•A Machine Learning model highlighted plans with expected low gamma passing rate•Complexity and expected gamma were monitored prospectively with Lean Six Sigma.•A Poka Yoke system automatically ...identified plans at risk of failure each day.•Plans considered at risk underwent measurement and were re-optimized if necessary.•Among 1722 volumetric modulated plans, 9 out of 29 at risk were actual failures.
Radiotherapy plans with excessive complexity exhibit higher uncertainties and worse patient-specific quality assurance (PSQA) results, while the workload of measurement-based PSQA can impact the efficiency of the radiotherapy workflow. Machine Learning (ML) and Lean Six Sigma, a process optimization method, were implemented to adopt a targeted PSQA approach, aiming to reduce workload, risk of failures, and monitor complexity.
Lean Six Sigma was applied using DMAIC (define, measure, analyze, improve, and control) steps. Ten complexity metrics were computed for 69,811 volumetric modulated arc therapy (VMAT) arcs from 28,612 plans delivered in our Institute (2013–2021). Outlier complexities were defined as >95th-percentile of the historical distributions, stratified by treatment. An ML model was trained to predict the gamma passing rate (GPR-3 %/1mm) of an arc given its complexity. A decision support system was developed to monitor the complexity and expected GPR. Plans at risk of PSQA failure, either extremely complex or with average GPR <90 %, were identified. The tool’s impact was assessed after nine months of clinical use.
Among 1,722 VMAT plans monitored prospectively, 29 (1.7 %) were found at risk of failure. Planners reacted by performing PSQA measurement and re-optimizing the plan. Occurrences of outlier complexities remained stable within 5 %. The expected GPR increased from a median of 97.4 % to 98.2 % (Mann-Whitney p < 0.05) due to plan re-optimization.
ML and Lean Six Sigma have been implemented in clinical practice enabling a targeted measurement-based PSQA approach for plans at risk of failure to improve overall quality and patient safety.
The authors' experience with a point matching algorithm for image registration belonging to a commercially available software package for conformal radiotherapy, is reported. The algorithm IFS (Image ...Fusion System) permits the registration of two image data-sets in two different manners: by use of a stereotactic localization frame, dedicated to brain studies, and by means of point markers that may be internal anatomical landmarks or external fiducials fixed on the patient skin. Position errors were obtained by evaluating the stereotactic coordinates of seven sources detectable by Magnetic Resonance Imaging (MRI) and Computed Tomography (CT), for the first method. The comparison of the geometric centers of cylindrical rods enclosed in a second phantom was employed to evaluate the registration accuracy of the second algorithm. The mean differences in source identification between CT and MRI images are inferior to 1 mm with both techniques, if MRI distortion phenomenon and patient movements are excluded. The software utility of the IFS algorithm to draw, after fusion, a target ROI that is the synthesis of the two information modalities undergoing registration may be a useful tool for the optimization of a radiotherapy treatment planning.
Fall armyworm (FAW),
Spodoptera frugiperda
, is a migratory polyphagous pest that causes major damage to economically important cultivated grasses, such as corn. Native to the neotropics in America ...but recently reported as an invasive pest in Africa and Asia, FAW imposes a serious threat to food security and sustainable crop productivity due to lack of effective management. In this study, the introduction of entomopathogenic fungi as endophytes was explored as an alternative more sustainable management strategy against FAW in corn. The study determined (1) the effect of isolates and inoculation methods on the ability of entomopathogenic fungi to colonize corn plants, and (2) the effect of colonized plants on
S. frugiperda
survival, development, reproduction, and food preference
.
Although all tested isolates (twelve of
Beauveria bassiana
and one each of
Metarhizium anisopliae
and
Metarhizium robertsii
) colonized inoculated plants, there was a highly significant interaction between isolates and inoculation methods. Highest plant colonization was obtained by
Beauveria bassiana
isolate (LPSc 1098) using foliar spray. Endophytic
B. bassiana
caused significant reductions in larval and pupal survival, length of different developmental stages, total
S. frugiperda
lifespan, and leaf area consumed by third instar larvae. Plant colonization also significantly reduced female longevity, fecundity, and fertility. This is the first report for the negative effects of endophytic
B. bassiana
on
S. frugiperda
growth, reproduction, and food preference. Our results highlight the promising potential of incorporating entomopathogenic fungi as endophytes in integrated pest management practices to protect corn against FAW if their efficacy is also confirmed under field conditions.
Entomopathogenic fungi are widely recognized as agents of biological control worldwide. Their use in agriculture for the regulation of pest populations is a promising alternative to conventional ...insecticides. Furthermore, recent studies have shown that entomopathogenic fungi fulfill an additional role in plants as growth promoters. The purpose of this investigation was to assess the growth and yield of corn plants colonized with
and its effect on the lepidopteran pest
Effects of the fungus on plant growth, crop yield, and vertical transmission were evaluated in the field. Feeding preferences of
larvae were assessed in the laboratory using a "choice test". Corn plants inoculated with
showed an increase in height, number of leaves, grain weight, yield, and percentage of seed germination compared to control plants. Consumption of
-colonized corn plants by
larvae was reduced compared to feeding levels observed on non-inoculated plants. This study showed that endophytic
can provide multiple benefits to
and can play an important role in future integrated pest management programs.
We demonstrate the effectiveness of three inoculation methods (foliar spray, seed immersion and root immersion) in establishing fungal the entomopathogen Beauveria bassiana as an endophyte in ...tobacco, corn, wheat and soybean. Colonisation of leaves by B. bassiana was assessed 7, 14, 21 and 28 days post-inoculation. There were significant differences (p < 0.001) in endophytic colonisation among the different inoculation techniques.
The first barrier, when penetrating an insect host, encountered by microorganisms like fungi is insects cuticle; fungi produce a wide variety of extracellular enzymes involved in the degradation of ...protein, chitin, and lipids. The main objectives were to assay the enzymatic activity of Cordyceps locustiphila anamorph, in solid and liquid medium at different temperatures and also to evaluate the pathogenicity against the South American locust, Schistocerca cancellata. Conidia of C. locustiphila anamorph were adjusted to 1 × 104, 1 × 106 and 1 × 108 conidia/ml and mortality was recorded for S. cancellata nymphs. The enzymatic activities were determined through a plate test and liquid medium. When assessing the pathogenicity, the fungus caused the highest mortality (84.5 ± 3.5%) at a dose of 1 × 108 conidia/ml. The proteolytic activity showed the highest values (1.56 ± 0.21) (U) at 26 °C. The highest lipolytic activity (1.13 ± 0.36) (U) was observed at 26 °C, while the highest chitinolytic activity was of 0.85 ± 0.1 (U) at 4 °C. Significant differences were observed for enzymatic production on liquid medium, the highest values were recorded for chitinolytic activity (1.63 ± 0.04) (U) and the lowest for caseinolytic activity (0.04 ± 0.001) (U). The results obtained on mortality as well as the quality and variety of enzymes produced by C. locustiphila suggest that this fungus has features that make it a good candidate to be used as a biological agent for the control of the South American locust.
Endophytic fungi are ubiquitous and live within host plants without causing any noticeable symptoms of disease. Little is known about the diversity and function of fungal endophytes in plants, ...particularly in economically important species. The aim of this study was to determine the identity and diversity of endophytic fungi in leaves, stems and roots of soybean and corn plants and to determine their infection frequencies. Plants were collected in six areas of the provinces of Buenos Aires and Entre Ríos (Argentina) two areas were selected for sampling corn and four for soybean. Leaf, stem and root samples were surface-sterilized, cut into 1cm2 pieces using a sterile scalpel and aseptically transferred to plates containing potato dextrose agar plus antibiotics. The species were identified using both morphological and molecular data. Fungal endophyte colonization in soybean plants was influenced by tissue type and varieties whereas in corn plants only by tissue type. A greater number of endophytes were isolated from stem tissues than from leaves and root tissues in both species of plants. The most frequently isolated species in all soybean cultivars was Fusarium graminearum and the least isolated one was Scopulariopsis brevicaulis. Furthermore, the most frequently isolated species in corn plants was Aspergillus terreus whereas the least isolated one was Aspergillus flavus. These results could be relevant in the search for endophytic fungi isolates that could be of interest in the control of agricultural pests.
Los hongos endófitos son ubicuos y se encuentran en el interior de los tejidos de las plantas de manera asintomática. Se sabe muy poco acerca de la diversidad y la función de estos hongos, particularmente en especies de importancia económica. El objetivo de este trabajo fue determinar la diversidad y la frecuencia de colonización de hongos endófitos en raíces, tallos y hojas de 2 variedades de maíz y de 4 variedades de soja; las muestras se tomaron de 6 áreas diferentes ubicadas en las provincias de Buenos Aires y Entre Ríos (Argentina). Con un bisturí estéril se obtuvieron porciones de 1 cm2 de raíz, tallo y hoja, que fueron colocados en placas con agar papa dextrosa más antibiótico.
Las especies de hongos fueron identificadas a partir de características morfológicas y moleculares. La colonización de hongos endófitos en soja estuvo influenciada por la variedad y por el tipo de tejido, en tanto que en el maíz solo hubo influencia del tipo de tejido. El mayor número de endófitos se encontró en los tallos de ambas especies. El aislamiento más frecuente en todas las variedades de soja fue Fusarium graminearum y el menos frecuente Scopulariopsis brevicaulis. En ambas variedades de maíz la especie con mayor frecuencia de aislamiento fue Aspergillus terreus y la de menor fue Aspergillus flavus. Estos resultados son relevantes para la búsqueda de especies de hongos endófitos que podrían ser de interés en el control de plagas agrícolas.
The South American locust Schistocerca cancellata (Serville) was the most serious agricultural pest in Argentina during the first half of the last century and remains as a threat when preventive ...control measures are relaxed in the outbreak area. In this study, we analysed in the laboratory, the effectiveness of 26 fungal strains (isolated from both insects and soil collected in Argentina) for S. cancellata control and determined the relationship between the chitinase, protease and lipase levels in these fungi and their insecticidal activities. We observed that Beauveria bassiana (isolate LPSC 1067) caused the highest mortality (90±1.03%), the highest values of chitinolytic, proteolytic and lipolytic activity were 6.13±0.05, 2.56±0.11 and 2.33±0.47, respectively, and the lowest median lethal time was 5.96 days. This is the first time that a wide variability in chitinase, protease and lipase activity as well as in virulence has been reported in a representative sample of different entomopathogenic fungal strains from Argentina.
Tolypocladium cylindrosporum is an entomopathogenic fungi that has been studied as a biological control agent against insects of several orders. The fungus has been isolated from the soil as well as ...from insects of the orders Coleoptera, Lepidoptera, Diptera and Hymenoptera. In this study, we analyzed the ability of a strain of T cylindrosporum, isolated from soil samples taken in Tierra del Fuego, Argentina, to produce hydrolytic enzymes, and to study the relationship of those activities to the fungus pathogenicity against pest aphids. We have made the traditional and molecular characterization of this strain of T cylindrosporum. The expression of hydrolase activity in the fungal strain was estimated at three incubation temperatures (4 degreeC, 12 degreeC and 24 degreeC), on different agar media supplemented with the following specific substrates: chitin azure, Tween 20, casein, and urea for chitinase, lipase, protease, and urease activity, respectively. The hydrolytic-enzyme activity was estimated qualitatively according to the presence of a halo of clarification through hydrolase action, besides was expressed semi-quantitatively as the ratio between the hydrolytic-halo and colony diameters. The pathogenicity of the fungus was tested on adults of the aphid Rhopalosiphum padi at three temperatures of incubation (4 degree C, 12 degree C and 24 degree C). The suspension was adjusted to a concentration of 1x10(7) conidia/ml. In pathogenicity assays at seven days post-inoculation, the fungus caused the mortality of adults of Ropalosiphum padi at different temperatures also showed a broad ability to grow on several agar-culture media, supplemented with different carbon sources at the three incubation temperatures tested. Although, the growth was greater with higher incubation temperatures (with maximum levels at 24 degreeC), the fungus reached similar colony diameters after 15 days of incubation on the medium supplemented with Tween 20 at the lower two incubation temperatures of 4 degreeC or 12 degreeC. In accordance with the results on colony diameters, the fungus revealed an ability to degrade casein, chitin derivatives, Tween 20, and urea as evidenced by the appearance of a halo around the fungal colony. Because of its origin and temperature tolerance, this Argentine strain has great potential for use as a biocontrol agent for insect pest control in cold and temperate environments.
PDF
