How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PEST

The adult psyllid is a small insect (about 0.12 inches or 3 mm) that resembles a cicada. The adults have white or yellowish markings on the thorax, clear wings, and lines on the abdomen between segments. The tiny eggs are laid on stalks most commonly on the underside of leaves and along leaf margins and are best seen with the use of a hand lens. Initially white, they turn a pink color a few hours after they are laid.

Nymphs hatch from eggs in 4 to 15 days and have scalelike flattened, oval, yellowish green to orangish bodies with red eyes and three pairs of short legs. Older nymphs are greenish and fringed with hairs and have wing buds, which make them easy to distinguish from whitefly nymphs. They develop through five stages (instars) in 2 to 3 weeks before becoming winged adults. Nymphs feed most often on the underside of leaves.

Tomato psyllids have an extensive range of acceptable hosts, but solanaceous plants (tomatoes, potatoes, nightshades) are preferred. Among tomato varieties, it has a preference for the yellow pear tomato. In potatoes, it is referred to as the potato psyllid.

DAMAGE

Nymphs and perhaps adults inject a toxin while feeding on the leaf that causes death in transplants, stunting, chlorosis and curling of leaves in preflowering plants, and either no fruit production or overproduction of very small, noncommercial-grade fruit in larger plants. These symptoms are collectively known as "psyllid yellows".

MANAGEMENT

Monitor for tomato psyllids during the growing season to detect populations that have the potential to stunt plants.

Biological Control
While predators and parasites may attack psyllids, most parasites attack too late in the psyllid life cycle to stop crop loss and biological control does not appear to be a promising control strategy in the field.

Organically Acceptable Methods
Sprays of the Entrust formulation of spinosad are acceptable for use on organically certified produce.

Monitoring and Treatment Decisions
Yellow sticky cards placed at the field margins near the tops of plants can be used as an indicator of psyllid movement into the field in areas where the pest occurs. If tomato psyllids are caught in the traps, examine foliage of tomato plants on the field margins for eggs and nymphs. Research indicates that as few as 15 nymphs/plant feeding for 5 days can cause psyllid yellows (or 5 nymphs feeding for 15 days). If adults are present, a treatment may be warranted.

Applications of imidacloprid (Admire Pro) at planting for thrips and whiteflies provide some control of psyllids. During the growing season, treat populations when an average of 5 to 10 nymphs/plant are present.

If psyllids are present in the field, it is very important not to use carbamates (Sevin-foliar applications, Lannate, Vydate) for the control of other pests as these materials actually promote the development of psyllid populations.

PUBLICATION

UC IPM Pest Management Guidelines: Tomato
UC ANR Publication 3470
Insects and Mites
F. G. Zalom, Entomology, UC Davis
J. T. Trumble, Entomology, UC Riverside
C. F. Fouche, UC Cooperative Extension, San Joaquin Co.
C. G. Summers, Entomology, UC Davis/Kearney Agricultural Center, Parlier
Acknowledgments for contributions to the insects and mites section:
N. C. Toscano, Entomology, UC Riverside

Top of page