In. Smyrnioudis et al., The effect of natural enemies on the spread of barley yellow dwarf virus (BYDV) by Rhopalosiphum padi (Hemiptera : Aphididae), B ENT RES, 91(4), 2001, pp. 301-306
The effects of two natural aphid enemies, adult Coccinella septempunctata L
inneaus, a predator, and Aphidius rhopalosiphi de Stefani Perez, a parasito
id, on spread of barley yellow dwarf virus (BYDV) transmitted by the bird c
herry-oat aphid, Rhopalosiphum padi (Linnaeus) were studied under laborator
y conditions. Predators or parasitoids were introduced to trays of durum wh
eat seedlings and the patterns of virus infection were observed after two,
seven and 14 days of exposure. More plants were infected with BYDV in contr
ol trays without A. rhopalosiphi than in trays with the parasitoid present,
both seven and 14 days after the introduction of parasitoids. Patterns of
virus infection were found to be similar over time in trays with a parasito
id present and in control trays. More plants were infected in trays with C.
septempunctata present than in control trays, both two and seven days afte
r the introduction of the coccinellid. The spread of virus infections progr
essed differently over time for the two treatments (predator and parasitoid
), differences between treatments being most marked after two days and seve
n days, when more plants exposed to predators but fewer exposed to parasito
ids were infected with BYDV compared to their respective controls. However,
by the 14th day 88% of all plants were infected and there was no significa
nt difference between the two treatments. The role of natural enemies in sp
read of BYDV is discussed.