The effect of the biological control agent Trichoderma harzianum T-22 on spot blotch disease in Libyan barley cultivars in a field experiment

Abstract: Spot blotch caused by Bipolaris sorokiniana (teleomorph Cochliobolus sativus) is aserious disease of barley in Libya. A small-scale field experiment was carried out in the UK totest the effectiveness of Trichoderma harzianum T-22 for controlling spot blotch in two Libyanbarley cultivars, Nibola and Rehan. Nibola was significantly more resistant to spot blotch thanRehan. Two methods of applying T-22, foliar spray and seed coating, were tested individuallyand in combination. There was some reduction in disease severity with all three applicationmethods, but the combined treatment most consistently reduced disease severity and increasedyields of both cultivars. The results provide evidence that combining disease resistance withbiological control may be beneficial for spot blotch management.