1. Koynov

Department of Plant growing, Faculty of Agronomy, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 05 June 2025; accepted for publication 4 August 2025)

Abstract.Lettuce (Lacuca sativa L.) is one of the most commonly grown vegetables in field and greenhouse conditions. Modern technologies allow it to be grown almost year-round, which can supply the market with fresh produce. Its biological features allow produce to be obtained within a short period of time (65 – 130 days). It is characterized by high cold resistance, allowing it to be grown during the cold months of the year, in unheated cultivation facilities. All these advantages allow lettuce to participate in the consolidation of vegetable crop rotations, which in turn makes it highly profitable. It is distinguished by very good taste, dietary and biological qualities and is an indispensable source of vitamins, minerals, phenolic compounds and flavonoids. One of the main problems in lettuce production is the control of the lettuce drop causal organisms Sclerotinia minor jagger and Sclerotinia sclerotiorum (lib.) de bary. Every year, pathogens cause significant losses of produce. This is due to their wide specialization, strong aggressiveness towards a wide range of hosts and their large-scale distribution in Bulgaria and around the world. Pathogens have great plasticity to environmental conditions, can develop on various hosts, grown both outdoors and in cultivation facilities. Control options of the disease are limited and there are no data on the effectiveness of the chemical control agents used and sources of resistance. The use of antagonistic strains of fungi and bacteria can be an alternative to the chemical products. The objective of this article is to gather information on the current status of available control agents, their effectiveness and identification of sources of resistance to the pathogens of lettuce drop (Sclerotinia minor jagger and Sclerotinia sclerotiorum (lib.) de bary).