Aphids

  • Symptoms

  • Trigger

  • Biological Control

  • Chemical Control

  • Preventive Measures

Aphids

Aphidoidea

Insect


In a Nutshell

  • Curled and deformed leaves.
  • Little insects under the leaves and shoots.
  • Stunted growth.

Hosts:

Apple

Pear

Grape

Raspberry

Bean

Capsicum & Chili

Eggplant

Cherry

Apricot

Plum

Peach

Carrots

Pea

Cucumber

Pumpkin

Zucchini

Tomato

Cabbage

Lettuce

Potato

Black & Green Gram

Pigeonpea & Red Gram

Chickpea & Gram

Cotton

Wheat

Soybean

Other

Onion

Garlic

Millet

Almond

Sorghum

Maize

Strawberry

Currant

Olive

Banana

Sweet Potato

Okra

Citrus

Peanut

Manioc

Sugarcane

Rye

Barley

Melon

Rose

Sugar Beet

Pomegranate

Lentil

Cauliflower

Pistachio

Ornamental

Symptoms

Low to moderate numbers are usually not harmful to crops. Severe infestation can cause leaves and shoots to curl, wilt or yellow and stunted plant growth. Overall, a general decline in plant vigor will also be noticed. The honeydew secreted by the aphids as they feed on plant tissues causes an additional infection with opportunistic fungi in many cases. The development of mold on the leaves indicates this. The honeydew attracts ants. Even small numbers of aphids can transmit viruses from plant to plant in a persistent way. Optimal conditions for their growth are dry and warm climates.

Trigger

Aphids are small, soft bodied insects with long legs and antennae. Their size ranges from 0.5 to 2 mm and the color of their body can be yellow, brown, red or black, depending on the species. Their aspect ranges from the wingless varieties, that are generally predominant, to the winged, waxy or woolly types. They usually settle and feed in clusters on the underside of well-fed young leaves and shoot tips. They use their long mouthparts to pierce tender plant tissues and suck out fluids. Low to moderate numbers are not damaging to the crops. After an initial invasion in late spring or early summer, the aphid population usually diminishes naturally due to natural enemies. Several species carry plant viruses that can lead to the development of other diseases.

Biological Control

Beneficial insects such as predatory ladybugs, lacewings, soldier beetles and parasitoid wasps are important agents to control populations of aphids. These natural enemies will take care of the sucking insects in field conditions. In case of mild infestation, use a simple soft insecticidal soap solution or solutions based on plant oils, e.g. neem oil (3 ml/l). Aphids are also very susceptible to fungal diseases when it is humid. A simple spray of water on affected plants can also remove them.

Chemical Control

Always consider a integrated approach with preventive measures together with biological treatments if available. Be aware that the use of chemical pesticides can cause resistance of aphids to those. Stem application with flonicamid and water @ 1:20 ratio at 30, 45, 60 Days after sowing (DAS) can be planned. Fipronil 2ml or thiamethoxam @ 0.2g or flonicamid @ 0.3g or acetamiprid @0.2g (per liter of water) can also be used. However, these chemicals can have negative impacts on predators, parasitoids, and pollinators.

Preventive Measures

  • Maintain a high number of different varieties of plants around fields.
  • Use reflective mulches to repel invading populations of aphids.
  • Monitor fields regularly to assess the incidence of a disease or pest and determine their severity.
  • Remove infected plant parts.
  • Check weeds in and around the fields.
  • Do not over-water or over-fertilize.
  • Control ant populations that protect aphids with sticky bands.
  • Prune the branches of your trees or remove the bottom leaves or your plants to favor the ventilation of the canopy.
  • If possible, use nets to protect the plants.
  • Control insecticide use in order not to affect beneficial insects.
  • Remove plant debris from previous cultures.