INRODUCTION Crossandra mainly grows in southern part of India. Tamil Nadu, Karnataka, Andhra Pradesh and Maharastra are important states growing Crossandra. This crop can be cultivated very easily by small farmers throughout the year. The flowers are MAJORLY used for hair adornment along with Jasmine flowers. Even though flower are not much fragrant, these flowers are very popular because of their attractive bright colour, light weight and long keeping quality. The flowers are used for making garlands, either alone or in combination with jasmine flowers. Steady market demand as well as guaranteed and regular income have made crossandra a profitable venture for south Indian farmers. Fungai, bacteria and nematodes are major pathogens that causes diseases in crossandra plants. Among the various fungal diseases wilt disease caused by Fusarium spp. is a major problem in Crossandra production and restrict the crop cultivation and is also associated with nematode such as Pratylenchus delettrei (Srinivasan and Muthukrishnan 1975). Control of this disease has become very difficult due to its soil borne and complex nature. Integrated disease management involves use of different individual methods like use of biological agents/chemicals/bio technological/Physical and cultural methods for management of plant diseases. In all the methods of disease control, activation of defense mechanisms in plants are very important for effective disease management. Kamalakannan (2004) reported that soil application of bio control agents such as Trichoderma and P. fluorescens induced higher amount of Peroxidase, Polyphenol oxidase, Phenylalanine ammonia - lyase and total phenols in coleus plants. Bradley et al. (1992) also reported that the increased levels of peroxidase (PO) activity has been correlated with resistance in many plant such as barley, cucurbits, cotton, tobacco and wheat. Usually polyphenol oxidase accumulates upon wounding in plants. Saravanakumar (2002) noticed different isoforms viz., PPO1, PPO2, and PPO3 in PGPR treated plants after inoculation with Macrophomina phaseolina. Fuerst et al. (2014) reported the role PO and PPO IN biochemical seed defense mechanism. Tyagi et al. (2000) clearly explained the role of peroxidase and polyphenol oxidase isozymes in wheat resistance to Alternaria triticina Keeping all in view, pot culture experiments were conducted to observe the changes in induction of defense enzymes in treated crossandra plants with bio agents, organic amendments, silver nano particles and fungicide. MATERIALS AND METHODS The local crossandra cultivar used in all pot culture studies. The pathogen (F. incarnatum) multiplied on sand maize medium was incorporated in the pots @ 3 per cent (w/w) and nematode inoculated @ 1 nematode per gram of soil. All the treatments like bio agents, nano particles, organic amendments and chemicals were applied as per schedule. The observations on enzyme studies were carried out after last application as mentioned in the treatment schedule. The leaves were collected from the pots at 0, 3, 5, 7 and 9 days after last application in each treatment. The collected leaves were washed several times with sterile distilled water before enzyme extraction. Every treatment was replicated six times with each replication containing three pots with two plants in each pot. Peroxidase (PO) Assay. One gram of fresh leaf taken from each treatment was ground in one ml of 0.1M phosphate buffer with pH 7.0 in a pre cooled pestle and mortar separately. The homogenate was centrifuged at 15,000 rpm at 4oC for 15 minutes. The supernatant taken from the leaves of each treatment was used as enzyme source. The reaction mixture consists of 1.5 ml of 0.05M pyrogallol, 0.1 ml of enzyme extract and 0.5 ml of one per cent H2O2. The changes in absorbance of the reaction mixture was recorded at 420 nm at 30 seconds interval for three minutes at room temperature (28  2°C). The boiled enzyme preparation used as check. The enzyme activity was expressed as change in absorbance of the reaction mixture min-1g-1 of leaf (Hammerschmidt et al., 1982). Polyphenol oxidase (PPO) Assay. One gram of fresh leaves collected from each treatment was ground in one ml of 0.1 M sodium phosphate buffer (pH 6.5) separately. The centrifugation carried at 15,000 rpm for 15 min at 4˚C and the supernatant used as the enzyme source. The reaction mixture consisted of 1.5 ml of 0.1M sodium phosphate buffer pH 6.5 and 0.1 ml of the enzyme extract. The reaction initiated by the addition of 0.2 ml of catechol (0.01M). The enzyme activity expressed as change in absorbance at 495 nm at 30 sec interval for three min. The enzyme activity also expressed as change in absorbance per minet per g of leaf (Mayer et al., 1965). The details of treatment schedule are as follow RESULTS AND DISCUSSION Induction of Peroxidase (PO) activity: The activity of peroxidase was increased in crossandra plants inoculated with F. incarnatum and P. delattrei followed by treated with bioagents, organic amendments, nano particles and chemicals in different combinations. The results reveales that the activity of PO was significantly higher in crossandra plants treated with T16 (0.513 changes in absorbance /min/g of leaf tissue) at five days after last application, whereas no significant difference was observed in the PO activity in the un inoculated plants throughout the period of study (Table 1). Peroxidase is a component of an early response in plants to pathogen attack and plays a important role in the biosynthesis of lignin which ristricts the extent of pathogen spread. The products of this enzyme in presence of hydrogen donor and hydrogen peroxide has antimicrobial and antiviral activity (Van Loon and Callow 1983). Increased levels of peroxidase has been observed in a number of resistant interaction involving plant pathogenic fungi, bacteria and virus (Chen et al., 2009; Nandhakumar et al., 2001; Kavitha et al., 2005). In the present study, peroxidase activity was two times greater than the un inoculated control. Increased activity of cell wall bound peroxidase has been reported in different plants such as cucumber (Chen et al., 2009), rice (Reimers et al., 1992), and tomato (Mohan et al., 1993). Increased activities of PO was also observed in P. chlororaphis isolate (BCA) and B. subtilis isolate (CBE4) treated hot pepper seedlings after challenging inoculation with the pathogen P. aphanidermatum (Nakkeeran et al., 2006). The application of endophytic microbes like B. subtilis and P. fluorescens, alone or in combination in green house and field experiments were found to be effective in managing the chilli Fusarium wilt by inducing systemic resistance (ISR) as supported by enhanced activities of PO, PPO, PAL, β-1,3-glucanase, chitinase and phenolics. These are involved in the synthesis of phyto alexins, so that promoting the growth of plants (Sundaramoorthy et al., 2012). Furthermore, interactions among the biocontrol agents may also have synergistic effects that could induce ISR and promotes the growth of the plants (Latha et al., 2009). Polyphenol oxidase. The results reveales that Polyphenol oxidase activity also reached the maximum at five days after last application. The induction of PPO was almost double times in treated plants than control. The treatment T16 recorded the maximum (0.954 changes in absorbance /min/g of leaf tissue) level of PPO activity at 5 days after last application and it was followed by T20 recording of 0.923. The PPO activity was slightly increased in the inoculated control, when compared to untreated control (Table 2). Polyphenol oxidase, enzyme contain copper which usually accumulates on wounding in plants. Many reports correlated the induction of PPO activity offering resistance in plants (Velazhahan and Vidhyasekaran 1994). The enzymes PO and PPO plays a vital role in catalyzing and the oxidation of phenolic compounds through a PPO-PO-H2O2 path way (Srivastava, 1987). The present study cofirms that the integrated module T16 significantly increases the activity of PPO in crossandra leaves. The similar results reported by Kavitha (2004); Kamalakannan (2004) that the applications of P. fluorescens isolate and B. subtilis isolate B 49 combination significantly increased PPO activity against the soil borne pathogens Pythim aphanidermatum and Macrophomina phaseolina. The increase in PPO activity may be due to activation of latent host enzyme, solubilization of host PPO, are due to de novo synthesis (Manibhushan Rao et al., 1988). The induced PPO might have involved in offering resistance in crossandra against wilt disease. Ramamoorthy and Samiyappan (2001) reported that treatment of chilli plants with P. fluorescens challenge inoculated with C. capsici increased PPO activity. Our results are similar with earlier workers that, the strains of B. subtilis and P. fluorescens were able to induce increased activities of PPO on challenge inoculation with A. alternata in watermelon (Uma Maheswari, 2009). Increased PO and PPO activity has been shown in a number of incompatible disease interactions involving plant pathogenic fungi, bacteria and viruses (Chen et al., 2009; Kandan et al., 2002; Saravanakumar et al., 2007). The application of B. subtilis and P. fluorescens, singly or in combination at green house and field conditions recorded effective in control of chilli Fusarium wilt as evidenced by enhanced activities of PO, PPO, PAL, β-1,3-glucanase, chitinase and phenolic involved in the synthesis of phytolaexins (Sundaramoorthy et al., 2012). The levels of PO and PPO in treated plants are associated in importing resistance in plants. Among the twenty two treatments with different combinations tested, the treatment of T16 recorded least per cent disease incidence (2.8%) with 96.5 per cent disease reduction over control indicating the role of PO and PPO in disease management. Saberi et al., (2021) reported the activity of polyphenol oxidase, and peroxidase in some wheat genotypes against take-all disease. Naz et al. (2021) also reported the induction of defense-related enzymes (PO & PPO) and enhanced disease resistance in maize against Fusarium verticillioides by seed treatment with Jacaranda mimosifolia. Taha, et al. (2021) also noticed the increased levels of peroxidase and polyphenol oxidase in tomato plants treated with soil Streptomyces isolates and induction of plant resistance against tomato mosaic virus. Liang et al. (2017). Observed increased activities of peroxidase and polyphenol oxidase enhance cassava resistance to mite Tetranychus urticae. Gopalakrishnan et al. (2021). Also got similar results with Streptomyces spp. and host-plant resistance induction against charcoal rot of sorghum.