Delay in Aceria guerreronis infestation may reduce necrosis and fruit drop in coconut trees

The coconut mite, Aceria guerreronis, colonizes the fruit perianth, a region covered by floral bracts, which hinders its control. Its attack causes epidermal necrosis, fruit deformation, and premature fruit drop, with yield losses ranging from 10% to 70%. Infestations generally begin in fruit up to three months old. Since the age of the fruit at the time of infestation can influence not only the severity of damage but also fruit abortion, these aspects were investigated through field experiments. Fruit aged 2 to 5 months were artificially infested with A. guerreronis, and every 15 days, necrotic area and number of aborted fruit were quantified until harvest (≈ 8 months). Both damage severity and abortion rate were significantly higher in younger fruit (2-3 months) than in older fruit (4-5 months); however, damage severity had no direct influence on abortion. These results indicate that the extent of necrotic lesions is not a determining factor for fruit abortion. Despite significant damage observed in some infested fruit, many remained attached to the plant and continued to develop. Others, however, aborted without any necrotic lesions. These findings suggest that other factors, such as physiological mechanisms of tolerance or compensation by the host plant, may influence fruit retention. Understanding these dynamics is essential to improve pest management strategies and avoid overestimating potential yield losses associated with mite infestation.