Honeydew is a sugar-rich, sticky substance secreted by many plant-feeding insect species from the order of Hemiptera and Lepidoptera. Aphids (Hemiptera: Aphididae), on the other hand, feed on nitrogen-poor, carbohydrate-rich phloem sap and excrete excess carbohydrate as honeydew from their anus. The aphids, constituting the main material of the study were sampled from the Catalpa bungei C. A. Mey (Bignoniaceae) tree located in the central campus of Niğde Ömer Halisdemir University and then preparation procedures were carried out for species identification under laboratory conditions. According to the identification key organized according to the host plant, the samples were identified as Aphis gossypii Glover. The honeydew of A. gossypii Glover, known as the cotton aphid, was collected from the host plant and the effects of two different concentrations of the honeydew (10 and 20 g/L) on fungal growth were determined using both solid and liquid media. Different Trichoderma strains and Beauveria bassiana were used to examine fungal growth. Fungal growth in the prepared nutrient media was determined as the amount of biomass (gram). The honeydew content (phenolic substance, sugar and amino acid amounts) was determined and supported by FT-IR analyses. The growth of fungal species in the PDA medium, which was preferred as the control medium, and the medium containing honeydew was compared. It has been determined that fungal growth is better in the medium containing honeydew, and therefore honeydew increases fungal growth. With this study, it is predicted that aphid honeydew can support the growth of both fungal agents used in biological control and plant pathogens.