Analysis concerning the rapid spread of apple proliferation phytoplasmas in a breeding orchard of apple seedlings
J. Blažek, R. Vávra, J. Kučerováhttps://doi.org/10.17221/3764-HORTSCICitation:Blažek J., Vávra R., Kučerová J. (2005): Analysis concerning the rapid spread of apple proliferation phytoplasmas in a breeding orchard of apple seedlings. Hort. Sci. (Prague), 32: 43-49.
The spread of apple proliferation (AP) phytoplasmas was monitored for 6 years in a breeding orchard in which nearly 16 thousand apple seedlings were planted. Out of this number 1,888 trees were identified as AP infected till the end of the growing season 2004, which corresponded to the proportion of 11.9%. 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 that influenced this spread of AP in this study was the use of fungicides for pest control in three different parts of this orchard. Some other factors – rootstock, age of trees or top-working were identified as influencing this AP spread in different ways. Their role in this spread is discussed in more detail. Trees of the age 10 years were the most frequently infected on average. Top-working significantly increased numbers of infected trees in the year of the treatment application in comparison with trees from adjoining rows without this treatment. The early removal of all AP infected trees from the orchard did not considerably reduce the rates of AP infection.
apple proliferation; phytoplasmas; apple; spread; vectors; breeding; insecticides