4519. PHOTOGRAPHY: Orange aphids

 

Orange aphids on milkweed are typically oleander aphids (Aphis nerii), a non-native species that feeds on milkweed sap, though they generally don't harm milkweed as much as native aphids. While you can physically remove them by rubbing them off, using a strong stream of water, or using a sticky tape, it's important to avoid insecticides and to carefully inspect for monarch eggs or caterpillars before removing any aphids. In many cases, it is not necessary to remove them, as beneficial insects will eventually control the population, and monarch caterpillars may even eat them. 

Identification

• Appearance: The oleander aphid is bright yellow or orange with black legs and antennae.
• Behavior: They reproduce quickly and appear in large clusters on milkweed stems, leaves, and seed pods.
• Impact: While they can weaken a plant, especially if it's stressed, they are not a major threat to monarch caterpillars and may even be eaten by them. 

Control methods

• Physical removal:
  • Rubbing: Gently rub the aphids off with gloved fingers or a soft cloth.
  • Hosing: Spray them off with a strong stream of water, being careful not to damage the plant or harm monarch eggs/caterpillars.
• Natural predators:
  • Encourage native predators like ladybugs and lacewings, which eat aphids but may also eat monarch eggs or larvae.
• Avoid chemical pesticides:
  • Do not use chemical insecticides, as they can harm monarch caterpillars.
• Pruning:
  • Trim off heavily infested parts of the plant and dispose of them away from your garden.
• Wait and see:
  • In many cases, it is acceptable to leave them alone. The population will often decrease on its own as beneficial insects arrive, and monarchs can handle the aphids. 

Prevention

• Avoid over-fertilizing milkweed, as this can attract aphids.
• Provide the right conditions for each species of milkweed to reduce stress on the plant.