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M. Jayasekhar ¹, K. Manonmani ¹, C. Gailce Leo Justin ¹

Affiliations
1 Horticultural Research Station, Krishi Vigyan Kendra, Pechiparai-629 161, IN

Abstract

Stem rot disease of vanilla caused by Fusarium oxysporum f.sp. vanillae is a major constraint in its cultivation in Kanyakumari District. The in vitro studies on the mycelial growth of the pathogen expressed the superior efficacy of the native isolate of Pseudomonas fluorescens (Pf_NI) that recorded an inhibition zone of 25.00mm and was followed by T. harzianum. Under field conditions soil application of Pf(_NI) followed by carbendazim spray (0.2%) after 30 days of Pseudomonas application recorded the lowest disease incidence of 3.77, 4.03 and 3.67 per cent in three years and exerted 79.95, 80.50, 80.48 per cent reduction in disease over the control plot respectively. Among the bioagents, the soil application of Pf(_NI) followed T. harzianum after 30 days and another dose of Pf(_NI) after 30 days recorded a significant disease reduction of 69.84, 68.24 and 70.21 per cent in three consecutive years.

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C. Gailce Leo Justin ¹, D. Rajakumar ¹, J. D. Nirmalatha ¹, J. Prem Joshua ¹, M. Jayasekhar ¹

Affiliations
1 Horticultural Research Station, Tamil Nadu Agricultural University, Pechiparai-629 161, IN

Abstract

Field trials were conducted for optimising the dose of insecticides for the management of the pseudostem weevil, Odoiporus longicollis (Oliv.) on banana. Studies revealed that pseudostem injection of monocrotophos or dimethoate along with water @ 1:5 ratio was significantly superior in controlling the pest. The insecticide water mixture was administered @ 2 ml/injection point at 60 cm of the stem and another 2 ml at 150 cm of the pseudostem from ground level in the opposite direction. These treatments recorded an average bunch yield of 10.86 kg/plant and 10.58 kg/plant with an average bunch recovery of 84.20 and 81.32 per cent respectively. The problems encountered in the pseudostem injection of monocrotophos along with water in the ratio of 1.5 : 3.5 are discussed.

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K. Manonmani ¹, R. Bhaskaran ², R. Jagannathan ², M. Jayasekhar ¹

Affiliations
1 Krishi Vigyan Kendra, Pechiparai, Kanyakumari, IN
2 Agricultural College and Research Institute TNAU, Madurai-625 002, IN

Abstract

Studies were conducted to screen out the compatible host and pathogen combination with acid lime and canker causing pathogenic culture of Xanthomonas axonopodis Pv. Citri (Xac). Among the 21 isolates collected from acid lime cultivating areas of Tamil Nadu, isolate I₃ was found to be the most virulent. This compatible combination was tested under controlled environment condition at 28°C and its effect on biochemical parameters of host metabolism was studied. The biochemical changes in the host during the course of pathogenicity include, slight increase in protein, phenol, phenyl alanine ammonia lyase (PAL), β-1, 3-glucanase and chitinase enzymes. Significant increase in the activities of peroxidase (POX), polyphenol oxidase (PPO) and catalase was observed in the infected tissues. Total and non-reducing sugars decreased, but reducing sugar content increased slightly.

Keywords

Acid Lime, Pathogenicity, Xanthomonas axonopodis Pv. Citri, Biochemical Changes.

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K. Manonmani ¹, M. Jayasekhar ¹, C. Gailce Leo Justin ¹, T. Thangaselvabai ¹

Affiliations
1 Krishi Vigyan Kendra, Horticultural Research Station (TNAU), Pechiparai-629161, IN

Abstract

Bactericidal action ofsome selected herbal extracts viz., Acalypha indica, Achyranthes aspera, Aloe vera, Azadirachta indica, Datura metal, Hibiscus rosasinensis, Nerium oleander, Ocimum sanctum, O. basilicum, Phyllanthus emblica, Polyalthia longifolia, Piper betle, Punica granatum, Solanum torvum and Solanum trilobatum were tested in vitro against the growth of citrus canker disease causing pathogen, Xanthomonas axonopodis pv. citri (Xac). The leaf extract of P. longifolia followed by A. aspera recorded the maximum growth inhibition of 9.77mm and 8.47mm diameter respectively. The 20-40% ammonium sulphate fraction of A. aspera and 40-60% fraction of P. longifolia exhibited inhibitory action on in vitro growth of the pathogen. The molecular weight of the fractions of leaf extracts was found to be 30 kDa and 19 kDa for P. longifolia and A. aspera respectively.

Keywords

Herbal Extracts, Citrus Canker, Xanthomonas axonopodis pv. Citri.

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T. Thangaselvabai ¹, C. Gailce Leo Justin ², S. B. Nirmal Johnson ¹, M. Jayasekhar ¹

Affiliations
1 Horticultural College and Research Institute, Coimbatore- 641 003, IN
2 Horticultural Research Station, Tamil Nadu Agricultural University, Pechiparai- 629 161, IN

Abstract

A field study was conducted to evaluate the crop maturity, productivity, quality and economic returns from banana cv. Rasthali in response to the split application of higher levels of nitrogen and Azospirillum. Application of Azospirillum along with 100g inorganic N (T7) produced higher yield (19.00kg/plant) of better quality fruits with the cost benefit ratio of 2.41 and recorded a minimum of 272 days to shoot. Similarly application of higher level of inorganic N ie., 200 g/plant in four split doses (T6) also increased the yield and quality of banana.

Keywords

Banana, Nutrients, Quantitative Traits, Qualitative Traits.

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K. Manonmani ¹, M. Jayasekhar ¹, M. Muthusamy ¹

Affiliations
1 Krishi Vigyan Kendra, Pechiparai-629161, IN

Abstract

Rice is affected by number of fungal, bacterial and viral diseases. Among the fungal diseases, sheath rot caused by Sarocladium oryzae has been reported to cause considerable loss in yield. Bacterial biocontrol agents viz., Pseudomonas fluorescens (Pf₁) and Bacillus subtilis have been formulated in different carriers viz., gypsum, peat soil and talc powder. Their longevity and biocontrol efficacy against sheath rot incidence were assessed under artificially inoculated condition. The results revealed that gypsum based formulation of two bioagents were effective in controlling the disease by recording the disease incidence of 10.67 per cent and 12.00 per cent respectively. Under field condition also, gypsum based formulation of these biocontrol agents were found to be more effective in controlling sheath rot incidence than the talc and peat based formulations.

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R. Swarna Priya ¹, J. Prem Joshua ¹, C. Gailce Leo Justin ¹, M. Jayasekhar ¹

Affiliations
1 Horticultural Research Station,Tamil Nadu Agricultural University, Pechiparai-629161, IN

Abstract

Experiments were undertaken to optimize the nutrient requirement for maximizing the bark yield in cinnamon. It was observed that the incorporation of vesicular arbuscular mucorrhiza (VAM) at 3 kg/tree had a synergistic effect and increased the plant height, girth and the number of branches. Bark yield was maximum in the treatment T₉ (250g N, 130g P and 250g K/tree/year and VAM 3kg/tree) during the first (1.615 kg/tree) and second harvests (2.050 kg/tree). The influence of VAM on the induction of higher bark yield in cinnamon is evident.

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K. Manonmani ¹, M. Jayasekhar ¹, C. Gailce Leo Justin ², T. Thangaselvabai ¹

Affiliations
1 Krishi Vigyan Kendra, Pechiparai-629 161, IN
2 Horticultural Research Station, Pechiparai, 629 161, IN

Abstract

Disease management options currently available to farmers do not provide adequate control of plant diseases and there is a need for new disease management strategies. Induced systemic resistance (ISR) of plants against pathogens is a widespread phenomenon that has been intensively reviewed with respect to the underlying signalling pathways as well as to its potential use in plant protection. Systemic acquired resistance (SAR) is also vital plant defense system that confers broad spectrum resistance accompanied by coordinated expression of SAR genes. The present review focuses on international and indigenous research efforts in resistance induction in plants to the pathogen attack. It provides a perceptible review on the agents inducing systemic disease resistance and the mechanism underlying the induction of resistance. Recent trends in plant disease management in India cover the use of chemicals, plant extracts, cultural methods and the use of biological agents. Each and every agent possesses inherent ability to induce resistance mechanism of the host systemically. Such hidden efficacy can be potentially utilized for plant disease management.

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C. Gailce Leo Justin ¹, K. R. Sudha ¹, T. Thangaselvabai ¹, M. Jayasekhar ¹

Affiliations
1 Horticultural Research Station, Tamil Nadu Agricultural University, Pechiparai - 629 161, IN

Abstract

The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Yponomeutidae), a serious pest of crucifers has become a single limiting factor in the production of quality heads. Due to high reproductive capacity and ability to withstand pesticides, DBM has developed resistance to all groups of insecticides. As a consequence of resistance and various undesirable side effects of intensive insecticide application, increasing attention has been paid to alternate strategies such as IPM, a programmed approach including both cultural and biological control and the use of more selective insecticides.

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C. Gailce Leo Justin ¹, J. Prem Joshua ¹, M. Jayasekhar ¹

Affiliations
1 Horticultural Research Station, Tamil Nadu Agricultural University, Pechiparai-629 161, IN

Abstract

Field evaluation of Bacillus thuringiensis Berliner formulations against the diamondback moth, Plutella xylostella (L.) revealed that all the Bt. formulations except Spicturin were significantly superior in reducing the larval population. Dipel and Centari though less effective than Delfin were significantly better than all other insecticides. The highest yield was observed in Delfin-treated plots which was higher than the other treatments. All the insecticidal treatments exhibited a significant reduction in the number of Cotesia plutellae cocoons over control except the biopesticide Delfin in most of the observations over control. However, the pest: parasitoid ratio was maximum in Delfin-treatment followed by Dipel and Centari. Fenvalerate recorded the lowest ratio which was almost equal to the control and this was followed by auinalphos. Neem formulations recorded a relatively higher ratio than the chemical insecticides.

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M. Jayasekhar ¹, E.G. Ebenezar ¹

Affiliations
1 Department of Plant Pathology, Agricultural College and Research Institute, TNAU, Killikulam - 628 252, IN

Abstract

Two field experiments were conducted by using cheap and ecofriendly plant products and biocontrol agents for the management of powdery mildew disease caused by Erysiphe polygoni in black gram which is causing severe yield loss. The mean per cent disease incidence ranged from 15.80 to 47.70 in different treatments. The maximum reduction of disease incidence was recorded in wettable sulphur 0.25% (15.80%) followed by carbendazim 0.1% (58.91%) and castor oil 1% with Ampelomyces quisqualis (48.53 %) However castor oil 1% followed by A. quisqualis application at 10 days interval recorded 20.28 per cent increased yield with maximum cost benefit ratio of 1 : 2.01.

Keywords

Black Gram, Disease Management, Erysiphe polygoni, Powdery Mildew.

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