Eurema hecabe Linnaeus

Eurema hecabe Linnaeus View in CoL ( Pieridae )

Based on the external morphological characters of the adults ( Figs. 2a, b View Figure 2 ) from this study and compared with those previously given by Yata (1995) and Azrizal-Wahid et al. (2015), the pest infesting C. fistula leaves in Vietnam was confirmed as Eurema hecabe Linnaeus, 1758 ( Lepidoptera : Pieridae ), subspecies Eurema hecabe hecabe . The characteristic features of this pest, based on morphological examination of 23 specimens, are as follows:

Male adults are yellow. Apex and termen of forewing deep black, narrowly along the costal margin to base of wing. The inner margin of the black area oblique and irregular, between veins 2 and 4 excavated on the inner side, and this excavation outwardly rounded between the veins and inwardly toothed on vein 3. Below vein 2 the black area is suddenly dilated into a square spot. Terminal margin of hindwing has a narrow black band which is attenuated anteriorly and posteriorly.

Female adults are similar to that of the male but without the sex-mark; the black areas on both forewings and hindwings slightly broader, with the inner edge of the black terminal band on the hindwing often diffuse.

Eggs are nearly diamond-shaped, white, 1.2–1.4 mm long. The surface texture is smooth. The eggs are in clusters on the underside of young leaves.

Larva is green with black head ( Fig. 2c View Figure 2 ). Late instar larvae are approximately 28.5–30.5 mm long. The larvae are gregarious at all stages of growth.

Pupa has a lopsided octagonal shape, green at first two days, then brown, 18.5–22.5 mm long ( Fig. 2d View Figure 2 ).

Damage symptoms: Larvae of E. hecabe consume the entire leaf ( Fig. 2c View Figure 2 ). The larvae often reside on the underside of intact or partially consumed leaves. Larvae move to new feeding sites at night or evening. Prior to pupation, mature larvae attach their bodies with silk to leaf petioles where the pupae will be suspended ( Fig. 2d View Figure 2 ). When larval density is high, larvae consume all the tree's foliage before moving to adjacent trees. This pest was recorded in all of the four locations studied.