Aims: To develop a post-harvest treatment system against post-harvest fungal pathogens of banana using natural products. Methods and Results: Colletotrichum musae was isolated and identified as the causative agent responsible for anthracnose peel blemishes while three fungi, namely Lasiodiplodia theobromae, C. musae and Fusarium proliferatum, were identified as causative agents responsible for crown rot. During the liquid bioassay, cinnamon [Cinnamomum zeylanicum (L.)] leaf, bark and clove [Syzygium aromaticum (L.)] oils were tested against the anthracnose and crown rot pathogens. The test oils were fungistatic and fungicidal against the test pathogens within a range of 0AE03)0AE11% (v ⁄ v). Conclusions: Cinnamon and clove essential oils could be used as antifungal agents to manage post harvest fungal diseases of banana. Significance and Impact of the Study: Cinnamon and clove essential oil could be used as alternative post-harvest treatments on banana. Banana treated with essential oil is chemically safe and acceptable to consumers. Benomyl (Benlate), which is currently used to manage fungal pathogens, can cause adverse health effects and could be replaced with volatile essential oils. INTRODUCTIONBanana is grown on a large scale in many districts of Sri Lanka due to its nutritional value and export potential. There are 29 cultivated varieties available in Sri Lanka and certain varieties are air-freighted in limited quantities to Europe, Middle Eastern countries and the Maldives (Chamara et al. 2000;Perera and Karunaratne 2000). Storage of banana is made difficult by the growth of fungi which cause post-harvest diseases such as anthracnose and crown rot. The average post-harvest loss of banana in Sri Lanka due to post-harvest diseases, mechanical damage and improper storage (during 1998) was 20%, i.e. 76 973 metric tones (Sarananda 2000). Crown rot is a disease complex caused by the pathogenic fungi Colletotrichum musae, Lasiodiplodia theobromae, Fusarium proliferatum and Verticillium theobromae (Stour 1972;Finlay and Brown 1993;Ploetz et al. 1994). Colletotrichum musae is the causative organism of anthracnose in banana, which causes the development of black circular ⁄ lenticular spots during ripening (Ploetz et al. 1994). Benzimidazole fungicides such as Benomyl (Benlate) are being used on banana as a fruit dip for effective control of post-harvest disease in several countries, including Sri Lanka (Perera and Karunaratne 2000). According to the Benomyl Fact Sheet, the United States Environmental Protection Agency has classified Benomyl as a possible human carcinogen which can also act as a chronic and a reproductive toxicant (http://www.pan-uk.org/pestnews/ actives/benomyl.htm). Therefore, the fruit sector urgently needs to develop alternative post-harvest treatments that are chemical free and acceptable to consumers. Essential oils are complex volatile compounds produced in different plant parts, which are known to have various functions in plants including conferring pest and disease resistance (Goubran and ...

Aims: To develop a natural fungicide against aflatoxigenic fungi, to protect stored rice, using the essential oil of lemongrass. Methods and Results: Aspergillus flavus Link. was isolated from stored rice and identified as an aflatoxigenic strain. Lemongrass oil was tested against A. flavus and the test oil was fungistatic and fungicidal against the test pathogen at 0AE6 and 1AE0 mg ml )1 , respectively. Aflatoxin production was completely inhibited at 0AE1 mg ml )1 . The results obtained from the thin layer chromatographic bioassay and gas chromatography indicated citral a and b as the fungicidal constituents in lemongrass oil. During the fumigant toxicity assay of lemongrass oil, the sporulation and the mycelial growth of the test pathogen were inhibited at the concentrations of 2AE80 and 3AE46 mg ml )1 , respectively. Conclusion: Lemongrass oil could be used to manage aflatoxin formation and fungal growth of A. flavus in stored rice. Significance and Impact of the Study: Currently, fungicides are not used to control fungal pests or mycotoxin production on stored rice. Rice treated with the essential oil of lemongrass could be used to manage fungal pests as well as the insect pests in stored rice. The essential oil is chemically safe and acceptable to consumers, as synthetic chemical fungicides can cause adverse health effects to consumers.

The crown rot pathogens isolated from banana samples collected from 12 localities in Sri Lanka were Lasiodiplodia theobromae, Fusarium proliferatum and Colletotrichum musae. Fungal pathogens isolated were able to cause crown rot disease alone or in combination. Disease severity was higher when combinations of virulent pathogens were used. Cymbopogon nardus and Ocimum basilicum oils displayed fungicidal activity against C. musae and F. proliferatum between 0.2-0.6% (v/v) in a Poisoned food bioassay. Slightly lower concentrations of the test oils were needed for similar activity during liquid bioassays. The combination of Cymbopogon nardus and O. basilicum oils demonstrated synergistic action during both in-vivo bioassays.

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This article reports a lack of pathogenic specialization among Australian Fusarium graminearum and F. pseudograminearum causing crown rot (CR) of wheat using analysis of variance (ANOVA), principal component and biplot analysis, Kendall's coefficient of concordance (W), and κ statistics. Overall, F. pseudograminearum was more aggressive than F. graminearum, supporting earlier delineation of the crown-infecting group as a new species. Although significant wheat line-pathogen isolate interaction in ANOVA suggested putative specialization when seedlings of 60 wheat lines were inoculated with 4 pathogen isolates or 26 wheat lines were inoculated with 10 isolates, significant W and κ showed agreement in rank order of wheat lines, indicating a lack of specialization. The first principal component representing nondifferential aggressiveness explained a large part (up to 65%) of the variation in CR severity. The differential components were small and more pronounced in seedlings than in adult plants. By maximizing variance on the first two principal components, biplots were useful for highlighting the association between isolates and wheat lines. A key finding of this work is that a range of analytical tools are needed to explore pathogenic specialization, and a statistically significant interaction in an ANOVA cannot be taken as conclusive evidence of specialization. With no highly resistant wheat cultivars, Fusarium isolates mostly differ in aggressiveness; however, specialization may appear as more resistant cultivars become widespread.

Mature Embul (Musa, AAB) bananas were treated with emulsions of either cinnamon bark or leaf (Cinnamomum zeylanicum) or clove (Syzygium aromaticum) oils to control postharvest diseases, packed under modified atmosphere (MA) using low-density polyethylene (0.075 mm, LDPE) bags, and stored in a cold room (14 ± 1°C, 90% RH) or at ambient temperature (28 ± 2°C). The effects of the essential oils on post-harvest diseases; physicochemical properties and organoleptic properties were determined and compared with controls and bananas treated with benomyl. Treatments with cinnamon bark and leaf oils controlled crown rot, whereas clove oil treatment did not affect crown rot development. Treatment with emulsions of cinnamon oils combined with MA packaging can be recommended as a safe, cost-effective method for extending the storage life of Embul bananas up to 21 days in a cold room and 14 days at 28 ± 2°C without affecting the organoleptic and physico-chemical properties.

Purpose: Stem-end rot (SER) is a major disease of mango that causes serious postharvest losses. Application of fungicides is environmentally unsound and is being practiced currently in its control. This study was conducted to develop essential oil treatment systems as eco-friendly strategies to control SER of Karthakolomban mango and to determine the pathogenicity of several SER associated fungi.Research Method: Pathogenicity of four fungal isolates in SER was assessed by inoculating them on Karthakolomban mango fruits. Karthakolomban mango fruits were subjected to spray and fumigation treatments using four essential oils and their pathological, physicochemical and sensory properties were evaluated after a 8-day storage at 12 -14 ºC.Findings: Lasiodiplodia theobromae, Pestalotiopsis sp., Phomopsis sp. and Xylaria feejeensis were the major SER pathogens of mango. X. feejeensis was identifi ed as a SER pathogen for the fi rst time in Sri Lanka. Spray and fumigation treatments conducted using basil, clove, cinnamon leaf and cinnamon bark oils eff ectively controlled SER of Karthakolomban mango stored at 12 -14 ºC for 8 days. Mango sprayed with 1.6 µL/mL cinnamon bark oil has displayed no SER after induced ripening. None of the treatments caused drastic alterations in physicochemical and sensory properties of mango.Research Limitations: Storage period of mango was restricted to 8 days due to the initiation of natural ripening which was the major limitation to achieving a further enhanced shelf life.Originality/value: The treatment strategies developed by this research could be commercialized as biosafe SER control strategies in reducing postharvest losses of mango in the local and international trade. *Percentage Stem-End Rot; Each data point represents the mean of eight replicates ± standard error. 1 Means sharing a common letter(s) are not signifi cantly diff erent by Tukey's pair-wise comparison test at p < 0.05. 2 Means sharing a common letter(s) are not signifi cantly diff erent by Kruskal Wallis non-parametric test at p < 0.05.

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