Özet:

Tenuipalpid mites represent an important group of Acari characterized by polyphagous habit on a wide variety of crops. Among the injurious species of tenuipalpids, Raoiella indica Hirst (Trombidiformes: Tenuipalpidae), the Red Palm Mite (RPM), is a serious pest on a variety of plants. In the present study, infestation and distribution of the species on Areca catechu L. (Arecales: Arecaceae), an important plantation crop of Kerala (India), were studied. The leaf sampling was carried out once in a month in Kozhikode and Malappuram districts of North Kerala between 2011 and 2013. Both uninfested and infested leaf samples were subjected to observation under a stereo zoom microscope (MVNSZ-450) to collect data on the population density of the mite. Feeding impact of the RPM on the areca palm was assessed through quantitative estimation of the total contents of nitrogen, phenolic compounds and chlorophyll, and free proline. Results of population studies revealed peak population density of RPM during April-May months. A positive correlation was recorded between mite population and temperature and a negative correlation between mite population and relative humidity. The percentage losses of ‘total nitrogen’ and ‘total chlorophyll contents were estimated as 51-53% and 59-60% respectively in RPM infested leaves. The percentage increases recorded in the proline and phenolic compound contents of mite infested leaf samples were 182-198% and 90-92%, respectively, thereby revealing the stress induced by the RPM to areca palms. Data obtained on the changes induced by RPM on chlorophyll, proline, phenolic compound and total nitrogen contents were found significant at 0.05 level, when subjected to statistical analysis following t-test, thereby establishing the pest status of RPM on A. catechu.

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