Biological Control Treatments Research Articles

The Antifungal and Inhibitory Effects of Massoia Essential Oil and C10 Massoia Lactone on Mycotoxin Production in Fusarium graminearum KACC 41047

In wheat and barley, Fusarium head blight is mainly caused by Fusarium graminearum, and its control is based on the agricultural practices of not leaving crop residues in the field, growing phytopathogenic fungi-resistant varieties, biological control, and chemical treatment, including using fungicides. Here, we investigated the antifungal and antimycotoxigenic activities of Massoia essential oil (MEO) and C10 Massoia lactone (C10) on Fusarium graminearum KACC 41047. Because DMSO, which was used as a solvent in this study, exhibited antifungal activity at 5% in a fungal growth medium, it was used in the antifungal and antimycotoxigenic experiments at 0.05%. Three assays were used to investigate the antifungal activities of MEO and C10, which exhibited potent antifungal activity in the agar dilution assay, with complete fungal growth inhibition at 100 mg/L. At 5–50 mg/L, MEO and C10 suppressed deoxynivalenol and 15-acetyl-deoxynivalenol production by >50% by downregulating the Tri10 gene, which expresses trichodiene synthase. MEO and C10 might be potent antifungal agents for F. graminearum control with less toxicological concerns because they are GRAS chemicals.

An In-Depth Study of Phytopathogenic Ganoderma: Pathogenicity, Advanced Detection Techniques, Control Strategies, and Sustainable Management.

Phytopathogenic Ganoderma species pose a significant threat to global plant health, resulting in estimated annual economic losses exceeding USD (US Dollars) 68 billion in the agriculture and forestry sectors worldwide. To combat this pervasive menace effectively, a comprehensive understanding of the biology, ecology, and plant infection mechanisms of these pathogens is imperative. This comprehensive review critically examines various aspects of Ganoderma spp., including their intricate life cycle, their disease mechanisms, and the multifaceted environmental factors influencing their spread. Recent studies have quantified the economic impact of Ganoderma infections, revealing staggering yield losses ranging from 20% to 80% across various crops. In particular, oil palm plantations suffer devastating losses, with an estimated annual reduction in yield exceeding 50 million metric tons. Moreover, this review elucidates the dynamic interactions between Ganoderma and host plants, delineating the pathogen's colonization strategies and its elicitation of intricate plant defense responses. This comprehensive analysis underscores the imperative for adopting an integrated approach to Ganoderma disease management. By synergistically harnessing cultural practices, biological control, and chemical treatments and by deploying resistant plant varieties, substantial strides can be made in mitigating Ganoderma infestations. Furthermore, a collaborative effort involving scientists, breeders, and growers is paramount in the development and implementation of sustainable strategies against this pernicious plant pathogen. Through rigorous scientific inquiry and evidence-based practices, we can strive towards safeguarding global plant health and mitigating the dire economic consequences inflicted by Ganoderma infections.

Cyclodepsipeptides: Isolation, Bioactivities, Biosynthesis and Total Synthesis

Abstract: Cyclodepsipeptides, mainly derived from marine organisms and soil microorganisms, are amphiphilic molecules consisting of short oligopeptides with fatty acid tails attached to form a macrocyclic structure. Studies on the activity of cyclodepsipeptides have shown that they have cytotoxicity, antibacterial and anthelmintic effects, and are widely used in biological control, drug development, environmental remediation and disease treatment. Cyclodepsipeptides play a prominent role in the development of new drugs and drug lead compounds, especially as antibiotics with great medicinal potentiall, and are slowly seeping into the public consciousness. The biosynthesis of cyclodepsipeptides is mainly based on the synthesis of non-ribosomal peptide synthases, and selection of key regulatory enzymes for homologue regulation and biosynthetic strategies using genetic engineering and metabolic engineering approaches. The biosynthesis method is miniaturised, recyclable, and safer. The total synthesis methods of cyclodepsipeptides are mainly combined solid-liquid phase methods, which synthesise cyclodepsipeptides faster and are easy to purify. This paper reviews the biological activities of cyclodepsipeptides, their biosynthesis, and total synthesis.

Efficacy of some Biological Control Treatments on Grey Mold Disease (Botrytis cinerea) of Strawberry Fruits

Efficacy of some Biological Control Treatments on Grey Mold Disease (Botrytis cinerea) of Strawberry Fruits

Efficacy of variable timing of Pythium oligandrum applications on red clover grown under field conditions

Biological control of root diseases of red clover (Trifolium pratense L.) could be effective but optimization of its application is needed to balance treatment efficacy with costs. Our objectives were to evaluate the effects of different Pythium oligandrum application treatments on root morphological development, plant root disease score and forage yield in a three-year field experiment. Red clover cv. Start was managed under a three-cut management in two harvest years with four treatments: (i) untreated control, (ii) multiple applications of P. oligandrum (intensive treatment), (iii) a single spring application, and (iv) a single autumn application. Plants from each plot were evaluated for root morphology traits and scored for root diseases in each autumn. Forage yield, compressed stand height and stem density were evaluated in each cut. All P. oligandrum treatments increased root dry matter and root potential index, but only the intensive treatment significantly improved forage yield (by 31%) in comparison with the control. This effect could be largely associated with plant growth stimulation resulting in increased stand height before cutting. Among single application treatments, autumn timing significantly reduced plant root disease score and showed higher stand height than spring application. One application later in the season seems likely to be effective for forage growth stimulation, but probably at least two applications are needed to produce maximum effect. Despite some drought stress during the first two years, this field study confirmed an effect of P. oligandrum on improved root development and a positive yield response, thus showing a high potential of this biological control treatment under field conditions.

Rapid impact of Impatiens glandulifera control on above‐ and belowground invertebrate communities

AbstractThe annual plant Impatiens glandulifera (Himalayan balsam) is the most widespread invasive non‐native weed in the British Isles. Manual control is widely used, but is costly and laborious. Recently, biological control using the rust fungus Puccinia komarovii var. glanduliferae has been trialled. We designed an experiment to assess the impact of these control methods on invertebrate communities in relation to unmanaged and uninvaded habitats, and to determine whether mycorrhizal inoculation aided post‐control recovery of these communities. Sixty invaded and twenty uninvaded field soil blocks were transplanted to the experiment site, where a mycorrhizal inoculum was added to half of all blocks. Biological and mechanical control treatments were applied to twenty invaded blocks independently; the twenty remaining invaded blocks were left intact. Above‐ and belowground invertebrate samples were collected from the blocks at the end of the growing season. Overall, aboveground invertebrate abundance increased with the removal of I. glandulifera, and several groups showed signs of recovery within one growing season. The effect of mechanical control was more variable in belowground invertebrates. Biological control did not affect aboveground invertebrate abundance but resulted in large increases in populations of belowground Collembola. Our experiment demonstrates that mechanical removal of I. glandulifera can cause rapid increases in invertebrate abundance and that its biological control with P. komarovii var. glanduliferae also has the potential to benefit native invertebrate communities.

Morphological Characterization and Determination of Aflatoxigenic and Non-Aflatoxigenic Aspergillus flavus Isolated from Sweet Corn Kernels and Soil in Malaysia

This study aimed to morphologically characterize and determine the aflatoxigenic and non-aflatoxigenic Aspergillus flavus isolates. Forty isolates of A. flavus were obtained from sweet corn kernels and soil samples collected from Kampong Raja, Rose Valley, Kea, and Klebang farms in Malaysia. They were cultured on potato dextrose agar (PDA), dichloran rose-bengal chloramphenicol (DRBC), Aspergillusflavus and Aspergillus parasiticus agar (AFPA), and coconut cream agar (CCA). Macromorphological characteristics were determined by observing the colony color and texture, while the micromorphological characteristics were determined by examining the spore color, size, structure, conidiophore structure, and vesicle shape. The production of aflatoxin was determined by direct visualization of the UV fluorescence of A. flavus colonies on CCA. Aflatoxin was qualitatively detected in 18 (45%) isolates of A. flavus using UV fluorescence screening while the remaining 22 (55%) isolates did not exhibit any aflatoxin production. The highest incidence of A. flavus (30%) and aflatoxin production (15%) was recorded in samples from Kampong Raja. On the other hand, isolates from Rose Valley (17%) and Kea (12%) were non-aflatoxigenic. Klebang recorded a 25% incidence of A. flavus in which 15% were aflatoxigenic while 10% were non-aflatoxigenic. The occurrence of aflatoxin-producing A. flavus emphasizes the need for the measure to eradicate their presence in food crops. A biological control treatment utilizing the non-aflatoxigenic strains to compete with the aflatoxigenic ones is underway. Validation of aflatoxin production through high performance liquid chromatography is also ongoing.

Botrytis cinerea and Table Grapes: A Review of the Main Physical, Chemical, and Bio-Based Control Treatments in Post-Harvest.

Consumers highly appreciate table grapes for their pleasant sensory attributes and as good sources of nutritional and functional compounds. This explains the rising market and global interest in this product. Along with other fruits and vegetables, table grapes are considerably perishable post-harvest due to the growth of undesired microorganisms. Among the microbial spoilers, Botrytis cinerea represents a model organism because of its degrading potential and the huge economic losses caused by its infection. The present review provides an overview of the recent primary physical, chemical, and biological control treatments adopted against the development of B. cinerea in table grapes to extend shelf life. These treatments preserve product quality and safety. This article also focuses on the compliance of different approaches with organic and sustainable production processes. Tailored approaches include those that rely on controlled atmosphere and the application of edible coating and packaging, as well as microbial-based activities. These strategies, applied alone or in combination, are among the most promising solutions in order to prolong table grape quality during cold storage. In general, the innovative design of applications dealing with hurdle technologies holds great promise for future improvements.

Antifungal Norditerpene Oidiolactones from the Fungus Oidiodendron truncatum, a Potential Biocontrol Agent for White-Nose Syndrome in Bats.

White-nose syndrome (WNS) is a devastating disease of hibernating bats caused by the fungus Pseudogymnoascus destructans. We obtained 383 fungal and bacterial isolates from the Soudan Iron Mine, an important bat hibernaculum in Minnesota, then screened this library for antifungal activity to develop biological control treatments for WNS. An extract from the fungus Oidiodendron truncatum was subjected to bioassay-guided fractionation, which led to the isolation of 14 norditerpene and three anthraquinone metabolites. Ten of these compounds were previously described in the literature, and here we present the structures of seven new norditerpene analogues. Additionally, this is the first report of 4-chlorophyscion from a natural source, previously identified as a semisynthetic product. The compounds PR 1388 and LL-Z1271α were the only inhibitors of P. destructans (MIC = 7.5 and 15 μg/mL, respectively). Compounds were tested for cytotoxicity against fibroblast cell cultures obtained from Myotis septentrionalis (northern long eared bat) and M. grisescens (gray bat) using a standard MTT viability assay. The most active antifungal compound, PR 1388, was nontoxic toward cells from both bat species (IC50 > 100 μM). We discuss the implications of these results in the context of the challenges and logistics of developing a substrate treatment or prophylactic for WNS.

Identification and characterization of hypovirus-infected Cryphonectriaparasiticaisolates from biological control plots in İzmir, Kütahya, and Sinop

In a pilot study, a biological control with hypovirus-infected Cryphonectria parasitica was applied in 3 study plots in Turkey, in June 2013. The aim of this study was to evaluate the success of the applied biological control by verifying the establishment of the released hypovirus (CHV-1) strains using molecular markers. C. parasitica isolates were sampled from cankers at 3 different time points: before the biological control treatments (April 2013), and 5 months (October 2013) and 11 months (May 2014) after the treatment. In total, 255 C. parasitica isolates were recovered and characterized. First, the culture morphology and vegetative compatibility type of these isolates were assessed. Next, the presence of hypoviruses in white isolates was checked by RNA extraction and subsequent RTPCR. Finally, a sequence analysis was performed to compare the hypoviruses to the released biological control hypoviruses by examining single nucleotide markers and reconstructing their phylogenetic relationship. The study sites in İzmir and Kütahya were found to be free of hypoviruses prior to the biological control, whereas in Sinop, the occurrence of hypoviruses of the Italian subtype was observed. Reisolations of the treated cankers and subsequent molecular analysis resulted in the detection of the released biocontrol hypovirus strains in all 3 study sites. The reisolated hypoviruses in İzmir and Kütahya originated from either one of the released biocontrol strains. In Sinop, both natural and artificially introduced hypoviruses were detected. Our study showed that the released biological control hypoviruses persisted in the treated cankers, which is promising for the biological control of chestnut blight in Turkey.

Acoustic Signal Applications in Detection and Management of Rhynchophorus spp. in Fruit-Crops and Ornamental Palms

Rhynchophorus ferrugineus (Olivier) (Coleoptera: Dryophthoridae) is an economically important, internally feeding pest of ornamental and fruit-producing palms in many subtropical regions. A related weevil, Rhynchophorus cruentatus (Fabricius) (Coleoptera: Dryophthoridae), is an internally feeding palm pest in the southeastern USA. Acoustic methods for detection of early instars hidden in palms in field environments have been investigated for both species. Acoustic methods also have been used to examine the effectiveness of physical, biological, and other control treatments. This report addresses several physical, physiological, and behavioral factors that influence the spectral and temporal patterns of sounds produced by palm weevil larvae under different laboratory and field experiment conditions, which must be considered carefully in interpreting larval sound production. Such factors include the leakage of fluid from the palm tree tissues into tunnels scraped out by larvae as they move and feed within the tree trunk, as well as occurrences of molting between periods of feeding activity, and frequency-dependent damping that distorts signals as the distance between insects and sensors increases. Methods are discussed that combine effects of environmental, physiological, and behavioral variability to facilitate reliable interpretations of Rhynchophorus and other insect larval acoustic activity in hidden environments.

Subterranean Acoustic Activity Patterns of Vitacea polistiformis (Lepidoptera: Sesiidae) in Relation to Abiotic and Biotic Factors.

Grape root borer (GRB), Vitacea polistiformis, is a root-feeding pest of grapevines in the US southeast that causes underground damage well before vines show visible symptoms. A 269-d study was conducted at 31 sites in a Florida vineyard to record short bursts of insect movement and feeding vibrations in grapevine root systems and provide information that can improve timing and targeting of GRB management efforts. Characteristic spectral and temporal patterns in the subterranean vibrations facilitated discrimination of GRB from background noise and non-targeted arthropods. Infestation likelihood of GRB at each site was estimated from previous studies relating infestation to burst rate. In all, 39% of recordings indicated low infestation likelihood. Sites with medium or high infestation likelihood were confined to a small region of the vineyard where a vine with larval feeding damage was confirmed. The restricted area suggests that the biological control or chemical treatments could be reduced elsewhere. Acoustic activity was significantly greater in fall and winter than in spring, and greater in evening than afternoon; fall evenings seemed best for GRB acoustic surveys. The GRB seasonal and circadian acoustic variation reflected phenological variation in grape root growth and nutrients and was not significantly correlated with temperature.

Improved real-time PCR protocol for the accurate detection and quantification of Rosellinia necatrix in avocado orchards

AIMS: This study aims to develop and validate a new molecular method of detection and quantification of Rosellinia necatrix fungus in soil samples and compare it with conventional methods. METHODS: We collected 40 soil and root samples (one as negative control) from the soil around avocado trees. The root samples were checked for typical symptoms of R. necatrix and the pathogen was identified using the conventional method of plate culture. These results were then corroborated using a new molecular method of detection and quantification of R. necatrix in soil samples, and a duplex TaqMan qPCR protocol was designed that included an internal positive control to avoid the detection of false negatives. RESULTS: The molecular detection and quantification method was effective, sensitive and reliable for all 40 soil samples analysed, whereas, with traditional methods, the fungus was isolated in only 24 out of the 26 symptomatic roots from 40 avocado trees sampled. This improved methodology reduces the sample preparation time compared with previous studies, and provides a molecular tool for the reliable and accurate detection and quantification of R. necatrix in naturally infested avocado soils. CONCLUSIONS: This technique could be applied for the rapid assessment of R. necatrix in soils at the pre-planting stage and evaluation of the efficacy of physical, chemical or biological control treatments.

Seed treatment containing Bacillus subtilis BY-2 in combination with other Bacillus isolates for control of Sclerotinia sclerotiorum on oilseed rape

Biological control treatments for soil-borne plant pathogens must provide enhanced levels of disease suppression and consistency of control over diverse soils before they enjoy wide-spread use. Bacillus megaterium A6 and two genetically distinct B. subtilis isolates, BY-2 and Tu-100, were applied individually and in combinations as seed treatments and tested in field trials conducted at four locations with different soils for control of Sclerotinia sclerotiorum on oilseed rape. The treatment containing isolate BY-2 resulted in significant reductions in disease relative to the non-treated and formulation-only controls at all four locations. Treatments containing isolate A-6 or Tu-100 resulted in a significant decrease in disease at two locations only. There were no significant reductions in disease with treatments containing combinations of these strains relative to treatments containing strains applied individually. In plant growth promotion studies conducted in pots, the seed treatment containing isolate BY-2 combined with A6 and Tu-100 resulted in seed yield greater than the non-treated control in four of the five soils tested. The seed treatment containing isolate A-6 combined with Tu-100 significantly increased yield in one soil. No other treatment containing a single isolate, or combination of two isolates, significantly increased yield in these pot studies. Field experiments reported here indicated that seed treatment with isolate BY-2 provided consistent reduction of disease at four field locations with different soil types. Pot studies suggested that combining other Bacillus isolates with BY-2 provided the added benefit of plant growth promotion.

The tea leaf microbiome shows specific responses to chemical pesticides and biocontrol applications

The plant microbiome is known to be influenced by certain biotic as well as abiotic factors. Nevertheless, the drivers for specific changes in microbial community composition and structure are largely unknown. In the present study, the effects of chemical and biological treatments for plant protection on the indigenous microbiome of Camellia sinensis (L.) Kuntze were contrasted. Assessment of bacteria-specific ribosomal RNA gene fragment amplicons from a representative set of samples showed an increased microbial diversity in treated plants when compared to untreated samples. Moreover, distinct microbial fingerprints were found for plants subjected to a conventional pesticide treatment with lime sulfur as well as for plants that were biologically treated with a Piriformospora indica spore solution. The bacterial community of pesticide-treated plants was augmented by 11 taxa assigned to Proteobacteria and Actinobacteria. In contrast, plants from biological control treatments were augmented by 10 taxa representing a more diversified community enrichment and included members of Actionobacteria, Proteobacteria, Bacteroidetes, Planctomycetes, and Verrucomicrobia. Complementary, molecular quantification of fungi in the samples showed a significantly lower number of internal transcribed spacer copies in plants subjected to biological control treatments, indicating the highest efficiency against fungal pathogens. The overall results show that leaves that are used for tea production show distinct microbiome shifts that are elicited by common pest and pathogen management practices. These shifts in the microbial population indicate non-target effects of the applied treatments.

Kiwifruit status in Iran: management and production

Here we report some information about the kiwifruit industry in Iran since the introduction of the species in the 1970s. Kiwifruit acreage and yield have greatly increased in the past 25 years, from 100 ha and 200 t in 1990 to 11,600 ha and over 300,000 t, with yields around 26-29 t ha‑1, in 2016. The main cultivars are Actinidia deliciosa ‘Hayward’ (accounting for 100% of exports), and the yellow-fleshed Actinidia chinensis ‘Hort. 16A’, introduced in 2003. The Caspian Sea region of the northern provinces of Iran has appropriate environmental and climatic conditions for kiwifruit culture, especially Guilan, Mazandaran and Golestan provinces. These regions are characterized by optimal climatic conditions (rainy with high humidity) and by rich and fertile soils with pH 5.5-5.6 suitable for kiwifruit cultivation. Orchards are mainly trained to the T-bar system, and the planting density is about 500 vines ha‑1; pollination is done with bees (8 hives ha‑1), and the male:female vine ratio is 1:8, considered a proper distribution for Iranian conditions. As far as pests and diseases are concerned, nematodes and fungi [such as Phytophthora spp. (gummosis, root-rot)] in addition to pests [mainly Pseudaulacaspis pentagona (crab louse)], are the most frequent. Both biological control (Prospaltella perniciosi) and/or chemical treatments (Diazinon) are performed. Pseudomonas syringae pv. actinidiae (Psa) is not a major problem for kiwifruit cultivation in Iran, although the disease has been reported by some growers.

The contributions of biological control to reduced plant size and biomass of water hyacinth populations

Water hyacinth is invasive in many countries, where it reduces aquatic biodiversity and limits water resource utilisation. Biological control of water hyacinth has been successful in South Africa, but has suffered from a lack of empirical data to prove causation. Insect exclusion trials were conducted to quantify the contribution of Neochetina eichhorniae and N. bruchi to the integrated control of water hyacinth on the Nseleni River, South Africa. Insecticide was not expected to induce phytotoxicity, but would prevent weevil damage in water hyacinth plants; and weevil herbivory was predicted to reduce plant petiole length, and above/below surface biomass. Results showed that insecticide had no phytotoxic effects and excluded weevils for 3 weeks, providing a baseline for field applications. Biological control on the Nseleni River directly affected water hyacinth biomass and petiole length, but did not affect plant cover. Plants subject to weevil herbivory demonstrated reductions in above and below surface biomass and had shorter petioles compared to insect-free plants. Dead biomass was also higher in biological control treatments. Biological control strongly affects plant size, biomass and vigour; however, further integrated control is required to facilitate reduction in mat cover, which is the goalpost for successful control of floating aquatic plants.

Biochemical features of winter wheat grain affected by biological and chemical control treatments

Biochemical features of winter wheat grain affected by biological and chemical control treatments

Cryphonectria parasitica, the causal agent of chestnut blight: invasion history, population biology and disease control.

Cryphonectria parasitica (Murr.) Barr. is a Sordariomycete (ascomycete) fungus in the family Cryphonectriaceae (Order Diaporthales). Closely related species that can also be found on chestnut include Cryphonectria radicalis, Cryphonectria naterciae and Cryphonectria japonica. Major hosts are species in the genus Castanea (Family Fagaceae), particularly the American chestnut (C. dentata), the European chestnut (C. sativa), the Chinese chestnut (C. mollissima) and the Japanese chestnut (C. crenata). Minor incidental hosts include oaks (Quercus spp.), maples (Acer spp.), European hornbeam (Carpinus betulus) and American chinkapin (Castanea pumila). Cryphonectria parasitica causes perennial necrotic lesions (so-called cankers) on the bark of stems and branches of susceptible host trees, eventually leading to wilting of the plant part distal to the infection. Chestnut blight cankers are characterized by the presence of mycelial fans and fruiting bodies of the pathogen. Below the canker the tree may react by producing epicormic shoots. Non-lethal, superficial or callusing cankers on susceptible host trees are usually associated with mycovirus-induced hypovirulence. After the introduction of C. parasitica into a new area, eradication efforts by cutting and burning the infected plants/trees have mostly failed. In Europe, the mycovirus Cryphonectria hypovirus 1 (CHV-1) acts as a successful biological control agent of chestnut blight by causing so-called hypovirulence. CHV-1 infects C. parasitica and reduces its parasitic growth and sporulation capacity. Individual cankers can be therapeutically treated with hypovirus-infected C. parasitica strains. The hypovirus may subsequently spread to untreated cankers and become established in the C. parasitica population. Hypovirulence is present in many chestnut-growing regions of Europe, either resulting naturally or after biological control treatments. In North America, disease management of chestnut blight is mainly focused on breeding with the goal to backcross the Chinese chestnut's blight resistance into the American chestnut genome.

Reducing infection and secondary inoculum of Phytophthora ramorum on Viburnum tinus roots grown in potting medium amended with Trichoderma asperellum isolate 04-22

Phytophthora ramorum is a concern of the ornamental nursery business because it is implicated in the movement on ornamental plants such as rhododendron and viburnum. Since there is a soil phase that infects the roots, above-ground symptoms are not often manifested and easily detected. Government agencies require that a P. ramorum-positive nursery be placed under some type of quarantine until it can demonstrate that it has mitigated P. ramorum. Typical methods of mitigation are often expensive, harmful to the environment, and impractical. Biological control using Trichoderma asperellum isolate 04-22 (Ta 04-22) has been demonstrated to reduce P. ramorum soil populations to below detectable limits when incorporated into soil or potting mix. The purpose of this study was to determine whether Ta 04-22 would reduce Viburnum tinus root infection and reduce secondary sporulation from infected roots. When rooted V. tinus cuttings were planted into potting mix amended with three different final concentrations (1×105, 1×106, and 1×107CFU/cm3 potting mix) of Ta 04-22 and drenched with either a P. ramorum sporangia or chlamydospore suspension, plants with any infected roots declined as the Ta 04-22 concentration increased. This was significant (P=0.039) when P. ramorum chlamydospores were used as the inoculum propagule but not (P=0.143) when sporangia were used. A second application of Ta 04-22 as a top-dressing after 4weeks did not result in a decrease in plants with infected roots. When P. ramorum-infected V. tinus roots were treated with Ta 04-22 grown on wheat bran, Ta 04-22 formulated as a wettable powder, or RootShield® Plus WP, flow-through of P. ramorum secondary inoculum was significantly reduced compared to non-treated controls (P<0.001). A second application did not reduce the secondary inoculum any further. These results demonstrate that various formulations of Ta 04-22 and, to a lesser degree, RootShield® Plus WP can be used as a microbial biological control treatment to reduce infection of V. tinus roots by P. ramorum and reduce plant-to-plant spread by reducing secondary inoculum.