The maize diseases of global importance that pose threats to maize yield and human health includes the fungal pathogens that attack the leaves, stem and ear (Balint-Kurti and Johal, 2009). The worldwide yield losses due to diseases in maize crop have been estimated at 4 to 14% of annual global harvest (Oerke, 2006). Maydis leaf blight, also named as southern corn leaf blight caused by the ascomycete fungus Cochliobolus heterostrophus (Drechs.) Drechs; synonym, Helminthosporium maydis Nisikado is a serious fungal disease of maize throughout the world where warm and humid conditions exists during crop growing season (White, 1999). It has now become one of the most prevalent and severe diseases in countries like Pakistan, India, Nepal, Indonesia, Vietnam and China. The crop grown in Kharif season in Indian subcontinent is prone to number of biotic factors like foliar diseases, stalk rots, and banded leaf and sheath blight where maydis leaf blight is the most important foliar disease in maize growing areas. In India, where tropical maize is cultivated, MLB and BLSB are major foliar threats to sustainable cultivation of maize. Maydis leaf blight appears in hills, plains and peninsular parts of the country. The currently predominant form of C. heterostrophus is Race O, which can cause yield losses of up to 40% (Byrnes et al., 1989). Maydis leaf blight causes considerable losses in production and productivity of the crop. The incidence of another major threat i.e. banded leaf and sheath blight is also increasing in maize growing areas of the country. The disease BLSB, incited by Rhizoctonia solani f.sp. sasakii, has a potential to inflict the economic losses up to 100% (Sharma et al., 2002a). This disease has attained damaging status and has rapidly gained economic importance in several parts of the world (Kumar and Singh, 2004). Both the diseases are well noticed in various maize growing states of India included, Jammu and Kashmir, Himachal Pradesh, Punjab, Rajasthan and Delhi and Haryana. Earlier work has been done on management of both the major diseases, but keeping in view the present damaging status of the diseases, use of outdated molecules and increase in area under maize cultivation there is need to develop eco-friendly management practices.

Previously the use of fungicide was rare, but during the last decade maize production has seen an increase in use of foliar fungicides. As per scanty information several fungicides like carbendazim, benodanil and validamycin have been found effective in vitro and in vivo conditions against both the pathogens (Ahuja and Payak, 1986; Sharma and Rai, 1999). Recently, Reddy et al. (2013) conducted some management studies against turcicum leaf blight of maize and found that mancozeb (0.25%) and carbendazim + mancozeb (0.25%) were significantly superior over other treatments. Hulagappa (2012) tested eight fungicides against maydis leaf blight of maize and recorded minimum percent disease index in case of crop sprayed with propiconazole at 0.10%. Nasir et al. (2012) tested nine fungicides screened in laboratory where propiconazole, chlorothalonil, triadimefon, mancozeb, carbendazim + moncozeb and thiram were found effective in reducing the radial growth of the Bipolaris sorokiniana. But when tested in vivo, only two fungicides namely propiconazole (0.1%) and chlorothalonil (0.2%) were found effective in reducing disease severity. Recently technologies including sarpagandha leaves at 10%, Trichoderma harzianum (TH-3) at 0.5% as seed treatment + bioagents fortified FYM (1:50) and spray at 0.5%, Trichoderma viride (TV-3) at 0.5% as seed treatment + bioagent fortified FYM (1:50) and spray at 0.5% and foliar application of propiconazole at 0.1%, hexaconazole at 0.1%, carbendazim at 0.1%, mancozeb at 0.2%, carbendazim 12 WP + mancozeb 63 WP at 0.125% are validated for effective management of maydis leaf blight disease of maize (ICAR-Indian Institute of Maize Research, 2016). Out of three often used fungicides, namely Bavistin, Rhizo-lex, and Thiophanate M, have shown absolute control of mycelial growth of R. solani f.sp. sasakii with 100% inhibition (Sharma et al., 2002a). Batsa et al. (2004) also studied about the comparative efficacy of cultural, chemical and biological control against BLSB in maize and found that the cost of control was minimum in leaf stripping however validamycin provided maximum (Rs 5.88) return from each rupee investment. Saxena (2002) tested efficacy of propiconazole (0.1%) and carbendazim (0.05%) and recorded remarkable effectiveness of propiconazole when the chemical was applied at initial stages at 30th or 40th day after planting and the second spray at 10 days after the first spray. Foliar sprays of carbendazim showed the ineffectiveness against BLSB. In recent year area under maize cultivation has increased and purported yield enhancement associated with quinine outside inhibitors (Qois) such as strobilurins have encouraged the use of foliar fungicides in the corn belt of America (Bradley, 2012).

Disease management through biological agents and botanical extracts is also of great importance. Several workers have reported antagonistic activities of Trichoderma spp against R. solani f.sp. sasakii (Subedi, 2015). Kumar et al. (2009) evaluated some plant extracts against maydis leaf blight under field condition and recorded significantly higher grain yield in plots sprayed with garlic clove extract (17.0 and 18.0 q/ha), tulsi leaf extract (13.5 and 14.5 q/ha) and neem leaf extract (16.0 and 15.3 q/ha) as compared to unsprayed plots. Yield recorded in plot sprayed with onion bulb extract, bael leaf extract and mentha leaf extract were at par with control. Kumar et al. (2005) also found that A. indica was quite effective in reducing the alternaria leaf blight under field conditions. Leaf extract of Rauvolfia serpentine at 10% concentration, significantly inhibited the spore germination of Bipolaris sorokiniana and increased grain yield in wheat by 28.9% over the check when applied as foliar sprays in the field (Malik et al., 2008). Both the disease i.e. MLB and BLSB are well noticed in Indian farming systems and affecting the yield potential of maize. Due to non availability of stable sources of resistance to the diseases, control by chemical and biological means is important to avoid crop losses. Therefore, there is an immediate need to identify the suitable sources of management through biorational approaches and also to examine their efficacy for effective management. Attempts were made in the present study to find out the suitable chemical and biological control measures for effective management of MLB and BLSB diseases.