Impact of cultural practices on two‐spotted spider mite ( Tetranychus urticae  Koch) infestation in tomato cultivation in the Central Rift Valley of Ethiopia

The two‐spotted spider mite (TSSM; Tetranychus urticae Koch) is a major pest of tomato ( Solanum lycopersicum L.), causing substantial yield and quality losses in Ethiopia and worldwide. The present study evaluated the impact of tomato branch pruning and trellising on TSSM populations and yield in the Central Rift Valley tomato production area of Ethiopia. Field experiments were conducted at the Melkassa Agricultural Research Center of the Ethiopian Institute of Agricultural Research during the hot dry tomato‐growing seasons of 2021 and 2022 using a randomized complete block design. The experimental treatments consisted of (a) pruning alone, (b) trellising alone, (c) a combination of pruning and trellising, (d) a chemical control (abamectin), and (e) an untreated control. Data were collected on spider mite populations (eggs, nymphs, and adults), tomato fruit yield, and fruit damage. The relative economic returns of the treatments were also calculated. The combined pruning and trellising treatment significantly reduced TSSM egg and adult numbers compared with the untreated control and resulted in a significantly higher marketable fruit yield than the control in either growing season. Moreover, the combined pruning and trellising treatment offered the highest benefit–cost ratio (5.07), exceeding those of the other treatments. This study demonstrated that combining pruning and trellising provides effective and economical control of TSSM.