Predict Peaks of Emergence and Generation Numbers of the Pink Bollworm, Pectinophora gossypiella Using the Interaction of Accumulation Heat Units with Plant Phenology

El-Sayed, A. A.; Nada, M. M.; Amer, A. E. A.; Fouad, H.

doi:10.21608/jppp.2025.354384.1306

Predict Peaks of Emergence and Generation Numbers of the Pink Bollworm, Pectinophora gossypiella Using the Interaction of Accumulation Heat Units with Plant Phenology

Document Type : Original Article

Authors

Plant Protection Research Institute, ARC, Dokki Giza, Egypt

10.21608/jppp.2025.354384.1306

Abstract

This work was carried out to conduct studies using degree days and plant phenological interaction to predict peaks of the emergence and generations of the pink bollworm, Pectinophora gossypiella (Saunders), during cotton growing seasons of 2021, 2022, 2023, and 2024. The coefficient of variation values ranged between 3.17, 4.4%, and 0.9, 4.3%, respectively. The lowest value was from April 18^th, 3.1%, and from January 1^st, 0.9%, respectively. The abundance of receptors, which is the presence of sufficient numbers of sensitive squares for pink bollworm larvae, which is related to the peak of male F₁ moths captured. This occurs when the plant has fruiting branches with an average number of 9.9±1.0 and 17.2±2.7 squares per plant. The average heat units and days for the four seasons from sowing date were calculated at 1140.3±7.9 units and 88.8±5.6 days with a coefficient of variation of 0.7 and 6.3%, respectively. The thermal units ranged between 523.8±4.5, 527.5±0.6 units, and 0.6, 1.8%, respectively. For days, they ranged between 33.3±1.9, 35.8±4.3 days, and 5.7, 11.9%, respectively, for the four seasons. These results indicate that thermal units, days, andthe interaction with plant phenology can help detect periods of high risk for the pink bollworm moth’s activity and can be used to manage this pest throughout the cotton crop season.

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