Kajian epidemi penyakit hawar ranting Choanephora (Choanephora cucurbitarum) pada tanaman cabai di provinsi Daerah Istimewa Yogyakarta

PARYOTO, Dr.Ir. Achmadi Priyatmojo, M.Sc

2005 | Tesis | S2 Agronomi

Kajian epidemi penyakit hawar ranting Choanephora (Choanephora cucurbitarum) pada cabai di Provinsi Daerah Istimewa Yogyakarta bertujuan untuk mengetahui agihan, laju infeksi, pengaruh faktor suhu, kelembapan, dan curah hujan terhadap perkembangan penyakit hawar ranting Choanephora, dan mengetahui patogenesitas C. cucurbitarum pada tanaman cabai. Intensitas penyakit hawar ranting Choanephora pada musim kemarau adalah 33,5%, sedangkan pada musim hujan sebesar 57,2%. Perkembangan penyakit pada musim hujan dengan laju infeksi sebesar 0,063 per unit per minggu, lebih tinggi dibanding dengan perkembangan penyakit pada musim kemarau dengan laju infeksi tertinggi sebesar 0,024 per unit per minggu. Faktor iklim (curah hujan, suhu, dan kelembapan udara) pada musim kemarau, kelembapan udara berpengaruh positif sedangkan curah hujan dan suhu udara berpengaruh negatif. Pada musim hujan faktor curah hujan dan kelembapan udara berpengaruh positif terhadap perkembangan penyakit hawar ranting Choanephora. Pada musim kemarau, kelembapan udara berpengaruh nyata terhadap perkembangan penyakit dengan nilai r = 0,594, sedangkan pada musim hujan faktor curah hujan dan kelembapan udara berpengaruh sangat nyata terhadap perkembangan penyakit dengan nilai r masing-masing sebesar 0,743 dan 0,913 Suhu 250C merupakan suhu optimum untuk pertumbuhan vegetatif C. cucurbitarum. Dua isolat P.02 asal Bantul dan P.27 asal Sleman menunjukkan tingkat patogenesitas paling tinggi dibandingkan dengan isolat P.33, P.34, dan P.44T. Isolat P.02 berkecambah dengan baik pada media PDA dibandingkan dengan perkecambahan di media agar-air. Pada pengamatan 24 jam spora berkecambah 100%. Tanaman hortikultura antara lain; cabai keriting varietas Laris, tomat varietas Ken Muller, terung varietas Mustang F1, mentimun varietas Venus, kapri lokal Muntilan, dan buncis varietas Chia Thai, merupakan inang C. cucurbitarum, sedangkan terhadap tanaman semangka varietas TM-Tiger Hibrid C. cucurbitarum tidak mampu menginfeksi.

Study on epidemic of Choanephora branches blight disease (Choanephora cucurbitarum) on papper at Special Region Province of Yogyakarta was aimed on identifying, distibution and infection rate of the disease as well as the effect of temperature, humidity, and rainfall on vegetative growth of C. cucurbitarum and the pathogenicity of C. cucurbitarum to papper plant. The intensity of the disease in dry and wet season was 33.5% and 57,2%, respectively. The development of the disease in wet season was faster at a rate of 0.063 per unit a week than in dry season that had of 0,024 per unit a week. In dry season, humidity had positive correlation while rainfall and temperature had negative correlation on the development of Choanephora branches blight disease. Meanwhile in wet season, rainfall and humidity had positive correlation on the development of the disease. In dry season, humidity had significantly affect the development of the disease in which depicted by the relatively high r value at 0,593. While in wet season, rainfall and humidity were the major factor on the development of the disease in which close to absolute value of r at 0,754 and 0,913, respectively. The optimum temperature for vegetative growth of C. cucurbitarum was 250C. Two isolates (P.02 and P.27) had a highest pathogenicity on papper. P.02 isolate could well germinate on PDA medium, in which 100% of spore germinated along 24 hours observation. The selected horticultural crops for pathogenicity test e.g.: papper var. Laris, tomato var. Ken Muller, eggplant var. F1 Mustang, cucumber var. Venus, indigenous green pea of Muntilan, and bean var. Chia Thai, showed that they could be infected by C. cucurbitarum. On the other hand water melon var. TM-Tiger Hybrid was resistance to C. cucurbitarum

Kata Kunci : Tanaman Cabai,Penyakit Hawar Ranting Choanephora,intensity disease, host range, humidity, rainfall, and source of inoculum