Biological control of carrot black rot

Diseased carrot seeds were treated with selected micro-organisms isolated f rom soils, carrot seeds and tap roots. Thee effects of those antagonists on the control of Alternaria radicina were evaluated by growing-on tests on w ater agar, filter paper, vermiculite and in a potting medium (BVB no. 4). T he germination percentage, emergence percentage and the disease severity of those carrot seeds treated with Burkholderia (Pseudomonas) cepacia no. 229 were significantly (P = 0.05) differed from the non-treated seeds and the seed treated with other antagonists. The effects of B. cepacia no. 229 in p romoting seed emergence and controlling disease were as good as those seeds treated with iprodione (100 p.p.m.). Black rot lesions on carrot tap roots were significantly reduced (P = 0.05) in size when roots were treated with B. cepacia no. 229 or Bacillus amyloliquefaciens no. 224 compared to the n ontreated roots. Also, B, cepacia no. 229 significantly (P = 0.05) reduced black rot on the foliage of carrot compared to check.