Influence of elevation and rainfall on leaf growth, bean characteristics and yield components of arabica and robusta coffee under changing climatic conditions in Karnataka state, India

The study was undertaken to analyze the behaviour of coffee under changing climatic conditions in different coffee liaison zones of Karnataka State, India, during 2017-2020. Sample estates were identified based on elevation and rainfall patterns in different zones of the Chikkamagaluru and Hassan districts. The leaf growth parameters, bean characteristics and yield components were recorded in all the sample estates. Correlation studies indicated a significant positive relationship between the elevation, rainfall with specific leaf area (r = +0.912) and productivity (r = 0.475) during the pre-monsoon period. The monthly summer rainfall during March and April showed a significant correlation with yield in robusta (r = 0.511) and arabica (r = 0.451), indicating that blossom shower during this period significantly influenced the productivity of coffee. The studies between elevation, the quantum of rainfall and bean defect parameters indicated a significant (p<0.05) positive correlation. A positive relationship was also found between elevation and peaberry production in both robusta (r = 0.716) and arabica coffee (r= 0.456), respectively. However, there was also a significant relationship between rainfall (2020) and Jollu percentage (r = 0.386) in robusta coffee, indicating that higher elevation and rainfall-induced more peaberry content and Jollu percentage under changing climatic conditions. The overall result indicated that changes in climatic conditions such as excess rainfall and continuous soil moisture led to more vegetative growth than reproductive growth. This also produced more bean abnormalities which in turn affected the yield and quality of the coffee

Assessment of crop loss in Arabica coffee due to white stem borer, Xylotrechus quadripes Chevrolat (Coleoptera: Cerambycidae) infestation

The coffee white stem borer (CWSB) is the most dreaded pest of Arabica coffee in India. Due to the concealed nature of this pest, the management measures are difficult and require the timely implementation of control measures. The recommended practices for the management of CWSB mainly targets on eggs and early instar larvae, apart from tracing and uprooting of infested plants before the commencement of flight periods (April-May and Oct-Dec). In general, youngArabica coffee plants infested by CWSB die within a year, whereas aged plants withstand the attack for few more years. However, such plants become less productive, susceptible to diseases and also serve as inoculum for further spreading of the infestation. A study was undertaken to assess the crop loss due to CWSB infestation on established Arabica plantation in Tamil Nadu. The result indicated a significant difference between healthy and infested plants and the crop loss was to the tune of 17.7 per cent. Further, quantitative data on out-turn percentages recorded at different stages of coffee processing (right from harvesting of fruits to marketable green coffee bean) are discussed in this paper