Ecofriendly Management of Wheat Panicle Blast Caused by Magnaporthe oryzae triticum

In this study, three wheat varieties were tested to determine seed germination and the incidence of Magnaporthe oryzae triticum (MoT). Among these varieties, BARI Gom 24 (Prodip) wheat seed exhibited the highest seed germination rate (93%) but also had the highest incidence (30%) of MoT. To manage blast disease in an ecofriendly manner, seven treatments were employed: T1 = Control, T2 = Garlic clove extracts, T3 = Aloe vera leaf extracts, T4 = Black cumin seed extracts, T5 = Neem leaf extracts, T6 = Nativo 75 WG, and T7 = Provax 200 WP. The experiment was conducted using a Randomized Complete Block Design (RCBD) layout with three replications using Prodip wheat variety that exhibited highest MoT infection severity based on laboratory analysis among collected varieties. Data were collected on blast disease incidence (%), disease severity, and various growth and yield parameters of wheat. The experiment’s results indicated that among all the treatments, T7 (Seed treatment with Provax 200 WP) and T5 (Foliar spraying with Neem leaf extract) performed better in controlling blast disease in wheat. The lowest blast disease incidence (%) was observed with T7 (Provax 200 WP), with values of 7.86, 9.86, and 10.19 recorded during the milking stage, soft dough stage, and hard dough stage of wheat, respectively. T5 (Neem leaf extract) also demonstrated a statistically equivalent reduction in blast disease incidence (%). In terms of disease severity, T7 (Seed treatment with Provax 200 WP) showed the lowest values of 1.03, 1.23, and 1.63 during the milking stage, soft dough stage, and hard dough stage of wheat, respectively. Foliar spraying with neem leaf extract also exhibited similar result as of Provax 200 WP regarding panicle blast severity. As a result of these findings, it can be concluded that T5 (Neem leaf extract) is recommended as an ecofriendly management approach for blast disease in wheat.

Efficacy of Plant Extracts on Morphology and Cultural Characteristics of Bipolaris sorokiniana, Causing Black Point Disease of Wheat in Bangladesh

Black point of wheat caused by Bipolaris sorokiniana (Bs) is very destructive disease of wheat in Bangladesh and all over the world. The symptoms of diseases caused by Bipolaris sorokiniana can vary depending on the host plant and environmental conditions. The conidia of Bs germinate from two poles, which differ physiologically as indicated by the rate, growth character, of length, breadth and number of septa on different media. The aim of this study was to evaluate the efficacy of selected plant extracts on the morphology and cultural characteristics of the fungus Bipolaris sorokiniana causing black point disease in wheat crops in Bangladesh. The efficacy of fifteen plant extracts on the growth and characteristics of Bs was conducted in vitro in 2019-2020. The treatments were: Untreated control, T1—Black berry Leaves, T2—Guava Leaves, T3—Lantena camera leaves, T4—Eucalyptus Leaves, T5— Turmeric Leaves, T6—Khoksha Leaves, T7—Papaya leaves, T8-Gurlic Bulb, T9—Chili dust, T10—Nigella seeds, T11—Turmeric dust, T12—Cloves, T13— Bohera fruits, T14—Black pepper and T15—Neem leaves. After 15 days of inoculation of Bipolaris sorokiniana, colony color and shapes were Gerrish blackish, greenish blackish, greyish blackish and shapes were round or irregular. In our study, conidia color was dark brown to light brown, conidiophore color was brown, dark brown, grayish brown, dark olivaceous, light brown and conidia shapes were elliptical, oblong or slightly curved. The septation of conidia was 2 - 5 and highest septation was seen in T4 and T14 treatments. The highest conidial length was 17.79 μm recorded in T2 treatment and lowest was 6.62 μm T9 treatment where conidial breath was 8.27 μm in control and lowest was 3.79 μm in T8 treatment. Mycelial growth rate of Bipolaris sorokiniana was different in different treatments in different days after inoculation (DAI) where at 7 DAI, % reduction of mycelial growth over control was highest in Bohera and Neem Leaves treatments respectively.

In Vitro Efficacy Assessment of Botanical Extracts against Botrytis gladiolorum Causing Gladiolus Leaf Blight

An experiment was conducted at the Mycology laboratory, Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh to find out the efficacy of selected botanical extracts against Botrytis gladiolorum (Bg) causing gladiolus leaf blight. Infected leaves samples were collected from gladiolus farmers’ field and brought to the laboratory for study. Ten selected botanicals were used against the colony growth of (Bg). The botanicals were Mehendi, Chrysanthemum, Basil (Tulsi), Onion, Neem, Bael, Arjuna, Garlic, Aloevera (Ghritkumary) and Turmeric. Botanical extracts were applied at the rate of 5%, 10% and 20%. The radial mycelia growth was found minimum (11.60 mm) in garlic extract treated plate at the dose of 5% at 5 DAI, which was statistically similar with turmeric extract treated (14.00 mm) plate and the inhibition of growth was 60% and 51.72%, respectively. Similar trend was found at 10 DAI and 15 DAI. At 15 DAI, garlic and turmeric extract gave the best result against Bg, which was statistically similar with onion (50.07% inhibition) and mehendi (49.93%). All botanicals showed significantly different results over control and found effective in reducing the mycelial growth at the dose of 10%. At 5 DAI, no radial mycelia growth was found in garlic treated plate, which was statistically similar with onion treated plate, means that the inhibition of growth was 100%. Similar trend was also found at 10 DAI, and 15 DAI but at 15 DAI, onion (30.20 mm) gave the statistically similar results with Garlic (30.10 mm) and the mycelia growth inhibition was (57.70%) and (57.84%), respectively. In case of 20% dose, garlic extract showed the best result at 5 DAI and the radial mycelia growth was found minimum (00.00 mm) which was statistically similar with onion extract treated (00.00 mm) plate and turmeric extract treated plate. The inhibition of growth was 100%. At 15 DAI, the inhibition of fungal growth was found (73.74%), (71.23%) and (66.90%), respectively with treated by turmeric (18.80 mm), garlic (20.60 mm) and onion (23.70 mm).

Morphological, Cultural, Molecular and Pathogenic Variation of Bipolaris sorokiniana in Wheat

One hundred and twenty isolates of Bipolaris sorokiniana of wheat were isolated, identified and characterized based on morphological, cultural, pathogenic and ITS (Internal Transcribed Spacer) based molecular parameters. Collected isolates differed in respect of radial mycelial growth rate, color of the colony, surface texture of the colony, shape of the colony, conidia production ability and shape and color of conidia. ITS1 and ITS4 based PCR products yielded a species-specific band of 600 bp (base pairs) on agarose gel for the confirmation of B. sorokiniana. The mycelial growth rate of the isolates ranged from 1.39 to 4.46 mm/day. The septation of conidia ranged from 1.4 to 8.6. On the basis of conidia morphology, the isolates were grouped into five different groups, whereas the isolates were grouped into 12 cultural groups based on cultural characteristics. Cultural group 8 [CG (Cultural Group)-8] was the most virulent [38.5% LAD (Leaf area diseased)] and [CG (cultural Group)-4] was the less virulent [2% LAD (Leaf area diseased)] group among 12 groups when inoculated at tillering stage of wheat cv. Kachan.

<i>In Vitro</i>Efficacy of Botanicals against Rice Blast Pathogen <i>Magnaporthe oryzae oryzae</i>

Rice is the most staple cereal crop of Bangladesh and rice blast caused by Magnaporthe oryzae oryzae (MoO) has become a major factor limiting rice yield in Bangladesh and throughout the world. Eight botanicals extracted both in water and ethanol namely Kalijira (Nigella sativa), Turmeric (Curcuma longa), Ginger (Zingiber officinalis), Garlic (Allium sativum), Onion (Allium cepa), Neem (Azadirachta indica), Allamanda (Allamanda cathartica) and Aloevera (Aloe vera) were tested against MoO in vitro in the Mycology Laboratory, Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh. All the botanicals significantly reduced radial growth of the tested pathogen. Maximum mycelia growth inhibition of MoO was achieved with water extract of turmeric (1:1 w/v) and ethanol extracts of neem (1:4 w/v) with 86.57% and 92.62% mycelia growth inhibition at 14 DAI, respectively.

Morphological, Pathological, Biochemical and Molecular Characterization of <i>Ralstonia solanacearum</i>Isolates in Bangladesh

One thirty samples (fifty-five potato tubers, twenty-seven potato stems, three chili stems, twenty-eight soil samples, five weed samples, three banana leaves, and nine water samples) were examined and one hundred six (106) Bangladeshi isolates of Ralstonia solanacearum were isolated and identified. Isolation was made on selective media (Tetrazolium chloride media) and R. solanacearum was identified based on morphological, pathological and biochemical properties and polymerase chain reaction (PCR) by using the species-specific primers. Studies showed that 81.54% (106) samples were positive on tetrazolium chloride solid medium. Among them 90 isolates were virulent and rest of them were avirulent. Fifty isolates were selected for chemical characterization based on hypersensitivity test. R. solanacearum is gram negative, aerobic facultative bacteria on the basis of chemical characterization. Fifty tested isolates expressed as race 3 while in biovar test forty-eight showed as biovar III and the rest two showed as biovar I. In nine tested isolates from the three districts a species-specific band of 280 bp was amplified in PCR that confirmed the identity of R. solanacerum.

Prevalence of Seed-Borne Fungi Associated with Seeds of Some Selected Flowers

The prevalence of fungi associated with seeds of some selected local flowers namely cosmos, marigold, calendula, and periwinkle collected from three different locations (Arboriculture Garden, Ramna Park Garden, and Horticulture Garden) in Dhaka district and four hybrid flower seeds (African marigold, cockscomb, petunia, and Portulaca) collected from Momin Beej Ghar, Dhaka district were recorded. The results showed that the highest percent germination (91.38%) of cosmos was obtained from Horticulture garden’s seed, marigold (95.25%) obtained from Arboriculture garden’s seed, and calendula (65.88%) periwinkle (79.38%) obtained from Ramna park garden’s seeds. But in the case of hybrid seeds, African marigold showed the highest percent seed germination (98.25%). The Horticulture garden’s seed was better than the others considering the incidence of fungi in all local flower seeds tested. But periwinkle was the lowest affected seed (12.58%, 12.20%, 8.07% incidence) and marigold was the highest affected seed (40.31%, 35.33%, 31.33% incidence) collected from Arboriculture Garden, Ramna Park, and Horticulture Garden, respectively. But in hybrid flower seeds, the lowest fungal infection (3.14%) was recorded in Portulaca and petunia seeds whereas the highest (6.20%) was in African marigold seeds.

Phytohormone-Induced Resistance against <i>Xanthomonas axonopodis</i>PV. <i>citri</i>in <i>Citrus aurantifolia</i>

Citrus canker is a perilous disease caused by Xanthomonas axonopodis pv. citri (Xac) which is hardly manageable. Till now, chemicals used against Xac either proved less effective against the disease or hazardous for environment. In this study, we investigated how phytohormones such as Salicylic acid (SA, 3 mM), Jasmonic acid (JA, 0.3 mM), 3-indolacetonitrile (IAN, 0.6 mM), Nicotinic acid (NA, 5 mM), Folic acid (FA, 0.5 mM) influenced canker disease. Disease severity and lesion diameter were significantly mitigated by exogenous application of these phytohormones compared with water (control) accompanied by the increase of latent period. However, these phytohormones did not show any in vitro antimicrobial properties against Xac. Concomitant with boosted resistance, phytohormones treated leaves showed the higher level of phenyl ammonia lyase (PAL) activity. Besides, total phenolic compounds (TPC) and potassium contents were also higher in phytohormone treated plants compared with control. Phytohormones showed the significant and better performance on disease mitigation than control among which, SA showed the highest performance while JA and INA showed the moderate performance. However, NA and FA showed the lowest performance. This result recommended that application of some phytohormones had elicited some biochemical and physiological events which induced the resistance against Xac.

Effect of Chemical Seed Treatment and BAU-Biofungicide on <i>Alternaria</i>Blight <i>(Alternaria brassicae)</i>of Mustard

The efficacy of three seed treating chemicals viz. Provax 200 WP, Brine solution, Rovral 50 WP and one Biofungicide viz. BAU-Biofungicide were evaluated against Alternaria blight of mustard caused by Alternaria brassicae and Alternaria brassicicola. Three varieties viz. var. BARI-6, Tori-7 and SAU-Shorisha-1 were used in this study. The field experiment was conducted in the farm of Sher-e-Bangla Agricultural University, Dhaka and laboratory experiment was conducted in the seed health Laboratory, Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka-1207 during the period from November 2008 to July 2009. Among the seed treating chemicals, Rovral 50WP showed the best performance in reducing disease incidence and severity as well as increasing seed yield. Application of Rovral 50 WP gave the best result in increasing the number of pod per plant, pod length (cm), number of branch per plant, 100 siliqua weight (g) and 1000 seed weight (g). BAU-Biofungicide also showed promising performance in controlling Alternaria blight of mustard and reduced 36% and 53% disease incidence and disease severity respectively over untreated control. BAU-Biofungicide may be recommended as an alternative means of chemical fungicide such as Rovral 50 WP for controlling Alternaria blight of mustard.