Pathogenicity And Aethiology Of Fusarium Species Associated With Pokkah Boeng Disease On Sugarcane [SB741.F9 S623 2007 f rb].

Kehadiran penyakit pokkah boeng pada tebu di dapati terdapat di hampir kesemua negara yang menanam tebu secara komersial. Tinjauan di jalankan di ladang tebu, kebun kecil dan perkarangan rumah yang menanam tebu di Semenanjung Malaysia (Kedah, Perlis, Pulau Pinang, Kelantan, Terengganu, Pahang dan Johor ) dan Jawa Timur (Indonesia). Pokkah boeng disease on sugarcane has been recorded in almost all countries where sugarcane is grown commercially. In our survey throughout sugarcane plantations, small holders and household compounds within Peninsular Malaysia (Kedah, Perlis, Penang, Kelantan, Terengganu, Pahang and Johor) and East Java (Indonesia), the first visible symptoms of pokkah boeng were chlorosis and yellowing of young leaves and the final results were usually a malformed and distorted top

First report of Fusarium species at nesting sites of endangered sea turtles in Terengganu and Melaka, Malaysia

In recent years, turtle eggs incubated in situ or in protected hatcheries in Malaysia have been reported to show symptoms and signs of fungal colonisation. However, there are no studies addressing this problem and potential relationship with frequent hatching failures. We identified Fusarium species from nesting sites of green turtle (Chelonia mydas) and hawksbill turtle (Eretmochelys imbricata) situated in Terengganu and Melaka, as well as the environments surrounding those sites. The eggs were incubated on the nesting beach (in situ) or relocated to the beach hatchery and styrofoam boxes (ex situ) in Peninsular Malaysia. Samples were collected from infected eggs, sand, plant roots and debris around the egg chambers. One-hundred and six strains of Fusarium spp. were isolated. They were identified morphologically as member of the Fusarium solani species complex (FSSC, 101 strains), F. oxysporum (four strains) and F. proliferatum (one strain). We conducted phylogenetic analysis based on nucleotide sequences of translation elongation factor 1-alpha gene (TEF-1α). The strains of the FSSC were further separated into three lineages, F. falciforme, F. lichenicola and F. keratoplasticum. This is the first report on Fusarium species isolated from symptomatic green and hawksbill turtle eggs in Peninsular Malaysia. Fusarium colonisation in sea turtle nests poses a serious risk to the survival of endangered sea turtles in Malaysia. It is, therefore, important to examine the nature of such colonisation and their relationship to hatching failures of the turtles in Malaysia or elsewhere in the region to mitigate pathogenic fungi impact

Effect of different concentrations of propolis extract coating on postharvest quality of banana artificially inoculated with Colletotrichum gloesporioides

The coating is one of the methods to prevent postharvest loss in the food industry. Propolis seems to be promising as a coating due to its waxy properties, high antifungal activity and less toxicity. In this study, propolis ethanol extract coating was tested for the antifungal activity against Colletotrichum gloeosporioides, the causative fungus that caused anthracnose disease on bananas (Musa acuminata). All samples were artificially inoculated with C. gloeosporioides and the disease severity index (DSI) was measured. Other postharvest qualities of banana tested were weight loss, total soluble solids (TSS), colour and titratable acidity (TA). Results showed that the control banana was more susceptible to the fungal infection (60% necrosis) compared to the treated banana. The propolis coating successfully inhibited the fungus activity of C. gloeosporioides activity on a banana during storage. The higher concentration of extract coating seems to be better effective against the fungus. Moreover, the control banana showed higher weight loss (6.92%) and total soluble solid (p<0.05) compared to coated banana during storage. In conclusion, bananas treated with an 11% concentration of propolis coating are promising for improving the colour, total soluble solid content and titratable acidity and can inhibit artificially anthracnose disease caused by C. gloeosporioides on a banana

Growth development and natural infection incidence of tobacco mosaic virus (TMV) on silicon-treated chilli (Capsicum annuum L.) cultivated in commercial soil

Chilli (Capsicum annuum L.) is one of the most important cultivated crops in Malaysia. It is largely cultivated for its fruits. The application of the chemical fertilizer solely is able to supply the desire nutrient for chilli plant but did not helping in resistant of pathogen attack. Therefore, this study attempts to determine the potential of silicon application on plant growth and disease resistant on treated plants. Chilli seedling were transplanted into individual polybag containing commercial soil and supplied with silicon at 0.5ml/L and 1.5ml/L concentrations for the period of 11 weeks. Control plants were supplied with water instead of silicon nutrient. Assessment was conducted from week 3 to 11 after transplanting. Result showed that the plant growth of chilli treated with both Si nutrient concentrations measured by plant height, leaf number, leaf diameter and stem diameter were significantly better than control plants. Besides, the natural occurrence of Tobacco Mosaic Virus (TMV) disease incidence observed on treated chilli were 26.7–44.4% reduced compared to control plants. This study provides the knowledge on the benefit of Silicon application on the cultivated chilli and could possibly help the farmers to produce higher and better quality of yield in the future

Effects of Host Resistance on Colonisation of Brassica napus (Oilseed Rape) by Leptosphaeria maculans and Leptosphaeria biglobosa (Phoma Stem Canker)

Leptosphaeria maculans and L. biglobosa co-infect winter oilseed rape plants to cause phoma stem canker disease. The sexual spores of both species are produced in pseudothecia on infected winter oilseed rape stem debris after harvest and this is the most important source of inoculum for infection of newly-emerged plants in autumn. Field experiments investigated the effects of host resistance on proportions of pathogens Leptosphaeria maculans and L. biglobosa in most leaf and stem tissues during 2011/2012, 2012/2013 and 2013/2014 growing seasons and on the pseudothecial development on crop debris on nine winter oilseed rape cultivars; cvs Adriana (Rlm4 + quantitative resistance (QR)), Bilbao (Rlm4), Capitol (Rlm1), Drakkar (no R gene against L. maculans), DK Cabernet (Rlm1 + (QR), Es-Astrid (QR), Excel (Rlm7), Roxet (Rlm7) and NK Grandia (QR). Cultivars with a combination of R-gene resistance and QR [Adriana (Rlm4 + QR), DK Cabernet (Rlm1 + QR)] or cultivars with only QR [(Es-Astrid and NK Grandia)] had more numbers of L. maculans leaf spots than other cultivars in autumn but less stem canker damage. There was greater number of L. biglobosa leaf spots on leaves of cvs Roxet and Excel with resistance gene Rlm7 than those of other cultivars and later more L. biglobosa DNA was detected in their stems than in those of other cultivars. In all cultivars in the three growing seasons, there was a greater amount of L. biglobosa DNA than L. maculans DNA in basal stem canker and upper stem lesions. The cv. Drakkar (no R gene against L. maculans) was susceptible in all three growing seasons, with a great number of L. maculans and L. biglobosa leaf spots and severe stem cankers. There were four cultivars (Adriana, Bilbao, Drakkar and NK Grandia) selected for the study of pseudothecial development under natural conditions with different times of exposure and in controlled environment conditions (20oC, continuous wetness). The fastest development was on the susceptible cv. Drakkar (no R gene against L. maculans), followed by Bilbao (Rlm4), Adriana (Rlm4 + QR) and NK Grandia (QR) for stem base cankers and upper stem lesions in controlled conditions. Results for pseudothecial development on stems of the nine winter oilseed rape cultivars that were exposed in natural conditions at Bayfordbury support the controlled environment results, with pseudothecia on stems of cultivars with a combination R-gene and QR consistently maturing later than those on other cultivars, regardless of the weather conditions in three growing seasons. Ascospores produced in pseudothecia are the primary inoculum that initiate phoma stem canker epidemics in autumn. Ascospore release was later in autumn 2011 than in autumn/winter 2012/2013 or 2013/2014 because of dry weather. The pattern of ascospore release had a peak, or maximum in autumn/winter 2011/2012 (4958 spores/m-3 on 22 Jan 2012) and several maxima in autumn/winter 2012/2013 (1307 spores/m-3 on 5 Nov 2012, 1291 spores/m-3 on 15 Nov 2012, 1306 spores/m-3 on 25 Dec 2012) and 2013/2014 (4575 spores/m-3 on 27 Oct 2013, 4619 spores/m-3 on 3 Nov 2013, 3674 spores/m-3 on 9 Nov 2013, 3521 spores/m-3 on 12 Dec 2013). Results from the qPCR showed that ascospores of L. maculans were released earlier than ascospores of L. biglobosa at Bayfordbury in the 2013/2014 growing season. There were differences in phenotype of isolates amongst ninety-five isolates of L. maculans and forty-eight isolates of L. biglobosa obtained from different sources (phoma leaf spots, upper stem lesions or basal stem cankers) on different cultivars. Cotyledon tests showed that the resistance genes Rlm4, Rlm5, Rlm6 and Rlm7 are still effective in England. Most isolates from phoma leaf spots carried avirulent AvrLm4 (39 isolates; 97.5%), AvrLm5 (39 isolates; 97.5%) and AvrLm6 alleles (36 isolates; 90%) and all 40 isolates carried the avirulent allele AvrLm7 (100%). Fewer isolates from basal stem cankers carried avirulent AvrLm4 (4 isolates, 16.7%) or AvrLm6 alleles (16.7%) but all 24 isolates carried the avirulent AvrLm7 (100%). Fewer isolates from upper stem lesions carried the avirulent AvrLm4 allele (5 isolates; 16.1%), but 15 isolates carried avirulent AvrLm5 (48.4%), 21 isolates carried AvrLm6 (67.7%) and all 31 isolates carried AvrLm7 (100%). By contrast, all isolates were virulent against Rlm1, Rlm2, Rlm3 and Rlm9. This knowledge, together with knowledge about R genes present in current winter oilseed rape cultivars, should be useful to provide recommendations on cultivar selection to growers based on regional frequencies of avirulent alleles of Avr allele genes in the L. maculans populations (races) and improved understanding of the race structure of L. maculans. There is a need to further investigate any R genes that operate against L. biglobosa (possibly from wild brassicas) and to study if any R genes or QR can provide resistance against both L. maculans and L. biglobosa

Antifungal properties of water extract propolis coating against anthracnose (Colletotrichum gloeosporioides) on strawberry (Fragaria anannassa)

Anthracnose is a major pre and post-harvest disease. Due to the consumer concerns of the residual effect of the synthetic fungicide, biocontrol from a natural source is highly required by the consumer to reduce the problem. Propolis is a natural antifungal that can be used as a coating to control fruit quality and postharvest losses. This study evaluated the physical and chemical characteristics of strawberry (Fragaria ananassa) induced with Colletotrichum gloeosporioides, coated with water extract propolis (WEP) and stored at 5°C. The effect of coating was evaluated with different concentrations of water extract propolis (WEP) which were control, 10%, 12%, and 14%. The post-harvest parameters such as weight loss, total soluble solids (TSS), anthocyanin, disease severity index (DSI), and firmness were evaluated at two days interval for 12 days of storage. The highest percentage of inhibition (in vitro) was shown by the highest concentration of WEP (14%). Fruits coated with propolis showed reduced deterioration and infection diameter of fungus, as compared to the control (without coating) which already spoiled at day 4. Strawberry coated with 14% concentration of WEP also showed the highest firmness compared to other treatments. Thus, this coating can be used as an alternative method for bio-control of disease to reduce the post-harvest loss of fresh produce

Isolation and identification of fusarium species associated with fusarium ear rot disease of corn

Fusarium species associated with corn (Zea mays) are very diverse and widely distributed throughout Malaysia. Out of 657 samples cultured, a total of 220 Fusarium isolates were obtained from corn plants showing the typical symptoms of Fusarium ear rot in 12 locations throughout Malaysia. All the isolates were identified into 10 species based on the morphological characteristics that emphasized on growth rates, colony features and microscopic characteristics. A total of 117 Fusarium isolates were classified into four species in the section Liseola and their allied, tentatively identified as F. proliferatum (58), F. subglutinans (34), F. verticillioides (24), and F nygamai (1). Meanwhile, F. proliferatum was the most prevalent species in all the sampling areas. 103 isolates, which were classified into six other Fusarium species belonging to different sections, were also isolated and identified, and these included F semitectum (47), F oxysporum (20), F. pseudograminearum (19), F solani (15), F equiseti (1), and F. longipes (1). F semitectum was the highest among other common saprophytic fungi in corn. F pseudograminearum was only isolated from the samples obtained from Cameron Highlands, Pahang. In term of species diversity, Fusarium species was the highest obtained in Semenyih, Selangor, with H'=1.72

Sheath Brown Rot Disease of Rice Caused by Pseudomonas fuscovaginae in the Peninsular Malaysia

Relative to the established and well known rice diseases, sheath brown rot caused by Pseudomonas fuscovaginae can be considered new but getting widespread and serious all over the world. Our research was aimed to monitor and quantify the incidence and importance of the disease in Malaysia. A series of field monitoring and sampling were conducted to quantify the incidence and severity of the disease. Laboratory analysis of the collected diseased plant was done to identify the causal organism. Disease resistance screening of selected rice cultivars were also conducted to overcome the problem. The disease was found to become more important,prevalent and widely spread throughout rice growing areas in Peninsular Malaysia. Infected plants in the field became yellowish,lower leaf sheaths turned light or dark brown, while grains produced by an infected plant were discoloured, malformed and empty. The highest disease incidence was recorded in the state of Pahang (62%) and Selangor (62%), while the most severe infection was recorded in Pahang (55%) and Terengganu (61%). The evaluations of varietal resistance evaluation showed that the pathogen naturally infected all tested rice varieties at different levels of infection. Several rice varieties i.e. MR240, MR243, MR244, MR245, MR246, MR248 and MR249, classified as moderately resistant to the disease, could be recommended for planting in the next planting seasonPeer reviewe

Nitrate Non-utilizing Mutants and Vegetative Compatibility Groups of Fusarium proliferatum and F. sacchari Isolated from Rice in the Peninsular Malaysia and Kalimantan, Indonesia.

A total of 26 isolates of Fusarium proliferatum and F. sacchari were isolated from rice in the Peninsular Malaysia and Kalimantan, Indonesia. Spontaneous chlorate-resistant sectors (CRSs) were recovered from all wild type of both Fusarium species when cultured on two chlorate media. The non-utilizing (nit) mutants were generated as crn (chlorate resistant, nitrate utilizing), nit1, nit3 and nitM based on phenotyping growth-types on diagnostic media with different sources of nitrogen. The nit mutants were paired on minimal medium (MM) for examining the vegetative compatibility. The majority of nit mutants (32.3-46.5%) recovered were nit1. Eight and seven vegetative compatibility groups (VCGs) of F. proliferatum and F. sacchari were identified, respectively. The isolates of F. proliferatum and F. sacchari were genetically diverse as shown by the number and distribution of the VCGs. No strong correlation was observed between VCGs of both species and locationPeer reviewe