Damage based identification key for endophagous herbivores on Common Reed (Phragmites australis) |
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| Author:
Patrick Häfliger © |
CABI
Europe - Switzerland, Rue des Grillons 1, CH-2800 Delémont |
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| The
Brown-Veined Wainscot Archanara dissoluta (Treitschke) (Lep.: Noctuidae) |
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Biology: Larvae hatch between mid-April and mid-May, feed through 2-3 reed shoots, and pupate after five moltings end of June and mid-July in a shoot internode. Adults emerge between mid-July and mid-August and live for 1-2 weeks. Eggs are laid in clusters under leaf sheaths of the host plant (picture 57). Description: Larvae up to 3.5 cm long, larval body whitish with several black spots on each segment, head capsule and parts of the neck shield and anal plate dark-brown/black, young larvae very difficult to distinguish from those of the Twin-spotted Wainscot; older larvae often with a rose tint (picture 46); pupae 13-20 mm, orange, head downwards; adults light-brown-winged (picture 44). Feeding pattern/damage: Freshly hatched larvae enter shoots above or below the growing point and severe the shoot tips from the base a few days later. Afterwards, larvae start to feed in the internodes and only later they feed above it. Such shoots die quickly and are characterized by the tiny entrance hole (0.4-0.5 mm wide) (sometimes broken off), a distinct severance of an upper internode just above a node, and a 1-1.3 mm wide exit hole above the growing point. In contrast to the other shoot boring Wainscots, feces of young larvae is usuallly found in the internodes too. The first change of shoots happens often in the forth instar only and larvae then feed in uppermost internodes up to the growing point. Shoot tips are thereby killed, but side shoots are developed from nodes below the damage. For pupation, larvae enter internodes at shoot base, and prepare an exit window (6x3 mm large). Pupae of the Brown-veined Wainscot always have their head directed downwards. Damage caused by the Brown-veined Wainscot is very similar to that of the other three stem-boring Wainscots. Distribution: Europe References: Bretherton et al., 1983; Häfliger et al., 2006 |
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