Damage to foliage of horse chestnut trees induced by the horse chestnut leafminer (Cameraria ohridella DeschkaandDimic)
2005
Pivk, A. | Milevoj, L. (Ljubljana Univ. (Slovenia). Biotechnical Fac., Agronomy Dept.)
In 2003 and 2004 research was carried out in the Tivoli park in Ljubljana with the aim of measuring leaf damage caused by horse chestnut leafminer (Cameraria ohridella DeschkaandDimic) on horse chestnut trees (Aesculus hippocastanum L.). In 2003 the area of mines and leaves was measured by means of the computer programme. In 2004 visual evaluation was used, in order to assess leaf damage. On the basis of calculations, the leaves were categorised into 8 classes according to damaged area. The results of categorization of leaf damage show that, in 2003 trees were more infested by horse chestnut leafminer than in 2004. Information gathered by observation in 2003 showed that, on average, over 80% of foliage was damaged from 10 to 50% in August and from 50 to 100% in September. In 2004 trees were infested less than 25% in all months of observation but at the same time they were also attacked up to 50% by the fungus Guignardia aesculi /Peck./Stev. A comparison of the average damage between individual groups in 2003 shows a difference in leaf damage to be related the age difference. The results showed that in June the youngest trees were less infested than the other two groups, whereas in July the infestation of these trees was more severe. In August and September the group of middle-age trees was considerably less attacked than the other two but at the same time more infected by Guignardia aesculi.
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