Ketahanan Aksesi Kapas terhadap Hama Pengisap Daun, Amrasca biguttula (ISHIDA) - I.G.A.A. Indrayani; Siwi Sumartini (Buletin Tanaman Tembakau, Serat & Minyak Industri, 2009)
Amrasca biguttula (Ishida) adalah salah satu hama utama kapas di Indonesia. Nimfa dan dewasanya meru-sak dengan cara mengisap cairan daun yang menyebabkan gejala seperti terbakar, kekeringan, dan gugur. Pengendalian hama ini semakin sulit karena terjadinya resistensi dan resurgensi hama akibat penggunaan insektisida kimia sintetis yang kurang bijaksana. Berkaitan dengan ketahanan terhadap A. biguttula, karakter morfologi tanaman kapas, khususnya trikom daun memegang peranan penting dalam mekanisme ketahan-an. Penelitian ini bertujuan untuk memperoleh aksesi-aksesi kapas yang tahan terhadap A. biguttula. Pene-litian evaluasi ketahanan plasma nutfah kapas terhadap A. biguttula (Ishida) dilakukan di KP Asembagus, Si-tubondo, mulai Januari hingga Desember 2008. Sebanyak 50 aksesi kapas digunakan sebagai perlakuan yang disusun dalam rancangan acak kelompok (RAK), dengan tiga kali ulangan. Ukuran plot perlakuan 10 m x 3 m, dengan jarak tanam 100 cm x 25 cm, satu tanaman per lubang. Parameter yang diamati adalah: po-pulasi nimfa A. biguttula, tingkat kerusakan tanaman, dan karakter trikom daun yang meliputi: kerapatan, panjang, dan posisi trikom. Hasil penelitian menunjukkan bahwa kerapatan trikom daun berhubungan de-ngan ketahanan terhadap A. biguttula. Aksesi dengan kerapatan trikom daun yang tinggi lebih tahan ter-hadap serangan A. biguttula dibanding aksesi dengan sedikit trikom atau tidak bertrikom. SK 32, LAXMI, dan SK 14 adalah aksesi kapas yang tahan terhadap serangan A. biguttula, sedangkan SATU 65, LASANI 1, G-cot-10, SAMARU 70, NH4, L 18, dan NIAB adalah aksesi-aksesi dengan tingkat ketahanan sedang (moderat). Selain itu, aksesi yang termasuk sangat rentan adalah: Stoneville 825, 7042-5W-79N, 1073-16-6x491L-619-4-77, dan M35-5-8, sementara aksesi lainnya termasuk rentan terhadap serangan. Terdapat korelasi negatif antara kerapatan trikom daun dan populasi nimfa (Y=-170,8x + 296,6; R2 = 0,414) dan antara kerapatan trikom daun dan tingkat/skor kerusakan tanaman (Y=-0,005x + 2,916; R2 = 0,622). Se-dangkan korelasi positif terjadi antara populasi nimfa dan tingkat/skor kerusakan tanaman (Y=0,469x – 0,071; R2 = 0,672). The cotton jassid, Amrasca biguttula (Ishida) is a key pest of cotton in Indonesia. The nymphs and adults suck the leaves resulting in hopperburn, drying, and shedding of leaves. The management of this pest is more difficult due to the insect resistance to chemical insecticides and resurgence caused by unwise applications of synthetic insecticides. Related to jassid resistance, morphology of cotton mainly hairiness of leaf, plays an important role in mechanism on the plant resistance. The objective of the study was to screen a large number of cotton accessions for susceptible or resistant to A. biguttula. The study was conducted at Asembagus Experimental Station from January to December 2008. Fifty accessions of cotton were planted in 10 m x 3 m of plot size with 100 cm x 25 cm of plant distance. All accessions were designed in randomized block with three replications. Each plot consists of two rows cotton accession and one row susceptible varie-ty, TAMCOT SP 37 as a attractant plant. Parameters observed were nymph population, plant damage, tri-chome characters and its density, length, and position on the leaf lamina. Results showed that cotton acces-sions with higher trichome density were more resistant to jassid compared to the less trichome of accession. SK 32, LAXMI, and SK 14 were more resistant accession to A. biguttula, while SATU 65, LASANI 1, G-cot-10, SAMARU 70, NH4, L 18, and NIAB were categorized as intermediate resistant accessions to the pest. Sto-neville 825, 7042-5W-79N, 1073-16-6x491L-619-4-77, and M35-5-8 were found as the most susceptible to A. biguttula. Negative correlation was occured between trichome density and nymph population (Y=-170,8x + 296,6; R2 = 0,414) and between trichome density and damage score (Y=-0,005x + 2,916; R2 = 0,622), while positive correlation was found between nymph population and damage score (Y=0,469x – 0,071; R2 = 0,672).