Effects of persimmon tannin on survival and reproduction of Halyomorpha halys (Hemiptera: Pentatomidae)

Halyomorpha halys (Hemiptera: Pentatomidae) occurs in sweet persimmon orchards from late July to early September and its damage level is negligible before mid‐July. It rarely appears in persimmon orchards after mid‐September, but is easily found in soybean fields. From the phenological observation of H. halys, it is assumed that seasonal migration of H. halys to sweet persimmon orchards may be related to the content of soluble tannin in sweet persimmon fruits. The feeding preference of H. halys was evaluated on sweet and astringent persimmon fruits, and the effects of persimmon fruits and purified persimmon tannin were tested on the survival of H. halys. Numbers of visiting bugs and feeding spots on the fruits were significantly higher on sweet persimmon than those on astringent persimmon. There was no significant difference in survivorships of H. halys fed sweet persimmon and soybean. However, the number of eggs laid by sweet persimmon fed adult females was significantly lower than those fed soybean. The higher concentration of persimmon tannin caused higher mortality of H. halys. Male and female H. halys fed with 3% persimmon tannin showed the lowest survival. Longevities of male H. halys fed with 0, 0.01, 0.1 and 1% persimmon tannin were 14.9, 12.7, 14.5 and 16.3 days, respectively. However, males fed with 3% tannin lived only 6.4 days. The longevities of female H. halys were similar to those of male (10.1, 14.4, 13.8, 12.0 and 6.1 days for 0, 0.01, 0.1, 1 and 3% tannin concentration, respectively). These results suggest that H. halys invades sweet persimmon orchards during late July and early September when more suitable foods, e.g. soybean, are in short supply and sweet persimmon fruits become suitable for feeding (e.g. lower tannin content).     

The importance of avocado (Persea americana Mill.) fruits anthracnose and factors influencing the disease in Mana district,south-western Ethiopia

Anthracnose disease surveys were conducted in 25 farmers’ orchards, wholesaler and retailer shops in south-west Ethiopia. In addition, harvesting and postharvest practices, and storage conditions influencing disease development were studied with observation and questionnaire. The assessment results indicated significant variation among farmers’ orchards with the highest incidence (84.0 ± 16.7%) and severity index (26.0 ± 5.4%). Anthracnose damage of fruit was higher at retailers (76.7 ± 20.8%) than in the wholesalers shop (56.7 ± 32.5%). The total number of isolates identified was 249 and Colletotrichum gloeosporioides was the predominant pathogen proved by pathogenecity test. Among the major factors, harvesting avocado fruits with children (88%) and climbing on the tree (72%) resulted in fruit dropping that caused substantial injury and bruise. Generally, anthracnose caused by C. gloeosporioides of avocado fruit was prevalent in producer orchards that aggravated by traditional harvest and postharvest practices coupled to inadequate transportation and storage facilities at wholesaler and retailer shops with subsequent decay and loss of avocado fruits.     

First Report of Dragon Fruit (Hylocereus undatus) Anthracnose Caused by Colletotrichum truncatum in China

Anthracnose disease was detected from dragon fruit (Hylocereus undatus) at a market of Yuanjiang County, Yunnan Province, China. The results of pathogenicity test, morphology studies and sequence analyses based on ITS and β‐tubulin loci indicated that the disease was caused by Colletotrichum truncatum. The pathogen produced elliptic, yellow spots with chlorotic halos on the surface of the fruit, and the lesion become depressed gradually. Grey to black acervuli appeared on the lesion surface in concentric circles later. This is the first report of dragon fruit anthracnose caused by this pathogen in China.     

Fruits of apple and sweet persimmon are not essential food sources for Riptortus pedestris (Hemiptera: Alydidae) which causes fruit-spotting

Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) has recently become an important fruit-spotting bug of apple and sweet persimmon trees in Korea. Although fruits of cultivated species are unsuitable food for some fruit-spotting bugs, the dietary importance of fruits of apple and sweet persimmon for R. pedestris is unknown. We evaluated harvested fruits of apple and sweet persimmon with or without soybean seeds as a food source for R. pedestris by investigating nymphal development time, immature mortality, preovipositional period, fecundity, and adult size in the laboratory. No first instars of R. pedestris that were fed only apple or sweet persimmon fruits became third instar nymphs. When supplemented with soybean seeds, both fruits supported nymphal development and reproduction of R. pedestris. However, fruits combined with soybean seeds were not a better diet than soybean seeds only. Therefore, apples and sweet persimmons are not essential food sources for the development and the reproduction of R. pedestris. These results suggest that R. pedestris may not reproduce on fruit trees, thus explaining the absence of eggs and nymphs of this bug on fruit trees in orchards. Management of nearby vegetation of fruit orchards would be important for reducing damage by adult R. pedestris.     

Assessment of sorghum genetic resources of Ethiopia for anthracnose (Colletotrichum sublineolum Henn.) resistance and agronomic traits

Sorghum anthracnose caused by Colletotrichum sublineolum Henn. is one of the key diseases limiting sorghum production and productivity. Development of anthracnose‐resistant sorghum genotypes possessing yield‐promoting agronomic traits is an important breeding goal in sorghum improvement programs. The objective of this study was to determine the responses of diverse sorghum genetic resources for anthracnose resistance and agronomic traits to identify desirable lines for breeding. A total of 366 sorghum collections and three standard checks were field evaluated during the 2016 and 2017 cropping seasons. Lines were artificially inoculated with a virulent pure isolate of the pathogen. Anthracnose disease severity was assessed to calculate the area under disease progress curve (AUDPC). Agronomic traits such as panicle length (PL), panicle width (PW), head weight (HW) and thousand grain weight (TGW) were measured. Lines showed highly significant differences (p < .001) for anthracnose severity, AUDPC and agronomic traits. Among the collections 32 lines developed levels of disease severity between 15% and 30% in both seasons. The following sorghum landraces were selected: 71708, 210903, 74222, 73955, 74685, 74670, 74656, 74183, 234112, 69412, 226057, 214852, 71420, 71484, 200126, 71557, 75120, 71547, 220014, 228179, 16212, 16173, 16133, 69088, 238388, 16168 and 71570. These landraces had a relatively low anthracnose severity possessing farmer‐preferred agronomic traits. The selected genotypes are useful genetic resources to develop anthracnose‐resistant sorghum cultivars.     

Inheritance of anthracnose resistance (Colletotrichum scovillei) in ripe and unripe Capsicum annuum fruits

Anthracnose, caused by Colletotrichum spp., is one of the most common diseases affecting sweet pepper and chilli pepper production worldwide, especially in tropical and subtropical zones. This disease results in severe fruit damage both pre- and postharvest. The development of resistant cultivars is the most effective strategy for disease control, which requires knowing the genetic basis of resistance. In this study, we analysed the inheritance of resistance of Capsicum annuum to Colletotrichum scovillei at two fruit development stages. The ripe and unripe fruits were inoculated by conidia suspension, and anthracnose severity was evaluated for 8 days using a score scale. It was found that the inheritance of resistance has independent expression in ripe and unripe fruits. In both cases, two main genes are responsible for resistance with polygenic effects. Genetic control, with a quantitative aspect, is more affected by dominance than the additive effects, in both fruit development stages of C. annuum.     

Effect of hot water treatment on development of anthracnose (Colletotrichum gloeosporioides) and quality of mango fruit at Jimma southwest Ethiopia

Anthracnose is the major postharvest disease of mango and occurs throughout mango producing areas of the world including Ethiopia. Evaluating effect of hot water treatment on development of anthracnose and quality of mango fruit is imperative. A total of three hot water levels 48, 52 and 56 °C at two time interval (5 and 10 min) were tested with factorial arrangement in completely randomised design. The study indicated that hot water treatment at different temperatures and time interval significantly (p < 0.001) affects disease development and shelf life and postharvest quality of mango fruits. Hot water treatments reduced the incidence and severity of anthracnose disease significantly (p < 0.001) in mango fruits as compared to control. There was a highly significant difference (p < 0.0001) on weight loss, total soluble solids, titratable acidity and fruit firmness of mango fruits due to treatment. The present study reviled that hot water treatment has a potential in reducing the postharvest loss due to anthracnose and improving the shelf life and quality of mango fruits. However, the reduction of disease pressure on fruits was not at applicable level, which call ups future effort on developing on integrated disease management strategies for reduction of postharvest loss of mango fruits.     

Assessment of potential antagonists for anthracnose (Colletotrichum gloeosporioides) disease of mango (Mangifera indica L.) in North Western Ethiopia (Pawe)

Mango (Mangifera indica L.) is considered as one of the most popular fruits among millions of people in the tropical area and increasingly in the developed countries. Anthracnose, caused by the fungus Colletotrichum gloeosporioides, is the most important pre- and post-harvest disease of mango. The objective of this research was to evaluate the prevalence of different promising antagonistic Trichoderma and Bacillus spp. on phyloplane of mango in Ethiopia and to evaluate their antagonistic potential against the pathogen. A total of 19 mango fields were surveyed and anthracnose affected all fields. Culture studies on potato dextrose agar for evaluation of antibiosis activity of Trichoderma spp. and Bacillus spp. revealed that they have inhibitory and lytic effect on C. gloeosporioides, which is an indication of their potential biocontrol agent for management of mango anthracnose as an alternative to chemical control. Significant differences (p?<?0.05) were observed among Bacillus isolates in causing lysis of pathogen mycelium, when inoculated on actively growing colony of C. gloeosporioides. Maximum reduction in growth rate of pathogen was observed with Bacillus spp. (B50), which restricted the growth to 2.7?mm compared to 8.3?mm in the control with 67.5% efficacies. There were similar effects (p?<?0.05) among Trichoderma spp. in formation of inhibition zones and lysis by varying degrees up to 59.7% efficacies in reducing linear growth of the pathogen in dual culture.     

Efficacy of combined application of Trichoderma asperellum NG T158, Aloe vera leaf extract and poultry manure for the management of Colletotrichum lindemuthianum causing anthracnose disease on cowpea

Anthracnose disease is a major constraint for the production of cowpea, accounting for significant yield losses in Nigeria. Trials were conducted in 2016 and 2017 to evaluate an integrated approach in the management of anthracnose disease on cowpea. The experiment was conducted in a screenhouse with ten treatments and three replications in a completely randomised design using a susceptible cowpea variety IT07K-298-9. Ten varieties of cowpea were evaluated for seed-to-plant transmission of pathogen with respect to disease incidence, severity, and yield. The highest yield of 12–14 pods per plant was observed in treatment of Trichoderma asperellum and poultry manure combined. Seed treatments using T. asperellum and soil amendment with poultry manure had a significantly (P?=?0.05) lower disease incidence of 8.4–10.5%. This study showed the potential of combining naturally occurring organic products in the ecosystem that compete favourably with synthetic fungicides in the management of anthracnose disease of cowpea.     

Antagonistic Yeasts for Biocontrol of the Banana Postharvest Anthracnose Pathogen Colletotrichum musae

The biocontrol potentials of Candida tropicalis YZ1, C. tropicalis YZ27 and Saccharomyces cerevisiae YZ7 against the postharvest anthracnose pathogen Colletotrichum musae were investigated. Treatments with all the three biocontrol agents (1 × 10⁸ CFU/ml) significantly reduced the natural anthracnose disease severity of harvested banana fruits stored at ambient condition. Germination and survival of C. musae spores were markedly inhibited by all the three yeast strains in in vitro tests. The niche overlap index (NOI) was used to determine the interaction between the antagonists and C. musae, and the results (high NOI values) suggest competitive exclusion of C. musae by the yeast strains. C. tropicalis YZ27 inoculated on banana wounds exhibited rapid colonization and maintenance of its population on the inoculated site. The biocontrol efficacy was also observed as a function of concentration of the antagonist applied. The fruits treated with C. tropicalis YZ27, 36 h before pathogen inoculation, showed the best results with 96.0% disease inhibition followed by those treated 24 h before with 84.0% inhibition. The above results point to competition for nutrients and space as the main mechanism of antagonistic action of C. tropicalis YZ27 against C. musae.     

Concurrent application of ethyl formate and 1‐methylcyclopropene to control Tetranychus urticae on exported sweet persimmons (Diospyros kaki Thunb. ‘Fuyu’)

Extending the shelf life of fruits during post‐harvest storage and eradicating pests associated with quarantine issues could together comprise the key steps toward expanding the exportation of sweet persimmon in South Korea. Here we firstly investigated the concurrent application of ethyl formate (EF), a methyl bromide alternative fumigant, which is currently considered a beneficial and safe fumigant in quarantine use, and 1‐methylcyclopropene (1‐MCP), an anti‐ethylene compound that is broadly used in post‐harvest systems, on sweet persimmon. We also suggest the proper fumigation methods to be follow when using these compounds. Tetranychus urticae, an important quarantine pest, was inoculated under the calyx of sweet persimmon, and the fruits were then fumigated using 35.0 mg L^?1 of EF for 6 h before and after treating with 1.0 μL L^?1 of 1‐methylcyclopropene for 24 h under storage conditions of 5°C. Our results showed that concurrent treatments with 1‐MCP and EF could be suitable for commercial purposes by extending shelf life, delaying color changes and softening, and offering complete control of the target pest, Tetranychus urticae.     

Changes in pectinase and cellulase activity of Colletotrichum capsici mutants and their effect on Anthracnose disease on capsicum fruit

Abstract

Colletotrichum capsici was identified as a major pathogen that causes Anthracnose disease on capsicum (Capsicum frutescence L.), fruits accounting for 25?–?30% post-harvest loss during storage and marketing. The infection was found to be latent in nature. Towards understanding the latent nature of the pathogen, experiments were carried out to obtain non-pathogenic strain of C. capsici by UV radiation treatment. Exposure of three days old mycelial mat to UV light (312 nm wavelength at 12 in distance from the source) for 15, 30, 45, 60, 75 and 90 minutes was tried. The UV light exposure for 45 minutes was found to be optimum to get less virulent pathogenic strain of C. capsici. It showed a reduction in 42.86% cellulase and 40% pectinase activity. The reduction in activity of these enzymes resulted in 3.5 days delay in manifestation of Anthracnose disease and also reduces the rate of spreading of disease. The UV treatment was found to reduce 40% of the vegetative growth of fungi and 10% decrease in the production of number of conidia. However, no linear response was obtained with increase in dosage of UV treatments.     

Potassium phosphites in the protection of common bean plants against anthracnose and biochemical defence responses

The aim of this study was to investigate the effectiveness of potassium phosphites for the control of anthracnose and the mode of action of these products on common bean plants against Colletotrichum lindemuthianum, comparing it with the standard resistance inducer acibenzolar‐S‐methyl. The protection of plants against anthracnose was evaluated in greenhouse after treatment with potassium phosphites (Phosphite A and B, 5.0 ml/L), acibenzolar‐S‐methyl (0.25 g/L), or no treatment (control). Two sprayings of the treatments were performed, respectively, at V4 stage (three trifoliate leaves) and at the R5 stage (flower buds present). The inoculation with C. lindemuthianum was performed 5 days after the first spraying. Phosphite formulations A and B reduced the severity of anthracnose by 68.7% and 55.6%, respectively, and the presence of phosphites in the leaf tissues were detected at concentrations between 1 and 3 mm by 7 days after spraying. These same concentrations of phosphites reduced the mycelial growth of C. lindemuthianum in vitro by 15.0% to 25.7%. In addition, the activities of defence enzymes and the levels of phenolic compounds and lignin were assessed. Phosphite treatments enhanced the activity of various enzymes, including superoxide dismutase, peroxidase, chitinase, and β‐1,3‐glucanase, and increased the lignin and a small increase in the levels of soluble phenolics. This study provides evidence that phosphite treatments control anthracnose by acting directly on C. lindemuthianum and by inducing the production of defence responses.     

Significance of Microsclerotia in the Epidemiology of Black Pepper Anthracnose and an Approach for Disease Management in Nurseries

Anthracnose incited by Colletotrichum gloeosporioides (Penz.) Penz. and Sacc. is a wide spread and economically important disease of black pepper. In the present study, role of microsclerotia (MS) in the trans‐seasonal perpetuation of C. gloeosporioides was investigated. Microscopical examination of the runner shoots exhibiting necrotic lesions revealed the presence of dark, melanized structures which resembled MS. The excised necrotic regions when subjected to high humidity produced acervulus with setae. Under in vitro conditions, C. gloeosporioides produced MS predominantly on the aerial surface as inseparable congregations, enmeshed in the mycelial mats in potato dextrose broth and as individual units 7–8 days after incubation on glass slides. Sequential events in the formation of MS included germination of conidia, formation of conidial anastomosis tubes, aggregation of hyphae, and the formation of melanized microsclerotial bodies. Three types of microsclerotial germination were observed under in vitro conditions viz., sporogenic, myceliogenic and both. PCR confirmation with CgInt species‐specific primer and ITS4 resulted in 450‐bp amplification. Since, runner shoots are predominantly used as propagating material in black pepper, an approach was devised to manage anthracnose under nursery conditions by treating the 2‐ to 3‐node cuttings (nursery planting material) with carbendazim (12%)—mancozeb (63%) @ 0.1% for 30 min. The results of the study suggests a new facet in the disease cycle of black pepper anthracnose, indicating that the pathogen survives as microsclerotia in planta and could act as a potential source of inoculum.     

Penetration by Botryosphaeriaceae species in avocado,guava and persimmon fruit during postharvest

Botryosphaeriaceae species have a wide host range and a worldwide distribution. These fungal species can colonize several plant organs, such as the trunk, leaves and fruit. Some Botryosphaeriaceae species cause important diseases on persimmon, avocado and guava fruit. However, there is a lack of information regarding the mechanisms of penetration by Botryosphaeriaceae species on these tropical and subtropical fruits. This study aimed to better understand the mechanisms involved in fungal penetration, host specificity and aggressiveness of Botryosphaeria dothidea, Lasiodiplodia pseudotheobromae and Neofusicoccum parvum on avocado (Persea americana), guava (Psidium guajava) and persimmon (Diospyros kaki) fruit. Scanning electron microscopy (SEM) image analysis showed that in avocado fruit, the three studied Botryosphaeriaceae species penetrated through lenticels. In guava fruit, penetration through stomata was verified for Botryosphaeria dothidea and Neofusicoccum parvum. In persimmon fruit, an appressoria-like structure was observed for B. dothidea, which suggests direct penetration. Disease incidence in wounded fruit was 24% higher than in non-wounded fruit. L. pseudotheobromae and N. parvum showed differences in aggressiveness in guava fruit. The longest incubation period was observed for N. parvum inoculated on guava, with an average of 4.5 days, and the shortest incubation period was verified for B. dothidea inoculated on avocado, with an average of 2.8 days. The area under the disease progress curve (AUDPC) did not differ between Botryosphaeriaceae species on avocado, whereas on guava and persimmon fruit, the AUDPC was lower for B. dothidea. The information regarding penetration mechanisms and aggressiveness is important to improve postharvest disease control strategies.     

豆类炭疽病病原物种类及其发生研究进展

炭疽病是重要的世界性植物病害,造成大豆、绿豆等品质变劣,产量损失严重。本文综述了国内外大豆炭疽病的发生情况、炭疽菌种类及其特征,为了解该病的流行病学和科学防治提供理论依据。     

A model for estimating infection levels of anthracnose disease of mango

Anthracnose disease of mango caused by Colletotrichum gloeosporioides var. minor, spreads by water-borne conidia from vegetative parts of the tree to attack inflorescences and prevent fruit set. An analysis of data from laboratory studies demonstrated that infection by conidia during wet periods was related both to the temperature and to the duration of the wet period. A model was used to estimate infection levels of anthracnose disease in two mango orchards over three seasons. The number of infection periods recorded and the estimated percentage of conidia forming appressoria in these periods matched disease development during flush growth and flowering. In 1980, only two infection periods were detected during flowering in one of these orchards and blossom blight did not prevent fruit set. In 1981 and 1982 however, higher estimated levels of infection were recorded more frequently during the same time and severe blossom blight developed. A second orchard, situated in an area less favourable to disease, was also monitored during 1982. Nine infection periods were recorded during flowering in this orchard compared to 14 in the first. A moderate level of blossom blight developed in this orchard.     

Effect of Cuticular Wax Layers of Green and Red Pepper Fruits on Infection by Colletotrichum gloeosporioides

Colletotrichum gloeosporioides isolate KG13 caused necrotic, sunken anthracnose symptoms on unwounded, wax-removed, and wounded green pepper fruits and on wounded red fruits 7 days after inoculation. Hypersensitive reactions with small brownish discolorations, on some occasions, were found on unwounded red fruits. The isolate produced whitish symptoms with brown margins, but not the typical anthracnose on red fruits wax-removed by chloroform treatment. Generally, wax-removed red fruits, but not green ones, produced larger lesions and more conidia than untreated controls. Wounded pepper fruits had larger lesions than those with other treatments. More germinated conidia, appressoria, and infection hyphae were found on wax-removed fruits than on controls; however, differences between green and red fruits were not found. Cuticular wax layers of fruits were dissolved partially by chloroform and the outer epidermal cells were disrupted slightly. Anthracnose development was negatively related with fruit developmental stage. Well-developed fruits had more cuticular wax than less developed fruits. These results suggest that the cuticular wax layers of pepper fruits may play a significant role in fruit infection by C. gloeosporioides isolate KG13, and mainly determine the incompatibility of red fruits to the isolate. Biochemical differences may also play a role.     

Molecular and phenotypic analyses reveal association of diverse Colletotrichum acutatum groups and a low level of C. gloeosporioides with olive anthracnose

Anthracnose (Colletotrichum spp.) is an important disease causing major yield losses and poor oil quality in olives. The objectives were to determine the diversity and distribution pattern of Colletotrichum spp. populations prevalent in olives and their relatedness to anthracnose pathogens in other hosts, assess their pathogenic variability and host preference, and develop diagnostic tools. A total of 128 Colletotrichum spp. isolates representing all olive-growing areas in Portugal and a few isolates from other countries were characterized by molecular and phenotypic assays and compared with reference isolates. Arbitrarily primed PCR data, internal transcribed spacer of rRNA gene and beta-tubulin 2 nucleotide sequences, colony characteristics, and benomyl sensitivity showed Colletotrichum acutatum to be dominant (>97%) with limited occurrence of Colletotrichum gloeosporioides (<3%). Among C. acutatum populations, five molecular groups, A2 to A6, were identified. A2 was widely prevalent (89%), coinciding with a high incidence of anthracnose and environmental conditions suitable to disease spread. A4 was dominant in a particular region, while other C. acutatum groups and C. gloeosporioides were sporadic in their occurrence, mostly related to marginal areas of olive cultivation. C. gloeosporioides, isolated from olive fruits with symptoms indistinguishable from those of C. acutatum, showed same virulence rating as the most virulent C. acutatum isolate from group A2. C. acutatum and C. gloeosporioides isolates tested in infected strawberry fruits and strawberry and lupin plants revealed their cross-infection potential. Diagnostic tools were developed from beta-tubulin 2 sequences to enable rapid and reliable pathogen detection and differentiation of C. acutatum groups.     

Induction of Peroxidase during Infection of Unripe Persimmon Fruit by Alternaria alternata: a Possible Quiescence Mechanism

Limited black spot symptoms (Quiescent infections) develop on persimmon fruits as Alternaria alternata hyphae penetrate the pericarp of green‐immature fruit. Inoculation of persimmon with A. alternata or treatment with a commercial preparation of purified cellulase induced similar black symptoms and higher peroxidase activity in green‐immature fruits but not in orange‐mature persimmon fruits. Both treatments induced the development of new peroxidase isoforms only in immature fruits – however, no effect was observed on polyphenoloxidase activity. A. alternata was transformed with a construct expressing green fluorescent protein (GFP). Histological analysis of hyphal development using GFP‐transformed fungi indicated that symptoms are always found ahead of the leading edge of the hyphae. We suggest that peroxidase increase, induced by the directly penetrating A. alternata, might be involved in the induction of quiescence infection by the pathogen in immature fruits.