Cotton bollworm (Helicoverpa armigera Hubner) - a key pest on sweet corn

Cotton bollworm (Helicoverpa armigera Hubner) is a particularly dangerous pest on sweet corn. It is characterized by high ecological adaptability and a high life potential. An outbreak of the species is observed under favorable conditions, causing substantial damages, resulting in reduced yield and deterioration of the commercial product quality. Studies were carried out in the 2016-2018 at the Experimental field of the Agricultural University, Plovdiv, Bulgaria. For our study we used 6 of the most commercial grown in our country sweet corn hybrids: "Challanger F1", "Erica F1", "Vega F1", "Honey Bantam F1", "GSS F1" and "Denitsa F1". The visual observation method was used. The damaged plants and fruit parts were established according to BBCH stages. The results of the observations showed that the extreme conditions that occurred (high temperatures of 40-41 degrees C, low relative humidity, lack of rainfall favored the outbreak of cotton bollworm (H. armigera) and the damaged cobs reached up to 70%. The different hybrids of sweet corn were infested at various levels by cotton bollworm (H. armigera). The largest percentage of damaged fruit parts were established on the hybrids "Veg. F1" and "GSS F1", 30 and 60%, respectively.