Sooty Mold Research Articles

Effect of sap-feeding insects, plant characteristics, and weather parameters on sooty moulds in the temperate zone

AbstractIn this study, relevant variables were determined to predict the probability of sooty mould biofilm (SMB) occurrence on willow leaves in a multivariate model. Despite a large temporal gap between the main sap-feeding insect (SFI) season in spring (May to June) and the main season of SMBs in late summer and fall (August to September), trees infested with SFIs on four or more observation dates had significantly more SMBs (3.7-fold) toward the end of the growing season. In addition, a horizontal leaf position and recessed leaf veins, traits that may increase the wettability of the leaves, positively influenced SMB occurrence (27.8-fold). Among the weather parameters, those that lead to higher moisture on leaf surfaces, namely high morning and evening relative humidity, higher precipitation sums, and lower vapour pressure deficit values, also had the strongest positive effect. In addition to these parameters, higher wind speeds also had a strong positive effect on SMB occurrence.

Chaetocapnodium zapotae sp. nov. on Manilkara zapota in central Mexico

A new sooty mould, Chaetocapnodium zapotae, was isolated from Manilkara zapota in central Veracruz, Mexico. An analysis of ITS+LSU nuclear rDNA concatenated sequences of our isolate revealed taxonomic identity at the genus level located in the same clade as Chaetocapnodium insulare and Chaetocapnodium placitae. Morphological examination confirmed that the new species differs from C. insulare in the absence of the sexual morph and the absence of setae on the pycnidia. Additional characters distinguishing C. zapotae from C. placitae are its narrower pycnidial size range, wider size ranges for the hyphae and conidia, and the dark brown color of its pycnidia.

A Review on Major Diseases of Citrus in Nepal and their Management

Citrus is one of the most important fruit crops cultivated in tropical and subtropical regions of Nepal. Climatic conditions of mid hill regions of Nepal having an altitude ranged between 800 to 2100 meter above sea level are conducive for all types of citrus fruit cultivation. Nepal produced 273,000 tons of citrus in 2019 and ranked 43rd in global citrus production. The average productivity was 9.4 mt/ha in 2017/18.Various biotic and abiotic factors are reported to decline productivity of the citrus in Nepal. Poor orchard management, improper manuring and fertilization, including insect pests and diseases are major factors for citrus decline and low productivity of the citrus in Nepal. A literature review was carried out to explore the common diseases of citrus and their management in the context of Nepal. Along with the diseases of citrus, their casual organisms, distribution, epidemiology, intensity, symptoms, survival or spread, environmental factors, losses incurred and integrated management strategies corresponded to citrus diseases of Nepal gathered and compiled thoroughly from different literature and websites. Different 16 fungal diseases, 42 viruses, 7 bacterial diseases and some nematodes causing diseases on citrus in addition to this many diseases are reported to attack citrus crops in Nepal. Citrus greening (HLB), Phytopthora induced diseases, citrus canker, citrus tristeza, twig blight, powdery mildew etc. are major yield limiting diseases of citrus. Anthracnose, sooty mould, pink disease, gummosis, scab disease, citrus root nematodes, ‘Ainjeru’ are the other diseases for declining citrus production and its quality. Citrus greening and citrus tristeza are major casual agents for rapid decline and citrus root nematode is considered as casual factor for slow decline of citrus.

First Report on Voracity and Feeding Preference of Predatory Beetle, Thalassa montezumae (Coleoptera: Coccinellidae) on Croton Scale, Phalacrococcus howertoni (Hemiptera: Coccidae)

The croton scale Phalacrococcus howertoni Hodges & Hodgson gen. nov., sp. nov. (Hemiptera: Coccidae), was first found in Florida, USA. This scale has become a pest because of its high reproductive rate and production of sooty mold. Here, we evaluated predation potential of the predatory beetle, Thalassa montezumae Mulsant (Coleoptera: Coccinellidae), as a biological control agent. To our knowledge, this is the first study of predation by T. montezumae on P. howertoni. Results of our studies showed that the predation by 4th instar T. montezumae was higher on 2nd stage nymphs than on 3rd stage nymphs P. howertoni; predation on adults was lowest. Mean consumption by adult T. montezumae was highest on 2nd stage nymphs followed by 3rd stage nymphs, and adult P. howertoni. There were no significant differences between male and female adult T. montezumae in the prey first visited when offered a choice of 2nd or 3rd instar nymphs, or adults of P. howertoni. Thus, the levels of acceptance did not vary significantly between stages of prey visited by the males and females. Females chose prey faster than males and used less energy to search for food. Egg fecundity did not vary among female beetles fed with different stages of croton scales. Should P. howertoni become a major pest, T. montezumae could be used as a biological control agent within a biologically based integrated pest management program.

Impact of powdery mildew and sooty mold diseases on mango by natural fungicide

An investigation was carried out to determine the efficacy of some organic materials to manage powdery mildew and sooty mold diseases on mango, under natural field condition at Sharqia and Ismaelia governorates in Egypt. PlcoCure natural fungicide applied as foliar spray to find out its efficacy and profitability compared with control (no spray) and chemical fungicides Super sard potassium soap, Malathion, mineral oil to control sooty mold. All the treatments controlled the diseases significantly compared with control. As chemical, the PlcoCure showed significant impact on disease reduction. This natural fungicide gave a higher benefit with minimum production cost and this approach is proposed to the mango growing farmers to control the diseases. So, organic combination might be a better option to control powdery mildew and sooty mold diseases on mango rather than chemical control as it is cost-effective, environment friendly and good yield.

Symptomology of Major Fungal Diseases on Olive and Its Management

The olive tree count among the most important oil-producing crops throughout the Mediterranean region. It has nutritional, social, economic, phytotherapeutic and ecological importance. All of the olive tree diseases cause considerable drops in yield and represent a permanent threat to olive growing in the world. The main fungal diseases of the olive are: Verticillium wilts, Root rot fungi, Sooty mold, Peacock spot, Anthracnose, Cercospora leaf spot of olives and Dalmaticosis of the olive. In this article we have cited for each disease the main symptoms and their means of control.

Sooty mould caused by Capnodium alfenasii on Azadirachta indica

AbstractIn October 2020, sooty moulds were found covering the leaves of neem trees (Azadirachta indica) in Vitória da Conquista, Bahia, Brazil. Sooty moulds usually grow on honeydew secreted by insects. However, in this observation, insects were not visible on the sooty mould‐infected plants. Rather, the sooty mould grew on the host secretions. Inoculation was performed to confirm the ability of the fungus to grow on host nectaries. Based on the morphological features and phylogenetic analysis, Capnodium alfenasii was identified as the sooty mould agent. To our knowledge, this is the first report on the occurrence of this fungus on neem plants.

Pest categorisation of Tetraleurodes perseae.

The EFSA Panel on Plant Health performed a pest categorisation of Tetraleurodes perseae (Hemiptera: Aleyrodidae), the red‐banded whitefly, for the territory of the EU. T. perseae is a tropical and subtropical species that originated in the Neotropical region and has now spread and established in the USA (California and Florida), Israel and Lebanon. T. perseae is not listed in Commission Implementing Regulation (EU) 2019/2072. It is oligophagous on Lauraceae and most frequently reported on avocado (Persea americana), on which it is considered a minor or secondary pest. No evidence was found indicating damage to other plants. T. perseae larvae develop on the foliage and don’t attack the fruit. The number of generations per year varies between one and ten. High populations may promote the growth of black sooty moulds on the foliage and fruit, and adults feeding on the buds can lead to deformed immature leaves and premature leaf drop. However, T. perseae populations are usually effectively controlled by hymenopteran parasitoids, at least one of which (Cales noacki) is widespread in the EU. The producers of organic avocados in the EU could encourage the use of C. noacki, although occasional outbreaks of T. perseae could temporarily impact the fruit quality. Adults disperse naturally by flying and all stages can be moved over long distances by the trade of infested plant material. Plants for planting provide potential pathways for entry and spread in the EU. Climatic conditions and availability of host plants in southern EU countries are conducive for establishment. Phytosanitary measures are available to reduce the risk. T. perseae satisfies all of the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. However, this conclusion has a high uncertainty regarding magnitude of potential impact as the insect is a minor and sporadic pest in its current area of distribution.

Chironji (Buchanania lanzan Spreng.): a new host for Idiocerinae leafhopper Busoniomimus mudigerensis (Viraktamath) Hemiptera: Cicadellidae from India

Idiocerinae leafhoppers are serious pests of economically important fruit crops like mango. Buchanania lanzan Spreng., commonly known as chironji is an underutilized potential dry fruit tree well known for its edible kernels with almond aroma. The Idiocerinae leafhopper species Busoniomimus mudigerensis (Viraktamath) was found to be feeding and damaging the Buchanania lanzan trees in Jhansi, Uttar Pradesh, India. Continuous feeding of nymphs and adults on the tender shoots and leaves resulted in characteristic white speckles on the upper surface of the leaf, downward leaf curling, withering, and drying of tender shoots. Excessive honeydew secretion by nymphs and adults also favored the growth of sooty mold on leaf surfaces were observed under field conditions. Also, the leafhopper genus and species were documented as a new record from North India (Jhansi: Uttar Pradesh) in the present study. Which was earlier restricted only to southern Indian state Karnataka. Taxonomic descriptions for a female are given in this study which is unknown from the original descriptions and the male characters are redescribed with photographic illustrations.

First record of the pyriform scale, Protopulvinaria pyriformis Cockerell (Hemiptera: Coccidae), on Laurus nobilis L. in Tunisia

AbstractThis paper reports the first finding of the pyriform scale, Protopulvinaria pyriformis Cockerell (1894), infesting laurel, Laurus nobilis L., in Tunisia. The pest was found in May 2020 in a private garden in the region of Jawhara, Governorate of Sousse, Coastal Tunisia. Heavily infested laurel trees were observed on which the upper surfaces of leaves were extensively covered with a black sooty mould. Brief notes on diagnostic features of this scale and symptoms of infestation are presented. Possible pest risks and control measures aimed at avoiding the potential further spread of the pest in Tunisia are discussed.

Phase-change-mediated transport and agglomeration of fungal spores on wheat awns.

Wheat and other staple crops are devastated by fungal diseases. Many fungal plant pathogens are spread via active or passive discharge of microscopic spores. Here, we described the unique transport of spores of the fungal pathogen Epicoccum tritici, causal agent of black sooty mould, on wheat awns. The unique multi-scale architecture of wheat awns, coupled with condensation and evaporation of dew droplets, facilitated the transport and agglomeration of spores of the fungus. First, dew droplets spontaneously transported spores from the tips of awn hairs to the neighbouring stomatal ridges, driven by gradients in Laplace pressure and surface wettability. Subsequently, spores agglomerated into dry clusters due to the Cheerios effect and evaporation, increasing the likelihood of passive spore removal via wind shear and/or rainsplash. Future plant breeding approaches should consider the development of modified spike structures, such as those without awns or awn hairs, to reduce the potential for spread of fungal plant pathogens.

Structure and Antimicrobial Activity of Rare Lactone Lipids from the Sooty Mold (Scorias spongiosa).

Two new lactone lipids, scoriosin (1) and its methyl ester (2), with a rare furylidene ring joined to a tetrahydrofurandione ring, were isolated from Scorias spongiosa, commonly referred to as sooty mold. The planar structure of these compounds was assigned by 1D and 2D NMR. The conformational analysis of these molecules was undertaken to evaluate the relative and absolute configuration through GIAO NMR chemical shift analysis and ECD calculation. In addition to the potent antimicrobial activities, compound 2 strongly potentiated the activity of amphotericin B against Cryptococcus neoformans, suggesting the potential utility of this compound in combination therapies for treating cryptococcal infections.

Status of (Gennadius) in Context of its Biology Bemisia tabaci and Ecology in Cotton Agroecosystem

Cotton is an important cash crop and extensively cultivated in different parts of the world. Many factors are responsible for its low productivity and production but the magnitude of insect pests that damage cotton crop from sowing to maturity, is most important. Introduction of Bt cotton lead to drastic reduction in bollworms incidence but sucking insect pests such as whitefly, mealybug, jassid and thrips aphids has increased. Among these, whitefly, is most serious pest of cotton. At present, it is globally distributed and known to infest several Bemisia tabaci plant species. It causes damage to cotton crop by direct feeding and contamination of lint by honey dew and sooty mould. It transmits a deadly cotton leaf curl virus. has strong relationship with abiotic factors like temperature, humidity and precipitation. Temperature has B. tabaci positive correlation and relative humidity has negative correlation with whitefly. A combination of temperature and relative humidity is highly important for its multiplication in cotton. For a multi-voltine and multi-crop pest like estimating rates of mortality in the field is extremely B. tabaci complex and difficult. So, life table studies are important to predict pest outbreaks and to develop pest management strategies.

The value of applying a myrrh extract to manage and control date palm aphids in Saudi Arabia and their classification

The date palm can be affected by aphids resulting in the development of sooty mould. Extracts from myrrh plants were utilized as biological insecticides on aphids to learn its impact. Myrrh extracts had been evaluated using four separate amounts, namely 500, 1000, 5000, and l0000 ppm. They were applied two times and then inspected at 12 and 24 h after the exposure to be contrasted to the unexposed samples. The aphids eating date palms were subjected to myrrh extracts and categorized. The bio-insecticidal effects have been investigated based on specific dynamics and genetic evaluation of both exposed and unexposed aphid samples. The biologically insecticidal effects are relevant (P < 0.05) regarding all the four selected factors. Moreover, the genetic evaluation indicated that unfinished genetic sequences have dramatically increased upon elevating amounts of myrrh extracts (0, 500, 1000, 5000, and 10000 ppm). Meanwhile, the average genetic distance has reduced with enlarged amounts of myrrh extract in the 24-h period in the case of the exposed aphids in contrast to unexposed samples. Myrrh extracts are very strong and perspective biological

Euantennaria pleioblasti sp. nov. (Euantennariaceae) and Metacapnodium cf. quinqueseptatum (Metacapnodiaceae), two mixed sooty moulds in subicula on Pleioblastus sp. in Taiwan.

Black subicula, comprising a mixture of two sooty moulds of Euantennariaceae and Metacapnodiaceae, on Pleioblastus were collected in Batongguan, alt. ca. 2800 m, Nantou County, Taiwan in 1984. The former sooty mould is described and illustrated as Euantennaria pleioblasti sp. nov., an asexually typified species of the genus, as currently circumscribed with the application of the single name nomenclature for pleomorphic fungi. It is characterized by cylindrical, finely to coarsely roughened hyphae and black synnemata bearing massive fusiform, straight, mostly 11-14-septate phragmoconidia in a subglobose to obovoid head; its reliable sexual morph is obscure. The latter was identified as Metacapnodium cf. quinqueseptatum. It features the capnobotrys- and capnophialophora-like asexual morphs, in addition to the sexual morph with 5-7-septate ascospores. These sooty mould taxa are newly added to the mycobiota of Taiwan.

Exogenous melatonin alleviates sooty mould on tea plants (Camellia sinensis L.)

Studies have been estimated the economic risk of sooty mould (SM) disease in various economical crops, however, the effects of SM on growth and development of tea plants are still unclear. The study investigates the impact of sooty mould on photosynthetic pigments, chlorophyll fluorescence (Fv/FM) and gas exchange parameters and recovery of plants by exogenous melatonin. The morphological and multilocus phylogenetic analyses showed that the sequences of ITS, EF1-α and ACT of these pathogenic isolates belong to the Cladosporium tenuissimum. Exogenous melatonin (10 mM) inhibits mycelial growth and melanin production of C. tenuissimum causing SM. The higher chlorophyll contents and more chloroplasts with starch granules were observed in the SM leaves. SM on tea plants reduced Fv/FM, net photosynthetic (Pn), transpiration rate (Tn), stomatal conductance (gsw) and intercellular CO2 (Ci) were 39, 88, 90 and 29%, respectively compared to control. Whereas, exogenous melatonin (10 mM) increased Fv/FM, Pn, Tn, gsw and Ci were 26, 63, 74 and 17%, respectively than SM infected. Besides, melatonin enhanced CAT, SOD, PPO and PAL activities by 27.6, 32.2, 65.3 and 27.1%, respectively compared to SM, but no significance in POD activity. CLH and NYC1 genes were down-regulated in SM plants and the genes expression was higher in the melatonin treatment. Meanwhile, melatonin up-regulated WRXY, PAL and β-gly genes expression involved in plant defence. This study provided the fundamental knowledge of SM and its impact on tea plants and the recovery of plants by exogenous melatonin.

INTRODUCTION TO THE COMPOSITAE – 3

INTRODUCTION TO THE COMPOSITAE – 3

New Record of Spiralling Whitefly Aleurodicus dispersus Russell on Brinjal From Manipur

The spiraling whitefly Aleurodicus dispersus Russell was found infesting brinjal in Imphal, Manipur during October 2020 and January 2021, with lifestages getting completed on leaves. The spiraling nature was also found with heavily infested leaves getting crinkled before drying out. The honey dew and black sooty moulds symptoms were also observed. Moderate infestation was found during rainy season but it was heavy during November to December. The biopesticide Verticillium lecanii was found to be effective with incidence and the number of spirals observed to be reduced within seven days.

Using a multi-convolutional neural network to automatically identify small-sample tea leaf diseases

Tea leaf disease is a factor leading to the decline of tea quality and yield. In this study, a multi-convolutional neural network (CNN) model, MergeModel, combined with diseased leaf segmentation and a weight initialization method, was used for automatic identification of tea leaf diseases in small samples. Diseased leaf segmentation could reduce the impact of complex backgrounds on the identification results. The integration of multiple CNN modules enabled MergeModel to extract a variety of discriminative features. The identification ability of MergeModel was improved compared with a single neural network. The weight initialization method encoded the diseased leaf features into the convolution filter, which helped the model to concentrate on learning important features at the beginning of training. In addition, this study used a small number of diseased tea leaf images as the original training samples and generated new training samples through the unconditional generation model, namely, SinGAN, for data augmentation. Experimental results showed that MergeModel could effectively distinguish diseased tea leaves from healthy tea leaves and identify common tea leaf diseases such as tea white scab, tea leaf blight, tea red scab, and tea sooty mould. Compared with the existing methods, the proposed method had higher accuracy in identifying tea leaf diseases in small samples.

Production of Non-Volatile Metabolites from Sooty Molds and Their Bio-Functionalities

In the current study, eleven sooty mold isolates were collected from different tropical host plants. The isolates were identified under Capnodium, Leptoxyphium and Trichomerium, based on morphology and phylogeny. For the secondary metabolite analysis, the isolates were grown on Potato Dextrose Broth (PDB). The well-grown mycelia were filtered and extracted over methanol (MeOH). The metabolites in the growth medium (or filtrate) were extracted over ethyl acetate (EtOAc). The antifungal activities of each crude extract were tested over Alternaria sp., Colletotrichum sp., Curvularia sp., Fusarium sp. and Pestalotiopsis sp. The metabolites were further tested for their total phenolic, flavonoid and protein content prior to their antioxidant and anti-fungal potential evaluation. The MeOH extracts of sooty molds were enriched with proteins and specifically inhibited Curvularia sp. The total phenolic content and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) activity was largely recovered from the filtrate corresponding to the inhibition of Alternaria sp.; while the flavonoid and free radical reduction suggested a relative induction of growth of the Fusarium sp., Colletotrichum sp. and Pestalotiopsis sp. Hence, this study reveals the diversity of sooty molds in Thailand by a modern phylogenetic approach. Furthermore, the preliminary screening of the isolates reveals the potential of finding novel compounds and providing insights for the future research on secondary metabolites of bio-trophic fungi and their potential usage on sustainable agriculture.