Rot Fungi Research Articles

Incidence, Distribution, and Pathogenicity of Fungi Causing Root Rot in Idaho Long-Term Sugar Beet Storage Piles.

Fungal rots in sugar beet roots held in long-term storage can lead to considerable sucrose loss but the incidence and distribution of fungal rots inside sugar beet piles and pathogenicity for some species is poorly understood. Thus, Idaho sugar beet held in five outdoor and two indoor piles in 2014 and 2015 were investigated. The root surface area covered by fungal growth and discolored and healthy tissue were assessed in nine 1-m2 areas per pile using a stratified random sampling design. Pathogenicity was evaluated indoors via plug inoculation in 2015 and 2016. Botrytis cinerea covered more root surface area inside indoor piles (6 to 22%) than outdoor piles (0 to 3%) (P < 0.0001). No trends were evident for the Athelia-like sp. (0 to 15%) and Penicillium-type spp. (0 to 8%). Penicillium-type isolates comprised the following species: 60% Penicillium expansum, 34% P. cellarum, 3% P. polonicum, and 3% Talaromyces rugulosus. Trace levels (<1% of root surface) of other fungi, including Cladosporium and Fusarium spp., were evident on roots and in isolations. Based on sample location in a pile, there were no trends or differences; however, two outdoor piles (OVP1 and OVP2) had more healthy tissue (90 to 96%) than other piles (28 to 80%) (P < 0.0001). When the pathogenicity tests were analyzed by species, all were significantly different from each other (P < 0.0001), except for P. polonicum and P. expansum: B. cinerea (61 mm of rot), P. polonicum (36 mm), P. expansum (35 mm), P. cellarum (28 mm), Athelia-like sp. (21 mm), T. rugulosus (0 mm; not different from check), and noninoculated check (0 mm). The OVP1 and OVP2 piles had negligible fungal growth on roots after more than 120 days of storage under ambient conditions, which indicates that acceptable storage can be achieved over this time period through covering piles with tarps and cooling with ventilation pipe.

To prune or not to prune; pruning induced decay in tropical sandalwood

Heartwood rot (a fungal disease) has the potential to significantly reduce the sandalwood oil production of Santalum album. With new plantations being established with sandalwood oil as the major product, it is imperative to know the consequences of routine form-pruning in tropical areas. Examining pruning wound responses in 1 and 5-year-old trees at the end of the dry and wet seasons, it was possible to ascertain the best pruning age and season in relation to occlusion. Pathogenic wood fungi were isolated from wounds and fungal spore monitoring was undertaken at the two trial sites at time of pruning. Younger trees had smaller wounds which were quicker to occlude and produced a lower decay rating which decreased over time. Wood inhabiting fungi were isolated from all pruning wounds and identified using the ITS gene region. There was a total of 531 fungal isolates, identified in 75 fungal taxa. Older trees had significantly more fungal species compared to younger trees. Pruning season did not significantly affect occlusion, the amount of resultant decay, nor the total number of fungal species isolated. Endophytes were isolated from every tree, comprising 52% of isolations. Younger trees had more endophytes, but less rot fungi than older trees. Canker fungi were isolated from almost all the older trees. In the older trees, rot fungi were predominant in trees pruned at end of the dry season. Metabarcoding of spores collected in spore traps resulted in 565 operational taxonomic units (OTU’s) which were placed in 211 genera and 114 families, with about 55% classified as unknown fungi. About 23% of all reads corresponded to potential pathogens, however, the proportion of spore groups present at time of pruning at each plantation was not indicative of the fungal niches isolated from wounds. This study has shown that it is better to prune S. album when they are young to decrease the amount of potential decay. To reduce the risk of heartwood rot fungal diseases entering via the pruning wound, it would be preferable to prune at the beginning of the dry season. This will be applicable to other tropical tree species.

Fungal Rot of Yam (Dioscorea alata Lin.) Sold At Nsukka Markets in Nigeria

Fungal Rot of Yam (Dioscorea alata Lin.) Sold At Nsukka Markets in Nigeria

Pre-harvest root application of soluble silicon improves postharvest quality and induces antifungal compounds in bitter gourd (Momordica charantia L.)

Beneficial effects of Silicon (Si) on disease control have been shown in a number of plant pathosystems. The present study ascertained the effect of root application of soluble Si on postharvest quality of bitter gourd (Momordica charantia L.) with special reference to the disease development by Fusarium oxysporum. Plants were treated with Potassium silicate (Si+) by amending the soil mix (200 mgSi /kg soil). Treatments were started at the four leaf stage and continued up to 28 days at seven days intervals. Soil amendments with Si significantly reduced the postharvest weight loss and extended the shelf life by 2 days through delayed ripening and reduced fungal rot development. Si analysis in bitter gourds, harvested from Si + plants revealed that fruit tissues accumulated nearly1.5 times as much silicon (0.54% dry weight) as those grown in control (Si-) mix (0.36% dry weight). Extracts from Si + plants exhibited a stronger antifungal activity on thin layer chromatography (TLC) against Cladosporium cladosporioides. Methanolic extracts of fruit pericarp separated on TLC plates showed four antifungal zones at Rf 0.17, 0.51, 0.64 and 0.93. Compound separated at Rf 0.64 was observed in samples from Si + and/or challenged with F.oxysporum. Antifungal zone at Rf 0.51 was present only when Si + fruits were challenged with the fungus. These results suggest that by using soil application of soluble Si, postharvest quality of bitter gourd can be improved and shelf life can be enhanced by 2 days compared to the control. Enhanced fungitoxic activity may have some role in Si-induced disease resistance againstpostharvest fungal pathogens.

Effect of high temperature treatment of Hevea brasiliensis on density, strength properties and resistance to fungal decay

Plantation grown Hevea brasiliensis (rubberwood)—a tropical wood species of low natural durability was thermally processed at four temperatures in the range of 150–240 °C for different durations under vacuum. Effect of heat treatments on various important physical and mechanical properties such as weight loss, density, flexural strength (modulus of rupture—MOR), stiffness (modulus of elasticity—MOE), compressive strengths and surface hardness as well as decay resistance were evaluated and compared with untreated wood. The weight loss due to heat treatments was found to be in the range of 1.0–14.6%. Density and flexural MOR were found to decrease with increasing temperature (up to 210 °C), while flexural MOE, compressive strengths and hardness were not much affected. Higher treatment temperatures (210–240 °C) were observed to have deleterious effect on the mechanical strength of wood. Heat treated rubberwood showed excellent durability against brown rot (Polyporus meliae) and white rot (Coriolus versicolor) fungi as evidenced by lower amount of weight loss of exposed samples. The decay resistance was found to increase with severity of treatments. Based on improved durability and moderate variations in mechanical properties due to relatively mild heat treatments (180–210 °C), thermally modified rubberwood is found to be suitable for certain nonstructural applications. Moreover, heat-treated rubberwood may also be considered as an ecological alternative to chemically impregnated wood which offers many potential and attractive opportunities to the timber processing and product industry for commercial market.

Efecto del subproducto industrial CaCO3 en los atributos de calidad, contenido fenólico y capacidad antioxidante de manzana cvs Golden Delicious y Top Red

Introducción: El calcio, es un nutriente importante para aumentar la calidad y rendimiento en los cultivos hortofrutícolas, ya que es considerado como el mineral más importante para la calidad de las manzanas, algunas investigaciones han demostrado su incidencia en la reducción de ciertas alteraciones fisiológicas (bitter pit, corazón acuoso y la descomposición interna), conseración de la firmeza de la pulpa y prevenir la incidencia de podredumbres fúngicas. El objetivo del presente estudio fue evaluar el efecto del subproducto industrial carbonato de calcio (CaCO3) en los atributos de calidad, contenido fenólico y capacidad antioxidante de manzanas cvs Golden Delicious y Top Red.Método: Se utilizaron árboles de 21 años de edad cultivados en la región de Cuauhtémoc, Chihuahua. México, los tratamientos fueron Kg ha-1 de CaCO3 (y su equivalente en Ca por ha): Testigo sin aplicación T1, 282.70 (100) T2;565.30 (200) T3; 847.90 (300) T4; 1130.60 (400) T5;1413.20 (500) T6; 1695.90 (600) T7; 1978.50 (700) T8; 2261.20 (800) T9;2543.80 (900) T10; 2826.50 (1000) T11; 3957.00 (1400) T12 respectivamente. Las variables evaluadas fueron: contenido de Ca, rendimiento, diámetro, peso, color, firmeza, sólidos solubles, acidez titulable, relación SST/acidez titulable, fenoles totales y capacidad antioxidante por el metódo de DPPH. Resultados: Los resultados mostraron diferencias estadísticas (p ≤ 0.05) entre cultivares, los tratamientos incrementaron el contenido de Ca, la firmeza fue significativamente más alta, el cultivar Top Red presentó los valores más altos de compuestos fenólicos con 3.587 mg g-1 de ácido gálico, mientras que el cultivar Golden Delicious presentó la mayor capacidad antioxidante con 2.27 mg g-1 de Trolox. Discusión o Conclusión: Se concluye que la aplicación de CaCO3 influyó en los parámetros de calidad, contenido de compuestos fenólicos y capacidad antioxidante en las cultivares Top Red y Golden Delicious.

Effects of environmental parameters on the chestnut gall wasp and its complex of indigenous parasitoids.

The chestnut gall wasp (CGW), Dryocosmus kuriphilus, an invasive pest native to China, has caused severe yield and economic losses to chestnut production in Europe since its arrival in 2002. In Southern Italy, the complex of indigenous parasitoids colonizing CGW was monitored between 2013 and 2015, with the aim of estimating the composition of the indigenous parasitoid complex, its ability to control CGW populations, and the interactions of both factors with several measured environmental parameters. We compared results among three differently managed field types. Results showed an increase in the rate of parasitism both when the host population density was lower and in unmanaged chestnut stands with more natural conditions. The percentage of parasitism in galls was related to morphological traits of the galls and to higher seasonal temperatures, which reduced the parasitism intensity because CGW develops earlier under such conditions. The host-parasitoid mortality inside galls varied among sites and was associated mostly with rot fungi during wet spring and summer months. Parasitoid species richness was similar among the study sites, but the proportion of parasitoid species differed between orchards and unmanaged coppice stands. The timing of attack by parasitoids followed a species-specific successional sequence throughout the larva-to-adult life cycle of the CGW. These interactions should be considered in future research on trophic relationships and when modeling invasive scenarios for new pest species.

Chemical composition of neem and lavender essential oils and their antifungal activity against pathogenic fungi causing ginseng root rot

The aim of this study was to assess in vitro, the antifungal activity and characterize the chemical constituents of the essential oils of Azadirachta indica (neem) and Lavandula angustifolia (lavender). The essential oils of A. indica and L. angustifolia plants were tested against several isolates of pathogenic fungal genera causing root rot disease of ginseng. Agar plate assay indicated that lavender oil at 10% exhibited the highest inhibition index of (86.0±0.7%) against Sclerotinia nivalis mycelial growth. Neem and lavender oils at 5% v/v showed inhibition index against Alternaria panax (72.9±2.1 and 45.0±1%, respectively). Lavender oil at 5% (v/v) inhibited growth of S. nivalis (83.1±0.2%) and Cylindrocarpon destructans (49.2±1%). The gas chromatography-mass spectrometry (GC-MS) analysis showed that the major constituents of neem oil were fatty acids (94.8%). However, sesquiterpenes were the dominant constituents of the lavender oil (57.6%). The antifungal indices demonstrated in this study are a clear evidence of the potentiality of neem and lavender essential oils to control plant diseases caused by phytopathogenic fungi. Key words: Ginseng root rot, fungi, essential oils.

Interactions among Cultivation, Weeds, and a Biofungicide in Organic Vidalia® Sweet Onion

Weed management in the organic Vidalia® sweet onion production system is largely dependent on multiple cultivations with a tine weeder. Earlier research suggested cultivation with a tine weeder did not predispose onion bulbs to infection during storage. Trials were conducted from 2012 through 2014 near Lyons, GA, to determine the interactive effects of cultivation, weed removal, and a biofungicide on weed densities, onion yield, grade, and diseases of stored onion. Cultivation twice or four times at biweekly intervals with a tine weeder reduced densities of cutleaf evening-primrose, lesser swinecress, and henbit compared with the noncultivated control, although weeds surviving cultivation were very large and mature at harvest. Cultivation generally improved onion yields over the noncultivated control, except in 2014, when baseline weed densities were high and weeds surviving cultivation were numerous. Weeds removed by hand weeding improved onion yields, but that effect was independent of cultivation. Four applications of a biofungicide derived from giant knotweed had no effect on onion yield. Cultivation had no effect on incidence of the fungal disease botrytis neck rot, with inconsistent effects on the bacterial diseases center rot and sour skin. Weed removal with hand weeding did not affect diseases of stored onion. The biofungicide had no effect on diseases of stored onion. These results demonstrate the limitations of cultivation when cool-season weed infestations are dense. With no interactions among main effects, weed control and onion yield response to cultivation and hand weeding are independent. Cultivation for weed control is much less costly than hand weeding. With no interaction between the cultivation and weed removal main effects, it is not necessary to supplement tine weeder cultivation with costly hand weeding.

Gross and histopathological study on common carp Cyprinus carpio L. diseases in rearing culturing ponds in Kirkuk Province – Iraq

The present study aimed to investigate the infection ratio and pathological lesions in common carp fish in Kirkuk province. To achieve these goals, a survey study was conducted from 01/12/2015 to 01/04/2016. Results of the survey study showed that the infection ratio of acidity and alkalinity of pond’s water 27.88% (46/165), bacterial kidney infection 20% (33/165), water mold (saprolegniasis) 12.12% (20/165), spring viremia of common carp 11.52% (19/165), Coccidiosis 11.52% (19/165), fungal gill rot infection 7.27% (12/165), hemorrhagic septicemia 6.67% (11/165) and enteric parasite infection 3.03% (3/165). Pathological study showed that lesions in acidic and alkaline of pond’s water consisted from necrosis with sloughing of scales and intestinal mucinous degeneration as well as necrosis of intestinal villi. In bacterial kidney infection lesion consist of diphtheric membrane cover abdominal cavity and presence of microorganisms in renal cortex and medulla. In Saprolegnia sp. infection the pathognomic lesions were recorded which consist from fungal hyphae extended from fish body into water. In spring viremia of common carp lesions consist from exophthalmia and pinpoint hemorrhage on fish body with presence of pseudodiphtheric membrane associated with hemorrhagic exudate as well as extensive necrosis of intestinal villi. In Eimeria sp. infection lesions composed from presence of infective stages of coccidian parasites in enterocytes. In fungal gill rot infection the mosaic appearance lesion was observed consisted from necrotic area (white color) and health area (red color). In hemorrhagic septicemia infection lesions consist from ulcers surrounded by areas of hyperemia with extensive necrosis of intestinal lining. In enteric parasites infection we noted presence of large numbers of worms in intestinal lumen, also there is nodule in intestinal mucosa contain nematods of 2 cm in length, in other cases there is presence of worms inserted in intestinal mucosa of 30 cm length covered with fibrous membrane. It concluded from this study that the infection ratio with different diseases in common carp varied in compared with other countries and depends upon changes in climate and breeding habits as well as the gross and microscopic lesions are identical to that recorded worldwide.

Integrated control of fungal rots of cherry in the UK

Integrated control of fungal rots of cherry in the UK

Control of Postharvest Fungal Rots on Grapes Using Essential Oil of Foeniculum vulgare Mill.

Fungal rots, caused by Botrytis cinerea and Colletotrichum acutatum, are the main causes of postharvest decay of table grapes in Brazil. The aim of this study was to assess the chemical composition and the fungicidal effect of Foeniculum vulgare essential oil in vitro, on mycelial growth (contact and volatile phase) and conidia germination, and in vivo on postharvest grapes against both fungi. The major compounds found in F. vulgare essential oil were trans-anethole (79.14%), fenchone (11.94%) and estragole (5.76%). The mycelial growth (contact phase) and conidia germination of B. cinerea were inhibited completely at concentrations of 50 and 100 ppm (µL mL-1), respectively. For C. acutatum, mycelial growth (contact phase) and conidia germination were inhibited completely at concentrations of 100 and 200 ppm, respectively. The volatile phase had a fungistatic effect on mycelial growth of both fungi at different concentrations tested, and the pure essential oil (100%) presented fungicidal effect against B. cinerea. In vivo tests were carried out using grapes of Vitis spp. cv. “Isabella” and the concentrations of essential oil tested were efficient, reducing the incidence of disease caused by B. cinerea and C. acutatum at postharvest, both in preventive and curative treatment. The concentration 200 ppm completely inhibited the incidence of both fungi. In conclusion, F. vulgare essential oil presented fungicidal action against postharvest fungal rots on grapes.

First Report ofTruncatella angustataCausing Postharvest Rot on ‘Topaz’ Apples in the Netherlands

In the Netherlands, about 30% of the organic apple (Malus domestica Borkh.) production consists of apple scab resistant cultivars, such as Topaz and Santana. However, organic ‘Topaz’ apples show a high incidence of fungal rot after storage. Hot-water treatment (HWT) of freshly harvested apple fruit prior to long-term storage is an important strategy for the control of postharvest diseases, especially in the organic production sector (Maxin et al. 2012). The recommended treatment temperatures and times vary according to the cultivar because of the risk of heat damage to the fruit peel. In January 2016, light peel damage caused by HWT was observed on ‘Topaz’ apples from an organic orchard. Also, up to 15% of the ‘Topaz’ apples showed typical rot lesions of an unknown causal agent. The lesions showed brown, irregular necrosis and were slightly sunken. To isolate the causal agent, fruits were rinsed with sterile water, lesions were sprayed with 70% ethanol until droplet runoff, the skin was removed aseptically with a scalpel, and tissue under the lesion was placed onto potato dextrose agar (PDA). The PDA plates were incubated at 20°C in the dark, and single spore isolates were transferred to fresh PDA plates. The colonies that appeared on PDA were cottony to woolly, dull white to brown in color, with black acervuli mainly in the center of the PDA plates. The isolates produced four-celled conidia, 16 to 19 × 7 to 9 µm, straight to slightly curved, with two brown to dark-brown median cells that had thick walls. More than one hyaline apical appendage, variable in size and branched dichotomically, were observed and a basal appendage was absent. The fungus was morphologically identical to Truncatella angustata (Pers.) S. Hughes (Sutton 1980). The identity of two representative isolates (PPO-45246 and PPO-45321) was confirmed by means of gene sequencing. To this end, DNA was extracted using the LGC Mag Plant Kit (Berlin, Germany) in combination with the Kingfisher method (Waltham, MA). Sequences of the ITS region were amplified using primers ITS1/ITS4, sequenced, and deposited in GenBank under accession numbers KX085227 and KX085228. MegaBLAST analysis revealed that both of our ITS sequences matched 99% with T. angustata isolates in GenBank (EU342216, JX390614, and KF646105). Koch’s postulates were fulfilled using 10 ‘Topaz’ apples. Surface sterilized fruits were inoculated with 20 μl of 10 5 conidiospores ml –1 in water, prepared from a 15-day-old PDA culture of the isolate PPO-45246, after wounding with a needle. Inoculated fruits were sealed in a plastic bag and incubated in darkness at 20°C. Symptoms appeared after 7 days on 100% of the fruits while mock-inoculated controls with water remained symptomless. Fungal colonies isolated from the lesions and cultured on PDA morphologically resembled the inoculated isolates. The identity of the reisolations was confirmed as T. angustata by sequencing. T. angustata has a worldwide distribution and has also been reported to cause leaf spot on Rosa canina (Eken et al. 2009), canker and twig dieback on blueberry (Vaccinium spp.) (Espinoza et al. 2008), and fruit rot of olive (Olea europaea) (Arzanlou et al. 2012). To the best of our knowledge, this is the first report of T. angustata causing fruit rot of apples. Importantly, we note that the occurrence of this fruit rot may be enhanced by wounding, in this case as a result of hot water treatment.

Phytophthora root rot of potato and its management in Kashmir Valley

Potato is an important crop and is grown allover the world. It is a promising food to millions of people especially in developing countries after rice, wheat and corn. Potato tubers are attacked by fungal diseases such as dry rots mostly in storage and soft rots at every stage and cause substantial loss. The present study was therefore carried out to study the incidence of fungal rot of potato in storage. It was revealed from the study that potato tubers in storage are attacked by Phytophthora infestans (Mont.) de Bary causing Phytophthora root rot. A study was also carried out for the management of fungal rot of potato with some systemic and non-systemic fungicides. Amongst all the fungicides used carbendazim proved highly effective in reducing the colony diameter and rot severity of Phytophthora infestans followed by hexaconozole, bitertanol, myclobutanil, mancozeb, captan and zineb respectively. Higher concentrations of the fungicide proved effective than lower concentrations.

Ecology and epidemiology of the emerging plant pathogen Gnomoniopsis castaneae

Gnomoniopsis castaneae is an emerging fungal pathogen causing nut rot on Castanea sativa , or living as an endophyte in the green tissues of the tree. The disease has been reported since the mid-2000s in European countries such as Italy, France and Switzerland. To date, the ecology and the epidemiology of G. castaneae have been mostly unexplored. The main goals of this work were: I) testing the association between the climate and the incidence of G. castaneae ; II) assess- ing the influence of the plantation density on the spatial pattern of the nut rot infection through the development of a new geostatistical test; III) investigating some possible ecological interactions between G. castaneae and the exotic pest Dryocosmus kuriphilus (Asian chestnut gall wasp); and IV) comparing a large set of Castanea spp. cultivars and the wild- type of C. sativa to assess their levels of susceptibility to G. castaneae. A combined approach involving isolations, molecular analyses and the application of non-conventional statistical tech- niques was used. The methods were adapted depending on the specific aims of each experiment. In 2011, based on the inspection of 12 sites, the incidence of G. castaneae in north-western Italy was comprised between 20% and 93%. Climatic analyses showed that warmer temperatures were associated with higher levels of G. castaneae incidence, while no significant effect of the rainfall was detected. A series of models ( Gno Mods) was fitted, resulting in equations predicting the incidence of the disease at site level as a function of the temperatures of the months before har- vesting. The Gno Mods were significant (P 0.72; P 0.05) indicated that the spatial distribution of the trees carrying nuts infected by the pathogen was randomized (P > 0.05), regardless of the plantation density. The incidence of trees infected was not significantly different among ar- eas (52.9%-71.4%; P > 0.05). The results suggest that the plantation density was not related to the spatial distribution of G. castaneae . To perform these analyses, new geostatistical tests (Mean Distance Tests - MDT) were developed, validated and embedded in a user-friendly software. MDT displayed reliable outcomes (power > 80%; type I error < 0.05) and can be applied to test the spatial pattern of any plant disease when the variable of phytopathological interest is categorical. DNA analyses showed that 40% of the adults of D. kuriphilus emerging from galls colonized by G. castaneae carried inoculum of the pathogen, yet the inoculum was not viable, since no fungal colonies could be isolated. Consequently, the pest is an unlikely vector of G. castaneae . On average, the emerging adults were significantly more abundant in galls colonized than in galls not colonized by the fungus (3.76 vs. 2.54, P < 0.05), indicating a possible fungus/pest synergy. The combined results of the Monte Carlo simulations, validated by isolation trials on chestnut buds inspected for D. kuriphilus eggs, showed that G. castaneae colonized 33.8% of the buds before oviposition, and that fungal colonization and oviposition were not associated (odds ratio 0.98, 0.71-1.33 95% CI). Consequently, the higher number of insects in galls colonized by G. castaneae might have been the effect of an interaction occurring after oviposition, probably during the insect development. The incidence of G. castaneae was compared between 85 chestnut cultivars and the wild-type of C. sativa growing in homogeneous environmental conditions. The statistical analyses showed that only cultivars significantly more susceptible (P < 0.05) than the wild-type (22% of the total number of cultivars in 2013 and 55% in 2014) could be identified. G. cas- taneae was isolated not only from C. sativa nuts, but also from nuts of Asian chestnut species and hybrids. The validation analysis revealed no significant association between the most susceptible cultivars detected in 2013 and 2014 (odds ratio 2.85; 0.18-176.61 95% CI). The results suggest that the levels of susceptibility of the chestnut cultivars and the wild-type were substantially homogeneous. In conclusion, the temperatures are strongly associated with the incidence of G. castaneae , while the plantation density of the orchards, the interaction with D. kuriphilus and the chestnut cultivars seem to play a negligible, or minor, role in the epidemiology of this plant pathogen.

Resistance of thermally modified ash (Fraxinus excelsior L.) wood under steam pressure against rot fungi, soil-inhabiting micro-organisms and termites

Thermal modification processes have been developed to increase the biological durability and dimensional stability of wood. The aim of this paper was to study the influence of ThermoWood® treatment intensity on improvement of wood decay resistance against soil-inhabiting micro-organisms, brown/white rots and termite exposures. All of the tests were carried out in the laboratory with two different complementary research materials. The main research material consisted of ash (Fraxinus excelsior L.) wood thermally modified at temperatures of 170, 200, 215 and 228 °C. The reference materials were untreated ash and beech wood for decay resistance tests, untreated ash wood for soil bed tests and untreated ash, beech and pine wood for termite resistance tests. An agar block test was used to determine the resistance to two brown-rot and two white-rot fungi according to CEN/TS 15083-1 directives. Durability against soil-inhabiting micro-organisms was determined following the CEN/TS 15083-2 directives, by measuring the weight loss, modulus of elasticity (MOE) and modulus of rupture (MOR) after incubation periods of 24, 32 and 90 weeks. Finally, Reticulitermes santonensis species was used for determining the termite attack resistance by non-choice screening tests, with a size sample adjustment according to EN 117 standard directives on control samples and on samples which have previously been exposed to soil bed test. Thermal modification increased the biological durability of all samples. However, high thermal modification temperature above 215 °C, represented by a wood mass loss (ML%) due to thermal degradation of 20%, was needed to reach resistance against decay comparable with the durability classes of ‘‘durable’’ or ‘‘very durable’’ in the soil bed test. The brown-rot and white-rot tests gave slightly better durability classes than the soil bed test. Whatever the heat treatment conditions are, thermally modified ash wood was not efficient against termite attack neither before nor after soft rot degradation.

Effectiveness of Neutral Electrolyzed Water on Incidence of Fungal Rot on Tomato Fruits (Solanum lycopersicum L.)

We assessed the effect of neutral electrolyzed water (NEW) on the incidence of rot on tomato ( Solanum lycopersicum L.) fruits inoculated with Fusarium oxysporum , Galactomyces geotrichum , and Alternaria sp. at sites with lesions. The inoculated fruits were treated with NEW at 10, 30, and 60 mg liter-1 active chlorine, with copper oxychloride fungicide, and with sterile distilled water (control) for 3, 5, and 10 min. In the experiment with F. oxysporum , 50 to 80% of the control fruits and 50 to 60% of the fruits treated with the fungicide exhibited symptoms of rot at the inoculated sites. The lowest incidence recorded was 30% for fruits treated with NEW at 60 mg liter-1 active chlorine with an immersion time of 5 min. In the experiment with G. geotrichum , incidence of rot on control fruits was 70 to 90%, and for treatment with fungicide rot incidence was 50 to 90%. NEW at 60 mg liter-1 active chlorine significantly reduced incidence of symptomatic fruit: only 30% of the inoculated fruits washed for 5 min had damage from rot. In the experiment with Alternaria sp., 60 to 90% of the fruits in the control group and 60 to 70% of the fruits in the fungicide group were symptomatic. The lowest incidence was recorded for the treatment in which the fruits were submerged in NEW with 60 mg liter-1 active chlorine for 3 min. In this group, 40 to 50% of the fruits exhibited symptoms of rot. These results were obtained 8 days after inoculation. NEW, with 60 mg liter-1 active chlorine, significantly reduced incidence of rot symptoms on fruits inoculated with one of the experimental fungi relative to the control (P ≤ 0.05). NEW at 60 mg liter-1 is effective in the control of fungal rot in tomatoes.

Evaluation of isolates of Trichoderma, Pseudomonas and Bacillus species as treatment for the control of post-harvest fungal rot disease of yam (Dioscorea spp.)

The efficacy of four biological control agents (BCAs): Trichoderma asperellum strain NGT158, T. longibrachiatum strain NGT167, Bacillus subtilis and Pseudomonas fluorescens for the management of post-harvest tuber rot among four yam species, Dioscorea rotundata, D. cayenensis, D. alata, and D. dumetorum was evaluated. Rotted yam tubers were collected across three agroecological zones in Nigeria to isolate six infecting fungal pathogens: Aspergillus niger, Lasiodiplodia theobromae, Rhizoctonia solani, Penicillium oxalicum, Fusarium oxysporum and Sclerotium rolfsii. The BCAs were isolated by serial dilution and rot inhibition of treated tubers was evaluated using destructive sampling method in vivo after six months of storage. Bacillus subtilis was generally most effective, especially when applied 24 h before the inoculation of test pathogens across the four yam species, with percent inhibition that ranged between 47.8 and 81.2%. However, the four BCAs showed good potential in the control of the fungal pathogens causing post-harvest yam rot.

Impregnated and covered birch plywood performance during external exposure

ABSTRACTWe evaluated the performance of covered and impregnated birch plywood (BP) in the outdoor environment. Fungal growth, crack formation, and surface hydrophobicity were regularly assessed over 36 months. After 2 months, uncovered BP was severely colonised by disfiguring fungi. During the test period, the surface of plywood with better coatings (solvent- or water-based) was not overgrown or was overgrown slightly with fungi, no cracks were formed, and the surface hydrophobicity was stable. Similar results were observed for laminates with phenol and melamine film. Plywood impregnated with copper and organic biocides, with retention conforming to Use Class 3 (EN 335:2013), did not protect the plywood from crack formation within several months and the severe growth of disfiguring fungi within a year. The blue stain fungus Aureobasidium pullulans was identified for all overgrown test variants. No rot fungi were detected after a 36-month exposure.

Potential of rosemary leaves and branches to enhance storage life of onion bulbs

ABSTRACT Although its importance as vegetable, a considerable amount of onion bulbs is lost in storage. That's why storage condition is one of the most important issues to maintain post-harvest quality. For this purpose, a factorial experiment based on randomized complete block design with two factors and three replicates was carried out. The factors were storage conditions of onion bulbs with five levels (4oC in the seed storage apparatus, 25 and 30oC without using rosemary leaves and branches in the incubator, and 25 and 30oC using rosemary leaves and branches in the incubator) and storage times with ten levels (10 consecutive weeks). The storage feedbacks of bulbs in terms of the weight loss (WL) and the average bud length (ABL) of bulbs were analyzed. The storage of bulbs at 25oC using rosemary fresh leaves and branches inside each bag of bulbs after 10 weeks resulted in the lowest weight loss and average bud length, and significantly controlled the post-harvest fungal rotting and improved the shelf life of bulbs. The findings of this study indicated the high potential of rosemary fresh leaves and branches, which can be considered as an alternative strategy to control post-harvest fungal rotting and to improve the storage life of bulbs considering its simplicity and efficacy in decreasing the storage cost, the weight loss and sprouting without causing any environmental toxicity.