Eucalyptus Species Research Articles

Exogenous silicon alleviates aluminum stress in Eucalyptus species by enhancing the antioxidant capacity and improving plant growth and tolerance quality

BackgroundAs an efficient and high-quality additive in agriculture and forestry production, silicon (Si) plays an important role in alleviating heavy metal stress and improving plant growth. However, the alleviating effect of aluminum (Al) toxicity by Si in Eucalyptus is still incomplete.ResultsHere, a study was conducted using two Al concentrations (0 and 4.5 mM) with four Si concentrations (0, 0.5, 1, and 1.5 mM) to investigate plant growth, tolerance and antioxidant defense system in four Eucalyptus species (Eucalyptus tereticornis, Eucalyptus urophylla, Eucalyptus grandis, and Eucalyptus urophylla × Eucalyptus grandis). The results showed that the stress induced by 4.5 mM Al increased oxidative damage, disturbed the balance of enzymatic and non-enzymatic antioxidant systems, and negatively affected plant growth and tolerance quality in the four Eucalyptus species. However, the addition of 0.5 mM and 1 mM Si alleviated the effects of Al toxicity on plant growth and improved plant growth quality by strengthening stress tolerance. Besides, adding Si significantly facilitated the synergistic action of enzymatic and non-enzymatic antioxidant defenses, increased the removal of reactive oxygen species, reduced lipid peroxidation, and oxidative stress, and promoted the phytoremediation rate of the four Eucalyptus species by 18.7 ~ 34.8% compared to that in the absence of Si.ConclusionsSilicon can alleviate the effect of Al toxicity by enhancing the antioxidant capacity and improving plant growth and tolerance quality. Hence, the application of Si is an effective method for the phytoremediation of Eucalyptus plantations in southern China.

Climate change favors expansion of three Eucalyptus species in China.

Eucalyptus has become one of the most widely planted species in tropical and subtropical regions in China, with important economic, ecological, and social values. However, it is currently unclear how climate change will affect different Eucalyptus species. Therefore, it is urgent to investigate the potential distribution and dynamics of Eucalyptus under current and future climate scenarios. In this study, we analyzed the potential distribution patterns of the three main Eucalyptus species (Eucalyptus grandis, Eucalyptus urophylla, and Eucalyptus tereticornis) under current and future climatic conditions (2041-2060 and 2061-2080) using the optimized MaxEnt model, which integrates a variety of environmental data including climate, topography, soil, and human influence. We also identified the main factors affecting the potential distributions of the three main Eucalyptus species. The model indicated that E. grandis exhibited heightened sensitivity to the mean temperature of the coldest quarter (7.0-20.0 °C) and annual mean temperature (11.9-24.2 °C), whereas E. urophylla displayed heightened sensitivity to precipitation of the warmest quarter (272-1694mm) and annual precipitation (812-2624mm). Conversely, E. tereticornis demonstrated heightened sensitivity to annual mean temperature (12.7-24.5°C) and temperature seasonality (63.8-598.9). Under the current climate, E. tereticornis had the widest suitable distribution area (124.91 × 104 km²), followed by E. grandis (124.89 × 104 km²) and E. urophylla (119.81 × 104 km²). Under future climate change scenarios, the suitable ranges of E. grandis, E. urophylla and E. tereticornis will continue to expand. This study highlights the importance of climate change in Eucalyptus distribution and provides quantified potential distribution maps for three Eucalyptus species under current and future climate conditions in China. This research offers valuable scientific insights pertinent to the management and rational site selection for Eucalyptus plantations.

Regeneration and Genetic Transformation in Eucalyptus Species, Current Research and Future Perspectives

Eucalyptus is an important plantation tree with a high economic value in China. The tree contributes significantly to China’s timber production. The stable and efficient Eucalyptus regeneration system and genetic transformation system are of great significance for exploring the regulatory function and possible genetic breeding capacity of important genes in the species. However, as a woody plant, Eucalyptus has problems, such as a long generation cycle, strong specificity of the regeneration system, and a low genetic conversion rate, which seriously limit the rapid development of Eucalyptus genetics and breeding programs. The present review summarizes the status of research on Eucalyptus regeneration and genetic transformation, with a focus on the effects of explants, media, plant growth regulators (PGRs), and concentrations in the Eucalyptus regeneration process. In addition, the effects of genotype, Agrobacterium, antibiotics, preculture, and co-culture on the genetic transformation efficiency of Eucalyptus are discussed. Furthermore, the study also summarizes the problems encountered in Eucalyptus regeneration and genetic transformation, with reference to previous studies, and it outlines future developments and prospects. The aim was to provide a reference for solving the problems of genetic instability and the low transformation efficiency of eucalyptus, and to establish an efficient and stable eucalyptus regeneration and transformation system to accelerate the process of its genetic improvement.

Antimicrobial and Cytotoxic Potential of Eucalyptus Essential Oil-Based Nanoemulsions for Mouthwashes Application.

Objective: An eucalyptus essential oil-based nanoemulsion was produced and evaluated for its antimicrobial properties against Streptococcus mutans and its cytotoxicity in the surface mucous cells of rabbits. Methods: The essential oil-based nanoemulsion was synthesized with two species of eucalyptus-Eucalyptus citriodora and Eucalyptus globulus-followed by physicochemical characterization and the determination of antimicrobial activity and cell viability. Subsequently, the mouthwash formulations (fluoride and fluoride-free) were functionalized with the nanoemulsion, and their in vitro antimicrobial actions were evaluated against S. mutans. Results: The nanoemulsion presented an average particle size of around 100 nm, a polydispersity index close to 0.3, a zeta potential between -19 and -30 mV, a pH close to 7, a spherical shape, and a cell viability above 50%. The antimicrobial activity analysis showed that the nanoemulsion was effective in the control of S. mutans. The mouthwashes functionalized with the nanoemulsion also presented bacteriostatic and bactericidal properties. Conclusions: The bio-based material produced with eucalyptus essential oil presented adequate physicochemical characteristics, with the potential to be used as an innovative material in preventive dentistry, contributing to the maintenance of oral and systemic health.

The Role of trnH-pbsA Spacer Gene in Eucalyptus Species Identification and its Importance in Phylogenetics

The Role of trnH-pbsA Spacer Gene in Eucalyptus Species Identification and its Importance in Phylogenetics

Natural durability of Eucalyptus species harvested as electricity transmission poles in two different ecological zones of Ghana

This study assessed the possibility and feasibility of using two Eucalyptus species for electricity transmission poles in Ghana as a means of minimizing the import of transmission poles in the country. Eucalyptus species are grown in private and government-owned plantations in Ghana due to its growing demand for use as power line transmission poles. The species are seldom used by the furniture industry. The demand from the pole treatment industry for raw materials exceeds the domestic supply of teak, which is commonly used as transmission poles, resulting in the importation of pine poles to cover the deficit, hence the need for this study. The natural durability of Eucalyptus alba and Eucalyptus robusta in the Coastal Savanna Zone (CSZ) and Moist Semi-Deciduous Forest Zone (MSDFZ) was tested using white rot fungus (Coriolopsis polyzona) under an accelerated laboratory test. The results indicated significant variations in the mass lossess be-tween trees in the two vegetation zones. The sapwood and outer heartwood of the E. alba tree species of CSZ recorded the highest mass losses of 41.21 % and 20.79 %, respectively, compared to the E. robusta trees felled from MSDFZ that recorded mass losses of 32.3 % and 5.42 %, respectively. Also, the outer heart- wood and inner heartwood of the E. robusta MSDFZ felled trees were highly resistant (5.42 % and 6.99 %). CSZ wood species were less naturally resistant to C. polyzona attack than those harvested from MSDFZ, which appeared to be less susceptible and more naturally resistant to decay by C. polyzona. Both species are feasible for use as transmission line poles; however, trees from both ecological zones would need chemical preservatives to improve their service life, especially for outdoor applications.

Fire and ant interactions mediated by honeydew and extrafloral nectar in an australian tropical savanna

Fire is a major disturbance affecting ecosystems globally, but its impact on mutualisms has received minimal attention. Here, we use a long-term field experiment to investigate the impact of different fire regimes on globally important ant–honeydew and ant–extrafloral nectar (EFN) mutualistic interactions in an Australian tropical savanna. These interactions provide ants with a key energy source, while their plant and hemipteran hosts receive protection services. We examined ant interactions on species of Eucalyptus (lacking EFNs) and Acacia (with EFNs) in three replicate plots each of burning every 2 and 3 years early in the dry season, burning late in the dry season every 2 years, and unburnt for > 25 years. The proportions of plants with ant–honeydew interactions in Acacia (44.6%) and Eucalyptus (36.3%) were double those of Acacia plants with ant–EFN interactions (18.9%). The most common ants, representing 85% of all interactions, were behaviourally dominant species of Oecophylla, Iridomyrmex and Papyrius. Fire promoted the incidence of ant interactions, especially those involving EFNs on Acacia, which occurred on only 3% of plants in unburnt plots compared with 24% in frequently burnt plots. Fire also promoted the relative incidence of behaviourally dominant ants, which are considered the highest quality mutualists. Contrary to expectations, frequent fire did not result in a switching of behaviourally dominant ant partners from forest-adapted Oecophylla to arid-adapted Iridomyrmex. Our findings that frequent fire increases ant interactions mediated by honeydew and extrafloral nectar, and promotes the quality of ant mutualists, have important implications for protective services provided by ants in highly fire-prone ecosystems.

Nectriaceae species associated to root rot of nursery and young Eucalyptus smithii trees in Uruguay with Ilyonectria charruensis as novel species.

Forestry constitutes an important agronomical activity in Uruguay, involving the cultivation of exotic trees mainly for cellulose pulp production with Eucalyptus species. Over the last decade, E. smithii emerged as a species of interest for cellulose pulping. However, its rapid expansion has coincided with high mortality rates among young trees ranging from 5 to 85%, especially during the first and second summer after plantation. Disease surveys conducted on nine E. smithii commercial fields and three nurseries in southern and eastern Uruguay, yielded a collection of 25 isolates from E. smithii root rot belonging to the Nectriaceae family. In this study, we aimed to identify and characterize these isolates employing phenotypical and molecular studies and to assess their pathogenicity on E. smithii seedlings. Based on morphological features, the Nectriaceae isolates were subdivided into two groups, one resembling Calonectria (n=15) and another Cylindrocarpon-like (n=10). DNA sequences of the partial histone H3 (his3), actine, calmodulin, RNA polymerase II second largest subunit, translation elongation factor 1-alpha (tef1) and β-tubulin (tub2) genes were amplified for Calonectria, as well as partial his3, tef1, tub2 and internal-transcribed spacer and intervening 5.8S (ITS) for the Cylindrocarpon-like group. Based on phylogenetic analysis and phenotypical features three species were identified and characterized; Calonectria pauciramosa (n=15), Dactylonectria novozelandica (n=2), and a novel taxon which we describe here as Ilyonectria charruensis sp. nov. (n=8). The pathogenicity trials revealed that isolates from the three species significantly reduced both shoot and root dry weights of inoculated E. smithii seedlings compared to control plants.

Structural Characterization and Grading of Timber Species for Engineering Applicability in Kenya

An investigation was carried out in Kakamega County to determine the characteristic grade of eucalyptus and cypress timber species that are commonly used in construction. The physical and mechanical properties of two timber species for structural use; eucalyptus and cypress were determined. Six logs of each species were obtained from different areas of Kakamega County, sliced into 2” by 12” size before seasoning under a shade and their structural strength properties were determined at a moisture content of 12%. These logs were cut into test samples for the determination of their strength properties. A total of 800 samples (100 samples for each test) free from visible defects were used for each species. Basic physical properties of the samples like moisture content and density were determined. Tensile strength, compressive strength parallel the grain, compressive strength perpendicular to the grain, and bending strength were the mechanical strength tests carried out according to Eurocode 5 (1995) and BS 5268 (2002) specifications on Universal Testing Machine (UTM). Results were analyzed statistically using Statistical Package for Social Sciences (SPSS) while grading was done according to Eurocode 5 (EC5). Cypress was graded into strength class C20 while eucalyptus was graded into strength class D24. Strength class C20 is used in load-bearing structures that require high strength, such as roof trusses and floor systems. D24 is a common structural grade for a variety of structures exposed to high environmental conditions.

The Gall Wasp Ophelimus migdanorum and Its Parasitoid Closterocerus chamaeleon on Eucalyptus globulus at Two Sites with Different Rainfall Parameters in Bogotá, Colombia.

As a pest, the gall wasp Ophelimus migdanorum poses a risk to several Eucalyptus species in Colombia. In the tropical Andes, its biological development and the damage it causes can be influenced by climate, particularly rainfall. In this regard, we examined gall phenology, population fluctuation, and leaf damage caused by O. migdanorum, and its parasitoid Closterocerus chamaeleon, over 5months at two sites with contrasting rainfall in peri-urban areas of Bogotá, Colombia. Gall phenology and foliar damage were assessed on 10 trees per site. We characterized gall phenology by assessing their size and color, wasps' developmental stages, as well as affected leaf area and gall density on the leaf blade. Additionally, the individuals found in five attraction traps at each site were quantified biweekly to record population fluctuations. The effect of rainfall on wasp frequency and gall density between sampling sites and dates was compared using the chi-square test, while the relationship with rainfall was evaluated using the Kruskal-Wallis test. Only females of the gall wasp and its parasitoid were observed during the study, displaying multivoltine behavior. Six developmental stages of the galls were differentiated, each characterized by distinct coloration. Drier microclimates favored gall size, wasps' development stage frequency, population trend, and foliar damage. The general trend indicated a greater abundance of the parasitoid C. chamaeleon compared to O. migdanorum. Our study suggests that O. migdanorum has a less damaging effect on E. globulus in areas with rainy microclimates.

Study of Eucalyptus pauciflora L. characteristics from Algeria and its impact on the mite affecting honeybees Apis mellifera

Essential oils play a crucial role in biological control against parasites threatening the beekeeping stock, both in Algeria and globally. Their appropriate use helps reduce the adverse effects of chemical products on human health and the environment. The purpose of this study is to analyze the components of Eucalyptus pauciflora essential oil grown in Algeria and to evaluate its impact on the marine shrimp Artemia salina and the mite Varroa destructor, while also comparing it to other species of Eucalyptus from the same region namely, Eucalyptus robusta, globulus, sideroxylon, and amygdalina, which have been examine in previous research. Steam distillation of fresh leaves from Eucalyptus pauciflora yielded 0.73% essential oils. This plant contains a total of thirty-nine chemical compounds, among which the most significant are 1,8-cineole (57.45%), β-cymene (5.44%), spathulenol (5.38%), trans-verbenol (4.31%), and α-pinene (3.11%). A lethality test on brine shrimp (BSL) revealed that Eucalyptus pauciflora exhibits toxicity with a median lethal concentration (LC50) of 53.51 ppm. Field trials conducted on hives infested with Varroa destructor showed that the acaricidal effect of Eucalyptus pauciflora is superior to that of amygdalina and sideroxylon species, but inferior to that of globulus and robusta species, all sourced from the same herbarium (Draa Naga) in northeastern Algeria. The results of this research highlight the benefits of Eucalyptus essential oils to be integrated into the formulation of natural acaricides that are environmentally friendly to combat Varroa destructor infestation.

Assessing soil CO2 emission on eucalyptus species using UAV-based reflectance and vegetation indices

Eucalyptus species play an important role in the global carbon cycle, especially in reducing the greenhouse effect as well as storing atmospheric CO₂. Thus, assessing the amount of CO₂ released by the soil in forest areas can generate important information for environmental monitoring. This study aims to verify the relation between soil carbon dioxide (CO₂) flux (FCO₂), spectral bands, and vegetation indices (VIs) derived from a UAV-based multispectral camera over an area of eucalyptus species. Multispectral imageries (green, red-edge, and near-infrared) from the Parrot Sequoia sensor, derived vegetation indices, and the FCO₂ data from a LI-COR 8100 analyzer, combined with soil moisture and temperature data, were collected and related. The vegetation indices ATSAVI (Adjusted Transformed Soil-Adjusted VI), GSAVI (Green Soil Adjusted Vegetation Index), and SAVI (Soil-Adjusted Vegetation Index), which use soil correction factors, exhibited a strong negative correlation with FCO₂ for the species E. camaldulensis, E. saligna, and E. urophylla species. A Multivariate Analysis of Variance showed significance (p < 0.01) for the species factor, which indicates that there are differences when considering all variables simultaneously. The results achieved in this study show a specific correlation between the data of soil CO₂ emission and the eucalypt species, providing a distinction of values between the species in the statistical data.

Phytochemical profile and allelopathic activity of eight Eucalyptus species on the performance of initial growth stage of four local species in the southern Tunisia

We aimed thought this survey 1) to investigate and compare the phytotoxicity features of eight Eucalyptus species frequently planted in southern Tunisia (Eucalyptus camaldulensis Dehn., Eucalyptus gomphocephala DC., Eucalyptus torquata Luehm., Eucalyptus microtheca F.Muell., Eucalyptus occidentalis Endl., Eucalyptus diversifolia Bonpl., Eucalyptus sargentii Maiden., and Eucalyptus torwood) on seed germination and radicle growth of Medicago sativa L., Corchorus olitorius L., Cenchrus ciliaris L., Peganum harmala L., and 2) to classify those species according to their allelopathic efficiency. The laboratory experiment was conducted using aqueous extracts made from dried and ground plant leaves to obtain concentrations of 5 % and 10 %. These were prepared alongside control treatments for comparison. Afterward, methanol extracts were utilized in the chemical composition identification procedure via HPLC-DAD-ESI-MS. Different responses were obtained for the species studied for germination and extraction. Results highlighted that C. ciliaris and P. harmala were the most susceptible to eucalypt extracts, while, M. sativa and C. olitorius were more resistant. Statistically, lower concentrations were less effective, but higher ones had noticeable inhibitory effects on seedling growth parameters. We assumed that E. occidentalis, E. gomphocephala, E. torquata and E. camaldulensis were recognized as the most noxious species, E. sargentii and E. microtheca produced moderate effects, while E. torwood and E. diversifolia were regarded as benign species. Phytochemicals especially ellagitannins and flavonols derivatives were the major compounds identified accounted for 21–78 % and 8–59 %, but hydroxycinnamic acids derivatives, gallic acid derivatives, total flavonols content and non-phenolic acids were acknowledged as the major causes for the observed outcomes.

Combustion and energy performance of non-commercial Corymbia and Eucalyptus wood for use in cogeneration systems in Brazil

The increased representation of biomass in the Brazilian energy matrix will contribute to reducing dependence on hydroenergy and mitigating negative impacts during increasingly frequent drought periods. However, given the changing climate, it is urgent to classify and select new genotypes for the expansion of energy plantations. The objective of this study was to evaluate the energy performance and combustibility of wood from Eucalyptus and Corymbia trees to support a knowledge-based and efficient use of such woods in thermochemical conversion systems. Eight species of Eucalyptus (Eucalyptus amplifolia, E. longirostrata, E. major, and E. urophylla) and Corymbia (Corymbia citriodora, C. variegata, C. henryi, C. torelliana), which are not generally used for energy purposes, were selected at 6 years of age from experimental plantations in southeastern Brazil. Wood basic density (WBD), ash content (AC), higher heating value (HHV), fuel value index (FVI), ignition (Di), flammability (Ci) and combustion (Si) indexes were determined. The wood of E. urophylla and C. torelliana presented showed the highest and lowest FVI, respectively. Regarding combustion indexes E. longirostrata had a higher combustion index (4.00 ×107 %2/(min2°C3)), flammability (1.49 %min−1/°C2) and ignition (4.39 % min−3) while C. variegata presented the lowest values. The FVI showed correlations with the combustibility of wood. Thus, this index can be used for the rapid and reliable classification of new genetic materials for energy forests in Brazil. E. urophylla and E. longirostrata woods demonstrated better energy performance and combustion indexes, making them the most suitable species for use in cogeneration systems and candidates for the expansion of energetic forests in Brazil.

Preferencia alimenticia y de oviposición de Gonipterus platensis(Coleoptera: Curculionidae) en tres especies comerciales de Eucalyptus en Colombia

Gonipterus platensis (Marelli, 1926), is a beetle that belongs to the family Curculionidae, a phytophagous species within the genus Eucalyptus. It is native to Australia, where it is not considered a pest due to the presence of biological controllers. In Colombia, eucalyptus trees are the second exotic species with the largest planted area, and because in 2016 was recorded the presence of G. platensis in the country, efforts have been made to study and determine the potential damage that this species can cause in plantations through studies of its feeding preferences and oviposition, among others. The present study aims to determine the preference of G. platensis for the three most planted commercial eucalyptus species in the country: Eucalyptus grandis W.Hill ex Maiden, E. urophylla S.T. Blake, and the hybrid E. grandis W.Hill ex Maiden × E. urophylla S.T. Blake (E. urograndis). An experiment was conducted using a multiple-choice design to assess feeding and oviposition preference. Two assays were carried out: one with seedlings and the other with an olfactometer. The present study reveals that G. platensis has a feeding preference for E. grandis, followed by E. urophylla, and to a lesser extent, the hybrid species E. urograndis. Furthermore, G. platensis is capable of ovipositing in all three eucalyptus species studied without making any differentiation.

Variation among Eucalyptus Species for Morphological, Physiological and Biochemical Traits under Simulated salt stress conditions

Variation among Eucalyptus Species for Morphological, Physiological and Biochemical Traits under Simulated salt stress conditions

Anthropogenic forests simplify seed- but not pollen-dispersal networks.

Natural native forests are rapidly being replaced by anthropogenic forests often with a strong presence of invasive alien plant species. Eucalypt species are widely planted worldwide, with Eucalyptus globulus plantations being particularly expressive in Portugal. Poor forestry practices often lead to the associated expansion of invasive species, such as Acacia dealbata. However, we still know relatively little about the functioning of anthropogenic forests, such as seed and pollen dispersal services. Here, we compared bird abundance and richness and the seed and pollen dispersal networks in both forest types. Anthropogenic forests presented lower bird abundance, and smaller, more simplified, and more random (abundance-based) seed dispersal services than those of natural forests. Interestingly, the pollen dispersal network was more similar than the seed dispersal network for both forest types and dominated by opportunistic and neutral processes, given the absence of specialized nectarivorous. The proportion of birds transporting seeds decreased, while those carrying pollen significantly increased in the anthropogenic forest compared to the native forest. Our work highlights the impact of anthropogenic forests on bird abundance, with consequences for seed dispersal services and forest regeneration.

Metabolites profiling of five Eucalyptus species by gas chromatography-mass spectrometry and multivariate analysis

Metabolites profiling of five Eucalyptus species by gas chromatography-mass spectrometry and multivariate analysis

The use of Pisolithus albus found in saline areas to improve the growth of Eucalyptus seedlings under high salinity conditions

ABSTRACT Salinity is an abiotic factor limiting plant fitness and therefore forest crop productivity, and salt-affected areas have been expanding throughout the world. Ectomycorrhizal (ECM) fungi can improve the salt tolerance of woody plants, including Eucalyptus species To screen for salt-resistant Pisolithus albus (PA) isolates, 16 PA isolates were cultivated on modified Melin-Norkrans agar containing NaCl at concentrations of 0, 10, 20, and 30 dS m−1. The P. albus isolate PA33 had the greatest salt resistance under 10 and 20 dS m−1 NaCl, which are soil salinity levels in salt-affected areas of Thailand. We studied the effect of PA33 on Eucalyptus camaldulensis × E. pellita cuttings under salt stress (0 and 16 dS m−1) for 1 month. PA enhanced the growth of the Eucalyptus seedlings, as indicated by higher relative growth rates in height and root collar diameter of inoculated seedlings compared with non-inoculated seedlings. Moreover, the inoculated seedlings had less cell damage from NaCl, as indicated by significantly lesser leaf thickness and electrolyte leakage than the controls. These findings could lead to practices conferring socioeconomic and environmental benefits, as abandoned salt-affected areas could be reclaimed using such Eucalyptus seedlings inoculated with salt-tolerant ECM fungi.

Compatibility of integrated management (chemical x biological, and botanical x biological) strategies deployed against Athelia rolfsii, causing Sclerotium rots

Athelia rolfsii induces severe Sclerotium rots on 500 plantspecies, thus efficient field and post-harvest management strategies for this disease exist. A completely randomized design with three replications was used to set up two sub-trials. Sub-trial 1: Interaction of Mancozeb (all concentrations) x Trichoderma species caused 29.3-100% inhibition and all Ketoconazole x Trichoderma species caused 95.8-100% inhibition of A. rolfsii. Ketoconazole and Mancozeb (main effects) ranged between 23.3-100% inhibition of A. rolfsii. T. virens, T. harzianum, and T. viride (main effects) ranged from 60.3-96.7% inhibition of A. rolfsii. Unfortunately, Ketoconazole inhibited Trichoderma species more than Mancozeb. The chemical fungicides and Trichoderma species were highly positively correlated (0.522**, P≤0.05). Sub-trial 2: The Plant extracts (Ricinus and Eucalyptus species: 100% concentration) x Trichoderma species interactions caused 95-100% inhibition of A. rolfsii. Botanicals (50% concentration) x Trichoderma species caused above 80% inhibition of A. rolfsii. Trichoderma species (main effects) (in environs of 50% botanicals) caused 57-84% inhibition. The results revealed that at 100% concentration, plant extracts completely inhibited A. rolfsii.