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Maydis leaf blight, caused by Bipolaris maydis, is a serious foliar disease of maize distributed widely throughout the world and causing significant yield losses. The study aimed to describe stages of the infection process of B. maydis on maize leaves. The adaxial surfaces of maize leaves were inoculated with a conidial suspension of B. maydis and leaf samples were collected from 24 to 120 hrs after inoculation (hai). At 24 hai, the germ tubes from the germinated conidia and fungal hyphae attempted to penetrate the leaf through the stomata. These results provide new insight into the infection process of B. maydis on maize leaves and may contribute to the development of more effective management of maydis leaf blight.

Banded leaf and sheath blight disease caused by Rhizoctonia solani f. sp. sasakii is a major constraint of Kharif maize. Wide host range of pathogen, its ability to survive as sclerotia under adverse environmental conditions and lack of resistant sources are some of the bottlenecks in its management. To reduce our dependence on chemicals, experiment was conducted at five hot-spots in India viz., Ludhiana (PAU and Ladhowal), Delhi, Karnal and Pantnagar centres to study the effect of leaf stripping method on disease severity and yield parameters of present day maize hybrids of different maturity groups as well as speciality corn cultivars. Per cent disease control achieved with leaf stripping treatment in different cultivars varied from 16.66 to 54.76% being highest at PAU, Ludhiana centre and lowest at Pantnagar centre. Maximum percent increase in yield was observed at Delhi centre (28.37%) closely followed by PAU, Ludhiana centre (28.23%). Positive correlation (r) was observed between mean per cent disease control and mean percent increase in yield.

Rhizoctonia solani, a devastating soil borne fungus inciting banded leaf and sheath blight (BLSB) disease is a constraint in maize production and improvement program. Rhizoctonia isolates collected from seven diverse maize cropping zones of India were examined for morphological and molecular variability. All the tested isolates caused symptoms of BLSB on maize and were also cross infective on rice and sugarcane hosts, but showed significant variability in hyphal diameter, mean hyphal cell size, weight, size and distribution of scleorotia, culture pigmentation, incubation period, pathogenicity and expression of symptoms. Neighbour joining cluster analysis placed the 62 isolates of R. solani into four major groups, A, B, C and D. Group A was more diverse and included isolates of diverse agro-ecological zones. The cluster analysis corresponded well with principle component analysis. Pathogenicity testing of R. solani isolates on maize genotype (CM 501) revealed highly variable virulence pattern of the pathogen population suggesting its high evolutionary potential, and hence adaptability to diverse geographical regions. The study reveals a strong evidence of inherent potential of the R. solani isolates to survive in diverse ecological zones and its probable spread to other maize cultivars across India. Sequence comparisons of the internal transcribed sequence-ribosomal DNA region of 62 isolates did not reveal much diversity among the isolates. Majority of the isolates (n = 61) clustered together with anastomosis group (AG) AG1-IA used as reference strain in the phylogram, distinct from AG1-IB, AG2–2IIIB and Waitea circinata used as reference strains. BLSB isolates representing distinct geographical locations shared identical sequences indicating long-distance dispersal of the pathogen. The study confirms that the genetic flexibility of the pathogen allows for its adaptation to variable ecological niches and long-distance introduction of new genotypes into the region. The study emphasizes that epidemiological studies may complement the molecular studies.

Turcicum leaf blight of maize caused by the fungus Setosphaeria turcica is a serious foliar disease of maize distributed widely throughout the world and causing significant yield losses. The disease is more prevalent in humid weather with temperature between 20–28 °C and causes small cigar-shaped lesions to complete destruction of the foliage. Though there are several management practices available, identification and deployment of host plant resistance is a pragmatic approach to control the disease. However, qualitative resistance is unstable and breaks down easily by emergence of new races of the pathogen in maize necessitating the development of durable TLB resistant cultivars. Application of modern molecular tools and availability of high-density molecular marker data are expected to accelerate efforts to develop resistant hybrids. This review provides a focuses on current status, and future research needs especially biological control and sustainable integrated management strategies of TLB.

Post-flowering stalk rot (PFSR) complex caused by Fusarium verticillioides (Sacc.) and Macrophomina phaseolina (Tassi) Goid, is among the important constraints that limits the productivity of maize ( Zea mays L.). The absence of high levels of stable resistant sources to the pathogens has necessitated the continued search and identification of new sources of resistance. The principal goal of this work was once to identify new sources of resistance to PFSR and validate their stability across multi-environments by multi-year testing. A set of 80 elite inbred lines screened in the field against PFSR for three consecutive years at four hotspots in India (Hyderabad, Ludhiana, New Delhi and Udaipur) under artificially created disease epiphytotics. The scores on the scale of 1 to 9 based on the disease reaction were recorded by splitting the stems of each plant. Significant (p=

Maize (Zea mays L.; 2N=20) is major staple food crop grown worldwide adapted to several biotic and abiotic stresses. Maydis leaf blight (MLB) and banded leaf and sheath blight (BLSB) are serious foliar fungal diseases may cause up to 40% and 100% grain yield loss, respectively. The present studies were undertaken to work out the efficacy of chemicals, botanicals and bioagents for the management of MLB and BLSB under field condition for two seasons Kharif 2014 and 2015. Five molecules (propiconazole 25 EC, hexaconazole 25 EC, carbendazim 50 WP, mancozeb 75 WP and carbedazim 12 WP + mancozeb 63 WP), two bioagents i.e. Trichoderma harzianum and T. viridae and three botanicals namely azadirachtin, sarpagandha and bel pathar were tested for their efficacy against MLB. Eight newer fungicides viz., difenconazole 250 SC, hexaconazole 5 EC, carbendazim 50WP, validamycin 3 L, tebuconazole 250 EC, trifloxystrobin 50 WG + tebuconazole 50 WG, azoxystrobin 250 EC and pencycuron 250 SC were evaluated against BLSB. Analysis revealed significant effects of propiconazole at 0.1%, carbendazim 12 WP + mancozeb 63 WP at 0.125% and sarpagandha leaves at 10% against MLB pathogen, whereas validamycin at 0.1% and trifloxystrobin 25 WG + tebuconazole 50 WG at 0.05% were found effective against BLSB. The slow rate of disease control virtually by the bioagents might have not shown instant effect on plant response to the yield enhancing components. The identified sources of management can be used further in strengthening the plant protection in maize against MLB and BLSB.

The high incidence of various soil-borne and foliar diseases is a major production constraint in the profitable cultivation of French bean. Compost and compost teas have been widely explored as an eco-friendly option for controlling plant diseases in container mixes. However, there is limited information regarding their disease suppressive potential under field conditions especially against diseases of French bean. The aim of this study was to investigate the suppressive potential of six composted substrates (farmyard manure, poultry manure, vermicompost, spent mushroom compost, Lantana camara and Urtica sp.), in comparison to a recommended chemical fungicide (carbendazim), against soil-borne and foliar diseases of French bean under the conditions of western Indian Himalayas. The field experiment was conducted over two growing seasons and the composts applied as a soil amendment and later as foliar sprays of their fermented extracts. There was a high level of root rot suppression (>33%) in the poultry manure, Lantana and Urtica compost treatments in both experimental years and these treatments were on par with the chemical seed treatment. All the compost treatments showed a moderate but significant reduction (>20%) in angular leaf spot severity also but none was comparable to that of chemical sprays. There was considerable variability in the suppressiveness of different composts. Overall, poultry manure, composted Urtica sp. and composted Lantana camara treatments were superior to other composts in suppressing both Rhizoctonia root rot ( Rhizoctonia solani Kuhn) and angular leaf spot ( Phaeoisariopsis griseola (Sacc.) Ferraris). The different compost treatments exerted a significant effect on the population of Trichoderma spp. and fluorescent pseudomonads in the plant rhizosphere. The highest population of these antagonists was recovered from poultry manure and Urtica compost treatments indicating that it may be a major factor contributing towards the higher disease reduction observed in these treatments. All composts increased yield over the control with maximum yields recorded in poultry manure and Urtica treatments. Although Lantana compost suppressed disease, the yield levels in this treatment were quite low indicating that the compost may be phytotoxic. Our results suggest that application of composts and compost extracts derived from poultry manure and Urtica sp. has the potential to provide effective control of diseases and improve yield in bean under field conditions.