Identification and Characterization of Triple Action Bioagents (TAB) and Their Potency against Fusarium Wilt of Lentil

Fusarium wilt is a severe disease that plays a significant role in reducing the yield of lentil. Under favorable conditions for disease growth, the disease can cause complete crop failure and can be a crucial limiting issue for lentil cultivation in specific geographical zones. The current work focused on isolating potentialbio-agents exhibiting copper oxychloride resistance and evaluating their efficacy in seed treatment for ecologically sustainable management of Fusarium wilt of lentil. Seventy biocontrol agent isolates were isolated and tested for resistance by growing them on Potato Dextrose Agar medium (PDA) amended with copper oxychloride at the rate of 2500 ppm. Isolate-H10 and isolate-C9 showed more excellent compatibility with copper oxychloride fungicide with 69 mm and 65 mm radial growths, respectively. The isolates H10 and C9 had the highest inhibitory percentages of 84.30% and 83.94% against Fusarium oxysporum f. sp. lentis, respectively, and the highest phosphorus solubilization index (PSI). Primers (ITS 1 and ITS 4) identified these putative bioagents as Trichoderma harzianum isolate skua-tab-1 and Penicillium crysogenum strain Tab2. Sequences were submitted to the NCBI and assigned the accession numbers MK414603 and MK418066. In pot culture, these isolates also demonstrated their superiority in reducing the disease incidence and severity if seeds were treated with H10 and C9 alone or in combination with copper oxychloride fungicide. The two isolated bioagents exhibit three fundamental properties: compatibility with copper oxychloride, antagonistic activity toward the pathogen fall armyworm, and the ability to dissolve phosphorus minerals.

Facile Synthesis of Crosslinked Cu:ZnS-Lignocellulose Nanocomposite: A Potent Antifungal and Antisporulant System Against The Tea Pathogen Exobasidium Vexans

The objective of the present study was to synthesize Cu doped ZnS nanocore crosslinked with lignocellulose (represented as Cu:ZnS-lignocellulose nanocomposite) for antifungal action against the devastating tea blister blight pathogen Exobasidium vexans. The characteristic features of the nanocomposite were analyzed via different physicochemical techniques like FTIR, XRD, XPS, SEM, SEM-EDX, Elemental mapping, PCS, and UV-PL studies. The FTIR and XPS investigations revealed the crosslinking between lignocellulose and the Cu:ZnS. The presence of lignocellulose was seen to attribute a potent antifungal efficacy, also enhancing the stability of the resulting nanocomposite in aqueous suspensions. The antifungal efficacy confirmed through disk diffusion and broth dilution assays have a maximum zone of inhibition of 1.75 cm2 and a MIC50 of 0.05 mg/ml against E. vexans. Additionally, the antisporulant activity was evident as the basidiospores failed to germinate in presence of the Cu:ZnS-lignocellulose nanocomposites. This shows potential for stemming the rapid infectivity of E. vexans by achieving disease inhibition at the early stage. Finally, the comparison with two commonly used commercial fungicides (copper oxychloride and fluconazole) demonstrated > 10-fold higher antifungal activity for Cu:ZnS-lignocellulose nanocomposites.

Root Rot Disease Incited by Macrophomina phaseolina in Arid Legumes and their Management: A Review

Macrophomina phaseolina (Tassi) Goid. is a soil- and seed-borne pathogen that causes charcoal rot and various rots and blights of more than 500 crop species. Dry root rot (DRR) also called as charcoal rot which causes yield loss ranged from 25-48 per cent. The pathogen is necrotroph and infects a wide range of crops. It is observed that mycelium of M. phaseolina in cotyledons, plumule and radicle, in the naturally infected seeds of mungbean and cowpea. The disease symptoms are clearly visible from the time of emergence and can be evaluated at various stages of development of the plant. The mechanical plugging of the xylem vessels by microsclerotia, toxin production, enzymatic action and mechanical pressure during penetration lead to disease development. Management of M. phaseolina aim to reduce the number of sclerotia in soil or to minimize the contact of the inoculum and the host. Soil solarization can be a cost-effective method for management of soil borne diseases. Disease suppression by biocontrol agents such as Trichoderma harzianum, T. viride and Bacillus subtilis are the sustained manifestation of interactions among the plant, the pathogen, the biocontrol agent, the microbial community on and around the plant and the physical environment and considerably inhibited growth of M. phaseolina. Essential oils and plant extracts contain a multitude of bioactive substances against fungi, bacteria and nematodes. It has been reported that neem oil, turmeric and garlic was effective against M. phaseolina in in vitro condition. Chemical control is an effective method when seed treatment and foliar spray of carbendazim, topsin M-70, captan, thiram, mancozeb, copper oxychloride against root rot and leaf blight (Macrophomina phaseolina) topsin M-70, captan, thiram, mancozeb, copper oxychloride against root rot (Macrophomina phaseolina). As non-chemical alternative methods can be time-consuming and less effective against soilborne plant pathogens. Chemical control is an effective method of controlling some soilborne diseases in agricultural crops. Varoius workers are reported compatibility of biocontrol agents with fungicides and found that Carbendazim and biocontrol agents Trichoderma viride, T. harizianum were found effective under in vitro and pot condition.

Asian Rust Severity in Soybean Sown in December and February in Mato Grosso State

The objective of this work was to assess the effect of December sowing time with February on the Asian soybean rust severity. In on-farm trials two soybean treatments sowing in December (2020) (DSS.) and February (2021) (FSS) were assessed for Asian soybean rust severity in 24 sites, in three regions of Mato Grosso state. The DSS treatment was established in the growers commercial farms and the FSS in a 5 ha area sown specifically for this treatment. The DSS treatment was conducted in 16 sites and the FSS in eigth. For rust control fungicides with efficacy higher than 60% were sprayed consisting of DMIs, QoIs and SDHIs in double or triple mixtures, always added by multisites (chlorothalonil, mancozeb, or copper oxychloride). About eighty soybean leaflets from four plots repetitiond, demarcated at random in each field, were taken in each smpling. In laboratory leaflet severity was appraised and area under disease progress curve (AUDPC) calculated. Related to DSS, the AUDPC overall mean was 174 units and receiving 6.9 fungicide spraying and for FSS 26 units with 4.8 fungicide sprayings. Our results reinforce that the sowing time can be changed from the end of December to February to maintain soybean crop sustainability.

​Integrated Management Protocol for Bacterial Wilt Disease of Tomato in Ralstonia solanacearum Affected Soils in Kerala State

Background: Management of bacterial wilt of tomato in Ralstonia solanacearum affected soils is a major issue in tomato cultivation in different agro-ecological regions in Kerala state which affects the production and productivity of the crop. To develop a suitable management protocol for this disease, the field experiments were conducted during 2019 and 2020 in a bacterial wilt-sick field at Kerala agricultural university, Thrissur, Kerala, India. Methods: Twelve different treatments viz. soil application of bleaching powder, soil test based lime application, streptocycline root dip, drenching of copper hydroxide and copper oxychloride at different doses, seed treatment and seedling dip with Pseudomonas fluorescens, drenching of Pseudomonas fluorescens, planting grafted seedlings and different integrations and combinations of the above treatments were assessed for the management of bacterial wilt. Result: The majority of integrations were superior over individual treatments. The higher yield with less disease incidence was obtained from the integration of soil treatment of bleaching powder (15 kg/ha) + soil test based lime application + streptocycline (@ 2 g/10 L) root dip + drenching of copper oxychloride (@ 0.3%) and therefore, this integration protocol is recommended for management of bacterial wilt of tomato in wilt affected soils in Kerala state.

Fasulye Bakteriyel Adi Yanıklık Hastalığına Karşı Farklı Bakırlı Bileşiklerin Etkililiği

Common bacterial blight (CBB) caused by Xanthomonas axonopodis pv. phaseoli is the most destructive bacterial disease affecting all bean varieties in production areas. In this study, the effectiveness of different copper preparations against CBB disease on dry beans of Alberto variety, which are widely grown in Konya and Afyonkarahisar provinces with different climatic characteristics, were investigated. In field conditions, after 5-week-old bean plants were inoculated with a bacterial suspension of 108 CFU mL-1 of high virulent Xap k133 isolate, and subsequently twice every with 5 days intervals after inoculation, copper hydroxide, copper sulphate pentahydrate, copper oxychloride + copper hydroxide and copper oxychloride were applied at the doses recommended by the manufacturers. Disease severity (%) and disease score were evaluated using the 0-9 scale, and the effectiveness of the chemicals was compared with the control plants sprayed with water and determined with the help of the Abbott formula. According to the statistical data obtained, the most effective copper compound was determined by the application of copper oxychloride with 42.59-47.25% efficiency rates, copper sulphate pentahydrate had the lowest efficiency with about 7.69-12.96%. In addition to the negative effects of excessive use of copper in agriculture on the environment and human health, copper-resistant strains develops in bacterial pathogens. In order to determine the most effective copper compounds against CBB disease in dry beans in our country, the effectiveness of used as common compounds have been investigated for the first time and an organic and environmentally friendly sustainable bean production is revealed by using less copper.

Facile synthesis of crosslinked Cu:ZnS-lignocellulose nanocomposite: a potent antifungal and antisporulant system against the tea pathogen Exobasidium vexans

The objective of the present study was to synthesize Cu doped ZnS nanocore crosslinked with lignocellulose (represented as Cu:ZnS-lignocellulose nanocomposite) for antifungal action against the devastating tea blister blight pathogen Exobasidium vexans. The characteristic features of the nanocomposite were analyzed via different physicochemical techniques like FTIR, XRD, XPS, SEM, SEM-EDX, Elemental mapping, PCS, and UV-PL studies. The FTIR and XPS investigations revealed the crosslinking between lignocellulose and the Cu:ZnS. The presence of lignocellulose was seen to attribute a potent antifungal efficacy, also enhancing the stability of the resulting nanocomposite in aqueous suspensions. The antifungal efficacy confirmed through disk diffusion and broth dilution assays have a maximum zone of inhibition of 1.75 cm2 and a MIC50 of 0.05 mg/ml against E. vexans. Additionally, the antisporulant activity was evident as the basidiospores failed to germinate in presence of the Cu:ZnS-lignocellulose nanocomposites. This shows potential for stemming the rapid infectivity of E. vexans by achieving disease inhibition at the early stage. Finally, the comparison with two commonly used commercial fungicides (copper oxychloride and fluconazole) demonstrated >10-fold higher antifungal activity for Cu:ZnS-lignocellulose nanocomposites.

In vitro efficacy of fungicides on mycelial growth and spore germination of Alternaria alternata and Mucor plumbeus

Tomato fruits were infected by various pathogens especially fungal pathogens under storage conditions as well as in field conditions. It was revealed that tomato fruits are attacked by Alternaria alternata causing Alternaria rot of tomato and Mucor plumbeus causing Mucor rot of tomato. Antifungal activity of some fungicides was undertaken during the present study. Different concentrations of fungicides brought about significant reduction in the mycelial growth and spore germination of Alternaria alternata and Mucor plumbeus under in vitro conditions. Hexaconozole proved highly effective in inhibiting the mycelial growth and spore germination of Alternaria alternata followed by carbendazim and copper oxychloride respectively. However, the most effective fungicide in inhibiting the mycelial growth and spore germination of Mucor plumbeus was hexaconozole followed by carbendazim and copper oxychloride respectively. Keywords: In vitro, fungicides, Alternaria alternata and Mucor plumbeus, mycelial growth, spore germination