The primary direct damage caused by Tomato (Potato) Psyllid (Bactericera cockerelli) results from nymph feeding and is commonly referred to as “psyllid yellows.” This condition is characterized by delayed plant growth, weakened and deformed new leaves, chlorosis or reddening, and in some cases, a purple discoloration at the bases of leaves and along the internodes. Affected plants often produce poor-quality fruit and suffer from overall decline. However, the most serious impact stems from indirect damage due to the transmission of the bacterium Candidatus Liberibacter solanacearum. This pathogen intensifies the effects of feeding and is responsible for “zebra chip” disease in potatoes—a condition that renders tubers unmarketable due to dark, zebra-like striping that appears when fried. Beyond zebra chip, the psyllid also spreads purple-top disease in potatoes and permanent yellowing disease in tomatoes. These disorders lead to systemic plant decline and substantial yield losses. Indirect damage poses the greatest threat, as its effects are broad, persistent, and currently without effective treatment or cure.

The Tomato (Potato) Psyllid (Bactericera cockerelli) has a distinct and identifiable life cycle. The eggs are oval-shaped and bright orange-yellow in colour, attached to the plant surface by a slender stalk. They are typically laid on the underside and edges of leaves. Egg hatching occurs within three to seven days, depending on environmental conditions.

After hatching, the psyllid passes through five nymphal stages (instars). Nymphs are flat and oval in shape, with prominent red eyes and a fringe of waxy filaments around the body. Their colour changes noticeably across the instars—starting as orange, transitioning to greenish-yellow, and finally becoming green.

The full development from egg to adult takes approximately 12 to 24 days. Newly emerged adults are yellowish-green with whitish wings that gradually become transparent. As they mature, the body darkens to a deep brown or black with white or yellow markings and a distinctive white band across the abdomen. Adults are small, measuring about 2.5 mm in length, and typically live for 20 to 60 days, depending on temperature and host plant conditions.

Preventing infestations of the Tomato (Potato) Psyllid involves an integrated approach combining crop monitoring and cultural practices. Regular scouting is essential to detect early signs of psyllid presence, including eggs on the undersides and edges of leaves and the characteristic symptoms of psyllid yellows. Using yellow sticky traps can assist in monitoring adult populations and gauging pest pressure over time. Implementing physical barriers, such as insect netting, can help reduce psyllid entry into protected cropping environments. Cultural controls, such as removing volunteer Solanaceous plants and weeds that can serve as alternative hosts, are also important to limit breeding sites. In regions with a known psyllid presence, staggering planting dates or implementing crop-free periods may help disrupt the pest's life cycle. By integrating these prevention strategies, growers can reduce the likelihood of infestation and minimize the risk of disease transmission by this economically damaging pest.

Biological control offers an effective and sustainable strategy for managing Tomato (Potato) Psyllid populations, with Tetrapar (Tamarixia triozae) standing out as a highly targeted solution. Tamarixia triozae is a parasitic wasp that specifically targets the nymphal stages of Bactericera cockerelli, focusing on the more mature fourth and fifth instars. Adult female wasps lay their eggs on or near these older nymphs, and upon hatching, the larvae develop by feeding internally on the host. In addition to parasitism, Tamarixia also causes host mortality through direct feeding (host feeding), further reducing psyllid numbers.

This biological agent is best used preventively or at the early onset of psyllid activity. Regular, strategic releases can keep populations in check and reduce the risk of disease transmission associated with psyllid feeding. In the case of localized outbreaks or concentrated infestations, Tetrapar should be released directly into hot spots as well as evenly distributed across the crop to maximize coverage and effectiveness.

Because it targets only specific nymphal stages, Tetrapar should be used in combination with other control tools—such as sticky traps for monitoring, cultural practices to reduce host plants, and complementary natural enemies—to ensure full lifecycle management of the pest. This integrated biological strategy aligns well with sustainable IPM programs and helps preserve beneficial insect populations within the crop environment.