Studies on the isolation, identification and enzyme activity of bioagent Pseudomonas fluorescens used for controlling brown spot disease of rice caused by Helminthosporium oryzae

In the present investigation studies was carried out ontheIsolation, Identification and Enzyme activity of bioagent Pseudomonas fluorescens used for controlling Brown spot disease of Rice caused by Helminthosporium oryzae(Breda de Haan).This is a fungal pathogen causing major disease that causes enormous losses in grain yield (upto 90%) particularly when leaf spotting phase assumes epiphytotic proportions.

Evaluation of nutritional amendments and fungicides against brown leaf spot of rice

Helminthosporium oryzae, the causal organism of bacterial leaf spot (BLS) has brought a tremendous loss of rice crop in the field. Rice seedlings of four commercial varieties (Nayab basmati, Kiran 434, Super basmati, and Pak 386) were screened against BLS in the field by using a randomized complete block design (RCBD). The present experiment was encompassed the evaluation of fermented farmyard manure, leaf manure, Boron, and NPK solution against BLS. The effect of different fungicides (Score, Flumax, Melodyduo, and Polyram) was also checked on the mycelial growth of Helminthosporium oryzae in-vitro and in-vivo. The results showed that Pak 386 was highly resistant with 17.22% disease severity and Super Basmati was found moderately resistant with 22.31% disease severity; variety Kisan 434 was found moderately susceptible (24.15%) and Nayab Basmati (24.82%) was susceptible. Among all NPK solutions showed the best results in growth enhancement, plant vigor as well as reduction in disease severity followed by FFYM, boron and leaf manure. Under in-vitro conditions, all the fungicides performed best at 150 ppm in terms of colony growth reduction. The maximum growth inhibition was recorded in Score followed by Flumax, Melodyduo, and Polyram. Score gave a significant reduction in BLS disease severity and maximized the agronomic attributes. The fungicides performed best at 150 ppm in terms of colony growth reduction. The maximum growth inhibition was recorded in Score followed by Flumax, Melodyduo, and Polyram. Score gave a significant reduction in BLS disease severity and maximized the agronomic attributes. Keywords: HBV, HCV, ICT, PCR, Risk factors, Mansehra

Pathogens associated with grain discolouration and their management in paddy (Oryza sativa L.)

Grain discoloration complex disease of rice is an emerging threat to rice crop all over the world and it acquires particular importance as it results in qualitative loss of harvested crop. So the present study was carried out to identify different fungi associated with disease and their management. The discoloured seed samples were collected from different farmer’s field during survey. Totally seven fungi including both saprophytic as well as pathogenic were isolated and identified from both blotter and potato dextrose agar method viz., Curvularia lunata (36.30 %), Helminthosporium oryzae (25.6 %), Fusarium moniliformae (19.6 %), Colletotrichum gloeosporioids (8.1 %) and Alternaria spp. (7.01 %) were predominantly associated with discoloured paddy seeds. Other saprophytic fungi like Aspergillus spp. (16.6 %) and Rhizopus spp. (12.1 %) were frequently observed. Similarly among the eleven treatment including control, seed treatment with carbendazim 50 WP (2 g kg-1) with two sprays of tebuconazole 250 EC at 0.1 per cent concentration and tricyclazole 18 % + mancozeb 62 % WP at 0.2 per cent first spray during flowering stage and second spray during 15 days after first spray reducing discoloured panicle by 61.46 per cent and 59.92 per cent, respectively.

Status of Rice Brown Spot (Helminthosporium oryza) Management in India: A Review

Rice is one of the most widely consumed staple food for more than half of the population in the world. Brown spot caused by Helminthosporium oryzae accounts for 5% yield loss worldwide annually. Adversely affected fields show yield loss as high as 45%. The present study focuses on the several management aspects that are currently used to curb out the disease incidence and measures to be taken in near future for designing effective disease management protocol. The disease is of historic significance and a devasting outbroke in the Bengal Province during 1943 ended as the Great Bengal Famine resulting in starvation and an estimated demise of 2.1 to 3 million people. Brown spot is still devastating on looking the present scenario of damage to rice. Different approaches have been adopted ranging from the use of brown spot resistant rice cultivars, chemical ameliorations and biological control measures for the management of the disease. But, still the disease seems to be chronic and adverse in the current scenario. In this review, we have highlighted epidemiology, control measures practiced and several quantitative and qualitative gaps with respect to disease management, which if rectified, would lead to a strong impact on crop disease control and the sustainable Rice production that are pertinent to the present situation of farmers.

FREQUENCY OF FUNGAL MYCOFLORA ON RICE

Introduction: Rice (Oryza sativa L.) is the second best essential cereal crop of the world as well as of Pakistan. There are various fungal pathogens that attack on rice and cause various rice diseases. Methods: Therefore, the present experiments were done to isolated different fungi associated with seeds, stems, and leaves of commercially grown rice varieties and of mainly isolated species. Results: Several fungi, namely, Magnaporthe oryzae, Curvularia lunata, Helminthosporium oryzae, Fusarium moniliforme, Alternaria alternata, Nigrospora oryzae, and Aspergillus niger were isolated from seeds, stems, and affected leaves of rice. Conclusion: In our research, the frequency of fungal mycoflora on rice has been calculated and the maximum isolates of Fusarium spp. have been found.

Biocontrol of Rice Seedling Rot Disease Caused by Curvularia lunata and Helminthosporium oryzae by Epiphytic Yeasts from Plant Leaves

Seedling rot disease in rice leads to significant loss in the production of seedlings. This research was conducted to explore yeasts that could be used as biological control agents against rice seedling rot disease caused by Curvularia lunata and Helminthosporium oryzae. In total, 167 epiphytic yeast strains were evaluated, revealing that 13 of these yeast strains demonstrated antagonistic activities against fungal pathogens and either C. lunata DOAC 2313 or H. oryzae DOAC 2293. The volatile organic compounds (VOCs) and biofilm produced were possible antagonistic mechanisms in vitro for all the antagonistic yeast strains. Using nursery trays in a greenhouse, this study evaluated the control of rice seedling rot disease caused by these two fungal pathogens using antagonistic yeasts, identified in the present study and from our previous study. Torulaspora indica DMKU-RP31 and Wickerhamomyces anomalus YE-42 were found to completely control rice seedling rot disease caused by both of these fungal pathogens. Furthermore, W. anomalus DMKU-RP04 revealed 100% disease control when the disease was caused by H. oryzae. This is the first report on using antagonistic yeasts to control rice seedling rot disease caused by C. lunata and H. oryzae. These three antagonistic yeasts also showed promising potential for development as biocontrol agents against rice seedling rot disease caused by fungi.

Synthesis and Evaluation of Isatin Derivatives as Antifungal Agents

Various types of isatin derivatives were synthesized by reacting isatin with different reagents viz substituted acetophenones, sodium nitrate, hydroxylamine hydrochloride and hydrazine hydrate. Characterization of the synthesized compounds was done by using various spectral techniques such as IR, 1HNMR, 13CNMR, elemental analysis and mass spectrometry. Synthesized compounds were further evaluated for their antifungal activity against Helminthosporium oryzae, Rhizoctonia solani and Fusarium moniliforme using poison food technique. 3-(2-Oxo-2-phenylethylidene) indolin- 2-one showed significant mycelium inhibition against all tested rice fungi.

KAJIAN MACAM PUPUK KANDANG PADA 3 JENIS PADI TERHADAP INTENSITAS PENYAKIT BERCAK DAUN (Helminthosporium oryzae.)

Kajian macam pupuk kandang pada 3 jenis padi terhadap intensitas penyakit bercak daun (Helminthosporium oryzae.) telah dilaksanakan mulai tanggal 17 Oktober 2018 sampai 31 Januari 2019 di Dusun Brongsongan, Desa Sidorejo, Kecamatan Bendosari, Kabupaten Sukoharjo dengan ketinggian tempat 104 m diatas permukaan laut dan jenis tanah gromosol. Tujuan penelitian ini untuk mengkaji macam pupuk kandang pada 3 jenis padi terhadap intensitas penyakit bercak daun (Helminthosporium oryzae). Penelitian ini menggunakan Rancangan Acak Kelompok Lengkap (RAKL) dengan metode Split Plot / tata letak RPT ( Rancangan Petak Terpisah ) yang terdiri dari 2 faktor perlakuan yaitu penggunaan macam pupuk kandang sebagai sub plot / anak petak dan jenis padi sebagai main plot / petak utama sehingga diperoleh 12 kombinasi perlakuan dan masing-masing diulang 3 kali sehingga di peroleh 36 kombinasi. Adapun kedua faktor tersebut adalah : (1). Jenis Padi (V) sebagai main plot / petak utama yaitu : V1 padi hitam, V2 padi merah, V3 padi putih (2). Macam Pupuk Kandang (P) sebagai sub plot / anak petak yaitu : P0 tanpa pupuk kandang, P1 pupuk kandang sapi, P2 pupuk kandang kambing, P3 pupuk kandang ayam. Data dianalisis menggunakan Analisis Ragam, yang dilanjutkan dengan Uji Beda Nyata Terkecil pada taraf 5 %. Hasil penelitian menunjukkan gejala penyakit bercak daun (Helminthosporium oryzae) muncul pertama kali pada umur 30 hari setelah tanam pada jenis padi hitam (V1), sedangkan gejala penyakit bercak daun (Helminthosporium oryzae) merata pada jenis padi hitam (V1) dan putih (V3). Intensitas penyakit bercak daun (Helminthosporium oryzae) terendah pada jenis padi merah sedangkan intensitas penyakit bercak daun tertinggi pada penggunaan pupuk kandang ayam pada jenis padi hitam dan putih Penggunaan pupuk kandang kambing pada jenis padi merah memberikan hasil tertinggi pada berat kering panen yaitu 421,21 gram dan berat kering gilling yaitu 283,70 gram.