Weather Factors Affecting the Seasonal Population Dynamics of Black Melon Bug Coridius viduatus F. in New Valley, Egypt

In New Valley Governorate, a study was conducted in Elkharga District to investigate the effect of max. and min. temperatures, relative humidity, and wind speed on the seasonal abundance and population dynamics of the black melon bug, Coridius (Aspongopus) viduatus F. (Hemiptera: Pentatomidae) infesting cucurbit crops (cucumber, cantaloupe, and watermelon) during two plantation dates (early summer and Nili) in 2020 and 2021. The Nili plantation had a higher population density compared to the summer plantation, particularly during the 2021 season. The population density in the Nili plantation exceeded that of the summer plantation, being approximately 7, 8, and 3.4 times greater for cucurbit, cantaloupe, and watermelon, respectively. In the early summer of the 2020 and 2021 seasons, the black melon bug (nymphs and adults) emerged in the field on the three cucurbit crops during the second half of March, culminating in a significant peak in the fourth week of May throughout the three crops. The peak occurred in the first half of May for cantaloupe and watermelon. In the Nili plantation during the 2020 and 2021 seasons, the pest first appeared in the field around the latter half of September. It then steadily increased its population, reaching its peak by mid-November and continuing until the first half of December, depending on either cucurbit crop type or the season year. A strong positive correlation between temperature and the presence of the black melon bug C. viduatus was observed in early summer plantations, but a negative correlation was noted in Nili plantations during both the 2020 and 2021 seasons. Conversely, relative humidity correlated negatively in summer plantations and positively in Nili plantations. Wind speed also showed significant negative correlations with population counts in both seasons.