Tomato Pinworm: Appearance, Territory, Damage and Life Cycle

Latin Name: Keiferia Lycopersicella

Appearance: The tomato pinworm targets tomatoes primarily, although it may also live in other Solanaceae species, particularly eggplant and potato. It is commonly mistaken with other species that may be present and have similar characteristics. It is sometimes mistaken with the eggplant leafminer due to the early harm of the larva that builds a mine. Pheromones are often employed to interrupt adult mating and inhibit oviposition.

Hosts Plants: Pinworms like to live in plants of the nightshade family. Tomato is the most usually affected plant, although eggplant, Solanum melongena L. var ‘esculentum’, is also affected.  In America, hosts include tomato, potato, eggplant, and a weed called Solanum bahamese L.

Territory: North America

Damage Insect Cause: The tomato pinworm feeds on both the leaves and the fruits of the tomato plant. The most prevalent kind of harm is caused by larvae mining in the leaves. The mine is initially long and narrow, but it gradually spreads to become blotch-shaped. Older larvae typically curl the leaf over itself or weave two leaves together, between which they eat. When older larvae dig under the calyx into the fruit, they inflict more severe harm to the crop. The term tomato pinworm is derived from the very small pinholes at the places of entrance, which are frequently indicated by the presence of frass or droppings.

Life History and Habits: The eggs are pale at first, then become brown or orange as they grow and are located on the underside of the leaves. When the pest population is large, it can be found on any portion of the plant. They appear 4 to 7 days after they are deposited. The larvae have a yellowish-grayish body that gradually changes to gray with purple patches or totally purple, with a dark brown head. The larva travels through four instars, which can span anywhere from 9 to 17 days depending on the temperature.

For pupation, the larva falls to the ground, burying itself and forming a green pupal cell that darkens to brown before the adult emerges. The number of days in this instar fluctuates greatly, taking anything from 8 to 20 days. At 25°C, the complete life cycle takes around 26 days, while at 13°C, it takes about 100 days. Adults are around 9 to 12 mm in size when they emerge, and their greatest distinguishing feature is their mottled brown coloration. It can live for approximately a week at 25°C, although it may live for up to three weeks in lower climates.