Impact of planting distances to arthropods abundance on kangkong

Abstract

Kangkong (Ipomoea reptans Poir) is the favourite green vegetable especially most of Asian people. The important factors affecting production of kangkong is the planting distance. The optimal planting distance create an ideal microhabitat around crop and potential to suppress development of insect pests. The research purpose is to study the impact of planting distance to arthropods abundance on kangkong. The research was conducted in Somba Opu District, Gowa Regency, South Sulawesi from February to May 2020. The arthropods identification was carried out at the Pest Laboratory, Department of Plant Pest and Diseases, Faculty of Agriculture, Hasanuddin University Makassar. The study was conducted in four treatments of planting distance, P1= 5 cm x 5 cm; P2 = 5 cm x 10 cm, P3 = 5 cm x 15 cm and P4 = the seeds was spread (without planting distance), respectively. Each treatment was repeated four times, the arthropods was caught by pitfall trap. The sampling method used the diagonal pattern. Observation of arthropods began when the kangkong 7 days after planting with interval 7 days until harvest. The arthropods results divided into two group (insect pest and natural enemies) showed that: 1) the highest number of insect pests in the pitfall trap was found in treatment P4 (Valanga sp. 1.25 individual); 2) the highest natural enemies number from Hymenoptera (Formicidae); and 3) the highest harvest number in the treatment P1 (13.1 kg) and the lowest in P4 (11.3 kg). Conclusion of the research: grasshopper Valanga sp. (Orthoptera: Acrididae) as the dominan insect pest in P4 (1.25 individual). Dominant arthropods as natural enemies in the kangkong field as Formicidae in P3 (14.5 individual). The highest harvest in kangkong field at P1 (13.1 kg) and the lowest in P4 (11.3 kg).