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Potato Psyllid - A New Pest in Greenhouse Tomatoes and Peppers

Author: Gillian Ferguson - Greenhouse IPM Specialist/OMAF; Eugenia Banks - Potato Specialist/OMAF; Hannah Fraser - Entomology Horticulture Program Lead/OMAF
Creation Date: June 2001
Last Reviewed: 5 August 2003

Table of Contents

Introduction

Potato psyllids (also referred to as tomato psyllids) (Paratrioza cockerelli) were recently identified in greenhouse tomatoes in southwestern Ontario. Although the potato psyllid is predominantly a pest of potatoes and tomatoes, it has a wide number of alternate hosts including eggplant, peppers, and common weeds such as pigweed, bindweed, mallow, lambsquarters, smartweed, and nightshade. Indeed, there is some concern that the insect may also be present in potato fields and weeds outdoors. Potato psyllids have been reported in the field in Alberta and Saskatchewan, and in greenhouse crops in British Columbia, Quebec, and once in 1998, in Ontario. Damaging infestations of potato psyllid are most common in the western areas of the US: California, Arizona, New Mexico, Colorado and Wyoming.

Life Cycle of Potato Psyllids

Potato psyllids have three life stages: eggs, nymphs and adults.

  • Eggs. The eggs are very small, football-shaped, yellow to orange in colour, and borne singly on very fine stalks (Figure 1), usually along leaf margins. A 10x hand-lens is necessary to see the eggs.
  • Nymphs are flattened and somewhat scale-like with a fringe of short spines around the edge. Younger nymphs are pale brown, turning green (Figure 2) with each successive molt. Nymphs are usually found on lower leaves and on lower leaf surfaces. When disturbed, they move quite readily. They secrete a white substance that looks like granulated sugar or salt (Figure. 2) and collects on leaves beneath the feeding nymphs.

Figure 1. Enlarged view of potato

Enlarged view of potato

Figure 2. Enlarged view of early and psyllid egg late nymphal stages of potato psyllid

Enlarged view of early and psyllid egg late nymphal stages of potato psyllid

Figure 3. Enlarged view of recently

Enlarged view of recently

Figure 4. Enlarged view of moreemerged adult potato psyllid mature adult potato psyllid

Enlarged view of moreemerged adult potato psyllid mature adult potato psyllid

A mature female can lay over 500 eggs during an average egg-laying period of 21 days. The average time required for development from egg to adult is 15 to 30 days, and a temperature of 270C favours their development and survival. Temperatures below 150C or above 320C are reported to adversely affect development and survival.

Damage Symptoms

Potato psyllids, like aphids and leafhoppers, suck plant sap through needlelike mouthparts. They feed in a similar manner to aphids, but instead of producing a shiny film of honeydew on the leaves, their sugary exudate resembles a white powder. The nymphs are the damaging stage because when feeding, they inject a toxin that causes a physiological condition known as "psyllid yellows." Feeding by this pest not only causes yellowing of the plant, but can also result in loss of vigour and yield due to a combination of reduced fruit set and fruit size. Symptoms reported by A. M. Al-Jabr, from studies carried out at Colorado State University on this pest include "retarded growth, erectness of new growth, chlorosis, and purpling of leaves. Secondary symptoms include malformation and distortion of foliage, widespread chlorosis, growth at a standstill for weeks to months, stimulated flower bloom, and production of numerous and small poor quality fruit." Infestations of pepper crops by psyllids are reported to be less damaging because no yellowing occurs. However, the powdery deposits on the fruit have to be washed off before they can be marketed.

Management Options

Monitoring

Weekly inspection of plants should be carried out to check for the psyllid nymphs which can occur either on the upper or lower leaf surfaces. The nymphs resemble flattened yellow or light green aphids. In addition, it would be useful to look out for the light dusting of a white powder on the upper surfaces of leaves, telltale signs of their presence. Yellow sticky cards hung close to the top of the plant canopy will also catch the winged black adults which resemble winged aphids. These should be closely examined for the characteristics described above.

Physical Control

This entails removal of infested leaves and provides a rapid means for reducing the population.

Biological Control

There is indication that the predatory bugs, Dicyphus hesperus and Orius insidiosus, and the parasitic wasp, Tamarixia triozae, may contribute to suppression of psyllids (Koppert Biological Systems). Indeed, Dr. Dave Gillespie of Pacific Agriculture Research Centre in BC has reported "cleaning up" of a population of psyllids in a small greenhouse by large numbers of Dicyphus. However, trials to determine exact rates and timing of introduction of Dicyphus have not yet been undertaken. Orius may not be as useful on tomatoes because young Orius nymphs tend to get caught on the sticky hairs present on tomato plant surfaces.

Chemical Control

There are no pesticides in Ontario that are specifically recommended for psyllids.

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