Preliminary Evaluation of the Impact of the Pine Woolly Aphid on Condition and Growth of Pines in the Southern Cape
Abstract
SYNOPSIS Pineus pini (L.) has spread rapidly along a 230 km long belt of pine plantations in the southern Cape. Pinus pinaster proved to be more susceptible to the aphid than P. elliotti and P. radiata and the percentage of trees infested was 89,2%, 54,2% and 27,2%, respectively. Severely infested trees showed pathological discolouration of foliage and dieback of leaves and shoots and some of them died. During a period of 42 months the increment of diameter at breast height and height of the badly affected P. pinaster trees was reduced by 63% and 65% respectively. The annual loss of increment in volume. assessed in young P. elliottii, P. pinaster and P. radiata stands, was 0,4%, 19,5% and 3.9%. respectively. Elimination of the fastest growing individuals by the aphid is, however, the most important loss to the forestry industry.