[Leaf spot and rust disease control on groundnut]

English. In Indonesia, early leaf-spot (Cercospora arachidicola), late leaf-spot (Cercosporidium personatum) and rust (Puccinia arachidis) are important diseases of groundnut and the yield losses caused by these diseases varies between 20-60 percent, depend on the disease intensities and leaves defoliation, but most of the farmers do not control the leaf-spot and rust diseases. Some wild species of Arachis are highly resistant to late leaf spot and rust. Several lines and improved varieties such as Rusa, Anoa, Biawak and Zebra are also resistant or tolerant to leaf spot and rust diseases. Rotation of groundnut with non-host crops of leaf spot and rust pathogen, sanitation and eradication of infected plants can reduce the disease intensities. Fungicides with active ingredient of dithiocarbamat, benomil, carbendazim, chlorotalonil, triadimefon, mancozeb and methylthiofanat were effective to reduce the leaf spot disease, while bitertanol, tebukonazol were effective for rust disease. In Indonesia, 4 to 6 times spraying of methylthiofanat, bitertanol, chlorotalonil and their combinations can reduce the leaf spot disease up to 55-90 percent and rust 28-89 percent. Spraying of methylthiofanat at 7 and 9 weeks after planting reduced the disease intensities by 20 percent and increase groundnut yield by 400 kg/ha dry pods. Government support to facilitate credit and other supplies such as resistant varieties, fungicides and others will help farmers to solve the leaf-spot and rust diseases problems

unknown. Di Indonesia penyakit bercak daun (Cercospora arachidicola) dan (Cercosporidium personalum) serta karat-karat daun (Puccinia arachidis) merupakan penyakit penting dan sering menimbulkan kerugian hasil kacang tanah yang cukup besar (20-60 persen). Tingkat kehilangan hasil kacang tanah tersebut berkorelasi positif dengan intensitas serangan dan tingkat defoliasi daun. Walaupun demikian sejauh ini sebagian besar petani tidak melakukan usaha pengendalian terhadap penyakit bercak daun/karat. Jenis-jenis kacang tanah liar mempunyai tingkat ketahanan yang tinggi terhadap infeksi jamur karat dan bercak daun akhir. Beberapa genotipe kacang tanah dan varietas unggul nasional seperti Rusa, Anoa, Biawak, Zebra mempunyai tingkat ketahanan/toleransi terhadap penyakit bercak daun dan karat. Rotasi tanaman kacang tanah dengan tanaman lain bukan inang jamur, sanitas dan eradikasi sisa tanaman sakit dapat menekan intensitas serangan penyakit. Fungisida dengan bahan aktif dithiocarbamat, benomil, carbendazim, klorotalonil, triadimefon, mancozeb, metiltiofanat cukup efektif untuk menekan penyakit bercak daun. Bitertanol dan tebukonazol efektif terhadap penyakit karat. Di Indonesia, penyemprotan fungisida thiofanatmetil, bitertanol, klorotalonil dan kombinasi fungisida tersebut sebanyak 4-6 kali dapat menekan serangan penyakit bercak daun 55-90 persen dan penyakit karat 28-89 persen. Penyemprotan fungisida thiofanatmetil pada umur 7 dan 9 minggu setelah tanam dapat menekan serangan penyakit sebesar 20 persen dan meningkatkan hasil polong kering 400 kg/ha. Bantuan pemerintah berupa kemudahan fasilitas kredit dan pelayanan penyediaan sarana produksi (varietas tahan, fungisida) akan membantu petani dalam mengatasi penyakit bercak dan karat