Bactericera cockerelli
(tomato/potato psyllid)

Preferred Scientific Name

• Bactericera cockerelli (Šulc) 1909

Preferred Common Name

• tomato/potato psyllid

Other Scientific Names

• Paratrioza cockerelli (Šulc) 1909
• Trioza cockerelli (Šulc) 1909

International Common Names

• English: potato, psyllid; tomato psyllid; tomato, psyllid
• Spanish: pulgon saltador de la papa (mexico); pulgon saltador de la tomato (mexico)
• French: psylle de la pomme de terre; psylle de la tomate

Local Common Names

• Germany: Blattsauger, Amerikanischer Kartoffel-; Blattsauger, Tomaten-

EPPO code

• PARZCO (Paratrioza cockerelli)

• Domain: Eukaryota
•     Kingdom: Metazoa
•         Phylum: Arthropoda
•             Subphylum: Uniramia
•                 Class: Insecta
•                     Order: Hemiptera
•                         Suborder: Sternorrhyncha
•                             Unknown: Psylloidea
•                                 Family: Triozidae
•                                     Genus: Bactericera
•                                         Species: Bactericera cockerelli

A brief history on the taxonomy and nomenclature of Bactericera cockerelli was recently provided by Butler and Trumble (2012).

B. cockerelli was originally described as Trioza cockerelli by Šulc (1909). In 1910, Crawford erected a new psyllid genus Paratrioza (Crawford, 1910) and Trioza cockerelli was assigned to this genus in 1911 (Crawford, 1911). In 1997, when the genus Paratrioza was reviewed and synonymized with the genus Bactericera, B. cockerelli also changed families from Psyllidae, subfamily Triozinae, to Triozidae (Burckhardt and Lauterer, 1997; Hodkinson, 2009). The subfamily Triozinae was elevated to family status as Triozidae.

Morphological descriptions of B. cockerelli can be found in Crawford (1911, 1914), Essig (1917), Ferris (1925) and Tuthill (1945). Also, a list of the synonyms of B. cokerelli is provided by Tuthill (1945) and Burckhardt and Lauterer (1997). Furthermore, a revised classification of pysllids was recently provided by Burckhardt and Ouvrard (2012).

B. cockerelli adults are small, measuring about 2.5-2.75 mm long. The adults generally resemble tiny cicadas, largely because they hold their wings angled and roof-like over their body. B. cockerelli adults possess two pairs of clear wings; the front wings bear conspicuous veins and are considerably larger than the hind wings. The antennae are moderately long, extending almost half the length of the body. The overall body colour ranges from pale green at emergence to dark green or brown within 2-3 days, and eventually becomes grey or black thereafter. Prominent white or yellow lines are found on the head and thorax, and dorsal whitish bands are located on the first and terminal abdominal segments. These white markings are spot characteristics of the psyllid, particularly the broad, transverse white band on the first abdominal segment and the inverted ‘V’-shaped white mark on the last abdominal segment (Pletsch, 1947; Wallis, 1955), along with the raised white line around the circumference of the head. Adults are active in contrast to the largely sedentary nymphal stages. These insects are good fliers and readily jump when disturbed.

The pre-oviposition period is normally about 10 days, with oviposition lasting up to 50 days. Total adult longevity ranges from 20 to 60 days, and females usually live two to three times longer than males (Pletsch, 1947; Abernathy, 1991; Abdullah, 2008; Yang and Liu, 2009). Females lay 300 to 500 eggs over their lifetime (Knowlton and Janes, 1931; Pletsch, 1947; Abdullah, 2008; Yang and Liu, 2009).

The eggs of B. cockerelli are deposited singly, principally on the lower surface of leaves and usually near the leaf edge, but some eggs can be found throughout suitable host plants. Often, females will lay numerous eggs on a single leaf. The eggs are initially light yellow and become dark yellow or orange with time. The eggs measure about 0.32-0.34 mm long, 0.13-0.15 mm wide, and are mounted on a stalk of about 0.48-0.51 mm. Eggs hatch 3-7 days after oviposition (Pletsch, 1947; Wallis, 1955; Capinera, 2001; Abdullah, 2008). Because nymphs prefer sheltered and shaded locations, they are mostly found on the lower surfaces of leaves and usually remain sedentary during their entire development. Nymphs and adults produce large quantities of whitish excrement particles, which may adhere to foliage and fruit.

Nymphs are elliptical when viewed from above, but are very flattened in profile, appearing almost scale-like. Potato psyllid nymphs may be confused with the nymphs of whiteflies, although the former move when disturbed. There are five nymphal instars, with each instar possessing very similar morphological features besides size. The size of the developing wingpads increases with each instar. Nymphal body widths are variable, ranging from 0.23 to 1.60 mm, depending on different instars (Rowe and Knowlton, 1935; Pletsch, 1947; Wallis, 1955). Initially, the nymphs are orange, but they become yellowish-green and then green as they mature. The compound eyes are reddish and quite prominent. During the third instar, the wing pads, light in colour, are evident and become more pronounced with each subsequent molt. A short fringe of wax filaments is present along the lateral margins of the body. Total nymphal development time depends on temperature and host plant and has been reported to have a range of 12 to 24 days (Knowlton and Janes, 1931; Abdullah, 2008; Yang and Liu, 2009).

In North America, driven primarily by wind and hot temperatures in late spring, B. cockerelli annually migrates from its overwintering and breeding areas in southern and western Texas, southern New Mexico, Arizona, California, Idaho and northern Mexico (Pletsch, 1947; Wallis, 1955). The migration occurs especially through the midwestern states and Canadian provinces along the Rocky Mountains (Romney, 1939; Pletsch, 1947; Jensen, 1954; Wallis, 1955). In these regions, damaging outbreaks of potato psyllid in potatoes and tomatoes occurred at regular intervals beginning in the late1800s and extending into the 1940s (List, 1939; Wallis, 1946; Pletsch, 1947). In more recent years, psyllid outbreaks have also occurred in regions outside of the midwestern United States, including southern California, Baja California, Oregon, Washington, Idaho, and Central America (Trumble, 2008; 2009; Munyaneza et al., 2009a; Wen et al., 2009; Crosslin et al., 2010; Munyaneza, 2010; Espinoza, 2010; Butler and Trumble, 2012; Crosslin et al., 2012a,b; Munyaneza, 2012). Information about migration of B. cockerelli within Mexico and Central America is lacking. In the southwestern United States, potato psyllids reappear in overwintering areas between October and November, presumably dispersing southward from northern locations (Capinera, 2001); however, their origin has not been determined.

In countries and regions where there are no significant seasonal changes during the winter, temperature is relatively cool, and where suitable host plants are available (e.g. Mexico, Central America), the potato psyllid is able to reproduce and develop all year round (Espinoza, 2010; Rubio-Covarrubias et al., 2011).

B. cockerelli was accidentally introduced into New Zealand, apparently sometime in the early 2000s (Gill, 2006; Liefting et al., 2009; Teulon et al., 2009; Thomas et al., 2011), and is now established on both North and South Island where it causes extensive damage to potato, tomato, pepper and tamarillo crops (Teulon et al., 2009). It is not clear how B. cockerelli arrived in New Zealand; however, it has been suggested that the psyllid was introduced from the western United States, probably through smuggled primary host plant material (Thomas et al., 2011).

B. cockerelli has historically been associated with ‘psyllid yellows’ disease of potato and tomato (Richards and Blood, 1933). Psyllid yellows disease is thought to be associated with feeding by psyllid nymphs (List, 1925) and may be caused by a toxin associated with the insect (Carter, 1939), although the actual etiology of the disease is yet to be determined (Sengoda et al., 2010). More recently, this psyllid has been found to be associated with the bacterium ‘Candidatus Liberibacter’ (Hansen et al., 2008; Liefting et al., 2009; Crosslin et al., 2010; Munyaneza, 2010; Munyaneza, 2012; Munyaneza and Henne, 2012) (see ISC datasheet on ‘Candidatus Liberibacter solanacearum’ for details).

The characteristic above-ground plant symptoms of infestation by B. cockerelli in potatoes and tomatoes include retarded growth, erectness of new foliage, chlorosis and purpling of new foliage with basal cupping of leaves, upward rolling of leaves throughout the plant, shortened and thickened terminal internodes resulting in rosetting, enlarged nodes, axillary branches or aerial potato tubers, disruption of fruit set and production of numerous, small, and poor quality fruits (List, 1939; Pletsch, 1947; Daniels, 1954; Wallis, 1955; Munyaneza, 2012; Munyaneza and Henne, 2012).

The below-ground symptoms on potato include the setting of an excessive number of tiny misshapen potato tubers, production of chain tubers and early breaking of dormancy of tubers (List, 1939; Pletsch, 1947; Wallis, 1955). Additional potato tuber symptoms include collapsed stolons, browning of vascular tissue concomitant with necrotic flecking of internal tissues and streaking of the medullary ray tissues, all of which can affect the entire tuber. Upon frying, these symptoms become more pronounced and chips or fries processed from affected tubers show very dark blotches, stripes, or streaks, rendering them commercially unacceptable (Munyaneza et al., 2007a,b; 2008; Secor et al., 2009; Crosslin et al., 2010; Miles et al., 2010; Munyaneza, 2012; Munyaneza and Henne, 2012); see the ISC datasheet on 'Candidatus Liberibacter solanacearum' for details.

Natural Dispersal

Adult potato psyllids are good fliers and can disperse over considerable long distances, especially with the onset of wind and hot temperatures. Adults have been shown to migrate en masse to northern western states of the United States and southern Canadian provinces in the spring from the insect overwintering sites in the southwestern United States and northern Mexico (a distance of several hundred kilometers). Immature stages of B. cockerelli are essentially sedentary and do not actively disperse.

Accidental Introduction

Long distance transport of different life stages of this insect pest is possible, particularly by commercial trade of plant material for propagation and produce in the family Solanaceae, which constitute major hosts for B. cockerelli. Based on the discovery of at least four haplotypes of potato psyllid in North and Central America, seasonal dispersal of this insect into potato crops was recently reviewed and discussed by Nelson et al. (2014). 

This insect was introduced into New Zealand, where it was recently found established in tomato glasshouses and several outdoors solanaceous crops (Gill, 2006; Liefting et al., 2009; Teulon et al., 2009; Thomas et al., 2011). It is not clear on how the insect arrived in New Zealand, but it was most likely transported with plant material, possibly as eggs (Crosslin et al., 2010; Thomas et al., 2011).

Entry on fruits of host species (e.g. tomato, pepper, eggplant) is possible, especially when they are associated with green parts (e.g. truss tomato). Entry on potato tuber is more unlikely.

Detailed information on the economic impact of B. cockerelli is provided by Munyaneza (2012). Historically, the extensive damage to solanaceous crops that was observed during the outbreak years of the early 1900s is thought to have been due to B. cockerelli’s association with a physiological disorder in plants referred to as ‘psyllid yellows’ (Richards and Blood, 1933), presumably caused by a toxin that is transmitted during the insect’s feeding activities, especially nymphs (Eyer and Crawford, 1933; Eyer, 1937). However, the nature of this toxin has not yet been identified. ‘Psyllid yellows’ is characterized by yellowing and curling of foliage, stunting or death of plants and a loss in yield (Richards and Blood, 1933; Eyer, 1937). Infected tomato plants produce few or no marketable fruits (List, 1939; Daniels, 1954). In potatoes, psyllid yellows results in yellowing or purpling of foliage, the early death of plants and low yields of marketable tubers (Eyer, 1937; Pletsch, 1947; Daniels, 1954; Wallis, 1955). In areas of outbreaks of psyllid yellows, the disorder was often present in 100% of plants in affected fields, with yield losses exceeding 50% in some areas (Pletsch, 1947).

In recent years, potato, tomato, and pepper growers in a number of geographic areas have suffered extensive economic losses associated with outbreaks of potato psyllid (Trumble, 2008, 2009; Munyaneza et al., 2009b,c,d; Crosslin et al., 2010; Munyaneza, 2010). This increased damage is due to a previously undescribed species of the bacterium liberibacter, tentatively named ‘Candidatus Liberibacter solanacearum’ (syn. Ca. L. psyllaurous) (Hansen et al., 2008; Liefting et al., 2009), now known to be vectored by potato psyllid (Munyaneza et al., 2007a,b; Buchman et al., 2011a,b); see the ISC datasheet on 'Candidatus Liberibacter solanacearum' for details. Potato psyllids acquire and spread the pathogen by feeding on infected plants (Munyaneza et al., 2007a,b). The bacterium is also transmitted transovarially in the psyllid (Hansen et al., 2008), which contributes to the spread of the disease between geographic regions by dispersing psyllids. It also helps maintain the bacterium in geographic regions during the insect’s overwintering period (Crosslin et al., 2010; Munyaneza, 2012).

Symptoms associated with liberibacter in tomatoes and pepper include chlorosis and purpling of leaves, leaf scorching, stunting or death of plants, and production of small, poor-quality fruit (Liefting et al., 2009; McKenzie and Shatters, 2009; Munyaneza et al., 2009c,d; Brown et al., 2010; Crosslin et al., 2010). During the outbreaks of 2001-2003, tomato growers in coastal California and Baja California suffered losses exceeding 50-80% of the crop (Trumble, 2009). In potatoes, foliar symptoms closely resemble those caused by psyllid yellows and purple top diseases (Munyaneza et al., 2007a,b; Sengoda et al., 2009). However, tubers from liberibacter-infected plants develop a defect referred to as ‘zebra chip’, which is not induced by the potential toxin causing psyllid yellows (Munyaneza et al., 2007a,b; 2008; Sengoda et al., 2009). Tubers show a striped pattern of necrosis, which is particularly noticeable when the tuber is processed for chips or fries (Munyaneza et al., 2007a,b; 2008; Miles et al., 2010). Chips or fries from affected plants are not marketable. The defect was of sporadic importance until 2004, when it began to cause millions of dollars in losses to potato growers in the United States, Central America and Mexico (Rubio-Covarrubias et al., 2006; Munyaneza et al., 2007a; 2009b; Crosslin et al., 2010; Munyaneza, 2010). In some regions, entire fields have been abandoned because of zebra chip (Secor and Rivera-Varas, 2004; Munyaneza et al., 2007a; Crosslin et al., 2010; Munyaneza, 2010). The potato industry in Texas estimates that zebra chip could affect over 35% of the potato acreage in Texas, with potential losses annually to growers exceeding 25 million dollars (CNAS, 2006). Finally, quarantine issues have begun to emerge in potato psyllid-affected regions, because some countries now require that shipments of solanaceous crops from certain growing regions be tested for the pathogen before the shipments are allowed entry (Crosslin et al., 2010; Munyaneza, 2012).

• Invasive in its native range
• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Highly adaptable to different environments
• Is a habitat generalist
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Tolerant of shade
• Capable of securing and ingesting a wide range of food
• Highly mobile locally
• Long lived
• Fast growing
• Has high reproductive potential
• Gregarious
• Has high genetic variability

• Host damage
• Negatively impacts agriculture
• Negatively impacts trade/international relations

• Pest and disease transmission

• Highly likely to be transported internationally accidentally
• Difficult to identify/detect as a commodity contaminant
• Difficult to identify/detect in the field
• Difficult/costly to control