Analysis concerning the rapid spread of apple proliferation phytoplasmas in a breeding orchard of apple seedlings
Blazek, J.(Vyzkumny a Slechtitelsky Ustav Ovocnarsky, Holovousy (Czech Republic))E-mail:blazek@vsuo.cz | Vavra, R. | Kucerova, J.
The spread of apple proliferation (AP) phytoplasmas was monitored for 6 years in a breeding orchard with nearly 16 thousand apple seedlings. Out of this number, 1,888 trees were identified as AP infected till the end of the growing season 2004. The epidemic started in 1999 when the first 18 trees were diagnosed as contaminated by AP. Since that time, the number of AP infected trees in the whole orchard increased exponentially yearly up to 877 specimens in 2004. The decisive factor influencing the spread of AP was the use of fungicides in three different parts of the orchard. Other major factors were rootstock, tree age and top-working. Ten year old trees were the most frequently infected. Top-working significantly increased the number of infected trees in the year of the treatment application. The early removal of all AP infected trees from the orchard did not considerably reduce the rates of AP infection.
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