Storage Rot Research Articles

Fungi Causing Storage Rot of Apple Fruit in Integrated Pest Management System and their Sensitivity to Fungicides

Abstract Apple fruit rot can be caused by several fungi. In Northern Europe, the most common storage rot, Bull’s eye rot, is caused by Neofabraea spp., bitter rot by Colletotrichum spp., brown rot by Monilinia fructigena, grey mould is caused by Botrytis cinerea and Fusarium rot by several Fusarium species. Blue mold decay caused by Penicillium expansum is an important disease in several European countries. Incidence of different causal agents may vary depending on cultivar, climate during growing season and agricultural practices. The main objective of the study was to obtain baseline information about apple rot-causing fungi, their incidence during fruit storage and to evaluate the fungicide sensitivity of most of isolated fungal species. The study was performed during the storage period of apples after the growth season of 2013. Rotten apples were sorted in the storage and part of them was brought to the laboratory in order to obtain fungal isolates. Fungi were identified according to the morphological characteristics and sequencing of the ITS1-5.8S-ITS2 region. During storage in February and March the total percentage of rotten apples in various cultivars varied from 3.6 to 58.9%. All post-harvest diseases described in Northern Europe were detected. In part of the storehouses apple rot caused by Cadophora luteo-olivacea was observed. Alternaria spp. and Cladosporium spp. were detected on few apples as secondary infection agents. Using the most often isolated fungal species, sensitivity tests were performed against five commonly used fungicides. In general, the sensitivity of tested fungi to the fungicides was high with exception of several Neofabraea and Alternaria isolates.

Storage rot fungi and seed-borne pathogens of onion

Surveys of fungi associated with postharvest deterioration of onion bulbs in four major markets in Kumasi Metropolis of the Ashanti Region of Ghana were conducted. Rotten onion bulbs obtained from the four markets (Abinchi, Anloga, Kwadaso and Central markets) were infected by five fungal species: Aspergillus niger , A. flavus, Penicillium sp., Rhizopus stolonifer and Fusarium oxysporum . Of these, A. niger and Penicillium sp. were the most frequently isolated fungi. A. flavus was the least encountered fungus. R. stolonifer and A. niger were the most pathogenic. Black mould, blue mould, soft rot, neck rot and basal plate rot were the major storage rots identified in a dry season survey in the markets. Incidences of these storage rots were higher in the wet season. Black mould enjoyed the highest incidence in all markets. Using the moist blotter method as recommended by the International Seed Testing Association (ISTA), seed-borne mycoflora of 37 samples of farmer-saved onion seeds from Bawku in the Upper East Region of Ghana were also examined. Nine different fungal species were identified and isolated from the seeds viz. A. niger, A. flavus, Penicillium sp., R. stolonifer, Fusarium oxysporum, Fusarium verticilloides, Fusarium poae, Alternaria porri and Botrytis sp. The most frequently encountered fungi were A. niger, R. stolonifer, A. flavus, Penicillium sp. and F. verticilloides with the occurrence of 33.3, 32.5, 25.8, 3.1 and 3.0%, respectively. The postharvest disease with the highest incidence in all the four markets surveyed was black mould. Some seed-borne fungi of onion were found to be associated with the onion bulb rots. Therefore, infected onion seeds could serve as inoculum source of the postharvest diseases of onion and contribute to the rot of bulbs during storage. In general, practices such as rotation, sanitation, optimum fertilization, preventive chemical applications, harvest timing and proper handling, harvesting, and storage are recommended for onion disease management. Keywords : Post-harvest, seed-borne, mycoflora, pathogenic, fungi

Effects of postharvest onion curing parameters on bulb rot caused by Pantoea agglomerans, Pantoea ananatis and Pantoea allii in storage

Crop loss of onion bulbs during storage carries an exceptionally high economic impact because a large portion of the production expenses has been expended before storage. Because of this, it is important to define practices that can reduce onion bulb losses caused by storage rots. This study investigates the impact of various curing parameters on disease development resulting from infection by Pantoea agglomerans, P. ananatis and P. allii on onion bulb cultivars Vaquero and Redwing, during storage. Overall, both the incidence and mean rot severity were similar amongst the bulbs under comparable conditions regardless of the species of Pantoea inoculated, although a significant difference was detected between the two onion bulb cultivars. In addition, a significant reduction of storage rot was observed when curing temperatures were ≤35°C. At temperatures >35°C, a shorter curing duration (2 days vs 14 days) decreased the severity of bulb rot due to Pantoea. This increased understanding of the inter‐relationships between the parameters used for curing, and the incidence and severity of bulb rot caused by Pantoea helps provide guidance towards using the curing process as a means to reduce the level of damage resulting from post‐harvest storage rot.

Storage diseases of onion under variable conditions

Onion (Allium cepa L.) is an important and familiar spice as well as vegetable crop throughout the world. Storage rot due to various diseases caused by bulb rotting fungi is a major constrain for storing onion year-round in Bangladesh. The fungi associated with onion collected from different markets of Mymensingh, Naogaon and Sathkhira districts of Bangladesh were studied aiming to record the incidence of storage diseases as well as storage variability and conditions on disease incidence of onion. Disease incidence was recorded from storage of the retailers in two local varieties of onion,viz.,Taherpuri, Faridpuri and one Indian variety Pusa Red. Initially, infected onion bulbs were found maximum in Faridpuri and minimum amount was found in Pusa Red. Month-wise disease incidence showed that highest number of infected onion bulbs was found in Pusa Red and lowest number of infected bulbs was found in Taherpuri. Similarly highest disease incidence (%) was recorded in Pusa Red and lowest disease incidence (%) was recorded in Therpuri. Among the different markets average number of fungal infected bulbs was highest in the samples collected from Dhamoirhat bazaar of Naogaon district and lowest in the samples collected from Natun bazaar of Mymensingh district. Highest infected bulbs were found in onions stored in cold room (6°C) followed by Free floor and Bamboo basket. Lowest infected bulbs were found in onions stored in dried sands followed by net-bag and jute bag. Thus, the fungal diseases in storage are higher in large sized onion bulbs than indigenous small sized onions and in cold room (6°C) than net-bag or jute bag.Progressive Agriculture 26:45-50, 2015

Influence of Harvest Timing, Fungicides, and Beet necrotic yellow vein virus on Sugar Beet Storage

Root rots in sugar beet storage can lead to multimillion dollar losses because of reduced sucrose recovery. Thus, studies were conducted to establish additional fungicide treatments for sugar beet storage and a greater understanding of the fungi involved in the sugar beet storage rot complex in Idaho. A water control treatment and three fungicides (Mertect [product at 0.065 ml/kg of roots; 42.3% thiabendazole {vol/vol}], Propulse [product at 0.049 ml/kg of roots; 17.4% fluopyram and 17.4% prothioconazole {vol/vol}], and Stadium [product at 0.13 ml/kg of roots; 12.51% azoxystrobin, 12.51% fludioxonil, and 9.76% difenoconozole {vol/vol}]) were investigated for the ability to control fungal rots of sugar beet roots held up to 148 days in storage during the 2012 and 2013 storage seasons. At the end of September into October, roots were harvested weekly for 5 weeks from each of two sugar beet fields in Idaho, treated with the appropriate fungicide, and placed on top of a commercial indoor sugar beet storage pile until early February. Differences (P < 0.0001 to 0.0150) among fungicide treatments were evident. Propulse- and Stadium-treated roots had 84 to 100% less fungal growth versus the control roots, whereas fungal growth on Mertect-treated roots was not different from the control roots in 7 of 12 comparisons for roots harvested each of the first 3 weeks in both years of this study. The Propulse- and Stadium-treated roots also reduced (P < 0.0001 to 0.0146; based on weeks 1, 3, and 4 in 2012 and weeks 1, 3, 4, and 5 in 2013) sucrose loss by 14 to 46% versus the control roots, whereas roots treated with Mertect did not change sucrose loss compared with the control roots in 7 of 10 evaluations. The predominant fungi isolated from symptomatic roots were an Athelia-like sp., Botrytis cinerea, Penicillium spp., and Phoma betae. If Propulse and Stadium are labeled for use on sugar beet in storage, these fungicides should be considered for root rot control in commercial sugar beet storage and on roots held for vernalization for seed production of this biennial plant species.

First report of Penicillium polonicum causing storage rots of onion bulbs in Ankara province, Turkey

Onion ( Allium cepa ) production is one of the most important agricultural crops in Turkey with bulb harvest of 1,904,846 tonnes from an area of 616,324 ha. In 2013, about 12% of this onion bulb harvest (approximately 153,478 tonnes) was …

Activity and Siderophores Production by Rhodotorula spp. Isolates, Potential Antagonists of Botrytis Storage Rot

Activity and Siderophores Production by Rhodotorula spp. Isolates, Potential Antagonists of Botrytis Storage Rot

English

Rotten white yam (Dioscorea rotundata) tuber samples were collected from farms in three communities. Nine fungal organisms were isolated by direct tissue plating on potato dextrose agar medium. These were: Fusarium oxysporum, Aspergillus flavus, Aspergillus niger, Penicillium spp., Lasiodiplodia theobromae, Trichoderma viride, Rhizopus spp., Pestalotia guepini and Alternaria solani. Each of these isolates caused rot lesions when inoculated into healthy yam tubers. These organisms were re-isolated, identified and compared with the initial isolates to confirm their pathogenicity. L. theobromae, A. niger, Rhizopus sp. and A.&nbsp; solani were the most frequently isolated fungi species from the rotten yam tuber samples, with frequency of isolation of 30.07, 16.08, 16.08 and 12.59%, respectively. Zingiber officinale rhizome and Piper nigrum seeds were tested against L. theobromae and F. oxysporum in vitro. The botanical extracts were prepared by cold water extraction method at a concentration of 60% w/v. The two extracts showed significance in inhibiting the growth of the two fungi when data was statistically analysed (p = 0.05) using Genstat 9.2 package. This implies that they have some anti-fungal properties which need to be further investigated in vivo to establish their suitability in protecting yam tubers from storage rot. However, P. nigrum showed to be much stronger than ginger in terms of bioactivity. Key words: Zingiber officinale, Piper nigrum, bioactivity, yam tuber rot, rot fungi.

Infection Courts and Timing of Infection of Apple Fruit by Phacidiopycnis washingtonensis in the Orchard in Relation to Speck Rot During Storage.

Phacidiopycnis washingtonensis is the cause of speck rot, a recently reported postharvest fruit rot disease of apple. The pathogen is believed to incite infections in the field, and disease symptoms become evident only during storage. To determine the timing of apple fruit infection in relation to development of speck rot in storage, 'Red Delicious' and 'Fuji' apple fruit were inoculated in the orchard with P. washingtonensis at different times during the growing season, harvested, and monitored for decay development during storage at 0°C. Fruit inoculated in both field and laboratory also were used to identify the infection courts and mode of apple fruit penetration by P. washingtonensis. In all 3 years, stem-end speck rot and calyx-end speck rot developed during cold storage on fruit inoculated during the growing season, regardless of inoculation time; and the incidence of total speck rot in storage increased as the fruit inoculation time approached harvest. On fruit floral parts, the pathogen colonized sepals at higher rates than stamens. Availability of naturally occurring necrotic tissues favored the colonization of the fungus on sepals. Histological studies indicated that infection occurred through micro-cracks on the surfaces of pedicels and sepals of the fruit, and invasion of these tissues was restricted between the cuticle and epidermis. Findings of this study will assist in the development of effective control strategies for speck rot.

Control of Rots and Spoilage of Agricultural Products: A Review

The most important losses in agricultural production which involve the greatest costs on the farm economy occur postharvest. It is estimated that worldwide between 10 and 40% losses of agricultural produce occur postharvest. Losses are more severe in developing than developed nations of the world. Several species of fungi and in some cases bacteria participate in postharvest deterioration and rots of tubers and agro- produce. These include species of Aspergillus, Fusarium, Colletotrichum, Macrophomina, Penicillium and Rhizopus amongst several others. In a bid to control these storage diseases several control techniques including physical, biological, and chemical and in recent times plant-based pesticides are employed. Chemical control has been identified as the most popular and most effective means of controlling plant diseases. However, it is being de-emphasized due largely to mammalian toxicity occasioned by chemical residues in crops. This in addition to many other demerits on ecological health and build-up of pathogens’ resistance to some of the most effective fungicides have prompted search for alternatives. Recently in plant pathology many tropical plants are being screened for fungitoxic properties. This review presents highlights of the different control techniques for control of myco- induced storage rots of tubers and agricultural products in the tropics. DOI: 10.5901/ajis.2014.v3n7p38

Detection, identification and differentiation of Pectobacterium and Dickeya species causing potato blackleg and tuber soft rot: a review.

The soft rot Enterobacteriaceae (SRE) Pectobacterium and Dickeya species (formerly classified as pectinolytic Erwinia spp.) cause important diseases on potato and other arable and horticultural crops. They may affect the growing potato plant causing blackleg and are responsible for tuber soft rot in storage thereby reducing yield and quality. Efficient and cost-effective detection and identification methods are essential to investigate the ecology and pathogenesis of the SRE as well as in seed certification programmes. The aim of this review was to collect all existing information on methods available for SRE detection. The review reports on the sampling and preparation of plant material for testing and on over thirty methods to detect, identify and differentiate the soft rot and blackleg causing bacteria to species and subspecies level. These include methods based on biochemical characters, serology, molecular techniques which rely on DNA sequence amplification as well as several less-investigated ones.

Biology and control of the apple canker fungus Neonectria ditissima (syn. N. galligena) from a Northwestern European perspective

A review of apple canker caused by Neonectria ditissima is presented for Northwestern Europe with a focus on the Lower Elbe region (Northern Germany). Whereas conidia released by rainsplash are produced mainly from spring to autumn, the liberation of wind-borne ascospores peaks in autumn and/or early spring. Infection occurs via natural as well as pruning-induced wounds, some of which are present throughout the year. Autumnal leaf scars are the most frequent entry point for N. ditissima. Wounds on tree trunks, especially bark cracks in the crotch regions, are potentially even more serious because cankers on trunks and leader shoots commonly cause the total loss of a tree. Surface moisture is a prerequisite for leaf scar infections but possibly not for an entry through other wounds. Irrespective of the entry route, successful infection of a wound requires a mass inoculum of at least 50–100 conidia or ascospores. Infections of trees originating in nurseries may enter a state of latency from which they can break out up to 3 years after the trees have been explanted into the production orchard. Streaks of brown wood discolourations can be caused both by systemic colonisation of the xylem by N. ditissima and by winter frost damage. Apple varieties may show pronounced differences in their sensitivity to canker. For highly susceptible varieties, this disease can be a major production-limiting factor. Flower infections by N. ditissima commonly lead to a pre-harvest rot at the blossom end of the fruit, whereas infections of the growing fruit before harvest lead to a storage rot. Rigorous pruning is an essential canker control measure. Chemical control during the growing season is achieved by apple scab fungicides such as dithianone, captan or dodine. At leaf fall and in winter, copper fungicides are indispensible for controlling canker on highly susceptible varieties in Northern Germany.

Control of Rots and Spoilage of Agricultural Products: A Review

The most important losses in agricultural production which involve the greatest costs on the farm economy occur postharvest. It is estimated that worldwide between 10 and 40% losses of agricultural produce occur postharvest. Losses are more severe in developing than developed nations of the world. Several species of fungi and in some cases bacteria participate in postharvest deterioration and rots of tubers and agro- produce. These include species of Aspergillus, Fusarium, Colletotrichum, Macrophomina, Penicillium and Rhizopus amongst several others. In a bid to control these storage diseases several control techniques including physical, biological, and chemical and in recent times plant-based pesticides are employed. Chemical control has been identified as the most popular and most effective means of controlling plant diseases. However, it is being de-emphasized due largely to mammalian toxicity occasioned by chemical residues in crops. This in addition to many other demerits on ecological health and build-up of pathogens’ resistance to some of the most effective fungicides have prompted search for alternatives. Recently in plant pathology many tropical plants are being screened for fungitoxic properties. This review presents highlights of the different control techniques for control of myco- induced storage rots of tubers and agricultural products in the tropics.

Scientific Opinion on the pest categorisation of Diaporthe vaccinii Shear

The European Commission requested the EFSA Panel on Plant Health to perform a pest categorisation of Diaporthe vaccinii Shear, the fungal agent responsible for twig blight, canker, viscid rot, fruit rot and storage rot of several Vaccinium species. The pest is listed in Annex IIAI of Directive 2000/29EC. D. vaccinii is a single taxonomic entity and methods exist for its discriminative detection. The host is restricted to Vaccinium species, the main cultivated hosts being blueberries and cranberries. Hosts are cultivated throughout Europe, and wild Vaccinium species are common components of forests. Conditions are conducive to disease development in most areas of Europe, but not in all Member States (MSs). The disease is currently present in Latvia with restricted distribution and the pest is under surveillance in The Netherlands. In the one Latvian report, storage losses were observed on cranberry, but these losses were caused by a complex of pathogens, including D. vaccinii, which was isolated with a low incidence. Detection methods are available but cultural and morphological identifications should be confirmed with molecular tools owing to the presence of other Phomopsis species on Vaccinium in Europe. The pathogen can spread via the movement of (asymptomatic) infected or contaminated host plants for planting. No information exists on any methods applied for the control of D. vaccinii in the EU. D. vaccinii does not have the potential to be a quarantine pest as it does not fulfil one of the pest categorisation criteria defined in International Standard for Phytosanitary Measures No 11, that of having a severe impact. Data are not sufficient to conclude on pest categorisation of D. vaccinii based on the criteria of the International Standard for Phytosanitary Measures No 21 because there is no information about the level of potential consequences as a result of the use of infected host plants for planting. © European Food Safety Authority, 2014

Control of Rots and Spoilage of Agricultural Products: A Review

The most important losses in agricultural production which involve the greatest costs on the farm economy occur postharvest. It is estimated that worldwide between 10 and 40% losses of agricultural produce occur postharvest. Losses are more severe in developing than developed nations of the world. Several species of fungi and in some cases bacteria participate in postharvest deterioration and rots of tubers and agro- produce. These include species of Aspergillus, Fusarium, Colletotrichum, Macrophomina, Penicillium and Rhizopus amongst several others. In a bid to control these storage diseases several control techniques including physical, biological, and chemical and in recent times plant-based pesticides are employed. Chemical control has been identified as the most popular and most effective means of controlling plant diseases. However, it is being de-emphasized due largely to mammalian toxicity occasioned by chemical residues in crops. This in addition to many other demerits on ecological health and build-up of pathogens’ resistance to some of the most effective fungicides have prompted search for alternatives. Recently in plant pathology many tropical plants are being screened for fungitoxic properties. This review presents highlights of the different control techniques for control of myco- induced storage rots of tubers and agricultural products in the tropics.

Infection of apple fruit by Sphaeropsis pyriputrescens in the orchard in relation to Sphaeropsis rot in storage

Sphaeropsis rot, caused by Sphaeropsis pyriputrescens, is an important postharvest disease of apple in the United States. The objectives of this study were to determine the timing of apple fruit infection in the orchard in relation to development of Sphaeropsis rot in storage and to identify infection courts and mode of penetration by S. pyriputrescens on apple fruit. Fruit of apple cvs Red Delicious, Golden Delicious, and Fuji were inoculated in the orchard from 3 weeks after petal fall to 2 weeks before harvest at 5 to 6-week intervals in three consecutive seasons. All fruit were harvested and stored at 0oC to monitor decay development. Light and scanning electron microscopy were used to examine the infection courts and mode of penetration of the fungus on/in the host tissues. At harvest, the fungus was re- isolated from the stem (pedicel), sepal, anther, or fila- ment of the inoculated fruit, but decay did not develop on fruit. Sphaeropsis rot developed on inoculated fruit during cold storage beginning 1-3 months after harvest. Stem-end rot was prevalent on cv. Golden Delicious, whereas calyx-end rot was prevalent on cv. Fuji. Both stem- and calyx-end rots were common on cv. Red Delicious. Infection also occurred at lenticels on fruit skin, particularly on cv. Golden Delicious, but at low incidence. Relationships between the incidence of Sphaeropsis rot in stored apple fruit and the timing of inoculation in the orchard varied with cultivar and year. On cv. Red Delicious apples, the incidence of Sphaeropsis rot generally increased as the timing of infection approached harvest. Histological studies indi- cated that infection took place through natural openings of plant organs such as stomata on stems and sepals and lenticels on fruit skin. Fungal penetration also was ob- served at micro-cracks on the stem and sepal and at trichome sockets where mechanical damage occurred in sepals. Direct penetration was observed on the stem and sepal of fruit, but most invasions were restricted between the cuticle and the epidermis. Our results indi- cate that wounding is not required for infection of apple fruit by S. pyriputrescens, though it may facilitate infections.

Control of Fungal Storage Rots of Apples by Hot-Water Treatments: A Northern European Perspective

In the Lower Elbe region of Northern Germany and in other Northern European fruit production areas, about 80 % of all storage rots of apples are caused by Neofabraea alba and N. perennans. Other pathogens include Colletotrichum acutatum, Monilinia fructigena, Phaci­diopycnis washingtonensis, Neonectria galligena, Botrytis cinerea, Penicillium expansum and Fusarium avenaceum. Hot-water treatments of freshly harvested fruits for 3 min at 50–52 °C gave high efficacies against most of these storage rots except F. avenaceum. Substantial evidence supported a heat shock-induced antimicrobial response rather than a direct killing of fungal inoculum as the principal mode of action of hot-water treatments in apples. Shorter exposures for < 30 s at 55–60 °C also provided good control of fungal storage rots and thereby offer new possibilities for this technology in Northern European fruit production. These possibilities include the integration of a hot-water unit into existing grading lines and the option to treat fruits at different time points, e.g. at harvest, after short-term storage and/or after long-term storage.

Role of Fungal Rots in Post-harvest Storage Losses in Some Nigerian Varieties of Dioscorea Species

Aims: To study storage rots in yam varieties cultivated in South East Nigeria and to determine under conditions of experimental storage, the influence of fungal rot on their post harvest storage losses. Place and Duration of Study: Laboratories, Department of Applied Microbiology & Brewing, Nnamdi Azikiwe University, Awka, Nigeria between January 2012 and July 2013. Methodology: Five yam varieties; Dioscorea dumentorum, two varieties each of D. alata and D. rotundata, obtained immediately after harvest were stored in an experimental barn (30oC and 95% RH) and examined at intervals for storage rots. Fungal causative agents of rots were isolated and identified using the partial ITS rDNA sequencing analysis and a BLAST search using the GenBank sequence database. Post harvest storage losses in terms of weight loss and reduction of shelf life among the varieties were determined. Results: All varieties of yams studied suffered fungal rots, predominantly, dry rots during storage. Seven distinct fungal isolates, which caused these rots, were fully characterized. The species were Aspergillus tamari, Fusarium solani, Lasiodiplodia theobromae, Aspergillus niger, Mucor circinelloides, Aspergillus flavus and Aspergillus sp. In all the yams, storage rots reduced shelf life and aggravated weight loss. Post harvest storage losses varied among the different varieties of yams. Conclusion: The varieties of yams studied suffer rots from various fungi, which are similar Original Research Article British Microbiology Research Journal, 4(3): 343-350, 2014 344 to those reported in other parts of the world. Severity of post harvest losses resulting from fungal rots varies among different varieties of yams. This should be taken into consideration in the development of storage techniques.

Incidence of Lasiodiplodia theobromae and other Fungi in Kolanuts (Cola nitida and Cola acuminata) in Nigeria

Aim: A study was conducted to determine the frequency of occurrence of fungi associated with kolanuts (Cola nitida and Cola acuminata) at processing and storage. Methodology: Healthy and infected kolanuts (Cola nitida and Cola. acuminata) collected randomly during processing and storage from various locations in Nigeria were used in this study. Infected kolanut samples were plated on potato dextrose agar (PDA). The plates were incubated at 25C and the incidence of associated fungi was recorded after 510 days depending on when growth could be observed. The fungal colonies emerging from the tissue piece were hyphal-tip-transferred onto new PDA plates to obtain pure cultures. Results: Lasiodiplodia theobromae, Fusarium pallidoroseum, Fusarium moniliforme, Fusarium cacispermum. Aspergillus niger, Aspergillus fumigatus, Aspergillus flavus and Paecilomyces variotii were obtained from the infected kolanuts. The means frequency of occurrence of Lasiodiplodia theobromae on Cola nitida and Cola acuminata ranged between 40-47% and 33.5-40% respectively. The mean frequency of occurrence of other isolated fungi ranged between 3-14% on both species of Cola. The pathogenesis tests established Lasiodiplodia theobromae as the causal pathogen of black rot disease of kolanuts. When kolanuts were artificially wounded before inoculation with Lasiodiplodia theobromae, 79.2% infection was recorded compared to 33.3% infection recorded in unwounded nuts. A highly significant positive correlation (r = 0.8844) existed between wounding of nuts and incidence of black rot diseases. Original Research Article American Journal of Experimental Agriculture, 4(12): 1764-1772, 2014 1765 Conclusion: The present study established that kolanuts were susceptible to fungal infections. This study confirmed the occurrence of storage rot fungi on kolanuts in all the locations of sampling, which represent the rain forest and guinea savanna zones of Nigeria.

Combined Inhibitory Effect against Postharvest Storage Rots and Their Effects on Postharvest Quality Parameters in Cherry Tomatoes by Cassia Oil and Calcium Chloride

The inhibitory effect of cassia oil alone or in combination with calcium chloride (CaCl2) against Alternaria alternata in vitro and in vivo was assessed on cherry tomatoes. The results demonstrated that concentrations of CaCl2 ranging from 0.25 to 3% enhanced the inhibitory effects of 200 μl of cassia oil per liter on the growth of A. alternata in vitro. The combination of 0.25% CaCl2 and 500 μl of cassia oil per liter showed a significant inhibition effect on decay development in both wounded artificially infected and unwounded naturally infected fruit. Importantly, these treatments did not reduce the overall quality of tomatoes. Defense-related enzyme activities were also evaluated. The results indicated that cassia oil alone or in combination with CaCl2 significantly enhanced defense-related enzyme activities, such as peroxidase and polyphenol oxidase. Together, these data suggest that the combination of cassia oil and CaCl2 may be an efficient method to limit cherry tomato decay caused by fungi.