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Plant Disease Apr 2024, native of Mexico (Reyes et al. 2011), holds economic importance as it is marketed as a potted plant and cut flower due to its drought-tolerant capabilities and...
, native of Mexico (Reyes et al. 2011), holds economic importance as it is marketed as a potted plant and cut flower due to its drought-tolerant capabilities and aesthetic appeal. In September 2023, a field sampling was conducted at the Research Center in Horticulture and Native Plants (18°55'56.6" N, 98°24'01.5" W) of UPAEP University. cv. Quilpalli plants with white mold symptoms were found in an area of 0.5 ha, with an incidence of 40% and severity of 50% on severely affected stems. The symptoms included chlorosis of older foliage, necrosis at the base of the stem, and soft rot with abundant white to gray mycelium and abundant production of irregular sclerotia resulting in wilted plants. The fungus was isolated from 30 symptomatic plants. Sclerotia were collected, sterilized in 3% NaOCl, rinsed with sterile distilled water (SDW), and plated on Potato Dextrose Agar (PDA) with sterile forceps. Subsequently, a dissecting needle was used to place fragments of mycelium directly on PDA. Plates were incubated at 23 °C in darkness. A total of 30 isolates were obtained using the hyphal-tip method, one from each diseased plant (15 isolates from sclerotia and 15 from mycelium). After 6 days, colonies had fast-growing, dense, cottony-white aerial mycelium forming irregular sclerotia of 3.67 ± 1.13 mm (=100). Each Petri dish produced 32.47 ± 7.5 sclerotia (=30), after 12 days. The sclerotia were initially white and gradually turned black. The isolates were tentatively identified as based on morphological characteristics (Saharan and Mehta 2008). Two isolates were selected for molecular identification. Genomic DNA was extracted using the CTAB protocol. The ITS region and the glyceraldehyde 3-phosphate dehydrogenase (G3PDH) gene were sequenced for two randomly selected isolates (White et al. 1990; Staats et al. 2005). The ITS and G3PDH sequences of the SsEg9 isolate were deposited in GenBank (ITS-OR816006; G3PDH-OR879212). BLAST analysis of the partial ITS (510 bp) and G3PDH (915 bp) sequences showed 100% and 99.78% similarity to S. sclerotiorum isolates (GenBank: MT101751 and MW082601). Pathogenicity was confirmed by inoculating 30 120-day-old cv. Quilpalli plants grown in pots with sterile soil. Ten sclerotia were deposited at the base of the stem, 10 mm below the soil surface. As control treatment, SDW was applied to 10 plants. The plants were placed in a greenhouse at 23 °C and 90% relative humidity. After 16 days, all inoculated plants displayed symptoms similar to those observed in the field. Control plants did not display any symptoms. The fungus was reisolated from the inoculated stems, fulfilling Koch's postulates. The pathogenicity tests were repeated three times. Recently has been reported causing white mold on cabbage in the state of Puebla, Mexico (Terrones-Salgado et al. 2023). To the best of our knowledge, this is the first report of causing white mold on in Mexico. Information about diseases affecting this plant is very limited, so this research is crucial for designing integrated management strategies and preventing spread to other production areas.
PubMed: 38568786
DOI: 10.1094/PDIS-01-24-0196-PDN -
Journal of Economic Entomology Jun 2024Helicoverpa armigera Hübner (Lepidoptera: Noctuidae; Hübner) is the major insect pest of pigeon pea [Cajanus cajan; Fabales: Fabaceae; (L.) Millspaugh] worldwide....
Helicoverpa armigera Hübner (Lepidoptera: Noctuidae; Hübner) is the major insect pest of pigeon pea [Cajanus cajan; Fabales: Fabaceae; (L.) Millspaugh] worldwide. Research to develop pest management strategies for H. armigera in pigeon pea has focused heavily on developing less susceptible cultivars, with limited practical success. We examined how pigeon pea crop stage influences plant susceptibility to H. armigera using a combination of glasshouse and laboratory experiments. Plant phenology significantly affected oviposition with moths laying more eggs on flowering and podding plants but only a few on vegetative plants. Larval survival was greatest on flowering and vegetative plants, wherein larvae mostly chose to feed inside flowers on flowering plants and on the adaxial surface of expanding leaves on vegetative plants. Larval survival was poor on podding plants despite moths laying many eggs on plants of this stage. When left to feed without restriction on plants for 7 days, larvae feeding on flowering plants were >10 times the weight of larvae feeding on plants of other phenological stages. On whole plants, unrestricted larvae preferred to feed on pigeon pea flowers and on expanding leaves, but in no-choice Petri dish assays H. armigera larvae could feed and survive on all pigeon pea reproductive structures. Our results show that crop stage and the availability of flowers strongly influence pigeon pea susceptibility to H. armigera. An increased understanding of H. armigera-pigeon pea ecology will be useful in guiding the development of resistant varieties and other management tactics.
Topics: Animals; Moths; Larva; Cajanus; Oviposition; Herbivory; Female; Helicoverpa armigera
PubMed: 38564410
DOI: 10.1093/jee/toae050 -
Open Veterinary Journal Feb 2024Ecto-parasite, varroa mite, (), is the primary pest affecting the apiculture sector globally in various regions.
BACKGROUND
Ecto-parasite, varroa mite, (), is the primary pest affecting the apiculture sector globally in various regions.
AIM
This study examined the toxicity of nine essential oils to L. and the acaricidal impact of those oils against .
METHODS
The acaricidal effects of nine essential oils, extracted from plant materials were used. In the screening experiment, 10 mg of the active ingredients of the plant material extracts were prepared in an alcohol solution with concentrations of 5%, 10%, and 15%. For each type of plant extract, five female were transferred to a Petri dish with five worker bees incubated at 70% humidity and 33°-34° for 2 days, for each treatment four replicates were used compared to the control. Forty-eight hours following treatment, the number of dead and live mites was counted to determine the mortality rate. In the second assay experiment, the best five essential oils of the previous experiment were selected to re-assess their effectiveness on varroa mites and honeybee workers by using a concentration of 15%. Five females of were transferred to a Petri dish with 10 adult bees and treated with the solution of the selected oils. Five replicates and control treatments were taken for each sample simultaneously. Dead and live bees were counted for each replicate at 48 hours after treatment.
RESULTS
There were no significant differences between the concentrations used of each oil on the rate of death of mites, and its effectiveness ranged between 70.0% and 53.3% compared to the control groups. In addition, the best oil used was bitter melon, with a death rate of 80% at a concentration of 15%, while peppermint oil showed the lowest death rate of 45% at a concentration of (5%). However, all these treatments were statistically highly significant compared with the natural death rate in control (2%). In the second test, the results of the statistical analysis indicated that there were highly significant differences (P <0.0001) in the average numbers of dead varroa mites compared to the control when using a 15% concentration of five selected oils. On the other hand, there was no statistically significant difference in the honey bee workers' mortality rate between the treatment and control groups (P <0.3390), and it was relatively low for all treatments except the basil oil, where the bee mortality rate was 16% compared to the control (10%).
CONCLUSION
It is clear from this experiment that bitter melon oil can be used to control varroa mites and it can be considered safe for honey bees as well as for the environment.
Topics: Female; Bees; Animals; Varroidae; Oils, Volatile; Acaricides
PubMed: 38549575
DOI: 10.5455/OVJ.2024.v14.i2.9 -
Plant Disease Mar 2024species are widespread soilborne pathogens that can cause damping-off, root rot, and wilting in soybean [ (L.) Merrill], subsequently leading to significant yield...
species are widespread soilborne pathogens that can cause damping-off, root rot, and wilting in soybean [ (L.) Merrill], subsequently leading to significant yield suppression. Several spp. have already been documented for their pathogenicity on soybean plants in the Republic of Korea. The nationwide monitoring of soybean diseases continues to identify new pathogenic spp. In 2016, five plant samples at R3-R4 growth stages, showing symptoms of wilting in the upper parts and root rot, were collected in Suwon, Gyeonggi, Republic of Korea. Fungal colonies were obtained from the diseased root samples, with the surface sterilized in 1% sodium hypochlorite for 2 min, rinsed thrice with sterile distilled water, and placed on water agar at 25°C. Five isolates were collected and purified by single-spore isolation. The fungal mycelium was subsequently cultivated on potato dextrose agar for ten days. The isolates produced abundant, aerial, and white mycelium and became purple in old cultures. Macroconidia were slender, falcate to almost straight, usually 3 to 5 septated, and thin-walled. Microconidia were formed in chains from polyphalides, clavate or oval, usually single-celled with a flattened base. These characteristics of isolates were consistent with the description of (Leslie and Summerrell 2006), and the representative isolate 16-19 was selected for molecular identification to confirm its identity as . Two evolutionarily conserved genes, the () and the () genes, were partially amplified using the primers described by O'Donnell et al. (2008), resulting in nucleotide sequences of 680 and 382 base pairs, respectively. These two sequences (GenBank accession numbers: OQ992720 and OR060666) showed 100 and 99.5% identity to the and of A40 (GenBank accession numbers: KP964907 and KP964842). For the Petri-dish pathogenicity assay (Broders et al. 2007), five surface-sterilized seeds were placed on water agar media with either sterile water or actively growing '16-19' culture. After 7 days of incubation in a growth chamber (25°C; 12-hour photoperiod), brown lesions were observed on the roots of the inoculated plants, while no symptoms were observed in the sterile water-treated controls. The experiment was conducted three times. For root-cut pathogenicity assay, conidial suspension (1×10 conidia/ml) of the isolate '16-19' was prepared with harvested mycelia cultured on PDA for 10 days with sterile water. The roots of 10-day-old soybean seedlings were partially cut and soaked in either the suspension or sterile water for 2 hours. The seedlings were transplanted into 12 cm plastic pots (11 cm in height) and grew in a greenhouse (26 ± 3°C, 13-h photoperiod). The experiment followed a completely randomized design with three replicates (i.e. three plants in a pot), and it was repeated twice. The inoculated plants began to wilt 7 days after inoculation, while the sterile water-treated controls remained healthy. Ten days after inoculation, all plants were collected, washed under running tap water, and evaluated for the presence and severity of root rot using a 0-4 scale (Chang et al. 2015). The inoculated plants exhibited reduced vigor and developed dark brown lesions on their roots. was reisolated from symptomatic root tissues of the infected plants, while not from those of the controls. Its colony and spores were morphologically identical to those of the original isolate. was previously reported as a causative agent of soybean root rot in the United States (Díaz Arias et al. 2011) and Canada (Chang et al. 2015). This is the first report of soybean root rot caused by in the Republic of Korea. This finding implies that may potentially threaten soybean production in the Republic of Korea and suggests that effective disease management strategies should be established for soybean protection against the disease, along with continuous surveillance.
PubMed: 38537140
DOI: 10.1094/PDIS-12-23-2551-PDN -
Plant Disease Mar 2024Agrocybe chaxingu is an edible and medicinal mushroom widely cultivated in China (Liu et al. 2021). Agrocybe chaxingu is extremely well-liked for the unique flavor and...
Agrocybe chaxingu is an edible and medicinal mushroom widely cultivated in China (Liu et al. 2021). Agrocybe chaxingu is extremely well-liked for the unique flavor and nutritional value. In May 2021, a serious white mucus disease was observed in the farms of A. chaxingu in the Ganxian district of Ganzhou City, Jiangxi Province, China, with an approximate disease incidence of 20%. In the years of 2022 and 2023, the same white mucus disease on A. chaxingu was observed in the farms in Nanchang City, Jiujiang City and Guangchang County, Jiangxi Province, China. The disease generally occurs on the media, stipe or pileus of A. chaxingu under condition of high humidity. The plasmodial slime molds migrated from the surface of culture media (78% hardwood sawdust, 15% wheat bran, 5% tea seed shell, 1% lime, and 1% gypsum) to the base of fruiting bodies, stipes and finally to pilei, showing as moist, sticky, and white reticulated structures. The infected fruiting bodies of A. chaxingu were completely covered by reticulated plasmodia, displaying a white or pale-yellow color. This resulted in the growth cessation, wilting and eventual death of fruiting body. Microscopic observation found that the plasmodia of slime mold enveloped the hyphae of A. chaxingu, resulting in the fragmentation of the hyphae. The disease can spread quickly, resulting in a 30% reduction in production. Slime mold cultures were isolated by transferring diseased fruiting bodies of A. chaxingu onto oat-agar medium (2% agar and 1% oatmeal) at 25 ℃. The isolates can be obtained after being subcultured for two to three generations. Purified plasmodia were placed on the semi-defined medium (1% tryptone, 1% glucose, 0.15% yeast extract, chick embryo extract and a balanced salt solution) to confirm the absence of bacteria (Daniel et al. 1964) and thus obtained the pure culture. Specimen of the voucher has been deposited in the Institute of Agricultural Applied Microbiology, Jiangxi Academy of Agricultural Sciences as number IAAM-W0002. The vegetative plasmodia have a large and well-developed scalloped structure that were white or milky white in colour. The white plasmodium became opaque pale yellow when exposed to light before fruiting. The veins merged and thickened. Fruiting bodies can be formed on the lid or side of the Petri dish under light condition. The fruiting bodies formed papillae with irregular shape, and then the color changed from translucent yellow to greyish black. Spores were usually spherical or subglobose, free, greyish brown in mass, purplish brown, 7-12 μm in diameter under light microscopy. These morphological characteristics were found to be consistent with those of Fuligo gyrosa (Synonym: Physarum gyrosum) (Kim et al. 2009; Shi et al. 2005; Jahn 1902). The identity of the isolates was further confirmed by sequence analysis of the 18S ribosomal RNA gene with primer SMNUR101/NS4 (Rusk et al. 1995; White et al. 1990). Using BLASTn searches, the sequence of 18S rRNA gene (GenBank accession number OR186216) matched the sequence of F. gyrosa (GenBank accession number LC744593) with the identity of 99.91% and coverage of 97%. A phylogenetic tree based on the 18S rRNA gene also demonstrated that the slime mold clustered with F. gyrosa. Over ten isolates have been obtained from the diseased A. chaxingu samples in different factories and identified as F. gyrosa. To test the pathogenicity of F. gyrosa, five healthy young fruiting bodies (three to five days of primordium) of A. chaxingu cultivated in mushroom-growing room were gently inoculated by a 12 mm diameter oat-agar medium with plasmodia at 24 ± 2 ℃ and then were kept with relative humidity of 90%-95%. Five fruiting bodies inoculated with a 12 mm oat-agar medium served as controls. After 5 days, white mucus characteristics and three fifths of death symptoms were observed on the fruiting bodies inoculated with the plasmodia, while the controls remained asymptomatic. The slime mold on the inoculated fruiting bodies was morphologically identical to F. gyrosa that was observed on the initial diseased fruiting bodies. It was also observed the envelopment A. chaxingu hyphae by the plasmodia of slime mold and fragmentation of the hyphae, and the fragmentation was not observed in the controls. Reisolations were prepared from the inoculated fruiting bodies and confirmed to be F. gyrosa based on morphological characteristics and 18S rRNA sequence, thus fulfilling Koch's postulates. Fuligo gyrosa has been reported to cause severe disease in oriental melon in Korea (Kim et al. 2009). This is the first report of F. gyrosa causing white mucus disease in cultivated A. chaxingu. The findings will provide important information on prevention and control of the disease, and be helpful for the development of A. chaxingu industry.
PubMed: 38537135
DOI: 10.1094/PDIS-09-23-1867-PDN -
Insects Feb 2024Human lice are the only hematophagous ectoparasites specific to human hosts. They transmit epidemic typhus, trench fever and relapsing fever, diseases which have already...
Human lice are the only hematophagous ectoparasites specific to human hosts. They transmit epidemic typhus, trench fever and relapsing fever, diseases which have already caused millions of deaths worldwide. In order to further investigate lice vectorial capacities, laboratory-controlled live lice colonies are essential. Previously developed lice-rearing methods significantly advanced research on louse-borne diseases and louse biology. In this study, we aimed to develop a rearing technique for the Orlando (Or) strain of body lice on an artificial membrane. We tested two systems, namely the Hemotek feeding system and a Petri dish with the lice being fed through a Parafilm membrane. Lice longevity and development were drastically affected by the blood anticoagulant. Additionally, heparinised human blood on a Petri dish was the best candidate when compared to the control group (reared on a rabbit). Therefore, this strategy was applied to 500 lice. Development into adulthood was recorded after 21 days (17 days for the rabbits), and 52 eggs were deposited (240 for the rabbits). In this study, we were able to maintain one generation of body lice on an artificial membrane with comparable feeding and longevity rates to those fed on live rabbits. However, lice fecundity decreased on the artificial membrane. In vitro lice-rearing experiments will enable pathogen infection assays and pesticide bioassays to be carried out in accordance with animal welfare requirements.
PubMed: 38535341
DOI: 10.3390/insects15030145 -
Journal of Agricultural and Food... Apr 2024The discovery of a lead compound is fundamental to herbicide innovation, but the limited availability of valuable lead compounds has hindered their development in recent...
The discovery of a lead compound is fundamental to herbicide innovation, but the limited availability of valuable lead compounds has hindered their development in recent years. By utilizing the structural diversity-oriented inactive group strategy, 3-(2-pyridyl)-benzothiazol-2-one was identified as a promising lead scaffold for herbicides, starting from benzothiazole which is an inactive moiety commonly found in herbicides such as mefenacet, benazolin, benzthiazuron, and fenthiaprop-ethyl. To investigate the structure-activity relationship (SAR) of these chemicals, a series of 2-(2-oxo-3-pyridyl-benzothiazol-6-yloxy)hexanoic acid derivatives () were synthesized through classical nucleophilic SAr reaction using halogenated pyridines and 6-methoxybenzothiazole-2-one. The chemical structures of all the title compounds were confirmed by NMR and MS analysis. Petri dish assays indicated that many compounds exhibited potent herbicidal activity against both broad-leaf weeds and grass weeds at 1.0 mg/L. The SAR analysis revealed that the presence of a trifluoromethyl group at the 5-position of pyridine is essential for herbicidal activity. Furthermore, carboxylic esters exhibit higher herbicidal activity compared to carboxylic amides and free acids, and the activity decreased with the extension of the carbon chain. The postemergence herbicidal activity of against 16 species of weeds was tested by pot experiments in a greenhouse. demonstrated comparable efficacy in controlling broadleaf weeds and superior efficacy in controlling grass weeds compared to carfentrazone ethyl. The present study has unveiled a novel molecular scaffold exhibiting remarkably potent herbicidal activity. These findings are anticipated to provide valuable insights for the advancement of new herbicides and offer an alternative approach for managing resistant weeds.
Topics: Herbicides; Caproates; Structure-Activity Relationship; Plant Weeds; Poaceae
PubMed: 38527909
DOI: 10.1021/acs.jafc.3c08213 -
Chemosphere May 2024The application of carbon nanoparticles (CNPs) and biochar in agriculture for improving plant health and soil quality and alleviating metal stress offers alternative...
The application of carbon nanoparticles (CNPs) and biochar in agriculture for improving plant health and soil quality and alleviating metal stress offers alternative approaches to meet the ever-increasing demand for food. However, poor understanding of their roles in improving crop production under Cu stress represents a significant obstacle to their wide application in agriculture. To clarify how CNPs and biochar affect corn (Zea mays L.) seed germination, seedling growth, plant health, and nutrient uptake under different Cu stress levels, soil-less Petri-dish and greenhouse soil-based bioassays were conducted. The results revealed that CNPs and biochar stimulated corn seed germination and seedling growth. Besides, they were effective in immobilizing Cu sorption in sandy soil and alleviating Cu stress for plant growth, as shown by the increased plant height and dry biomass. The plant nutrient uptake efficiency (NUE) was significantly increased by CNPs, with a maximum increase of 63.1% for N and 63.3% for K at the highest Cu stress level (400 mg Cu L). In contrast, non-significant effects on NUE were observed with biochar treatments regardless of Cu stress levels. Interestingly, CNPs significantly increased plant uptake of Cu in the Petri dish test, while biochar inhibited plant uptake of Cu under both experimental conditions. Principle component analysis (PCA) and Pearson correlation analysis indicated that CNPs mitigated Cu stress mainly by elevating antioxidant enzyme activities, enhancing plant photochemical efficiency, and increasing plant uptake of N and K, while biochar was more likely to reduce bioavailability and uptake of Cu in the plant. These findings have great implications for the application of CNPs and biochar as plant growth stimulators and de-toxicity agents in agriculture.
Topics: Copper; Zea mays; Charcoal; Soil; Seedlings; Seeds; Soil Pollutants; Nanoparticles
PubMed: 38521100
DOI: 10.1016/j.chemosphere.2024.141745 -
Pest Management Science Mar 2024Myzus persicae, a serious sap-sucking pest of a large variety of host plants in agriculture, is traditionally controlled using chemical insecticides but there...
BACKGROUND
Myzus persicae, a serious sap-sucking pest of a large variety of host plants in agriculture, is traditionally controlled using chemical insecticides but there is interest in using biopesticides as restrictions are increasingly placed on the use of broad-spectrum pesticides.
RESULTS
Here, we show that in Petri dish experiments, high concentrations of the fungal entomopathogen Beauveria bassiana led to rapid mortality of M. persicae, although at a low concentration (1 × 10 conidia mL) there is a hormetic effect in which survival and fecundity are enhanced. Hormetic effects persisted across a generation with reduced development time and increased fecundity in the offspring of M. persicae exposed to B. bassiana. The whole-plant experiment points to a hormetic effect being detected in two out of three tested lines. The impact of these effects might also depend on whether M. persicae was transinfected with the endosymbiont Rickettsiella viridis, which decreases fecundity and survival compared with aphids lacking this endosymbiont. This fecundity cost was ameliorated in the generation following exposure to the entomopathogen.
CONCLUSION
Although B. bassiana is effective in controlling M. persicae especially at higher spore concentrations, utilization of this entomopathogen requires careful consideration of hormetic effects at lower spore concentrations, and further research to optimize its application for sustainable agriculture is recommended. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
PubMed: 38469952
DOI: 10.1002/ps.8075 -
BDJ Open Mar 2024This in vitro study was accomplished to demonstrate the antibacterial efficacy of BioMin F and NovaMin toothpastes against the recently-isolated Streptococcus Mutans in...
OBJECTIVE
This in vitro study was accomplished to demonstrate the antibacterial efficacy of BioMin F and NovaMin toothpastes against the recently-isolated Streptococcus Mutans in comparison with a commonly used fluoride toothpaste.
MATERIALS AND METHODS
Dental plaque collection method was adopted to isolate streptococcus mutans in children with dental caries. Then an ideal Streptococcus Mutans colony was incubated in 20 Petri dishes that contained Mueller-Hinton medium. Each dish had 3 wells; one well for each toothpaste (BioMin F, NovMin, and Signal) to perform the agar diffusion test. After incubating for 24 hours, the inhabitation zone around each well of each Petri dish was noticed and measured. Statistical Analysis was achieved using a statistical package, SPSS Windows version 17, by applying Kruskal-Wallis with Mann-Whitney U test (α = 0.05).
RESULTS
BioMin F showed the highest mean of inhibition zone diameter ( = 2.67 mm) in compared with NovaMin and Signal ( = 0.39 mm and = 2.19 mm; p < 0.001 in each pairwise comparison).
CONCLUSION
BioMin F toothpaste showed superior antibacterial effect against Streptococcus mutans to Signal and NovaMin toothpastes. Novamin showed the lowest antibacterial effect. This in vitro study suggests that BioMin F toothpaste shows encouraging potential to be recommended as a preventive measure to reduce the caries risk.
PubMed: 38467637
DOI: 10.1038/s41405-024-00202-x