EFFECT OF CLIMATE CHANGES ON GROWTH PATTERN OF COTTON PLANTS IN RELATION TO THE INFESTATION WITH PINK BOLLWORM, PECTINOPHORA GOSSYPIELLA (SAUND.) IN SHARKIA GOVERNORATE, EGYPT

Abstract

he effect of future predicted temperature increase in 2025, 2050, 2075 and 2100 on four phenomena accumulated heat units (AcHU), infestation of cotton fruits with pink bollworm (PBW), Pectinophora gossypiella (Saund.), the growth patterns of cotton plants, Gossypium barbadense (L.) in five sowing dates related starting from March 10 to April 30, with 10 days intervals compared to the current seasons (CS) (1999-2002) were directed. The experiments were carried out at Sharkia Governorate for four cotton seasons (1999-2002) current seasons (CS). Results showed that the first phenomenon, during CS average of AcHU recorded 3814 unit, whereas in the predicted seasons it increased than the CS with 258 units in 2025 continued in increasing until reached to 715 units in 2100 season. The second phenomenon, occurrence of male moths fluctuated through CS and recorded four peaks for each season. Moth emergence of the first peak, overwintered as diapause larvae, depended on AcHU from fixed date, Jan., 1; occurred over the last third of May; while at the expected seasons occurred early abut month, over at the last third of April on 2100 season. The other three peaks depended on sowing dates. Whenever, delayed sowing date fruiting structures will be subjected for attack by peak of moth's emergence for short period of time. The third phenomenon, the period in days required for occurring 50 percent of fruit structures on cotton plants and occurring green cotton bolls preferred for infestation with PBW larvae, decreased at the expected seasons. The first dates of cultivation had been highly reduction but the fifth one was the lowest. The fourth phenomenon, in over the four expected cotton seasons, Julian days required for the five cotton sowing dates were short where reduction in days percentages ranged between 35.1 and 22.6% in 2100 cotton seasons comparing to average days in the four CS. The physiological time required for occurrence of these phenomena were decreased over the five sowing dates at the expected seasons, it cleared that the cotton plant and PBW can get the heat unit required in short time. Under climate change regimes, Agricultural lionizers should take into consideration, it will result in earliness in beginning cotton cultivation, growth of cotton pattern, the first peak of PBW moth's emergence, increase number of its generations. As for, planting dates, climate changes play an important role to suffer more damage or escape some damage depending on the actual response to climate changes.