Identification of Stem Borer Pests and Damage Description in Clove Plants (Syzygium aromaticum L.)

Department of Silviculture, Faculty of Forestry, Gadjah Mada University, Jalan Agro No. 1, Bulaksumur 55281, Yogyakarta, Indonesia

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Abstract

Clove (Syzygium aromaticum) is economically important in community forest systems, but its productivity is constrained by stem borer infestation. This study identified the principal stem borer species, described its biological characteristics, and quantified damage in clove stands. Field observations were conducted in a community clove forest in Borobudur District using 20 × 20 m plots. A total of 215 clove trees were assessed and classified as saplings (36), poles (94), or mature trees (85). Notopheus sp. was confirmed as the dominant clove stem borer (CSB). External symptoms consisted of entry holes and frass, while internal damage was characterized by upward galleries within the stem. The overall infestation rate was 50.23%, increasing from saplings (4.2%) to poles (55.1%) and mature trees (69.9%). Damage intensity showed a similar trend, at 0.8%, 20.7%, and 28.8%, respectively, indicating greater susceptibility as plant maturity increased. The relationship between stem diameter and borer holes differed among planting patterns, with significant positive relationships in monoculture and mixed-garden agroforestry stands, but not in clove-coffee agroforestry stands. Overall, stem diameter showed only a weak positive association with borer holes (R² = 0.1123), suggesting that stand structure, cropping composition, and other ecological factors influence CSB infestation dynamics. These findings also indicate that mixed planting systems may serve as an alternative stand arrangement to help suppress CSB occurrence in community forests.