EFFICACY OF SEED TREATMENT WITH PLANT EXTRACTS ON LEAF BLIGHT (Bipolaris sorokinianai DEVELOPMENT AND YIELD OF WHEAT

Abstract

Wheat (Triticum aestivum L.). an important cereaJ crop ... is produced aJI over the country. Leaf blight caused by Bipolaris sorokiniana is a common constraint of limiting wheal production in Bangladesh. Use of plant extracts as a biocontrol agent against plant diseases is a relatively recent approach. Efficacy of plant extracts in controlling leaf blight (Bipolaris sorokinianas of wheat was studied during the cropping season 2006-2007. The experiments were conducted in the Seed Health Laboratory. Department of Plant Pathology and in the farm of the Sher-e-Bangla Agricultural University, Dhaka. Initially 33 plant species were evaluated for their efficacy against Bipolaris sorokiniana by an in vitro test. Among them 13 species were found promising and selected for field evaluation against leaf blight disease. A remarkable reduction of the severity of leaf blight was achieved by treating seeds with botanicals. The treatments showed significant effect in respect of leaf blight severity (0-5 scale) for flag leaf and penultimate leaf at flowering, milking and bard dough stages. The lowest severity of flag leaf and penultimate leaf in every stage was found in the treatment T12 (Seed treatment with turmeric rhizome extract) followed by treatment T (Seed treatment with garlic clove extract) whereas the highest disease severity was recorded under the Ill 2 treatment T1 (untreated control). Significantly the highest plant height (93.09 cm) was found in the treatment T2~ ear length (15.58 cm) in treatment Ts (Seed treatment with kalijira seed extract) and the number of spikelets Ices (19.I 1) in treatment T5 (allamanda leaf extract). The number of grains/ear, number of healthy grains/ear, weight of grains/ear and weight of healthy grains/ear were increased by using seeds treated with extracts of kaliji.ra (Ts), garlic (T2). allamanda(T and turmeric (T Seed treatment with plant extracts significantly increased grain yield over untreated control. Among the plant extracts, turmeric rhizome extract 12). treated seeds resulted the highest grain yield (3.60 t/ha) which was 39.44 % higher over untreated control. Thus plant extracts have definite antifungal effect on Bipolaris sorokiniana which could be employed as an ecofriendly approach in controlling leaf blight of wheat.