Maize cultivation has enormously increased in Southeastern Turkey in recent years. The naked grass-mealybug, Heterococcus nudus (Green, 1926) (Hemiptera: Pseudococcidae), is known as a pest for many uncultivated Poaceae plants. The aims of this study are to report maize as a new host plant for H. nudus and its early region-wide distribution in Southeastern Turkey and to examine its parasitoids. The mealybug was detected on the first (sown in March-April) crop maize plants in Çınar during periodic surveys in June and August 2018. In total, forty-two maize fields from fourteen counties belonging to five provinces, namely Adıyaman, Batman, Diyarbakır, Mardin, and Şanlıurfa, were checked for the presence of the mealybug and its parasitoids. The mealybug was recorded in only two counties, Bismil and Çınar of Diyarbakır province while it was not present on maize plants in other surveyed provinces. Mealybug specimens were found feeding between leaf sheets and the stem of maize plants. Mean infestation ratios, i.e. the number of adults + larvae (±SEM), were 2.69 (± 0.52) and 0.5 (± 0.23) adult ± larvae for Çınar and Bismil respectively. The pest did not infest second crop maize plants (sown in June-July). In addition, incubation of collected grass mealybug individuals yielded no parasitoids. Since the pest is not widely distributed throughout the region and currently has very low population densities, no control practices are recommended for the pest.