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Open Access
Management of foot rot of black pepper (Piper nigrum L.) with mycoinoculant enriched vermicompost
(Department of Plant Pathology, College of Agriculture, Vellayani, 2002) Divya, S; Sasikumar Nair
The study, "Management of foot rot of black pepper (Piper nigrum L.) with mycoinoculant enriched vermicompost" was done at the Department of Plant Pathology, College of Agriculture, Veliayani to explore the possibility of using vermicornpost as a carrier material for mass production of biocontrol agents and to test its efficacy in controlling the disease. The talc based inoculum of Trichoderma harzianum and soil based granular inoculum of Glomus Jasciculatum were mass produced in vermicompost either alone or in combination with farmyard manure or neem cake in the ratio 1 : 1 and 5 : 1 respectively and the efficacy was compared with the standard carrier material of FYM + neem cake (10 : 1). The population of T. harzianum 15 DAI was maximum in the treatment combination of VC + NC (5 : 1). However, the influence of these carrier materials on percentage of mycorrhizal infection 50 DAI was not statistically significant. Vermicompost as a carrier material for biocontrol agents was further tested in pepper var. Karimunda inoculated with P. capsici. Carrier materials as such had no significant influence on disease control. Reduction in foliar infection, disease index, stem infection and percentage mortality was observed in treatments with biocontrol agents. Disease control was maximum with the treatments involving T. harzianum while plant growth promotion was maximum with G. Jasciculatum. The physiological changes in pepper plants after inoculation with P. capsici and biocontrol agents were studied. The phenol and OD phenol content was more in pathogen inoculated plants. The defence related enzymes peroxidase, polyphenol oxidase and phenylalanine ammonia lyase were enhanced with pathogen inoculation as well as with the application of biocontrol agents. SDS-PAGE analysis of proteins with samples extracted from plants one day after inoculation of pathogen showed the presence of two novel proteins with molecular . weights of 78 kDa and 28 kDa in diseased samples which were absent in treatments without pathogen and also in plants treated with COC.
Open Access
Etiology and ecofriendly management of fungal diseases of thippali ( piper longum L)
(Department of Plant Pathology, College of Agriculture, Vellayani, 2007) Poornima, R; KAU; Santha Kumari, P
A survey was carried out at the medicinal garden of College of Agriculture, Vellayani and medicinal garden of Ayurveda Research Institute, Poojappura, Thiruvananthapuram to study the diseases associated with Piper longum L. (Indian long pepper or thippali). The major disease observed was anthracnose caused by Colletotrichum gloeosporioides (Penz.) Penz and Sacc. Pathogenicity test proved that C. gloeosporioides was the pathogen associated with the disease. Cross inoculation studies conducted using C. gloeosporioides isolate of thippali, black pepper and betel vine - the sister plants – showed that the thippali isolate was highly host specific. The colony and conidial morphology of the three isolates also showed considerable difference. C. gloeosporioides of thippali had very small conidia and the culture was also found to be shy sporulating. Studies on the survival of C. gloeosporioides showed that the pathogen survived for 105 days in the infected leaves, under laboratory conditions. In the soil, it survived for 150 days. Of the eleven fungal and four bacterial isolates tested against C. gloeosporioides, T. viride and A.terreus were found to be most effective under in vitro condition. Among the different resistance inducers tested in vitro, SA (1 g/l) was selected for field evaluation, as it had no direct action on the pathogen. Of the two plant based chemicals tested, Ovis reported the highest suppression of the pathogen. These four eco friendly materials selected from the in vitro studies and neem cake were tested in the field to determine their effectiveness in controlling the disease. Their combinations were also studied. Among the different eco friendly materials tested in the field, treatment T12 (T2T5 - A. terreus + neem cake) was found to be best in disease suppression at 45 DAT. Estimation of DRE showed that PO and PPO activity was highest in T3 (Ovis) where as PAL activity was maximum in T1 (T. viride). Combination of treatments revealed that maximum PO activity was in treatment T14 (T3T5 - Ovis + neem cake).The PPO and PAL activity was maximum in T7 (T1T3 - T. viride + Ovis).
Open Access
Management of phytophthora disease of black pepper (piper nigrum L. walp) using plant growth promoting microbial inoculants
(Department of Plant Pathology, College of Agriculture, Mannuthy, 2003) Beena Nair, S; KAU; Anith, K N
The study, "Management of Phytophthora disease of black pepper (Piper nigrum L. Walp) using plant growth promoting microbial inoculants" was conducted at the Department of Plant Pathology, College of Agriculture, Vellayani to investigate the effect of plant growth promoting rhizobacterial strains belonging to fluorescent pseudomonads and Bacillus spp. and the root endophytic fungus, Piriformospora indica on the suppression of nursery wilt of black pepper incited by Phytophthora capsici. Two strains of fluorescent pseudomonads viz., Pseudomonas putida strain 89B61 and P. jluorescens strain RCL3R4, two strains of Bacillus viz., BY -1 and BY -2 and P. indica were included in the study to explore their potential in plant growth promotion and disease suppression. P. capsici inoculated control, uninoculated healthy control, chemical control (0.20 per cent COC drenched at 15 days intervals) and combined application of Trichoderma harzianum and an AMF, Glomus fasciculatum were maintained for comparison. In the dual culture assay, conducted in vitro for preliminary screening, though P. indica exhibited a slight mycelial growth inhibition initially, the pathogen later overgrew the antagonist. Among the bacteria, fluorescent pseudomonad strains exhibited better mycelial growth inhibition 'on both PDA and Carrot Agar. The influence of different biocontrol agents on growth promotion of the black pepper cuttings was not statistically significant. However, the fluorescent pseudomonad, P. putida strain 89B61 exhibited maximum growth promotion. In the experiment conducted to test the potential of vanous plant growth promoting microbial inoculants in suppressing nursery wilt, the plants treated with spore suspension of P. indica exhibited the highest wilt percentage of 93.22 per cent which was more than that in the inoculated control (37.48). The plants treated with the fluorescent pseudomonad, P. jluorescens strain RCL3R4 recorded a wilt percentage of 6.70. All other treatments were highly effective and checked the infection completely. The Bacillus strain, BY -2 exhibited better disease suppression in vivo. The fluorescent pseudomonad, P. putida strain 89B61 also showed disease suppression in vivo, which indicated that it has the dual function of plant growth promotion and disease suppression.
Open Access
Management of bacterial blight of anthurium (anthurium andreanum linden) using botanicals
(Department of Plant Pathology, College of Agriculture, Vellayani, 2002) Sabitha, S R; KAU; Mary, C A
Anthurium (Anthurium andreanum Linden) suffers from a serIOUS disease viz., bacterial blight incited by Xanthomonas axonopodis pv. diefJenbachiae (McCulloch and Pirone) Vauterin et al. A survey was conducted in Thiruvananthapuram district and information on disease intensity and varietal reaction of the disease was studied from randomly selected thirty anthurium gardens. Plants with disease infection upto 50 per cent was noticed in most of the gardens. Generally pink varieties exhibited tolerance while red varieties were susceptible. Both foliar and systemic symptoms were observed. The bacterium was a gram negative, motile, short rod. Potato Sucrose Agar was the best solid medium for growth of the bacterium. Morphological, physiological and biochemical characters of the ten isolates were compared and some characters like nature and rate of growth, virulence and hydrolysis of starch were found varying. Aglaonema sp., Alocasia sanderiana, Anthurium ornatum, Colocasia esculenta, Dieffenbachia spp., Philodendron spp., Syngonium sp. and Xanthosoma sagittaefolium of Araceae family and ornamental plants like Orchid spp., Dracaena spp. Heliconia sp., Sterilitzia reginae and Maranta arundinaceae were hosts of the pathogen. Among the fifteen botanicals tested under in vitro conditions crude extract and 2 : 1 dilution of Allium sativum and Tagetes erecta, crude and two per cent concentration of neem cake extract and one and two per cent neem oil and coconut oil were 'effective in inhibiting the growth of the pathogen. The relative efficacy of five ecofriendly management practices viz., application of A. sativum, T. erecta, neem oil, coconut oil and neem cake extract, at two levels and 100 ppm streptocycline were tested on seven month old tissue culture plants. Pre and post inoculation sprayings with crude extract of neem cake and T. erecta reduced the disease by 85 per cent. When the same spraying schedule with these two botanicals and 100 ppm streptocycline was given on flowering plants, crude extract of neem cake was the most effective followed by crude extract of T. erecta. The effect of streptocycline 100 ppm was on par with T. erecta. The study thus indicates that botanicals could be used as a substitute for antibiotics in the management of bacterial blight of anthurium.
Open Access
Bioherbicidal potential of fungal pathogenes of water hyacinth [Eichhornia crassipes (Mart.) Solms]
(Department of Plant Pathology, College of Agriculture,Vellayani, 2003) Ancy Salim, M; KAU; Naseema, A
The study entitled "Bioherbicidal potential of fungal pathogens of water hyacinth [Eichhornia crassipes (Mart.) Solrns]", was conducted at College of Agriculture, Vellayani, Thiruvananthapuram during 2001-2003. Fourteen pathogenic fungi of water hyacinth obtained from the survey conducted as a part of the DST project on "Biocontro l of water hyacinth using mycoherbicides" were used for the study. Fungi which were not identified earlier were characterized and identified based on the cultural and morphological characters and was confirmed by sending to Agharkar Research Institute, Pune. These three fungi viz., Bipolaris tetramera, Drechslera sp. and Pestalotiopsis guepinii, were new records on water hyacinth. The fungi varied in the symptom development on water hyacinth with respect to nature of symptoms, parts affected and the time taken for the symptom development. The intensity of infection by the fungi varied from 9.94 to 58.80 per cent. Only five fungi viz., A.eichhorniae, F. moniliforme, F. oxysporum (isolate 2), F. pallidoroseum (isolate 3) and I M. advena gave more than 45 per cent intensity of infection. Cell free metabolites of the various fungi also varied in the symptom development. Intensity of damage varied from 8.03 to 89.00 per cent. Maximum was recorded by M. advena followed by F. pallidoroseum (49.80 per cent), A. eichhorniae (48.80 per cent) and F. oxysporum (47.20 per cent). Host range of A. eichhorniae, F. moniliforme and F. oxysporum was studied in detail. A. eichhorniae infected only three weed plants out of the 37 cultivated and 39 weed plants tested. F. moniliforme infected five 11 cultivated and 11 weed plants. F. oxysporum was found to be pathogenic to seven cultivated and nine weed plants. Combined application of A. eichhorniae and F. p allidorose um recorded higher intensity of infection than when sprayed alone. A. eichhorniae was found to give effective destruction of the weed at 107 spores per ml concentration. A. eichhorniae at 107 spores per ml and F. p all idoroseum at lOll spores per ml together recorded more intensity of infection of 89.84 per cent than when sprayed alone. Talc based combination product of A. eichhorniae and F. pallidoroseum when sprayed at 10.00 per cent concentration recorded an intensity of infection of 93.20 per cent, 10 days after spraying. The formulated product could retain the viability of spores of the pathogens at room temperature for 15 days.
Open Access
Biocontrol of bacterial wilt in tomato using arbuscular myaorrhizal fungi
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2003) Nandakumar, A; KAU; Surendra Gopal, K
The studies on "Biocontrol of bacterial wilt in tomato using arbuscular mycorrhizal fungi" were carried out at the Oept. of Plant Pathology, College of Horticulture, Vellanikkara during the period 2000 - 2002. The main objectives of the study were to identify suitable native AMF from high and low wilt incidence areas of Thrissur and Palakkad districts, screen them against Ralstonia solanacearum in pot culture under sterile and wilt sick conditions, to determine the optimum inoculation time and inoculum density of :\\1f and to test ~h,- ,,;;;cicncy 0: Aj,\1f in thc wilt sick field. The soil samples collected from Thrissur and Palakkad district were analyzed for their nutrient status, pH, Ralstonia population and total AMF spore count. The Vellanikkara soils were acidic with low ,K, Ca and Mg and high P content when compared to Ozhalapathy and Eruthiampathy soils. The Ralstonia population were generally higher in Vellanikkara soils. On the other hand, Ozhalapathy soils had higher AMF spore count. The Glomus sp. was found to be the most predominant AMF in the soils of high wilt (Vellanikkara, Thrissur district) and low wilt incidence (Ozhalapathy and Eruthiampathy, Palakkad district). The screening of the predominant native AMF cultures against R. solanacearum were carried out individually and in combinations under sterile conditions along with the TNAU commercial culture [or comparison. The treatments with the native AMF combinations 1'i2., GIOIllIlS sp. (OT) + Glomus sp. (ER), Glomus sp. (OT) + Glomus sp. (VM) and Glomus sp (OM) - Glomus sp. (VBT) recorded the least percent wilt incidence with the native A0.1F combination Glomus sp. (OM) + Glomus sp. (VBT) recording the maximum number of days of plant survival (11 days). The dry weight and root length were also higher for these three native AM F combinations. The determination of the optimum inoculation time (at the time of sowing, at 15 days before transplanting and at the time of transplanting) in combination with the inoculum density (@ 25 g kg 1 soil, 50 g kg 1 soil and 75 g kg -I soil) were carried out using different species of AMF in pot culture using wilt sick soil. The inoculation time at 15 days before transplanting 75 g kg -I soil was found to be optimum. This was evaluated further, under pot culture and field experiment studies using the native AMF combinations selected from the screening experiment. The selected native AMF combinations from the screening experiment were tried at 15 days before transplanting @ 75 g kg -I soil in pot culture using wilt sick soil in comparison with the TNAU commercial culture to select the best two combinations for the field experiment. The native AMF combinations recorded the least percent wilt incidence and maximum number of days of plant survival when compared to the TNAU commercial culture. The AMF combinations Glomus sp. (OM) + Glomus sp. (VBT) and Glomus sp. (OT) + Glomus sp. (VM) were found to be the best. A field experiment to test the efficacy of the selected native AMF culture combinations were carried out using the tomato varieties Pusa Ruby (susceptible) and Mukthi (moderately resistant). The native AMF combination Glomus sp. (OT) + Glomus sp. (VM) recorded maximum number of days of plant survival (32 and 50 days respectively) in both the tomato varieties. However, it could not prevent wilt incidence in the case of Pusa Ruby variety, which recorded 100 percent wilt, and Mukthi variety 97 .. 9 % wilt incidence. The same native AMF combinations Glomus sp. (OT) + Glomus sp. (VM) also recorded maximum fruit number in Mukthi whereas Pusa Ruby did not produce fruits as they did not survive even upto flowering. The present study clearly indicated that the native AMF combination Glomus sp. (OT) + Glomus sp. (VM) was the best in pot culture studies using wilt sick soil and could delay the disease incidence in the susceptible Pusa Ruby variety of tomato upto 82 days after transplanting. However, under field conditions it could delay the disease incidence in the susceptible variety Pusa Ruby only upto 32 days and in the moderately resistant variety Mukthi upto 50 days. So more extensive studies are needed to develop a suitable native AMF to control the bacterial wilt in tomato which is effective under field conditions.
Open Access
Utilization of fungi for composting and mushroom production on coirpith
(Department of Plant Pathology, College of Agriculture, Vellayani, 2003) Sherin Salam, A; KAU; Geetha, D
The present study entitled "Utilization of fungi for composting and mushroom production on coirpith" was conducted during 2001 to 2003 at College of Agriculture, Vellayani, Thiruvananthapuram district with the objective to isolate most efficient fungi for degradation of coirpith and standardization of technology for mushroom production on coirpith. Four lignocellulolytic fungi viz., Aspergillus niger, A. ochraceous, Trichoderma harzianum and Rhizopus stolonifer were isolated from retted coirpith. Three mushrooms viz., Pycnoporus sanguine us, Ganoderma applanatum and Pleurotus tuber-regium collected during surveys conducted in different parts of Thiruvananthapuram district, and Lentinus edodes, Pleurotus florida and Calocybe indica were procured from TNAU and College of Agriculture, Vellayani. P. tuber-regium, a mushroom collected during the study is a new report from India. This edible mushroom has a biological efficiency of 46 per cent and is ideally suited for cultivation in Kerala. T. harzianum was the fastest colonizer on retted coirpith followed by G. applanatum and L. edodes. The maximum reduction of organic carbon, C:N ratio, cellulose and lignin and the maximum increase of nitrogen content in retted coirpith was recorded when it was degraded by T. harzianum, Among the different substrates used for mushroom production, the maximum yield of P. florida was realized in a substrate containing 1: 1 combination of retted coirpith and spent mushroom substrate while the maximum yield of C. indica was observed in a substrate containing 1:3 combination of non-retted coirpith and paddy straw. , Composted coirpith was found to be unsuitable as a substrate for large scale cultivation of oyster and milky mushrooms.
Open Access
Integrated management of leaf rot of coconut
(Department of Plant Pathology, College of Agriculture, Vellayani, 2002) Vrinda, T S; Joseph, P J
The study entitled as "Integrated management of leaf rot of coconut" w as conducted at the Department of Plant Pathology, Co l.cge of Agr iculturc. Ve l l a van i and Iie ld trial was conducted at RARS. Kumarakorn. Extensive iso lai io n s. pathogenicity and characterization studies of the pathogens assoc i aic d with leaf rot infected spindle leaf of coconut from di ffercnt r e g ions 0 I' f ve southern districts of Kerala revealed that Collct otrichu m g/oco.,porioidcs. Fusarium so/ani, Fusarium. monil if..rniae, Fusari utn oxvsp or utn, Cephalosporium sacchari. Exserohilum rostrat um. Gl iocl adi um roselllll.<';C\!o!idillll7 sp. and Curv ular i a sp. played ct io lo gj 0" LRD. Based on frequency 01' isolarions. Fusarium spp. .ind C .g/()(;o.,porioides Viere identified as major pathogens or LRD in these areas. The present study constitutes the first report or the ct io log ica l ro l c of Scvt ul uliurn ::;0 in leaf rot incidence. Symptomatology of the disease based on natural incidence in the I'dd and upon artificial inoculation were clearly described The in vit ro interactions of different dual combinations of LRD pathogens were found to be predominantly associative rather than inhibitory in nature. The rapid lesion development of certain dual combinations of the pathogens upon artificial inoculation further signified the associative nature of these pathogens. Extensive in vi/m screening and leaf bit assay of different antagonistic microorganism identified T9 culture of Trichoderma sp. PSI culture of Pse u domonasfluorescens as two potential agents against i he major pathogens of LRD. The in vitro interactions study of the selected fungal and bacterial antagonist showed that both are incompatible and hence unsuitable for combined delivery. Bioassay results showed that fungicides hcxaconazo lc and propiconazole completely inhibited the growth of C. gloeosporioides. E. rostra/um and F. solani while mancozeb was more effective at higher concentrations. one of the fungicides was inhibitory to P. j7uorescens while Trichoderma sp. was inhibited by hex aconazo!e and hence the fungal antagonist was unsuitable for combined delivery with the fungicides. Evaluation of different components of disease management indicated that phytosanitation coupled with hexaconazole application was effective in reducing disease severity of leaf rot in the field.
Open Access
Biological management of phytophthora pod rot of cocoa
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2004) Bhavani, R; KAU; Koshi, Abraham
Phytophthora pod rot (PPR) is one of the serious diseases of cocoa in Kerala. Fifteen isolates of the pathogen were isolated from different locations of Thrissur district and their pathogenicity established. The cultural and morphological characters of 15 isolates of the pathogen like growth on Carrot Agar, mycelial width, length of sporangiophore, sporangial ontogeny, length and breadth of sporangia, L/B ratio, and pedicel length were studied. Based on these characters, the different isolates were identified as Phytophthora palmivora (Butler) Butler. To find out the variations among the isolates of P. palmivora the morphological, virulence and protein profile characteristics of 15 isolates were studied in addition to their sensitivity towards fungicides and antibiotics. Analysis of data on protein profiles and sensitivity towards fungicides did not show much variation among the isolates. But the isolates showed some variations with regard to their morphology, virulence and sensitivity to antibiotics. Among 225 cocoa types screened for host resistance, eight cocoa types viz., G VI 14, G VI 73, G VI 77, G VI 124, G VI 138, G VI 154, G VI 279, G VI 284 showed moderately resistant reaction. Sixty three types were moderately susceptible and rest highly susceptible. Quantitative estimation of epiphytic microflora from cocoa pods yielded more bacteria than fungi and actinomycetes. The epiphytic fungi and bacteria showed antagonistic activity against P. palmivora. Actinomycetes were not antagonistic to the pathogen. Eight fungal and seven bacterial antagonists including standard cultures of T. harzianum and P. fluorescens [Pf (K) and Pf (T)] exhibited maximum inhibition on the pathogen. Studies on the detached pods revealed the efficacy of epiphytic fungal isolate 20F and two bacterial isolates 23B and 24B against the pathogen. The efficient fungal isolate 20F was identified as T. viride Pers. ex. S.F. Gray and the bacterial isolates 23B and 24B as P. fluorescens Pelleroni. The mechanism of antagonism of epiphytic T. viride and standard T. harzianum was studied. The antagonists overgrew the pathogen and showed interactions like coiling, penetration, hyphal malformations and disintegration of host hyphae. Three P. fluorescens isolates including Pf (K) produced HCN and siderophores. T. viride (20F) and T. harzianum were compatible with Akomin 40 and Indofil M45. They were incompatible with Bordeaux mixture, Bavistin and Kocide. Fytolan was partially compatible. The two fungal antagonists were compatible with insecticide phorate, while Sevin was partially compatible. Ekalux, Nuvacron and Endosulfan were incompatible. Ammonium chloride, Rajphos and MOP were compatible with two Trichoderma spp. while ammonium sulphate was incompatible. Two native P. fluorescens (23B and 24B) and standard Pf (K) were compatible with Akomin 40, Indofil M45 and Bavistin and incompatible with Bordeaux mixture, Kocide and Fytolan. With regard to insecticides, the lower two concentrations of Sevin, Ekalux, Endosulfan and Nuvacron were compatible with the bacterial antagonists, while higher concentration was incompatible. Phorate was partially compatible. Fertilizers like Rajphos and MOP were compatible with antagonists. Urea was incompatible. Ammonium sulphate and ammonium chloride were partially compatible. Among different fungicides screened, Bordeaux mixture, Fytolan and Kocide completely inhibited P. palmivora. The lower two concentrations of Akomin 40 and Indofil M45 at all concentrations permitted slight growth. Bavistin was not inhibitory to the fungus. Nuvacron at all concentrations, the highest concentration of Ekalux and two higher concentrations of Endosulfan were inhibitory to the pathogen. Sevin and phorate exerted varying levels of inhibition. Urea and MOP were not much inhibitory to the pathogen. Ammonium chloride, ammonium sulphate and Rajphos showed partial inhibition. Field evaluation of isolates of P. fluorescens [23B, 24B, Pf (K)] and two Trichoderma spp. revealed the efficacy of fluorescent pseudomonads in reducing the incidence of PPR of cocoa. The efficacy was comparable with the recommended fungicides.

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