Spore Density Research Articles

EFEKTIVITAS BIOPESTISIDA BERBAHAN AKTIF TRICHODERMA HARZIANUM PADA BERBAGAI FORMULASI DAN LAMA PENYIMPANAN DALAM MENGENDALIKAN PENYAKIT DAMPING-OFF TANAMAN KEDELAI (GLYCINE MAX (L.) MERILL)

Rhizoctonia solani is a soil-borne pathogen found in soybean plants. The attack can cause the soybean plants to collapse. The attack phase of Rhizoctonia solani occurs in the seedling phase of soybean plants. One of the control techniques for suppressing the attack of the fungus can be done with preventive measures using biopesticides. This study aims to determine spore viability, spore density, incubation period, disease incidence, disease severity, and effectiveness of control after the application of Trichoderma harzianum active ingredient biopesticide with different storage times. The research was conducted at the HPT Green House, Faculty of Agriculture, University of Jember. The experimental design used a factorial design and was repeated 3 times. The results showed that the effect of giving fish meal formulations on the germination ability of Trichoderma harzianum, incubation period, disease incidence, disease attack, and control effectiveness at 30 days of storage was able to suppress the attack of the fungus Rhizoctonia solani. The results of the analysis test were significantly different when compared to the control treatmen.

Vascular plant and cryptogam abundance as well as soil chemical properties shape microbial communities in the successional gradient of glacier foreland soils

In the glacier forelands, microbes play a fundamental role in soil development and shaping the vegetation structure. Such ecosystems represent various stages of soil development and are, therefore, an excellent place to study the interrelationship between soil, plants, and microorganisms. The aim of the study was to assess the effects of vegetation and soil physicochemical properties developing after glacier retreat on soil microbial communities. Specifically, abundance, species richness and the composition of arbuscular mycorrhizal fungi (AMF), as well as microbial biomass and community structure in soils were compared between plots established in 800-meter transects of three glacier forelands in northern Sweden. The cover of vascular plants and cryptogams, soil C content, AMF spore density and species richness, AMF biomass indicators, total microbial biomass, and bacterial phospholipid fatty acids (PLFA) were significantly and positively related to the distance from the glacier terminus. On the other hand, macronutrient concentrations and pH decreased along with increasing distance. No significant impact of the distance from the glacier terminus on the ratio fungal/bacterial PLFA was observed. Moreover, we found a significant effect of both glacier and the distance from the glacier terminus on the microbial community structure. AMF species richness and spore density in the glacier forelands were generally low, which is probably due to a limited supply of inoculum in primary successional ecosystems. Most microbial biochemical markers and AMF parameters were positively associated with the number of arbuscular mycorrhizal plant species and vascular plant and lichen cover as well as C content in soil, whereas negatively with soil macronutrients and pH. This could be related to an increase in plant cover and a decrease in soil nutrient levels as plant succession progresses. Our results showed that vegetation, soil C content, and microbial communities are interlinked and exhibit concordant patterns along successional gradients.

Potential of Local Isolates of Entomopathogenic Fungi Metarhizium sp. and Beauveria sp. on Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae) Larvae

Spodoptera frugiperda is an important pest which is an invasive insect that attacks maize plants. One alternative control that can be used is entomopathogenic fungi. The aim of this study was to analyze the potency of local isolates and flour formulations of the entomopathogenic fungi Metarhizium sp. and Beauveria sp. against S. frugiperda larvae in maize. This study used randomized block design (RBD) which consisted of five treatments (control, local isolates of the entomopathogenic fungi Metarhizium sp. and Beauveria sp., and flour formulations of the entomopathogenic fungi Metarhizium sp. and Beauveria sp. that comes from a pesticide shop) which was held from September 2021 until January 2022 in screen house and Laboratory of Plant Pest and Disease, Faculty of Agriculture, University of Sumatera Utara at an altutide of ±25 mdpl. Each treatment used a spores density of 108 spores/ml/ FAW’s larvae with five replications. The results showed that the highest larvae mortality (96,00%) was found on local isolate of Beauveria sp. The symptoms of infection with Beauveria sp. were the body of the larvae of S. frugiperda overgrown with white fungal colonies and infection with Metarhizium sp. were the body of the larvae of S. frugiperda overgrown with green or dark brown fungal colonies. The shortest lethal time (LT50) (4,75 days) was found on local isolates of Beauveria sp and the longest one (5,65 days) was found on flour formulations of Metarhizium sp. The highest attack intensity (56,40%) was found on flour formulations of Metarhizium sp. while the lowest one (28,40%) was found on local isolate of Beauveria sp.

Arbuscular mycorrhizal fungi in the soil using cover crops with and without nitrogen addition.

This study aimed to evaluate the occurrence of mycorrhizal fungi and glomalin content in soil under different cover crops with and without the application of nitrogen in the cover. The following cover plants were used: Crotalaria juncea (Crotalaria juncea L.), wild beans from Ceará (Canavalia brasiliensis Mart. ex Benth.), Guandú 'BRS mandarin' [Cajanus cajan (L.) Millsp.], millet 'BR05' [Pennisetum glaucum (L.) R.Br.] and sorghum 'BR 304' [Sorghum bicolor (L.) Moench]. The absolute control of the experiment was the treatment without the use of cover crops, that is, the vegetation of spontaneous occurrence in the area. The experimental design was randomized blocks in subplots with three replications. Spore density, mycorrhizal colonization rate, easily extractable glomalin, and species present in the rhizosphere of the cover crops were determined. No differences were found in the diversity of mycorrhizal fungi associated with the different cover crops studied or in the values of spore density, root colonization, or glomalin content. Nitrogen application did not influence the mycorrhizal activity in the investigated cover crops. The most frequent species associated with cover crops were Scutellospora pellucida and Scutellospora persica in C. juncea; Gigaspora sp. on Sorghum; Glomus macrocarpum in Guandu; G. macrocarpum and Glomus clavisporum in millet; and Glomus microaggregatum and Glomus tortuosum in Spontaneous Vegetation.

Diversity of Arbuscular Mycorrhizal Fungi of Kalappia celebica: An endemic and endangered plant species in Sulawesi, Indonesia

Abstract. Husna, Tuheteru FD, Albasri, Arif A, Basrudin, Nurdin WR, Arman E, Agustin DI, Saribadu J, Rahmat, Dermawansyah A, Daliana, Lody LP, Deri AS, Safitri I. 2022. Diversity of Arbuscular Mycorrhizal Fungi of Kalappia celebica.): An endemic and endangered plant species in Sulawesi, Indonesia. Biodiversitas 23: 5290-5297. Arbuscular Mycorrhizal Fungi (AMF) are a group of fungi belonging to Phylum Glomeromycota. AMF has a symbiotic relationship with higher plants, including endangered species in various climatic regions and land types. Research on AMF diversity related to endemic and endangered tree species in the tropics is still limited. This study aimed to examine the diversity of AMF in the natural habitat of Kalappia celebica Kosterm. (kalapi) in Southeast Sulawesi Province, Indonesia. Samples of soil and roots of K. celebica were collected from six natural habitat locations, i.e., Konawe District (Anggatoa and Abuki Villages), East Kolaka District (Lalingato and Anggaloosi Villages) and Kolaka District (Lalonaha and Lapao Pao Villages). The AMF spores were isolated by using the pouring method, followed by wet filtration. AMF identification was carried out by observing the morphology of AMF spores. A total of eight AMF species belonging to three genera Viz. Glomus, Funneliformis and Rhizophagus were isolated. Among the species identified, five species belong to genus Glomus, two species belong to the genus Funneliformis and one species belongs to the genus Rhizophagus. Glomus sp.1 and 2 and F. mosseae had the highest spore density, relative density and frequency, and importance index values. The AMF highest spore density was obtained in Anggaloosi Village of East Kolaka District. Soil properties such as organic C, total N and clay were positively correlated with spore density and negatively correlated with AMF colonization. The Simpson’s Index ranged from 0.42 ± 0.117 to 0.86 ± 0.068. The range of Shannon-Wiener Index was 0.12 ± 0.208 to 0.99 ± 0.198, while the Evenness Index ranged from 0.17 ± 0.189 to 0.75 ± 0.106. These findings indicated that K. celebica species are rich in AMF diversity. These symbiont fungi are key components of the ecosystem. Further research is needed to develop their use as promoters of plant establishment in conservation and restoration of those sites.

Diversity of Arbuscular Mycorrhizal Fungi of Kalappia celebica: An endemic and endangered plant species in Sulawesi, Indonesia

Abstract. Husna, Tuheteru FD, Albasri, Arif A, Basrudin, Nurdin WR, Arman E, Agustin DI, Saribadu J, Rahmat, Dermawansyah A, Daliana, Lody LP, Deri AS, Safitri I. 2022. Diversity of Arbuscular Mycorrhizal Fungi of Kalappia celebica.): An endemic and endangered plant species in Sulawesi, Indonesia. Biodiversitas 23: 5290-5297. Arbuscular Mycorrhizal Fungi (AMF) are a group of fungi belonging to Phylum Glomeromycota. AMF has a symbiotic relationship with higher plants, including endangered species in various climatic regions and land types. Research on AMF diversity related to endemic and endangered tree species in the tropics is still limited. This study aimed to examine the diversity of AMF in the natural habitat of Kalappia celebica Kosterm. (kalapi) in Southeast Sulawesi Province, Indonesia. Samples of soil and roots of K. celebica were collected from six natural habitat locations, i.e., Konawe District (Anggatoa and Abuki Villages), East Kolaka District (Lalingato and Anggaloosi Villages) and Kolaka District (Lalonaha and Lapao Pao Villages). The AMF spores were isolated by using the pouring method, followed by wet filtration. AMF identification was carried out by observing the morphology of AMF spores. A total of eight AMF species belonging to three genera Viz. Glomus, Funneliformis and Rhizophagus were isolated. Among the species identified, five species belong to genus Glomus, two species belong to the genus Funneliformis and one species belongs to the genus Rhizophagus. Glomus sp.1 and 2 and F. mosseae had the highest spore density, relative density and frequency, and importance index values. The AMF highest spore density was obtained in Anggaloosi Village of East Kolaka District. Soil properties such as organic C, total N and clay were positively correlated with spore density and negatively correlated with AMF colonization. The Simpson’s Index ranged from 0.42 ± 0.117 to 0.86 ± 0.068. The range of Shannon-Wiener Index was 0.12 ± 0.208 to 0.99 ± 0.198, while the Evenness Index ranged from 0.17 ± 0.189 to 0.75 ± 0.106. These findings indicated that K. celebica species are rich in AMF diversity. These symbiont fungi are key components of the ecosystem. Further research is needed to develop their use as promoters of plant establishment in conservation and restoration of those sites.

Optimisation of talcum powder formulation based on Nocardiopsis albirubida strain NA2 spores for biocontrol of Bipolaris sorokiniana root rot in durum wheat seedlings

ABSTRACT Bipolaris sorokiniana root-rot of wheat seedlings remains a serious worldwide problem. Spores of Nocardiopsis albirubida strain NA2 were bioformulated as talcum wettable powder (TWP) and clay-alginate pellets (CP) biofungicides before screening for their biocontrol effect. Based on their promising biocontrol results, the talcum powder biofungicide was selected to optimise the bioformulation parameters using the response surface methodology (RSM). The biofungicides TWP and CP significantly (P < 0.05) and respectively reduced the disease severity index (DSI) to 25.6% and 58.2% compared to a positive control (84.0%). Furthermore, the talcum powder biofungicide showed no significant differences compared to a marketed chemical control agent (Difenoconazole®). The TWP biofungicide was selected and a Placket-Burman screening design was explored to evaluate the composition for an optimised biofungicide. Two variables: washed spore density and talcum powder quantity, respectively, showed an important in planta biocontrol effect on B. sorokiniana. The RSM optimisation for the two influencing variables allowed a very notable reduction of the DSI, passing from 25.6% (standard formulation process) to 5.1% (optimised talcum powder biofungicide) by using 25 ml of washed spore suspension (≈107spores ml−1) and 125 g of autoclaved talcum powder. The coefficient of determination R 2 = 0.950 indicated that 95.0% of the response variability can be simulated with the suggested mathematical equation. The spore viability and the biocontrol efficacy have been demonstrated after 12 months storage. The TWP biofungicide based on washed NA2 spores open up promising applications for the biocontrol of B. sorokiniana root rot.

Dry-Season Soil and Co-Cultivated Host Plants Enhanced Propagation of Arbuscular Mycorrhizal Fungal Spores from Sand Dune Vegetation in Trap Culture.

The use of arbuscular mycorrhizal fungi (AMF) as biofertilizer in agriculture is a sustainable approach to fertilization. The first step in the production of AMF biofertilizer is inoculation of mycotrophic plants with a composite of soil and native plant roots, containing potentially viable AMF spores from natural habitats, to a trap culture. A single host plant or a consortium of host plants can be used to propagate AMF spores. However, the difference in the comparative efficiency of mono- and co-cultivated host plants used for the production of AMF spores and the maintenance of original AMF community composition has not been well elucidated. Here, we prepared trap culture with nutrient-poor soil from coastal sand dune vegetation collected during the dry season when the AMF spore density and relative abundance of Glomeromycota ITS2 sequences were significantly higher (p = <0.05) than in the wet season. The AMF communities in the soil were mainly composed of Glomus spp. Maize (Zea mays L.) and/or Sorghum (Sorghum bicolor (L.). Moench) were grown in trap cultures in the greenhouse. Our results demonstrated that co-cultivation of the host plants increased the production of AMF spores but, compared to mono-cultivation of host plants, did not better sustain the native AMF community compositions in the coastal sand dune soil. We propose that the co-cultivation of host plants in a trap culture broadens AMF-host plant compatibilities and thus sustains the symbiotic association of the natively diverse AMF. Therefore, the results of this study suggest that further research is needed to confirm whether the co-culturing of more than one host plant is as efficient a strategy as using a monoculture of a single host plant.

Soil moisture and pH differentially drive arbuscular mycorrhizal fungal composition in the riparian zone along an alpine river of Nam Co watershed.

The riparian zone is an important ecological corridor connecting the upstream and downstream rivers. Its highly complex biological and physical environments significantly affect the biogeographical pattern of species and various ecosystem functions. However, in alpine riparian ecosystems, the distribution patterns and drivers of arbuscular mycorrhizal (AM) fungi, a group of functionally important root-associated microorganisms, remain poorly understood. In this study, we investigated the AM fungal diversity and community composition in near-bank (wetland) and far-bank (alpine meadows) soils along the Niaqu River in the Nam Co watershed, and assessed the relative importance of abiotic and biotic filtering in shaping these distributions. Overall, 184 OTUs were identified in the riparian ecosystem, predominantly belonging to the genus Glomus, especially in the downstream soils, and Claroideoglomus in near-bank soils. AM fungal colonization, spore density, and α diversity showed an overall increasing trend along the river, while the extraradical hyphae declined dramatically from the middle of the river. AM fungal communities significantly varied between the wetland and alpine meadows in the riparian zone, mainly driven by the geographic distance, soil water content, soil pH, and plant communities. Specifically, soil pH was the principal predictor of AM fungal community in near-bank wetland soils, while soil water content had a most substantial direct effect in alpine meadows. These findings indicate that abiotic factors are the most important divers in shaping AM fungal communities at the watershed scale, which could be helpful in alpine riparian biodiversity conservation and management.

Insights into the deriving of rhizosphere microenvironments and its effects on the growth of authentic Angelica sinensis seedlings under continuous monoculture

PurposeContinuous monoculture leads to deterioration of soil microenvironment, which can severely threat the quality and efficiency of Angelica sinensis (A. sinensis), especially for seedlings production. However, little attention has been paid to investigate how continuous monocropping affects the growth of A. sinensis seedling, rhizosphere microbial populations, and nutrient status.MethodsA field experiment consisting of two different planting patterns — raising A. sinensis seedlings in reclamation alpine uncultivated meadow (RW) and 1-year continuous monoculture (CC), was carried out at Min County, Gansu province, China.ResultThe results showed that compared with RW, the growth rate and valid quantity of A. sinensis seedlings were significantly reduced by 195.4% and 36.7% in CC, respectively. Continuous monocropping significantly increased the rhizosphere soil pH value during the growing season, ranging from 6.18 to 7.10, while reducing the content of SOM, total N, and available P and K. Glomalin, AMF spore densities, and the number of actinomycetes, ammonifiers, and azotobacter were also decreased by CC. The CC treatment significantly increased the abundance of fungi. The diversity and richness of bacteria in CC were lower than RW. Furthermore, the composition and structure of bacterial and fungal flora also changed and that the abundance of beneficial bacteria decreased, while the abundance of pathogens increased in CC. Thus, CC appeared to completely upend the relationship between soil nutrient availability and microbial activity.ConclusionThe results illustrated that continuous monoculture led the flora of bacteria and fungi to changed dramatically, with the abundance of beneficial bacteria decreased and the abundance of harmful microbes, such as Lasiosphaeriaceae, Vishniacozyma, Myrmecridium, and Hypocreales, increased. The function of microbial population has changed from “beneficial bacteria dominated” to “harmful microbes dominant.” We concluded that continuous monoculture significantly reduced the growth and the efficiency of A. sinensis seedlings and deteriorated the rhizosphere soil microenvironment by increasing pH and decreasing nutrient availability, as well as altering the function of interactions between soil nutrients and microbial populations, thereby resulting in an unsuitable microenvironment for A. sinensis seedlings growth.

Colonization by arbuscular mycorrhizal in mandarin 'Montenegrina': interaction between rootstocks and sazonality

The objective was to evaluate the influence of seasonality on mycorrhizal colonization in roots of six rootstocks in an orchard of 'Montenegrina' mandarin (Citrus deliciosa Tenore). Rootstocks evaluated were: 'Flying Dragon' [Poncirus trifoliata var. monstrosa (T. Ito) Swing.]; 'Troyer' citrange [C. sinensis (L.) Osb. × P. trifoliata (L.) Raf.]; 'Swingle' citrumelo [C. paradisi Macf. × P. trifoliata]; 'Rangpur' lemon (C. limonia Osb.); 'Volkamer' lemon (C. volkameriana Ten. &amp; Pasq.); 'Caipira' orange (C. sinensis). Roots were collected in the four seasons. The density of structures, root colonization (number of infected segments/total analyzed) and spore density were determined. The rootstocks showed high percentages of colonization in the spring (above 96.60%). In winter, only 'Swingle' and 'Rangpur' showed high colonization rates (96.60 and 95.00 %, respectively). On the other hand, 'Flying Dragon', 'Troyer' and 'Volkamer' showed low colonization in winter (11.60 to 33.30 %). 'Flying Dragon' showed an increase in mycorrhizal colonization from the winter season (33.30 %) to spring (100.00 %) and a subsequent decrease from summer (95.00 %) to autumn (63.30 %). Mycorrhizal colonization occurs naturally and at a high rate on rootstocks, varying between rootstocks and seasons. There is a negative correlation between foliar nutritional content and the presence of AMFs.

Native arbuscular mycorrhizal fungi improve growth, biomass yield, and phosphorus nutrition of sorghum in saline and sodic soils of the semi–arid region

Exploiting symbiotic plant-microbe interactions with arbuscular mycorrhizal fungi (AMF) adapted to hostile soil can be a promising approach for enhancing crop productivity and tolerance to salinity and sodicity-related stresses in salt-affected agroecosystems. This study was conducted to characterize the native mycorrhizal ecotype and its responsiveness to sorghum in saline and sodic soils under controlled conditions. The AMF spore density in sodic soil under the rice-wheat cropping system was greater than in the sorghum-based systems. The spore density was greater under sodic compared to saline soils. The sequence of the amplified fungal ribosomal DNA of the 18 S region of the isolated culture from the rice-wheat system under sodic soil conditions showed the Funneliformis mosseae and Funneliformis geosporum as the dominant AMF species. The colonization and arbuscular abundance of Funneliformis sps. inoculated sorghum was greater for sodic and normal soil, respectively. Plant height and fresh and dry biomass of AMF inoculated plants were greater in normal soil followed by sodic and saline soils. Sodic soil showed a greater increase in root-to-shoot ratio compared to saline soils. The P content, P uptake, and K + / Na + were greater in AMF inoculated soils. The increase in Olsen’s-P in AMF inoculated soils was in the order of normal > sodic > saline soils. Sodic soils showed a maximum 15–35 fold increase in the EE-GRSP and DE GRSP because of AMF inoculation ( P ≤ 0.05 ). Dehydrogenase and alkaline phosphatase enzymes were greater in AMF inoculated ( P < 0.05 ) . The soil electrical conductivity , glomalin, and arbuscular abundance alone explained about 76 % variability in the plant response to AMF inoculation in these soils. This study concludes that the use of native AMF with the important cropping system can be an agronomically sound option to cope with abiotic stress in salt-affected soils. • AMF spore density greater in sodic soils and rice-wheat cropping system. • AMF identified as Funneliformis mosseae and F. geosporum. • Inoculation increased growth and biomass yield. • AMF inoculation increased P content, P uptake, and K+ / Na+ ratio. • 15–35 fold increase in glomalin content in inoculated soils.

Long-term persistence and recycling of Bacillus thuringiensis israelensis spores in wetlands sprayed for mosquito control

Bacillus thuringiensis subsp. israelensis (Bti) is the main larvicide used to control mosquitoes worldwide. Although there is accumulating evidence of Bti having environmental effects on non-target fauna, relatively few field studies have documented the fate of Bti spores in the environment. Spore density was quantified over a 6-yr period (2012–2017) in Mediterranean marshes sprayed with Vectobac 12AS (32 ITU/ha) since 2006 to reduce the nuisance caused by Aedes caspius. Bti spores were naturally found in all habitat types. Spore density expressed as colony-forming units per gram of soil (CFU g−1) increased significantly at treated sites by a factor of 22 to 500 times relative to control sites, with mean values of 7730 CFU g−1 in halophilous scrubs, 38,000 in reed beds, 49,000 in bulrush beds and 50 000 in rush beds. Spore density varied little in the first months after the spraying season (April-October), but increased sharply in spring, just before the annual launch of mosquito control. Considering that Bti is an insect pathogen that cannot proliferate without a suitable insect host, this unexpected recrudescence in spring could be related to the warming of water that triggers activity and development of benthic organisms such as chironomids, which may contribute to Bti proliferation by ingesting accumulated spores at the surface of sediments. While spore density tends to decrease over time, presumably during the summer period as a result of increased UV exposure, three to four years were necessary for spore density to return to normal levels after mosquito-control interruption. This study is important because it demonstrates that environmental effects of mosquito-control using Bti can far exceed the short period of Bti efficacy against lentic mosquitoes. Considering that Bti is a microbial agent, these long-term effects should be addressed at multiple levels of ecosystem organization from a one-health perspective.

Arbuscular Mycorrhiza Fungi Integrated with Single Super Phosphate Improve Wheat-nitrogen-phosphorus Acquisition, Yield, Root Infection Activity, and Spore Density in Alkaline-calcareous Soil

Arbuscular Mycorrhiza Fungi Integrated with Single Super Phosphate Improve Wheat-nitrogen-phosphorus Acquisition, Yield, Root Infection Activity, and Spore Density in Alkaline-calcareous Soil

Discovering the Diversity of Arbuscular Mycorrhizal Fungi Associated with Two Cultivation Practices of Theobroma cacao

In recent years, new data on the diversity of genera and species in the phylum Glomeromycota continue to be added and rearranged. Arbuscular mycorrhizal fungi are key to plant nutrition and agriculture. Studies report different short- and long-term cultivation practices that influence the abundance and diversity of Glomeromycota. To the best of our knowledge, there are no known studies of the fungal communities in the fine aroma cocoa cultivars. In this context, our work aims to discover the diversity of arbuscular mycorrhizae associated with two cocoa cultivation practices (conservative and semi-conservative) through the isolation of spores using microscopy and metabarcoding of the internal transcribed spacer region (ITS). Morphological analysis showed that the density of Glomeromycota spores exhibited significant differences between production systems. Although the metabarcoding analysis showed that diversity indices showed a higher increase in the roots than in the cocoa soil, independently of the cultivation practice. An abundance of 348 and 114 taxa were observed, corresponding to the conservative and semi-conservative practices, respectively. Seven genera were observed for the first time in cocoa crop agroforestry systems, including P. scintillans, R. diaphanus, R. fasciculatus, R. custos, D. disticha, M. perpusilla, and D. bernensis.

Initial In Vitro Assessment of the Antifungal Activity of Aqueous Extracts from Three Invasive Plant Species

The development of new, safe, and effective methods of managing fungal pathogens is required. This study was conducted to perform an initial in vitro assessment of the antifungal activity of water-based plant extracts from three plants which are invasive in Egypt: Prosopis juliflora, Ipomoea carnea, and Leucaena leucocephala. These extracts were tested against three pathogenic fungi species that cause high crop losses in Egypt: Fusarium solani, Alternaria solani, and Colletotrichum circinans. Three extract concentrations, 10%, 20%, and 30%, were tested using a completely randomized design, with three replicates per treatment. Antifungal activity was determined based on the effects of plant extracts on fungal radial growth inhibition, average daily growth of fungi, spore formation, spore germination, and total biomass. Inhibition of the growth of fungal strains increased with increasing plant extract concentration, with the highest inhibitory rate at the 30% extract concentration. In addition, spore density, spore germination, and total biomass decreased significantly with increasing extract concentration. The three fungal pathogens differed in their inhibition and their response to these plant extracts. Prosopis juliflora had the highest inhibitory effect on the three fungal pathogens, compared to the extracts from the other two invasive plants. The results of this feasibility study indicate that P. juliflora extracts have high antifungal activity and follow-up in vivo assays should be conducted to determine their efficacy in the safe and sustainable management of these and other fungal pathogens.

Soil sodicity affected the arbuscular mycorrhizal community and its interactions with bacteria in the Western Songnen Plain

Soil sodicity affects plant growth and is a crucial factor degrading soil fertility and threatening grain yield worldwide. AM fungi form mutualistic symbiosis with plant roots and alleviate salt stress for the host plant. Therefore, understanding their distribution pattern and interactions with bacteria in natural saline-sodic soils would be essential to improve plant growth. Therefore, we examined AM fungal community and co-occurrence with soil bacteria across a wide sodicity gradient in the Western Songnen Plain. AM fungal traits, including root colonization and ERH (extraradical hyphal) density, showed negative correlations with soil sodicity, while spore density did not show correlation with soil sodicity. In total, 188 AM fungal OTUs were annotated at 97 % identity across 108 soil samples. Soil sodicity decreased AM fungal alpha-diversity and exerted strong influence on their community composition. Rare AM fungi were more sensitive to sodicity than abundant AM fungi, as confirmed by their decrease with the increasing soil sodicity and almost all rare AM fungi belonging to z- OTUs. Abundant rather than rare AM fungi contributed greatly to soil nutrient availability as shown by conducting a random forest analysis. Network analysis revealed a less connected AM fungi-bacteria co-occurrence network in moderately and extremely saline-sodic soils. Further analysis indicated that some bacteria that positively correlated with AM fungi indeed exhibited positive correlations with AM fungal hyphal and spore density. Overall, our results provide evidence that AM fungal community was greatly shaped by soil sodicity in the Songnen Plain, and provides an alternative way to identify positive AM-bacteria interactions in saline-sodic environments.

Uji Sinergitas Rendaman Tembakau (Nicotiana tabacum L.) dengan Jamur Trichoderma spp. Secara In Vitro dan Potensinya Sebagai Gabungan Biopestisida Alami

Management of plant pests and diseases can prevent crop failure of agricultural commodities. Trichoderma spp. is a type of biological control fungus. Tobacco can be used as a vegetable pesticide. However, the synergy of tobacco and Trichoderma spp. when applied simultaneously in controlling pathogens is not yet known, considering the content of the active compound nicotine in tobacco which has antifungal properties, it is necessary to conduct this study with the aim of knowing the effect of tobacco immersion on the growth of the fungus Trichoderma spp. and if there is no inhibition then both will have the potential as a combination of natural biopesticides. This study used a completely randomized design (CRD). The treatment tried was different concentrations of tobacco soak mixed with PDA as a culture medium for Trichoderma spp. The concentrations tested were 0% (T0, positive control), 5% (T1), 10% (T2), 15% (T3), and 20% (T4). The negative control used a fungicide with the active ingredient mankozeb. Each treatment was repeated 3 times. Colony thickness and color data were observed visually by descriptive method. Meanwhile, data on colony diameter, number of spores, dry weight of mycelium were analyzed by F test, if significantly different, then followed by DMRT test with a confidence level of 5%. Based on research that has been carried out from July-August 2021, the results obtained on PDA media with tobacco soaking content with concentrations of 0% (K+), 5% (T1), 10% (T2), 15% (T3), 20% (T4 ) can be grown with Trichoderma spp., while the media with the addition of synthetic fungicides made from mankozeb is not grown. The difference in concentration showed different growth results and the effective concentration in this research was 15%, because at 20% concentration there was a decrease in spore density and mycelium dry weight.

STUDY OF EFFECTIVITY Bacillus thuringiensis BASED BIO-INSECTICIDE AGAINST Oryctes rhinoceros LARVAE AT SHADE HOUSE

Oryctes rhinoceros is an important pest in oil palm plantations. Adult stage of the beetle causes damage, however larval stage is very important to be controlled to break the cycle of life. An entomopathogenic bacterium Bacillus thuringiensis is one of biological agents to control these insects. Its toxic protein content provides specific insect targets as stomach poison. Objectives of the research was to study the impact of B. thuringiensis propagated in bio-urine enriched with 5 per cent molasses towards Oryctes larvae. The research was carried out in the shade house of Plant Protection Study Program, Faculty of Agriculture, Sriwijaya University from August to November 2021. Experiment was designed in a randomized complete block design with 7 treatments and 4 replications. A total of 20 ml of bio-insecticide was dissolved in 280 ml of water, sprayed evenly on the soil mixed with male palm flowers as feed of larvae. The treatments were 6 isolates of B. thuringiensis isolated from soil in oilpalm plantation, namely with codes: C14, C15, A15, OJ, BK, and LK as well. The results showed density of B. thuringiensis spores in bio-urine media was different in each isolate. The highest spore density in isolate code LK was 4.83 x 1010 spores/ml and the lowest (in isolate A15) was at 3.5 x 1010 spores/ml. Mortality rates were significantly different between isolate treatments starting from day 3 to day 12 of observation. C15 isolate lead the highest mortality rate of 100% on day 12 while other isolates showed mortality data below 100% (88-98%). Body weight and length showed significantly differences on days 0, 6 and 12 after application. Symptoms of infection begin with a change in skin color from white to brown, dark brown and black. Death is characterized by a soft body texture and wet rot.

Effect of Physico-chemical Properties on Spore Density and Root Colonization of Mycorrhizal Fungi in Industrial Wastelands in Kota, Rajasthan

This study was conducted in selected industrial waste dump sites in the Kota district of Rajasthan, India to investigate the impact of various edaphic factors on spore density and root colonization of arbuscular mycorrhizal (AM) fungi. The current research shows that AMF root colonization rates were insignificantly negatively correlated with EC, soil temperature, P, K, Fe, Cu, Zn, and Mn but significantly positively correlated with soil pH, soil moisture, and insignificantly positively correlated with N and OC (P &lt; 0.05). Spore density of mycorrhiza was insignificant and negatively correlated with soil moisture (P &lt; 0.05), EC, soil temperature, P, K, Fe, Cu, Zn, and Mn but significantly positively correlated with soil pH and insignificantly positively correlated with N and OC.&#x0D; Edaphic factors may influence the root colonization and spore density of mycorrhiza differentially. Except for pH and soil moisture, almost all other parameters have a very insignificant influence on mycorrhizal root colonization and spore density in industrial wastelands.