Application of Mixtures of Chemical and Biocontrol Agents Against Anthracnose (Colletotrichum gloeosporioides) of Citrus and Pathogen Variability in Local Zone

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Mango Anthracnose: Economic Impact and Current Options For Integrated Managaement.

Annona squamosa is a tropical fruit susceptible to various diseases that significantly impact its yield and quality of the fruits. Colletotrichum spp. rank among the top ten most destructive fungal pathogens globally, occupying the 8th position due to their significant impact on agriculture. These fungi are hemibiotrophic in nature, with over 1,000 known species, and most crops are susceptible to at least one of these. They cause various diseases, including leaf spots, blights, and fruit rots. Symptoms manifest on horticultural crops' leaves, flowers, fruits, and branches, often resulting in substantial yield losses. Colletotrichum species exhibit a latency mechanism that can exacerbate damage during post-harvest storage, leading to up to 80 % production losses in some instances. Experiments were carried out in Randomized Block Design with seven treatments and three replications at the C1 block of Regional Research Station, TNAU, Aruppukottai, Virudhunagar District, Tamil Nadu, to identify and manage the pathogens causing leaf spot and fruit rot in custard apples. Pathogens isolated from the rotten fruit rind and mesocarp were identified as Colletotrichum siamense (Acc No: OM736073) and Colletotrichum gloeosporioides (Acc No: OM736066), respectively, through morphological and molecular analyses. The isolated DNA of the respective pathogens were amplified using PCR with ITS 1 & 4 primers. Then, the amplified product (550bp) was sequenced and submitted to the NCBI website. Pathogenicity tests confirmed these isolates as the causative agents for the leaf spot and fruit rot symptoms. Field experiments were conducted for two consecutive years to evaluate the efficacy of various treatments in managing leaf spot and fruit rot diseases. Before spraying, the leaf spot and fruit rot incidence are 77 and 27, respectively, in the control plot. The combined fungicide formulation, Tebuconazole 25 % + Trifloxystrobin 50 % WG (0.1 %), showed the highest disease reduction (60.44 %) and yield enhancement (15.50 kg/tree). The spraying of neem seed kernel extract (5 %) and Bacillus subtilis (0.5 %) also resulted in significant disease reduction and yield improvement. The study highlights the importance of combining chemical and biocontrol agents with integrated disease management strategies to manage custard apple diseases effectively. Neem products are always safe for the environment, Humans and animals and when they are used in correct concentration they won't leave any residues. Likewise, biocontrol agents are target-specific and never harm the beneficial microbes in soil and the plant system.

Abstracts, The Canadian Phytopathological Society annual meeting, London, Ontario, 2001

Mango (Mangifera indica L.), known as the "King of Fruits," is a major fruit crop cultivated in India and worldwide. Anthracnose, caused by Colletotrichum gloeosporioides, is a primary biotic stress affecting mango production, yield, and export quality in all mango-growing regions. This study evaluated the response of mango varieties to anthracnose and its management using effective fungicides and biocontrol agents. Ten C. gloeosporioides isolates were isolated from samples collected from the Kollam and Thiruvananthapuram districts in Kerala. Among them, isolate C10 from Thiruvananthapuram was the most virulent. Among five local mango varieties (Kottukonam, Priyoor, Neelam, Rumani, and Totapuri) screened through artificial inoculation, Totapuri displayed the lowest disease severity (45.4%), followed by Neelam and Rumani, while Kottukonam exhibited the highest (72.33%). In vitro, the study of different biocontrol agents showed that Bacillus amyloliquefaciens VLY24 showed 37.08% inhibition against the pathogen, followed by 32.87% inhibition by Bacillus velezensis PSCE-10. Carbendazim 50% WP at 0.1% and 0.2% exhibited 100% mycelial growth suppression.

BackgroundMango anthracnose, caused by Colletotrichum gloeosporioides, is one of the most important diseases of mango crop. It mainly attacks leaves, flowers, young fruits and twigs and also appears as a post-harvest disease of ripened fruits. Application of bio-control agents has huge potential in plant disease management. The goal of the present research was to establish the potential of individual and combined bio-control agents for the management of mango anthracnose under in vitro and under field conditions.ResultsThe antagonistic reaction of six fungi, six bacteria and nine yeasts against C. gloeosporioides on potato dextrose agar medium and malt extract agar medium was observed among which Trichoderma harzianum was found to be the most efficient with 89.26% mycelial growth inhibition. Evaluation of bio-control agents against anthracnose disease development on mango fruit revealed that dip treatment of mango fruits in spore suspension (1.2 × 104 cfu/ml) of T. harzianum for 5 min was the most effective and provided disease control to the tune of 81.67%. Combined application of effective bio-control agents as a post-harvest fruit dip treatment was also evaluated against the mango anthracnose on mango fruits, where the treatment of T. harzianum + Pichia anomala was very effective with 93.39% disease control. Under field conditions, three consecutive sprays of T. harzianum, starting with the initiation of disease on leaves, followed by other two sprays at an interval of 15 days during 2015 and 2016 were found the best for the management of mango anthracnose disease both on leaves and on fruits at two locations.ConclusionsThe combined and individual applications of bio-control agents, viz.T. harzianum, Bacillus subtilis and P. anomala, through foliar spray or by fruit dip had the potential to control mango anthracnose. The bio-formulations of these bio-control agents had the potential to replace chemical fungicides and also protect the natural environment, thus playing a significant role in integrated disease management.

Mango anthracnose caused by Colletotrichum gloeosporioides Penz. is economically important disease of mango (Mangifera indica L.). The experiments were conducted to evaluate the germplasm and efficacy of fungicides, biocontrol agents against anthracnose in mango nursery at Punjab Agricultural University, Ludhiana, University Seed Farm, Ludhiana and M S Randhawa Fruit Research Station, Gangian, Hoshiarpur during 2017-18. Twenty five mango cultivars were screened both under laboratory conditions by using detached leaf method and under field conditions. All the cultivars had shown susceptible reaction under laboratory and field conditions with highly susceptible reaction of Malika under laboratory conditions. The fungicides (carbendazim, thiophanate methyl, azoxystrobin, propiconazole, difenoconazole, copper oxychloride, mancozeb) and two biocontrol agents (Trichoderma harzianum and Pseudomonas fluorescens) were evaluated in vitro through poisoned food technique and dual culture technique, respectively. Azoxystrobin and propiconazole were found to be highly effective in inhibiting the mycelial growth (100%) of C. gloeosporioides at 50 μg/ml and 100 μg/ml and at 100 μg/ml, respectively. All the fungicides and biocontrol agents, tested in vitro were also evaluated under field conditions for management of mango anthracnose. Azoxystrobin and propiconazole were significantly effective in reducing per cent disease index and providing disease control at Ladhowal, Ludhiana and Gangian, Hoshiarpur.

Abstract. Pangastuti A, Pratiwi H, Setyaningsih R. 2023. Screening for endophytic bacteria from Ambon Banana (Musa paradisiaca L.) as biocontrol agent of anthracnose (Colletotrichum gloeosporioides) on bananas fruit. Nusantara Bioscience 15: 238-244. Post-harvest Ambon Bananas (Musa paradisiaca L.) are sensitive to anthracnose disease, caused by Colletotrichum gloeosporioides, and causes the fruit to rot quickly. Thus, chemical fungicides are employed, damaging living organisms and the environment. One solution is biocontrol using endophytic microorganisms as antagonistic agents against the anthracnose fungus that causes anthracnose disease. This study aimed to obtain potential endophytic bacteria from the Ambon Banana plant that had inhibitory activity against the growth of the pathogenic fungus C. gloeosporioides that causes anthracnose in bananas. Endophytic bacteria were recovered from Ambon Banana roots by crushing plant components. Therefore, bacterial isolates were tested for antagonistic interactions with pathogenic fungi using the dual culture approach. The 16S rRNA gene sequence analysis was used to identify bacterial isolates with the most significant inhibitory potential. According to the findings of this study, seven isolates of endophytic bacteria, A2-1, A2-2, A5-2, A6-2, A6-3, A8-1, and A9-1, can limit the growth of the pathogenic fungus C. gloeosporioides. The strain A6-3, identified as Pseudomonas pseudoalcaligenes, exhibited the greatest potential as a biocontrol agent against the pathogenic fungus C. gloeosporioides. It achieved the highest inhibition rate of 43.59%, resulting in an extended fruit shelf life and reduced harm susceptibility.

Mitigating postharvest quantitative and qualitative losses in mango fruits through the application of biocontrol agents: An in-vivo and in-vitro assessment

Twenty-five isolates of Colletotrichum gloeosporioides causing mango anthracnose were collected from different agroclimatic zones of India. The isolates were evaluated for their pathogenic variability on mango seedlings and genetic characterization using random amplified polymorphic DNA (RAPD molecular techniques). The random primers OPA-1, 3, 5, 9, 11, 15, 16 and 18 were used and the twenty-five isolates were grouped into two. The amplified DNA fragments (amplicons) obtained was compared by agarose gel electrophoresis. Isolate specific RAPD fingerprints were obtained. Out of eight primers in RAPD, OPA-1, 3 and 18 were able to produce reproducible banding pattern. Each of these primers generated a short spectrum of amplicons, located between 661 and 2291-bp markers, indicative of genetic polymorphism. Dendogram revealed more than 75% level of similarity. 4.36% polymorphism was also found in individual isolates that was not statistically significant (P > 0.05) among the sample, it also indicates that all the isolates tested had approximately same genetic identity. The data suggest that RAPD may be of value by virtue of its rapidity, efficiency and reproducibility in generating genetic fingerprints of C. gloeosporioides isolates. Key words: Colletotrichum gloeosporioides, genetic identification, mango anthracnose.

Occurrence of leaf rot disease (LRDC) of coconut is related to increased incidence of root wilt disease (RWD). The palms with RWD irrespective of age are susceptible, young ones are more susceptible to LRDC. Tender leaves especially the spindle play a critical role in LRDC incidence and the disease attributed to fungal complex. Among the 14 species of LRDC Angi, several were proved to be pathogenic; Colletotrichum gloeosporioides (Penzig) Penzig and Sacc and Exserohilum rostratum (Drechsler) Leonard and Suggs are discerned as the main pathogens. C. gloesporoides was aggressive during monsoons and positively correlated with rainfall and relative humidity (11% RH, whereas Erostratum less strongly correlated Fusarium spp. predominated in dry seasons. Importance of microclimate, survival and quiescence of the pathogens are to be determined. Diagnosis of RWD by techniques such as PCR and understanding the molecular basis of vulnerability of palms to LRDC would help to initiate early control measures. Planting of RWD cum LRDC resistantl tolerant varieties after eradicating the RWD infected palms is desirable. Protection ofyoung leaves by chemical or biocontrol agents or a combination of both with phytosanitation is important. 4 system approach with integrated measures needs to be utilizedfor sound management of LRDC.

Banana ( Musa paradisiaca L.) is the most popular tropical fruit crops grown in India. It is affected by several post-harvest diseases among them anthracnose ( Colletotrichum gloeosporioides (P. Henn), caused huge loss in quality and quantity of fruits. Therefore affords were made to screen the different systemic, contact and combination of six fungicides, botaniclas and biocontrol agents in vitro condition against test fungus. Among systemic fungicides, carbendazim 50 per cent WP at 50 ppm, contact fungicides copper oxychloride 50 per cent WP at 500 ppm and combination of fungicides carbendazim 12 per cent WP + mancozeb 63 per cent WP at 100 ppm concentrations were found the most effective and gave cent per cent growth inhibition of C. gloeosporioides . Lantana leaves extract at 10 per cent solvent was also effective and resulted 66.41 per cent growth inhibition of C. gloeosporioides . Among the biocontrol agents, Trichoderma harzianum gave 62.43 per cent growth inhibition of C. gloeosporioides (62.43%).

Control of fungal phytopathogens is a significant challenge in modern agriculture. The widespread use of chemical fungicides to control these pathogens often leads to environmental and food contamination. An eco-friendly alternative that can help reduce reliance on these chemicals is plant growth–promoting bacteria (PGPB), particularly those of the genus Paenibacillus, which appear to be highly effective. The review aims to summarize the existing knowledge on the potential of Paenibacillus spp. as fungal biocontrol agents, identify knowledge gaps, and answer whether other species of the genus Paenibacillus, in addition to Paenibacillus polymyxa, can also be effective biocontrol agents. Paenibacillus spp. can combat plant phytopathogens through various mechanisms, including the production of lipopeptides (such as fusaricidin, paenimyxin, and pelgipeptin), the induction of systemic resistance (ISR), hydrolytic enzymes (chitinase, cellulase, and glucanase), and volatile organic compounds. These properties enable Paenibacillus strains to suppress the growth of fungi such as Fusarium oxysporum, F. solani, Rhizoctonia solani, Botrytis cinerea, or Colletotrichum gloeosporioides. Notably, several strains of Paenibacillus, including P. polymyxa, P. illinoisensis KJA-424, P. lentimorbus B-30488, and P. elgii JCK1400, have demonstrated efficacy in controlling fungal diseases in plants. Importantly, many formulations with Paenibacillus strains have already been patented, and some are commercially available, but most of them contain only P. polymyxa. Nevertheless, considering the data presented in this review, we believe that other strains from the Paenibacillus genus (besides P. polymyxa) will also be commercialized and used in plant protection in the future. Importantly, there is still limited information regarding their impact on the native microbiota, particularly from the metataxonomic and metagenomic perspectives. Expanding knowledge in this area could enhance the effectiveness of biocontrol agents containing Paenibacillus spp., ensuring safe and sustainable use of biological fungicides.

BackgroundFusarium odoratissimum (Foc TR4) is a devastating fungal pathogen that causes Panama wilt in Cavendish banana, a high value crop that generates significant revenue. The excessive use of synthetic fungicides for disease control poses risks to both human health and the environment. Consequently, there is a pressing need for eco-friendly alternatives to manage this disease. One potential approach is the utilization of biocontrol agents, which have shown promise in disease control. This study aimed to evaluate the biocontrol potential of fungal endophytes isolated from the naturally-resistant cultivar Cardaba banana against Foc TR4. These fungal isolates were subjected to a dual culture assay, characterized based on morpho-cultural characteristics, and confirmed molecularly using the internal transcribed spacer (ITS) region of rDNA.ResultsOf the 15 fungal endophytes isolated from Cardaba; Blakeslea trispora, Pseudopestalotiopsis theae, Xylaria badia, Nigrospora hainanensis, Colletotrichum gloeosporioides, Xylaria feejeensis, Gymnoascus reessii, Fusarium subglutinans, Rigidoporus vinctus, and Macrophomina phaseolina showed potential antagonistic activity against F. odoratissimum. Isolates X. feejeensis (USMJMTBL10), G. reesii (USMJMTBL11), and M. phaseolina (USMJMTBR1) had the highest antagonistic activity of 87.8–96.6% against F. odoratissimum in vitro.ConclusionThis study presents evidence of the potential of Cardaba-associated endophytes isolated and identified in this research, as effective biocontrol agents against F. odoratissimum, the causal agent of Panama disease in Cavendish banana. Our findings suggest that these endophytes hold promise as a biocontrol agent for managing Foc TR4-infected banana plants. Future research will focus on in planta testing, validation in greenhouse and field trials, as well as development of formulations and application protocols to optimize the utilization of these biocontrol agents in an integrated management approach for Foc TR4-infected bananas.

Pre-harvest application of biocontrol formulations consisting of 1. the two plant growth promoting rhizobacterial strains FP7 and Pf1 of Pseudomonas fluorescens; 2. a strain of Bacillus subtilis Bs-1; and 3. a strain (Sc-1) of the yeast Saccharomyces cerevisiae, given at fortnightly or monthly intervals and with or without a chitin amendment, were evaluated in two trials for their ability to reduce anthracnose in mango caused by Colletotrichum gloeosporioides. Growth of C. gloeosporioides in vitro was significantly reduced by strain FP7 and in both field trials the bacterial strain in combination with chitin significantly reduced infection. Pre-harvest application of these formulations at fortnightly intervals also significantly improved flower initiation, yield parameters (mean number of fruits and fruit yield) and fruit quality (total soluble solids, ascorbic acid, free acidity, total, reducing and non- reducing sugar content). The delay in latent symptom expression increased by 15 days under stored conditions. The highest levels of phenolic content, peroxidase and polyphenol oxidase on mango leaves, flowers and fruits were achieved with FP7 +chitin.