. The results indicated that the pyrolysis temperature of liquid smoke production and the concentration of liquid smoke had a significant effect on S. commune fungus growth inhibition. Medang wood liquid smoke effectively inhibited the growth of S. commune fungus about 98.57% at a concentration of 2.5% with liquid smoke pyrolysis temperature used is 430°C.Keywords: efficacy, inhibition of fungal growth, liquid smoke, medang wood, Schizophyllum commune

Influences of Marine Environment to the Characteristics of Palm Oil Biodiesel during Storage

Biodiesel from palm oil is one of the alternative energies developed in Indonesia and has been implemented since 2018 for marine transportation, especially for ships. However, there are pertinent cases that experienced many obstacles related to the occurrence of gels, engine power reduction, blocking filters, and injection in the engine. The occurrence of those cases is due to the prolonged storage of biodiesel onboard of ships. During a significant storage process, periodic biodiesel monitoring is required which is difficult to do onboard. In this paper, a study on the physical/chemical characteristics of biodiesel and microbiological growth had been carried out in a controlled effect of the marine environment. Samples of biodiesel blends B20 were placed in locations near the sea and land base areas. It was found that there were significant changes in some chemical parameters of the biodiesel, such as flash point, viscosity, and acid number after 30 days. Microbiological growth, specifically bacteria, appeared on the 45th day of the outdoor-land sample. On the other hand, fungus growth on the out-door-sea was also detected on the same day. It suggested that the growth of microorganisms, growth of fungus and change in characteristics of the marine environment causes the degradation of biodiesel.

Low Efficacy of Isaria fumosorosea against Box Tree Moth Cydalima perspectalis: Are Host Plant Phytochemicals Involved in Herbivore Defence against Fungal Pathogens?

Buxus sp. is an important native and ornamental tree in Europe threatened by a serious invasive pest Cydalima perspectalis. The larvae of this moth are able to defoliate box trees and cause their death. The development of novel biopesticides targeting this pest might help protect Buxus trees grown wildly or in city parks. Laboratory experiments were conducted to assess the efficacy of entomopathogenic fungus Isaria fumosorosea strain CCM 8367 against C. perspectalis. The last-instar larvae of the box tree moth were treated by the suspension of fungus conidia at concentrations ranging from 1 × 104 to 1 × 108 spores per 1 mL. Fungus infection was observed mostly in pupae, but the maximum mortality did not exceed 60%, indicating a very low susceptibility of C. perspectalis to I. fumosorosea. Furthermore, a number of ungerminated fungal conidia were found on larval cuticles using a low-temperature scanning electron microscopy. Our data also reveal that the hydroalcoholic extract from B. sempervirens leaves significantly inhibits both the germination of I. fumosorosea conidia and fungus growth. It can be speculated that the strain CCM 8367 of I. fumosorosea is not a potent biocontrol agent against C. perspectalis and low virulence of the fungus might be due to the accumulation of host plant phytochemicals having antimicrobial activity in larval cuticle of the pest.

Antifungal activity of Xenorhabdus spp. and Photorhabdus spp. against the soybean pathogenic Sclerotinia sclerotiorum

The fungus, Sclerotinia sclerotiorum, causes white mold disease and infects a broad spectrum of host plants (> 500), including soybean with yield losses of up to 70%. Biological control is a potential alternative for management of this severe plant pathogen, and relative to chemical fungicides, provides broad benefits to the environment, farmers and consumers. The symbiotic bacteria of entomopathogenic nematodes, Xenorhabdus spp. and Photorhabdus spp., are characterized by the production of antimicrobial compounds, which could serve as potential sources for new bio-fungicides. The objectives of this study were to assess cell-free supernatants (CFS) of 16 strains of these bacteria cultures on S. sclerotiorum mycelium growth; assess the volatiles of X. szentirmaii cultures on the fungus mycelium and sclerotium inhibition; and evaluate the X. szentirmaii cultures as well as their CFS on the protection of soybean seeds against the white mold disease. Among the 16 strains, the CFS of X. szentirmaii showed the highest fungicidal effect on growth of S. sclerotiorum. The CFS of X. szentirmaii inhibited > 98% of fungus growth from mycelium and sclerotia, whereas the volatiles generated by the bacterium culture inhibited to 100% of fungus growth and 100% of sclerotia production. The bacterial culture diluted to 33% in water and coated on soybean seeds inhibited S. sclerotiorum and protected soybean plants, allowing 78.3% of seed germination and 56.6% of plant development. Our findings indicate potential for a safe and novel control method for S. sclerotiorum in soybean. Moreover, this is the first study to indicate that volatile organic compounds from Xenorhabdus spp. can be used in plant disease suppression.

FORMULASI SEDIAAN SABUN CAIR EKSTRAK ETANOL DAUN TURI (Sesbania grandiflora L.) DAN UJI ANTIJAMUR TERHADAP Candida albicans

ABSTRACTThe leaves of Hummingbird (Sesbania grandiflora L.) contain flavonoid compounds, saponins and tannins that are antifungal. This research aims to formulate liquid soap extracts of Hummingbird leaf ethanol and test the effectiveness of the antifungal preparations of the liquid soap of Hummingbird leaf ethanol with a concentration of 4%, 6%, 8%, 10% and 12% of the fungus growth of Candida albicans. This research uses experimental methods. The formulation of this liquid soap of Hummingbird leaf ethanol is conducted organoleptic test, pH, high foam, moisture content, free alkaline content, and type weights. Testing the effectiveness of antifungal to Candida albicans growth is done by diffusion method. Liquid soap preparations of Hummingbird leaf ethanol extract meet the standards set by SNI for organoleptic testing, pH test, Foam High test, water content test, free alkali rate test, and type weight test. Based on the anti-fungal testing of the preparation of a liquid soap extract of Hummingbird leaf ethanol to the fungus Candida albicans obtained the results of all preparations have a resistance to fungi and strong categorized.Keywords: Hummingbird leaves, Liquid soap, AntifungalABSTRAK Daun Turi (Sesbania grandiflora L.) memiliki kandungan senyawa flavonoid, saponin dan tannin yang bersifat sebagai antijamur. Penelitian ini bertujuan untuk memformulasikan sabun cair ekstrak etanol daun Turi dan menguji efektivitas antijamur sediaan sabun cair ekstrak etanol daun Turi dengan konsentrasi 4%, 6%, 8%, 10% dan 12% terhadap pertumbuhan jamur Candida albicans. Penelitian ini menggunakan metode eksperimental. Formulasi sediaan sabun cair ekstrak etanol daun Turi ini dilakukan pengujian organoleptik, pH, tinggi busa, kadar air, kadar alkali bebas, dan bobot jenis. Pengujian efektivitas antijamur terhadap pertumbuhan Candida albicans dilakukan dengan metode difusi. Sediaan sabun cair ekstrak etanol daun turi memenuhi standar yang ditetapkan SNI pada pengujian organoleptik, uji pH, uji tinggi busa, uji kadar air, uji kadar alkali bebas, dan uji bobot jenis. Berdasarkan pengujian antijamur sediaan sabun cair ekstrak etanol daun Turi terhadap jamur Candida albicans didapatkan hasil semua sediaan memiliki daya hambat terhadap jamur dan dikategorikan kuat.Kata Kunci: Daun Turi, Sabun Cair, Antijamur