Maledetta, trovata, ecco la colpevole
Trioza alacris
Ed ecco le cattive notizie
dall'HRS...
"Bay sucker (Trioza alacris)
Plants affected: Bay (Laurus nobilis)
Symptoms
Bay tree leaves thicken and curl at the margins and turn yellow. The discoloured areas later dry up and become brown.
Cause
Most of the damage is caused by the nymphal stages of an insect, the bay sucker, that sucks sap from the young leaves. The winged adults are greenish brown and about 2mm long, and they overwinter in sheltered places.
In April to May the adult suckers emerge and start to feed, causing the leaf margins to start curling under. In May the females lay eggs under the curling leaf margins. The young nymphs are grey, flattened wingless insects, whose bodies are covered with a white fluffy material. Like the adults, these also suck sap and increase the leaf curling. Two or three overlapping generations occur between May and September.
Control
For light infestations pick off and burn infested leaves. Badly affected shoots can be pruned out in winter and also burnt. This will encourage new growth in the spring and may remove some overwintering adults.
There are currently no pesticides effective against bay sucker available to home gardeners.
Andrew Halstead"
E
qui si scannano sulle contromisure, per finire con il solito confidor
Se la vedete sulle foglie delle vostre piante, fatela fuori subito...
[Modificato da xypod 10/05/2006 17.13]
[Modificato da xypod 10/05/2006 17.27]