The tobacco aphid (Myzus persicae subsp. nicotianae) probably evolved from the peach potato aphid in the Far East and is a key pest of tobacco crops in both the United States and South America. The tobacco aphid (Myzus persicae subsp. nicotianae) is also encountered in a range of crops in greenhouses, such as sweet pepper, aubergine, chrysanthemum, and various pot plants and cut flower crops.
Life cycle and appearance of Tobacco aphid
Aphids have a complex life cycle, with both winged and wingless forms of adults and a great variety in colour. When reproduction is asexual, the young aphids are born as developed nymphs. They immediately start to feed on plant sap and grow rapidly. Aphids moult four times before reaching adulthood. With each moult they shed white skin, betraying their presence in the crop.
The wingless tobacco aphids (Myzus persicae subsp. nicotianae) are always pink or red. They appear matt, never glossy. Winged individuals have a brown-black head and thorax and a reddish abdomen. There is a dark brown spot on the abdomen and several transverse black bands across the body. The antennae are 0.7-1.0 times the body length, reaching to the siphunculi. The body length is 1.2-2.3 mm.
Nymphs and adults extract nutrients from the plant and disturb the balance of growth hormones. As a result, the plant’s growth is retarded giving rise to deformed leaves or, if the infestation occurs early enough in the season, the death of young plants. Retarded growth and defoliation reduce yield.
Plant sap is rich in sugars, but has a low protein content. Aphids therefore need to extract large quantities of sap to get sufficient protein. The excess sugar is secreted in the form of honeydew, making the crop and its fruit sticky. Black fungal moulds (Cladosporium spp.) grow on this honeydew, contaminating fruit and ornamental crops and rendering them unsuitable for market. At the same time, photosynthesis in the leaves is reduced, affecting production. They are usually found in closely packed colonies, although they are also capable of dispersing through the crop by walking. The tobacco aphid tends to form denser colonies, closer to the top of the plant, than the peach potato aphid. It is not known to what extent tobacco aphids (Myzus persicae subsp. nicotianae) can also transmit viruses.