Status and Management of Biting Ant, Tetramorium aculeatum (Formicidae: Hymenoptera) on Arabica Coffee at Bebeka, South western Ethiopia

Abstract

Ethiopia is the birthplace and the largest Arabica coffee producer in Sub-SaharanAfrica. However production and productivity is low due to various reasons. In largescale coffee producing area like Bebeka and lower parts of Tepi, biting ants arebecoming important pest in coffee production system. Biting ants are not directlyaffecting coffee crop growth but hindering the agronomic and ripe berry pickingactivities. As a result ripe coffee beans stay longer in the field subjected todeterioration. Therefore, this study was undertaken to assess the current status andmanagement practices of the biting ant, Tetramorium aculeatum, at Bebeka CoffeeEstate Share Company. To figure out current status of biting ants number of nestswith colony was counted from ten sampled coffee trees replicated three timesconsidering coffee plants under shade and without shade, compact and open canopynature, and productive and less productive blocks. Five coffee varieties wereconsidered to determine number of nests with colony and different ant growth stagesper nest. Yield loss caused by biting ant was compared between infested and noninfested coffee blocks. For the management of biting ant two round applications ofDecis, Dan anticides, horticultural oil and manual ant nest destruction at fourteendays interval were tested to evaluate efficiency of each management options. Theresult showed yield loss was 29% higher in ant infested blocks. Number of ant nestswith colony based on canopy nature was significantly (P<0.0001) higher thancompact coffee variety. It was also higher on under recommended shade than nonshaded coffee tree (P=0.0035). No significant difference (P=0.5387) result wasobserved between less productive and productive blocks. Ant management optionresults showed that manual ant nest destruction and immediately inserting indetergent solution had better ant management efficiency followed by spraying ofDecis and Dan anticides. Spraying of horticultural oil was the least effective tomanage the ant. Therefore, to reduce the population of the ant and its effect onhindering the agronomic and ripe berry picking activities manual ant nestdestruction could be recommended. In the future ant population and infestation levelat different seasons and other alternative integrated management options should bestudied.