Vol. 10, Issue 3 (2021)

Author(s):
RN Sharma and RB Gaur

Abstract:
Field trials were laid out at Agricultural Research Station (S.K. Rajasthan Agricultural University), Sriganganagar (Rajasthan) to test the bioefficacy of different dosage of (0.075, 0.1, 0.125, 0.15 and 0.2%) Copper hydroxide 46.1% DF (Kocide 3000) against canker and stem-end rot of Kinnow (Citrus deliciosa Ten.) during two consecutive years (2010-11 and 2011-12) in randomized block design. Foliar application of each dose of fungicide was applied twice during February-March and twice during July-August at 15 days intervals along with Streptocycline (0.01%) + Copper oxychloride (0.2%) which is recommended for citrus canker. Copper hydroxide when sprayed at higher concentration (0.2%), proved significantly superior over rest of the spray treatments in reducing canker intensity on leaves and incidence on leaves and fruits, which statistically at par with the dose of 0.15 per cent. The canker intensity on leaves at 0.20 & 0.15% concentration of Copper hydroxide was 13.03 and 15.84% respectively, as compared to intensity of 22.51% observed under recommended spray schedule. Similarly, Copper hydroxide @ 0.2 & 0.15% proved significantly superior against canker incidence on leaves (29.83 and 34.17%) as well as fruits (1.77 and 2.58%) over recommended spray which exhibited 44.67 and 8.55 per cent incidence on leaves and fruits, respectively. Sprays of Copper hydroxide at 0.2 and 0.15% concentration proved significantly superior over rest of the treatments in reducing stem end rot incidence in fruits. The per cent fruit rot at these spray concentrations (0.2 & 0.15%) was 3.87 & 6.01 per cent respectively as compared to 29.08 per cent under control. Maximum fruit yield was obtained under 0.2 per cent dose of Copper hydroxide which was at par with 0.15 per cent dose of Copper hydroxide.