Keywords : microbial polysaccharide

Improvement of the Efficiency of the Fungicide Dithane M-45 By the Use of the Polysaccharide for the Control of Fungi Causing Damping off of Okra (Ablelmoschus Esculentus L)

Doha Ismaeel Ibraheem

Kirkuk University Journal-Scientific Studies, 2020, Volume 15, Issue 1, Pages 53-67
DOI: 10.32894/kujss.2020.15.1.4

Laboratory tests of three fungicides, dithane M-45 (mancozeb), captan 50 and rhizolexwith four concentrations each 0.0, 50, 100 and 200 mg active inegradient/l of Potato DextroseAgar (PDA) medium on the growth of fungi Macrophomina phasealina 2 isolates of Fusarium solani and Rhizoctonia solani, the causal agents of damping off and root rot ofokra, Dithane M-45 showed high inhibition (100%) effect for the mycelial growth of pathogenic fungi at 100 mg a.c/l PDA. Treating okra (Ablelmoschus esculentus) seeds (localcultivar) by various concentrations of dithane M-45 (0.0, 1.0, 2.0 and 3.0) gm/kg seeds withthe microbial polysaccharide produced by the fungus Alternaria alternata or Arabic gum (5gm/l distilled water) was superior than the fungicide alone through all the treatments incausing significant decrease in % infection and disease severity of the seeding damping offdisease at conc. 3 gm/kg seeds with the polysaccharide which gave 4 %, 5.33 % and 0.07respectively and 8.7 %, 10.0 % and 0.15 with the arabic gum respectively. There were nosignificant differences noticed between the treatment of the seeds with the polysaccharidewith the arabic gum in reducing% infection and disease severity of the disease. Also, it causedsignificant increase in the length of shoot and root systems and dry weight of the plants whichreached 16.33 cm, 6.04 cm and 0.0204 gm at 3 gm/kg seeds with the polysaccharide and13.91 cm, 4,99 cm and 0.144 gm for arabic gum respectively as compared with the treatmentby the fungicide dithane M-45 alone (without sticking material) which gave 11.95 cm, 3.95cm and 0.124 gm respectively.