Resistance of Georgian Hazelnut (Corylus L.) to Brown Marmorated Stink Bug – Halyomorpha halys (Stål)

Brown Marmorated Stink Bug (BMSB), Halyomorpha halys (Hemiptera: Pentatomidae) (Stal, 1855) is an invasive, highly polyphagous, severe agricultural pest, that reduces the availability, quality, and value of hazelnut production. The most important method against H. halys is the use of resistant hazelnut varieties. The purpose of our work is to investigate the potential of hazelnut resistance to H. halys. Research objects are Georgian commercial varieties Berdznula (Corylus avellana) and Tita (Corylus pontica) in the condition of West Georgia. Hazelnut fruit shell thickness, qualitative and quantitative lignin contents and H. halys stylet length were determined by microscopic and biochemical methods, also H. halys and nut phenologies, and the degree of nut damage were evaluated according to the number of healthy kernels. It was demonstrated that overwintered insects and individuals of all ages of the first- and second-generation damage hazelnut fruit before the shell ripens, which is synchronized with the early stages of hazelnut fruit development. H. halys cannot damage the fruit after lignification of the pericarp. Lignin content and damage intensity are inversely proportional to each other according to Pearson's correlation. Hazelnut resistance depends on the synchronous development of H. halys and hazelnut phenopases, and also on the time and quantity of lignin biosynthesis in hazelnut pericarp. According to the above-mentioned resistance markers, Berdznula is more resistant than Tita. Research results contribute to maintaining a healthy environment, sustainable crop production, and food security.