Hubungan antara densitas populasi awal Meloidogyne incognita ras 1 dan hasil tanaman kubis.

BAHASA: Dalam upaya meneliti hubungan antara densitas populasi awal Meloidogyne incognita ras 1 dan hasil kubis, telah dilaksanakan percobaan plot mikro di Balai Penelitian Hortikultura Lembang dari Agustus sampai November, 1992. Kubis var. Gloria Osena ditumbuhkan pada plot mikro yang telah diinokulasi dengan spesies nematoda bengkak akar yang paling prevalen eksistensinya di kawasan sayuran dataran tinggi di Indonesia yaitu M. incognita ras 1. Bobot hasil kubis ternyata berkorelasi negatif dengan densitas populasi nematoda, dengan penurunan bobot maksimum sebanyak 32 persen pada densitas 12.000. Pada densitas populasi nematoda 750 per kg tanah, bobot kubis turun sebanyak 2,63 persen. Pada densitas populasi 1.500, 3.000, 6.000 dan 12.000 nematoda per kg tanah, penurunan bobot kubis tercatat berturut-turut 11,65 persen, 22,34 persen, 28,36 persen dan 32,17 persen. Hasil penelitian ini memberi indikasi bahwa pertumbuhan tanaman kubis bagian atas distimulasi apabila densitas populasi awal larva Meloidogyne incognita ras 1 rendah (tidak lebih dari 500). Hubungan antara densitas populasi awal nematoda dan bobot hasil kubis memberi indikasi bahwa nilai ambang kerusakan kubis sekitar 1.500 larva per kg tanah.

English. In order to investigate the relationship between initial population densities of Meloidogyne incognita race 1 and yield of cabbage, microplot experiment was carried out at Lembang Horticultural Research Institute during August to November, 1992. Cabbage var. Gloria Ocena were grown in microplots inoculated with the most prevalent species of root-knot nematode found in highland vegetable growing areas in Indonesia, namely, M. incognita race 1. Cabbage yields were inversely correlated with nematode population densities, with a maximum decrease of 32 percent at the 12.000 density. At a nematode population density of 750 nematodes per kg of soil, yields of cabbage were reduced by 2.63 percent respectively. At population densities of 1.500, 3.000, 6.000 and 12.000 nematodes per kg of soil, the reduction in yields of cabbage were 11.65 percent, 22.34 percent, 28.36 percent, and 32.17 percent. Results of this experiment indicated that top growth of cabbage plants was stimulated by low initial population densities (not more than 500) of larvae of M. incognita race 1. The relation between initial nematode population densities and yield suggested a damage threshold of 1.500 larvae per kg of soil for cabbage.