Digital phenotyping of coconut and mite infestation 417 Research Article Journal of Plantation Crops, 2013, 41(3): 417-424 Abstract Observations were recorded on traits associated with mite infestation related at two stages of button on six different coconut cultivars over three years. Highly significant correlation was found between mite damage score with color or weight of tepal. Step-wise multiple regression of the data analysis showed color of inner tepal as major trait associated with infestation by eriophyid mite. Other traits are ratio of tepal weight to tepal area, per cent of buttons with pink discoloration or with resin, tepals of regular aestivation and gap between fruit and tepal. Digital phenotype data of 83 image files were used to calculate color signature and correlated the same to mite damage score over three years. Red spectral values were found to vary from 14 to 251, green values to 12 to 237 and blue to vary from 5 to 183. Spectral values red max, green max, 3* Red + Green max had high significant negative correlation (>-0.4) with mite damage. Color and firmness of fruits and tepals of three coconut varieties were further analyzed where, fruits and tepals of COD variety showed high red/green (a* value of Hunterlab) >12. Firmness of 3 month old tepal and fruit of Benualim (BGRT) tall variety was (penetrometer reading >38) higher than other varieties. Keywords: Colour, Hunterlab, palms, penetrometer, spectral, tepal Digital phenotyping of coconut and morphological traits associated with eriophyid mite (Aceria guerroronis Keifer) infestation V. Arunachalam * , B. Augustine Jerard 1 , S. Elain Apshara 2 , C. Jayabose 3 , K. Subaharan 1 , N. Ravikumar 4 and C. Palaniswami 3 ICAR Research Complex for Goa, Old Goa - 403402, Goa 1 Central Plantation Crops Research Institute, Kasaragod - 671 124, Kerala, India 2 CPCRI Research Station, Vittal, Dakshina Kannada - 574 243, Karnataka 3 Sugarcane Breeding Institute, Coimbatore - 641 007, Tamil Nadu 4 Central Research Institute for Dryland Agriculture, Hyderabad - 500 059, Andhra Pradesh (Manuscript Received: 19-03-13, Revised: 19-08-13, Accepted: 01-10-13) Introduction Eriophyid mite (Aceria guerreronis Keifer) (Eriophyidae: Acari) is originaly a pest of coconuts grown in Jamaica, Mexico and other Latin American and Caribbean countries. The pest has later spread to African countries and it became a serious pest of coconut. It had further spread to few Asian countries in late 1990s. The incidence of the pest was reported for the first time in Kerala, India in 1998 (Sathiamma et al., 1998). Coconut palm suffers serious economic loss due to the mites feeding the fruit just below tepals or (most commonly, but erroneously referred to as bracts). Host plant resistance is an important and effective way of managing the pest under the IPM strategies. High degree of mite tolerance was seen in a Cambodian variety with tight tepals (Mariau, 1986). Biophysical traits of microhabitat of the pest in the plant provide an indirect means to select resistance to mite. Among the traits analyzed, shape (Julia and Mariau, 1979; Mariau, 1986; Moore and Alexander, 1990) colour of the fruit (Moore and Alexander, 1990), tightness of tepals (Howard and Rodriguez, 1991), gap between the rim of the fruit (Aratchige et al ., 2007), aestivation of tepals *Corresponding Author: vadivelarunachalam@yahoo.com