Survey of insect pests and diseases of Gabing San Fernando, Xanthosoma sagittifolium (L.) Schott and Melet in selected areas of Luzon and Zamboanga City, Philippines.
Different insect pests were observed on Gabing San Fernando (GSF) (Xanthosoma sagittifolium (L) Schott and Melet) in GSF growing areas in Luzon and Zamboanga City, Philippines through monitoring conducted from August, 2015 to October, 2016. The most prevalent were the leaf feeders, 'harabas' or cutworm (Spodoptera litura Fabricius) and the wooly bear caterpillar (Olepa ricini Fabricius). The striped albatross caterpillar (Appias olferna peducaea Fruhstorfer), noted in Kasibu, Nueva Vizcaya is a novel host that will be of interest to butterfly breeders and has potential for livelihood. Tussock moth caterpillar (Orgyia spp.) attacked GSF occasionally at the Central Experiment Station of University of the Philippines Los Baños (UPLB), and the National Crop Protection Center (NCPC) experimental plots. The lepidopterous pests' damage only affects 2-3 leaves and 1-2 plants. Banana aphids (Pentalonia nigronervosa Cocquerel) were also found in the inner stalk at the NCPC area. The aphids were suspected vectors of the virus, Dasheen Mosaic (DsMV). Majority of the surveyed areas had 2 or 3 plants with DsMV symptoms but remained healthy. It was observed that the GSF populations in most areas were resistant to DsMV. Notable among the destructive insects found attacking GSF was the grub of the coconut rhinoceros beetle (Oryctes rhinoceros Linnaeus), covered with decaying debris and found feeding in the corm. The infested GSF had dried leaves. Other insects were observed on GSF plants but they were occasional dwellers, transient visitors, and many were beneficials. The insect pests, disease and beneficials are new records for GSF in the Philippines.