The large blackberry aphid are host specific, they are pale or yellowish green with pale cornicles. The body length is 2-5 mm and the cauda is short and triangular. Adults may be winged and wingless. Blackberry aphids feed on the young growth and can quickly damage young plants. Aphid colonies can lead to the decline of plants and reduce yield, if left unchecked.
Retarded plant growth
Adults and nymphs feed on plant sap disturbing the growth hormone balance. As a result, the plant’s growth is retarded giving rise to deformed leaves, meristems or fruit. If the infestation occurs early in the season, it may result in the death of young plants.
Black sooty mold
Aphids secrete a sticky honeydew on which black fungal mold develops. Plant sap has a low protein content but is rich in sugars. Aphids therefore need to extract large quantities of sap in order to obtain sufficient proteins. The excess sugar is secreted in the form of honeydew, making the crop and its fruit, sticky. Black fungal molds grow on the honeydew, contaminating fruit and ornamental crops and rendering them unsuitable for the market. Additionally, photosynthesis in the leaves is reduced, affecting production.
Malformations of growing tips
The aphid’s saliva can induce strong “allergic” reactions such as malformations of the growing tips. Aphid vector plant viruses (pathogenic organisms) can be transmitted to the plant. Cucumber mosaic virus (CMV) is an example. An aphid colony has a clear effect on a plant. A growing plant will translocate more resources to an affected part in order to maintain growth, which of course further advantages the aphid colony.
There are natural enemies of the blackberry aphid.
For more information contact your local BioBee field agent.