Peanut aphid

Aphis craccivora 

General 

• The aphid Aphis craccivora is widely distributed throughout the world. This aphid is frequently encountered on the stems, leaves and pods of beans ( Vigna sp. and Phaseolus sp.).

• Distribution in the Overseas Departments:

• The aphid Aphis craccivora is quite polyphagous, but it particularly affects legumes.

• Observed in the open field as well as under shelters.

Symptoms, damage

• In the event of a large population, aphids, through their feeding bites, lead to a general weakening of the plant and a reduction in yield.
• Aphids produce honeydew causing sooty mold to appear on the foliage of infested plants. These fungi when they are in abundance, can limit photosynthesis and lead to a reduction in yield.
• The aphid Aphis craccivora is capable of transmitting viruses to beans, in particular CMV (Cucumber mosaic virus) and certain potyviruses (Figure ...) responsible for mosaics on the leaves.
  
  

Biology

• In hot climates, Aphis craccivora multiply by parthenogenesis: reproduction takes place without fertilization. The eggs are produced directly by the adult female.
• Females give birth to larvae after hatching from the egg inside the body.
• The color of A. craccivora can vary from pink for larvae to black for adults. The female, 2 mm long, has 2 black cornicles and a cauda, ​​the antennae are shorter than the body. The ends of the legs are brown.
• These aphids are usually located on the stems or pods of beans, often in association with ants guarding them (Figure 3).

Protection

• Weed the crop and its surroundings.
• Check the sanitary quality of the plants before and during their introduction into the crop or shelter.
• Proper management of fertilization by limiting excess inputs limits the susceptibility of plants to attacks by aphids and other pests.
• Several auxiliaries have an action on the aphid Aphis craccivora . Auxiliary predators: ladybug and hoverfly larvae eat aphids. Some parasitoid wasps, Aphelinus spp. are known to lay their eggs in aphids. The presence of these natural auxiliaries can be favoured:
  • For Aphelinus and adult Syrphids, flower nectar is an important source of food that can be provided by spontaneous flora as well as the planting of flower strips.
  • For ladybugs, planting sorghum can promote their presence because this plant can harbor the grass aphid ( Rhopalosiphum maidis ) on which ladybug larvae feed. This specific grass aphid is a source of food for ladybirds and does not attack the main crop (Source Bio Savane).
• The associated cultivation of broad beans with coriander showed a reduction in the presence of A. craccivora on legumes.