|Publication Type:||Journal Article|
|Year of Publication:||1980|
|Authors:||Alexandrakis, V., Neuenschwander, P.|
The parthenogenetic strain of A. chilensis How in Greece shows 2 maxima of abundance, 1 in spring and the other in autumn. In 79.2% of all cases the parasite attacks young .female. of A. nerii, in 18.9% .male. pronymphs, and it is found only rarely on ovipositing .female., .male. L2 or nymphs. Up to 4 parasites can develop on a young scale .female.. Of all scales, 40.2% exhibit superparasitism at the egg level, which then decreases to 13.7% in the nymphs. This parasite is capable of maintaining a high parasitization rate over a wide range of host densities (2-20 parasitizable scales/leaf). The parasite is more efficient on old leaves than on new ones. For every living immature parasite found in a sample, the aprasite .female. has killed another young scale .female. through host-feeding. Over a period of 4 yr each peak in active parasitism, which increases from 18.4% in 1975 to 61.4% in 1977, coincides with a corresponding increase in the maximum scale mortality, which runs from 61.7-88.2%. During the same period the scale density dropped about 20 times. These results demonstrate the practical importance of the indigenous A. chilensis in the biological control of A. nerii.