TY  - BOOK
AU  - Anupama P R
AU  - Sainamole Kurian P (Guide)
TI  - Phyllosphere microorganisms for the management of anthracnose disease of Cowpea (Vigna unguiculata (L.) Walp.)
U1  - 632.3 
PY  - 2022///
CY  - Vellanikkara
PB  - Department of Plant Pathology, College of Agriculture
KW  - Plant Pathology
N1  - MSc
N2  - Microorganisms associated with aerial parts of plants such as stems 
(cauloshere), phylloplane (leaves), anthosphere (flowers) and carposphere (fruits) 
which are collectively known as phyllosphere. Phyllosphere microbes includes 
bacteria, filamentous fungi and yeasts. They offer natural biological control of 
diseases affecting aerial plant parts. Being better adapted to the phyllosphere niche, 
they are potential biocontrol agents which are under exploited in agriculture which 
allow them to adapt to the phyllosphere environment and inhibit the growth of 
microbial pathogens, thus sustaining plant health. Hence, microbial 
biocontrolbyphyllosphere microorganisms is a fast growing field of research. 
Considering the importance of the potential of phyllosphere antagonists, the research 
project entitled “Phyllosphere microorganisms for the management of anthracnose 
disease of cowpea (Vigna unguiculata (L.) Walp.).” was carried out. Phyllosphere 
microbiome enhance plant tolerance to withstand biotic and abiotic stress conditions 
in the current facet of climate change. 
A purposive sampling survey was conducted in 21 locations of Kerala where 
cowpea and/or yard long bean are grown as a vegetable crop. The survey covered six 
districts namely, Thrissur, Palakkad, Malappuram, Kozhikode, Kannur and Kasaragod 
and five agro ecological units. Fungi associated with anthracnose symptoms and 
phylloshere microrganisms associated with healthy and symptomless plants from the 
fields were isolated. On pathogenicity test, six fungi were confirmed as pathogens and 
they were identified as Colletotrichum Siamense, three isolates of Colletotrichum sp., 
Ectophoma multirostrata and Curvularia verruculosa based on cultural, morphological 
and molecular characterization.C. siamense and Ectophoma multirostrata infecting 
cowpea is the first report in the world. Similarly, first report of Curvularia verruculosa
infecting cowpea and producing anthracnose symptoms from India. 
Enumeration of phyllosphere microorganisms on cowpea grown at different 
locations showed that population of fungi distributed on all plant parts and more 
abundant on flowers. Likewise, bacteria are more abundant on cowpea flowers, and 
fluorescent pseudomonads and yeasts are more abundantly seen on cowpea pods. 
Based on colony characters, a total of 183 different isolates of phyllosphere microbes 
were made into pure cultures and were screened for antagonism towards C. siamense. 
Forty one isolates expressed antagonism in varying degrees which were again 
subjected to dual culture screening in vitro. Five promising anatgonists were selected 
based on per cent inhibition of mycelium of the pathogen on PDA. The five were 
identified as Trichoderma longibrachiatum, Trichoderma asperellem, Bacillus 
amyloliquefaciens, Bacillus velezensis and Candida tropicalis based on cultural, 
morphological and molecular characterization. Cell free culture filtrates of promising 
phyllosphere antagonists showed maximum growth inhitbion of C. siamense ranging 
from 86 per cent for Candida tropicalis to 100 per cent for Trichoderma 
longibrachiatum and Trichoderma asperellem
In order to study the induction of systemic resistance in cowpea by 
phyllosphere antagonists, a pot culture experiment was conducted and the results 
showed that all the antagonists accelerate the production of defence related enzymes 
such as peroxidase, polyphenol oxidase and phenylalanine ammonia lyase when 
challenge inoculated with the pathogen. Bacillus amyloliquefaciens induced higher 
activity of peroxidase (1.2 min-1g-1 fresh tissue over control), similarly polyphenol 
oxidase by Candida tropicalis (0.5min-1g-1 fresh tissue over control) and 
phenylalanine alanine by Trichoderma asperellem (0.8 μmol of transcinnamic acid 
formed g-1 fresh tissue over the control).
To test the biocontrol efficacy and plant growth promotion of phyllosphere 
antagonists against C. siamense causing cowpea anthracnose, a field experiment was 
conducted. The semi trailing cowpea variety ‘Anashwara’ was used in the experiment. 
The treatments included conventional biocontrol agents such as Trichoderma sp. 
(KAU) and Pseudomonas fluorescens (KAU) and chemical check with hexaconazole 
(systemic), mancozeb (contact) and carbendazim + mancozeb (systemic +contact) and 
a control without treatments were also included along with five phyllsophere 
antagonists such as T. longibrachiatum, T. asperellem, B. amyloliquefaciens, B. 
velezensis and C. tropicalis. All the treatments were given as seed treatment, and foliar 
spray. Higher vigour index of seedlings was recorded in the treatment with Bacillus 
amyloliquefaciens (1408). Biometric observations such as plant height, number of main 
branches, number of pods per plant, number of seeds per pod, fresh weight of pods, 
pod length, days to first harvest, days to last harvest and total yieldand per cent disease 
incidence and severity were recorded at regular interval. Results of the field experiment 
indicated significant reduction in disease incidence and severity effected by 
phyllosphere antagonists such as T. asperellem, B. amyloliquefaciens, B. velezensis, C. 
tropicalis, Trcihoderma sp. (KAU), Pseudomonas fluorescens, hexaconazole, 
mancozeb and carbendazim + Mancozeb. In terms of yield all the five antagonists 
along with Trichoderma sp. (KAU) recorded significant yield increase in cowpea 
compared to other treatments. 
The bacteria, B. amyloliquefaciens has gained more attention and an emerging 
evidence has identified its health beneficial effects as probiotics, hence farmers can 
safely use this as a biocontrol agent. Focusing on efficient and safer (non pathogenic 
nature), the phyllosphere antagonists such as T. asperellem and B. amyloliquefaciens
are selected as the best among all the treatments. So, it can be concluded that out of the 
eleven treatments, T. asperellem and B. amyloliquefaciens could promote the growth of 
the plants and reduce the disease incidence and severity than the other treatments. 
However, multilocational field studies should be conducted to validate the findings of 
the current study, so that these bioagents can be formulated and made available to the 
farming community
UR  - https://krishikosh.egranth.ac.in/handle/1/5810208469
ER  -