Aphids

 Image of Aphids

Class: Insecta
Order: Hemiptera
Suborder: Sternorrhyncha
Superfamily: Aphidoidea
Common name
: Plant lice, Greenflies (in Britain)

Aphids are small plant-eating insects. Aphids are among the most destructive insect pests on cultivated plants in temperate regions. Most aphids have soft, green bodies, but other colors are common, such as black, brown, and pink. Aphids have antennas with as many as six segments. Aphids feed themselves through sucking mouthparts called stylets, enclosed in a sheath called a rostrum, which is formed from modifications of the mandible and maxilla of the insect mouthparts. They have long, thin legs and two-jointed, two-clawed tarsi.

Plants exhibiting aphid damage can have a variety of symptoms, such as decreased growth rates, mottled leaves, yellowing, stunted growth, curled leaves, browning, wilting, low yields and death. The removal of sap creates a lack of vigour in the plant, and aphid saliva is toxic to plants. Aphids frequently transmit disease-causing organisms like plant viruses to their hosts. The green peach aphid (Myzus persicae) is a vector for more than 110 plant viruses. Cotton aphids (Aphis gossypii) often infect sugarcane, papaya and groundnuts with viruses.

Control:

  • Wash off aphids with a steady stream of water.
  • Avoid heavy applications of nitrogen fertilizer which can encourage succulent plant growth.
  • Natural predators such as lady beetles and aphis lions feed on aphids but may not always provide adequate control.