Psyllid (Plant Lice)

Psyllid

There are over 100 species of psyllids found throughout North America. Here’s how to control them using proven, organic methods.

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Sometimes called jumping plant lice, psyllids feed on a variety of plants including most fruit trees and small fruits as well as tomato and potato. Both adults and nymphs feed by piercing the leaf surface and extracting cell sap. This causes foliage (especially the upper leaves) to turn yellow, curl and eventually die. Honeydew secreted by the psyllids encourages the growth of dark sooty molds. Many species transmit disease-carrying viruses.

Adults (1/10 inch long) are reddish brown in color with transparent wings and strong jumping legs. They are very active and will hop or fly away when disturbed. Nymphs are flat and elliptical in shape, almost scale-like. They are less active than adults and are most numerous on the undersides of leaves. Newly hatched nymphs are yellowish in color but turn green as they mature.

Note: Psyllids are monophagous which means that they are host specific (each species feeds on only one plant type).

Life Cycle

Adults overwinter in crevices on tree trunks. In early spring they mate and females begin depositing orange-yellow eggs in the crevices about the buds, and after the foliage is out, on the leaves. Hatching occurs in 4-15 days. Yellow to green nymphs pass through five in instars in 2-3 weeks before reaching the adult stage. There are one to five generations per year depending on species.

Psyllid Control

  • To get rid of psyllids spray horticultural oil in early spring to destroy overwintering adults and eggs.
  • Beneficial insects, such as ladybugs and lacewing, are important natural predators of this pest. For best results, make releases when pest levels are low to medium.
  • If populations are high, use a least-toxic, short-lived natural pesticide to establish control, then release predatory insects to maintain control.
  • Diatomaceous earth contains no toxic poisons and works quickly on contact. Dust lightly and evenly over vegetable crops wherever adults are found.
  • Safer® Insecticidal Soap will work fast on heavy infestations. A short-lived natural pesticide, it works by damaging the outer layer of soft-bodied insect pests, causing dehydration and death within hours. Apply 2.5 oz/ gallon of water when insects are present, repeat every 7-10 day as needed.
  • Surround WP (kaolin clay) forms a protective barrier film, which acts as a broad spectrum crop protectant for preventing damage from insect pests.
  • 70% Neem Oil is approved for organic use and can be sprayed on vegetables, fruit trees and flowers to kill eggs, larvae and adult insects. Mix 1 oz/ gallon of water and spray all leaf surfaces (including the undersides of leaves) until completely wet.
  • If pest levels become intolerable, spot treat with insecticides approved for organic use every 5-7 days. Thorough coverage of both upper and lower infested leaves is necessary for effective control.

Tip: Do not over water or overfertilize – sucking insects like plants with high nitrogen levels and soft new growth.

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