Degree of arbuscular mycorrhizal (AM) association and its diversity were investigated in the coconut palm (Cocos nucifera L.) cultivated in crop mixed system under rain-fed condition in a highly productive humid tropical zone in Malappuram district of Kerala, India. Forty AM species belonging to ten genera viz. Acaulospora, Claroideoglomus, Dentiscutata, Diversispora, Funneliformis, Gigaspora, Glomus, Redeckera, Scutellospora and Septoglomus were recorded indicating high level of AM richness in coconut rhizosphere. Of these, eighteen AM fungal species are being reported for first time from this palm. Claroideoglomus, Glomus and Gigaspora were the most commonly present genera and Claroideoglomus etunicatum and Glomus aggregatum the common species. The diversity indices (Shannon indices values) of AM fungi associated with coconut palm in a crop mixed system and mono crop varied significantly. The Shannon index, Simpson's index and evenness ranged from 1.40±0.10 to 2.70±0.01, 0.65±0.033 to 0.90±0.004, 0.51±0.01 to 0.82±0.01, respectively. Correlation between soil physio chemical characters and mycorrhizal parameters were worked out. Soil pH had negative correlation with spore count, root colonization, species richness, Shannon H and Simpson indices but had positive correlation with species evenness. Electrical conductivity showed positive correlation with root mycorrhizal colonization which indicated active AMF mediated uptake of nutrients.

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Carnation (Dianthus caryophyllus L.) is a cut flower with greater stipulation in the world cut flower market. In India, carnations are cultivated under polyhouses in Nilgiris and Kodaikanal districts in the state of Tamil Nadu. Carnations cultivation is impeded by various diseases, among them stem rot caused by Sclerotinia sclerotiorum (Lib.) de Bary was found to be predominant in all varieties. Survey among commercially cultivated varieties of carnation during 2013, revealed the occurrence of stem rot incited by Sclerotinia sclerotiorum, for the first time in India. The pathogen was identified as Sclerotinia sclerotiorum on the basis of phenotypic and genotypic characteristics. Carpogenic germination was induced artificially, and life cycle of the fungi was studied. Microscopic studies of the apothecium revealed the presence of spermatia, croziers, paraphyses as well as monomorphic ascospores specific to S. sclerotiorum.