A sweet potato story the likelihood of porina feeding on kumara

Abstract

The caterpillar stage of the endemic Wiseana spp complex commonly known as porina are foliage feeders Research indicates that porina will feed on harakeke (Phormium tenax) red tussock (Chionochloa rubra) and hard tussock (Festuca novae zealandiae) In 1952 Miller reported that porina were abundant in kumara plantations and caused damage to the plants The accuracy of this observation is uncertain due to taxonomic changes and the ambiguous nature of Millers identification Feeding bioassays were undertaken to determine if porina caterpillars would feed on the leaves stems or tuber of the Owairaka kumara plant (Ipomoea batatas) using white clover foliage (Trifolium repens) as a control Over a 6week Porina provided with tuber had a weight increase of >01 g within the first two weeks which was a 122 gain (compared to clover) The leaves and stems supported less weight gain over the two week period (92 and 85 compared to clover respectively) These results suggest that porina can feed on kumara plants but further field testing will be required to support this claim