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Host plants and damage
The two aphids come from the areas of the Atlas chain and are specifically dedicated to coniferous trees of the genus Cedrus.
Cedrobium laportei preferably attacks Cedrus atlantica and Cedrus libanotica, while Cinara cedars is common on Cedrus atlantica and on Cedrus deodora.
They are both cortexicles and live in thick colonies arranged in a sleeve on the branches of diameter less than 2 cm and on the smaller twigs, forming an abundant honeydew that falling, like a very fine rain, smears the soil and the things underlying the plants.
Aphidic colonies are commonly frequented by ants. The damages caused are considerable and manifest themselves with the redness and the fall of the needles. The branches have reduced vegetation, limited to the distal part. When the colonies are localized on the trunk of the young plants or in the cimale of those already developed, the vegetation at the apex of the branches turns yellow and dries up.
The honeydew produced by the aphids then develops an abundant fumaggine which, by incorporating the solid particles present in the atmosphere, forms thick blackish incrustations which, in addition to disfigure the ornamental appearance of the plants, exert an asphyxiated action on the vegetation. The severely affected individuals perish and may even die within a few years.
The two aphids multiply through the continuous succession of parthenogenetic generations. Only in winter the colonies are reduced, but survive the rigors of the season. By the work of the foundresses and the female parthenogenetic bee survived the winter cold, the aphid colonies resume growth, to reach the maximum density in June, when with the arrival of the summer heat produce the greatest damage.
In the case of Cinara cedars, winter is also surpassed with durable eggs laid in December forwarded onto needles.
Cedar Aphid: Defense
The two phytophagous are naturally fought by different predators: larvae and adults of coccinellids, larvae of chrysopid neurotters and sylphids.
When infestations tend to worsen, it is however appropriate to intervene by spraying the entire plant with aficidi such as: acephalous, pirimicarb, etiofencarb or with other specific preparations with low toxicity.