Chiang Mai Journal of Science

     The symptoms of “shot hole leaves” and “excess bud growth” in Arabica coffee have significantly increased in northern Thailand since 2017, resulting in the death of shoots and reduced flowering, ultimately leading to yield loss. This study investigates whether the “shot hole leaves” symptom is caused by the tea mosquito bug (Helopeltis theivora Waterhouse) (Hemiptera: Heteroptera: Miridae) by rearing tea mosquito bugs with coffee and reproducing the same symptoms under laboratory conditions. Furthermore, we examine whether the “shot hole leaves” symptom is associated with the “excess bud growth” symptom in the field. Our results show that H. theivora can complete their life cycle on Arabica coffee trees. Female bugs lay an average of 87.60±41.82 eggs underneath the soft tissue near young leaves on coffee branches, with a hatching rate of 73.97±6.69%, and an average incubation period of 8.20±0.97 days. The longevity of the first to fifth nymphal stages was 4.02±1.58, 3.36±0.93, 3.27±0.74, 3.23±0.96, and 3.83±1.18 days, respectively. The adult bugs had a lifespan ranging from 2 to 24 days, with an average of 11.61±7.89 days. The “shot hole leaves” symptom appear approximately 14 days after H. theivora begin feeding on young coffee shoots. We found that the bud number is significantly higher on twigs with the symptom, indicating that both symptoms are caused by H. theivora. The study concludes by discussing control practices of H. theivora on coffee trees.