Mendel, Z., Fadlon, N., Golan, Y., Madar, Z., & Weinstein, A. 1983 [Effect of seed origin on susceptibility of Pinus halepensis to Matsucoccus josephi.. La-Yaaran 33: 33-36, 48.

Notes: International provenance trials of Pinus halepensis initiated by AFO and IUFRO provided the opportunity to study the relation between seed origin and susceptibility to the Israeli pine bast scale Matsucoccus josephi. Results suggest that there are significant differences, the Greek and Israeli provenances displaying a high resistance compared to North African and Spanish provenances. The lower susceptibilty is expressed by higher percentage of unaffected trees, small rate of injury and low density of ovisacs (Table 1). It may be assumed that the relative resistance of the Greek and Israeli seed sources is the result of two different mechanisms. On the one hand, investigations of isozymes and monoterpenes of the Greek provenances showed evidence of introgression with P. brutia, which is not affected by the scale. On the other hand, the relative resistance of the Israeli provenances may be due to the long existence in our area of P. helepensis and M. josephi, the latter probably endemic to Israel. Therefore, present seed collection practices are to be reconsidered, and the emphasis should be on seed sources that are more resistant to M. josephi.