sdu faculty of forestry journal special edition 2009 - Orman Fakültesi

Eggs hatching (%)
100
50
0
SDÜ Faculty of Forestry Journal
0 2 4 6 8 10 12 14 16 18 20 22
198
days
Control-25
Mycotal-25
Figure 4: Percentage of Cryptococcus fagisuga’s eggs hatching after treatment with
Lecanicillium muscarium (Mycotal®) over a 21-day period.
4. CONCLUSION
The scale insect Cryptococcus fagisuga, exposed to Lecanicillium muscarium
(Mycotal®) and Beauveria bassiana under laboratory conditions, reduced the noncrawling
nymphal stage population by 50%. This percentage could have been
higher, but the experiment on bark disks cannot last longer than 10 to 12 days;
because of the high rate of humidity, fungal hyphae invade the disks making
further observations impossible. The fall population treated with entomogenous
fungi had a mortality rate reaching 50% in 10 days. Scale insects collected in
winter show a higher rate of mortality after biological treatment; the difference
with fall is probably the mortality caused by the very cold temperatures during the
winter. Finally, if eggs are not directly invaded by fungal hyphae, the young
crawlers are rapidly colonized by the fungi soon after hatching (data not shown).
Field trials with these biological control agents will be the next step of this study.
5. LITERATURE CITED
Castlebury, L.A., Rossman A.Y., Hyten A.S., 2006. Phylogenetic relationships of
Neonectria/Cylindrocarpon on Fagus in North America. Can. J. Bot. 84, 1417-1433.
Crosby, D., Bjorkbom J.C., 1958. Timely salvage can reduce losses from beech scale Nectria attack.
U.S. Forest Serv., Northeastern Forest Experiment Station, Forest Research Note 82, 4p.
Ehrlich, J., 1934. The beech bark disease. A Nectria disease of Fagus, following Cryptoccus fagi
(Baer.). Can. J. Res. 10, 593-692.
Evans, C.A., Lucas J.A., Twery M.J. (Eds.), 2005. Beech Bark Disease: Proceedings of the Beech
Bark Disease Symposium. General Technical Report NE-331. Newtown Square PA, US
Department of Agriculture Forest Service, Northern Research Station, 149 p.