One or more of the features that are needed to show you the maps functionality are not available in the web browser that you are using.
Please consider upgrading your browser to the latest version or installing a new browser.
More information about modern web browsers can be found at http://browsehappy.com/
Feeding damage weakens fruit trees, reducing vigour and sugar content of fruit and sometimes causing slight curling of the leaves. Honeydew is produced by the aphid, which can crack fruit and be colonized by sooty mould fungi, often making fruit unfit for sale (Bindra and Varma, 1977).
The preferred period for chemical control is during the delayed dormant period to kill eggs. Mineral oils, diazinon, chlorpyrifos and esfenvalerate can be used. Application of mineral oils during winter, however, can cause some young shoots to burn or die back, especially in years when trees are water-stressed, or have recently been subjected to freezing temperatures or to dry winds.
Insecticides can be applied during April (if oil is used) or May (for other materials) if control has not been achieved with the delayed dormant treatment. A suitable threshold when aphids are present in spring is an average of more than three colonies per tree. Appropriate insecticides for spring use include diazinon and neem oil.
H. pruni has been implicated in the spread of plum pox potyvirus, potato Y potyvirus and millet red leaf luteovirus (for example, de Bokx and Piron, 1990; Avinent et al., 1994; Gaborjanyi and Basky, 1995), but is not listed as a virus vector by Brunt et al. (1996).