The bean aphid, commonly discovered in dense clusters on delicate new growth, is a soft-bodied insect that ranges in color from dark green to dark gray. It is a member of the Aphididae family and possesses a piercing sucking mouthpart that it employs to consume plant sap. Due to its exceptional reproductive abilities, the bean aphid has gained a reputation as a formidable adversary for farmers and gardeners, being regarded as one of the most destructive insect pests.

LIFE CYCLE

The bean aphid predominantly reproduces through parthenogenesis, with adult female aphids directly giving birth to smaller aphids instead of laying eggs. In the rare instances when eggs are laid, they hatch into wingless female aphids, which eventually start reproducing through parthenogenesis. The newly born aphids have the remarkable ability to begin reproducing in approximately one week.

IDENTIFICATION

Bean aphids, despite their small size (often too tiny to be seen with the naked eye), closely resemble the adults in appearance. They have approximately 2mm long bodies with a spherical shape, light-colored legs featuring darker “knees” and “ankles,” twin “jet-pipe” cornicles, and their bodies range from olive-green to black. Additionally, some bean aphids may possess wings while others do not. These aphids possess mouthparts specialized for piercing and sucking, enabling them to extract plant juices.

FEEDING & DAMAGE

Bean aphids inflict harm on crops through two primary means: direct damage from their sap-sucking activities and indirect damage through the transmission of viruses such as the BWY virus, which negatively impact crop performance.

Infested plants exhibit the following distinct characteristics:

  • Curling and distortion of leaves, particularly noticeable in young leaves located at the center of the plant crown.
  • Abundance of aphid colonies densely clustered on the undersides of leaves, accompanied by remnants of white cast skins from previous generations.
  • Yellowing and wilting of leaves, primarily starting from the edges.
  • Presence of honeydew, a sticky substance secreted by aphids, and the subsequent growth of black sooty mold on plant surfaces.

MANAGEMENT STRATEGY

The objective is to reduce the initial colonization and establishment of bean aphids while also slowing down their population growth once they have established.

Due to their rapid multiplication, it is crucial to implement control measures for bean aphids before they begin reproducing to achieve effective management.

Various methods can be employed to manage and control these pests, including the following:

Chemical control

The use of insecticides is employed as a method to manage bean aphids.

The following insecticides possess both contact and systemic properties, making them highly effective against bean aphids:

  • AMAZING TOP 100WDG at a rate of 5g per 20 liters of solution
  • BACIGUARD 16WDG at a rate of 15g per 20 liters of solution
  • EMERALD 200SL at a rate of 10ml per 20 liters of solution
  • EMERALD GOLD 700WDG at a rate of 5g per 20 liters of solution
  • EPITOME ELITE 500SP at a rate of 10g per 20 liters of solution
  • KINGCODE ELITE 50EC at a rate of 10ml per 20 liters of solution
  • LEXUS 247SC at a rate of 8ml per 20 liters of solution
  • LOYALTY 700WDG at a rate of 5g per 20 liters of solution
  • PENTAGON 50EC at a rate of 10ml per 20 liters of solution
  • PRESENTO 200SP at a rate of 5g per 20 liters of solution
  • PROFILE 440EC at a rate of 30ml per 20 liters of solution
  • SINOPHATE 750SP at a rate of 20g per 20 liters of solution
  • TAURUS 500SP at a rate of 10g per 20 liters of solution

Non- chemical method

  • Removing and composting stems that harbor clusters of aphids.
  • Introducing beneficial insects such as lady beetles and lacewings, which are natural predators of aphids.
  • Spraying cold water on the leaves, as a sudden cold blast can dislodge the aphids.
  • Dusting the plants with flour, which can obstruct the pests’ digestive system.
  • Implementing crop rotations with non-host plants.
  • Choosing and planting resistant varieties of crops.
  • Maintaining field hygiene and sanitation practices.
  • Ensuring proper weed control measures are in place.

Note:

  • While aphids can be effectively controlled using insecticides, it is recommended to alternate between different chemicals throughout the crop season. This helps prevent the development of resistance in the pest population towards any specific insecticide.
  • When spraying insecticides, it is advisable to mix them with INTEGRA at a rate of 3ml per 20 liters of solution. INTEGRA acts as a sticker, spreader, and penetrant, enhancing the effectiveness of the chemical treatment.
  • To eliminate sooty mold, JAMBO CLEAN is applied at a rate of 100ml per 20 liters of solution.
  • Timely management of the pests is of utmost importance.

 

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