Degree of damage and infestation of coconut leaf beetle Brontispa longissima (Gestro) on seedlings of selected coconut varietie

Abstract

The Coconut Leaf Beetle, scientifically known as Brontispa longissima (Gestro), is an introduced species that is becoming an alarming pest of coconuts in the Philippines. The infestation caused by this pest is damaging to all stages of coconut growth. This study was conducted to assess the degree of damage and infestation caused by Brontispa longissima on the seedlings of 10 selected tall and dwarf coconut varieties in the National Coconut Research Center at Visayas State University, Leyte, Philippines. Among the selected varieties, seedlings of Baybay Tall (green and brown) and Albuera Dwarf varieties succumbed to more damage by B. longissima beetles compared with the other varieties observed with 41-80% of the first openned leaf area damaged. Seedlings of Malayan Yellow Dwarf and Malayan Red Dwarf varieties had the least damage with 0-20% of the first openned leaf area damaged. The high damage ratings of Baybay Tall and Albuera Dwarf were expected because these varieties had high infestation rates and harbored the most numbers of B. longissima adults, eggs, and larval stages, which indicated the preference of B. longissima for these varieties. The developmental period of B. longissima in Baybay Tall and Albuera Dwarf of 44 days and 45 days on the average, respectively, was shorter than in other varieties, indicating that these are suitable and preferred hosts. Baybay Tall seemed to be the most preferred variety. The beetles had least preference for Malayan Yellow Dwarf and Malayan Red Dwarf varieties.