Distribution and molecular characterization of Lasiodiplodia theobromae and Aceria guerreronis associated with coconut

Aim: A survey was conducted in major coconut-growing areas of Tamil Nadu in order to determine the presence of a fungus Aceria guerreronis, and a mite Lasiodiplodia theobromae and their interactive effects. The objective of the study was to ascertain the interaction, pathogenicity and cross infectivity reaction to infection. Methodology: Pathogenicity studies demonstrated the intensity of pest incidence, both individually and in combination, through morphological and molecular studies. Interestingly, interactions in a few crops were confirmed through PCR amplification. Results: The survey revealed a significant positive correlation between mite and fungus infestations and GPS location (χ² = 2114.22, df = 1; P < 0.001). Molecular studies identified product sizes of 347 bp for Lasiodiplodia theobromae KKLT01 and 500 bp for Aceria guerreronis KKAG01. Cross-infectivity tests demonstrated that toddy palm and arecanut experienced the same effects as coconut, which was confirmed through PCR amplification. Interpretation: The present study shows that apart from mite infestation, the fungus also play a major role in increasing infestation and the interaction was positively correlated for cross infectivity. The results of the present study will help to restructure the existing management strategy. Key words: Aceria guerreronis, Coconut, Infestation, Lasiodiplodia theobromae, Morpho-molecular variations