## 1 Introduction  
\"Rocha\" pear (_Pyrus communis_ [PERSON]) is an exclusively Portuguese pear variety, whose production is mainly concentrated in the west region of the country and has major economic relevance (average annual fruit production of about 173,000 tons, data from Associacao Nacional de Produtores de Pera Rocha), accounting for 95% of the Portuguese pear production. Fungal infection is a constant threat to fruit production. Particularly, in what concerns \"Rocha\" pear production, infection by _Stemphylium vesicularum_ (Wallr.) [PERSON]. [PERSON], the causal agent of brown spot disease, has become one of the main concerns. In fact, the incidence of this disease in \"Rocha\" pear has been increasing in recent years causing significant yield reduction and important economic losses. In 2015, brown spot disease was responsible for losses of 25% of \"Rocha\" pear production [1]. Brown spot disease was reported in several European pear-producing countries like Spain, Italy, France, the Netherlands, Belgium, and Portugal [2]. The disease symptoms consist of necrotic lesions on fruits, leaves, and shoots. Fruit lesions gradually expand and deepen in round-shaped brown areas that can decay [3]. Infected fruits lose their commercial value and severe outbreaks can lead to fruit abscission prior to harvest [4]. Brown spot is a complex disease because of the biology and ecological ability of the causative agent [5]. _S. vesicularum_ can colonize pear leaf and dead tissues of herbaceous plants on the ground [6]. It is known that the incidence of brown spot disease is higher in pear orchards with a lawn of herbaceous plants than in bare soils [3]. With regard to chemical treatments, several resistant strains have been detected in _S. vesicularum_. The emergence of these resistant strains has been connected with serious failures in field control [7]. Therefore, to control brown spot disease an integrated approach should be used, including preventive measures to reduce the presence of inoculum in the orchard, complemented with preventive chemical and/or biological control [1; 8]. The severity of brown spot of pears allied with its high incidence and difficulty in treatment, motivate the search for new control methods. Propolis is a resinous material produced by bees (_Apis mellifera_) by combining plant exudates, with the bees' salivary enzymes, waxes, and pollen. Honey bees use propolisis in their hives to repair fissures and as a surface cover, hardener, and preservative. The composition and characteristics of propolisis is correlated to the specificity of the flora at the collection site, as well as factors such as seasonality and type of collector used in apiary [9; 10]. More than 300 constituents have already been identified in propolisis from different origins. Among these constituents, there are minerals and organic compounds such as phenolic acids or their esters, flavonoids, aldehydes, terpen, alcohols, and fatty acids [11; 12; 13; 14]. Propolis has been used in alternative medicine for a long time, as an antifungal, antibacterial, antiviral, or anti-inflammatory agent [14; 15; 16]. These biological activities are attributed to flavonoids and other phenolic compounds, as well as to diterpenes which have been identified in propolis, and whose antioxidant and/or antimicrobial activities have been widely described [15; 17; 18]. Several studies reported the effectiveness of various propolisis extracts to inhibit the in vitro growth of different phytopathogenic fungi, including _Colletotrichum gloesporioides_[17], _Penicillium italicum_[19], _Botryodipidia thebromae_[17], _P. digitatum_[19; 20; 21], _P. expansum_[22], _Colletotrichum_ spp. [23], or _Botrytis cinerea_[23; 24]. Moreover, propolisis extracts were able to efficiently reduce _P. expansum_ growth in vivo, in artificially wounded pears inoculated with the pathogen [22], as well _P. digitatum_ and _P.