Phthorimaea operculella

Phthorimaea operculella, also known as the potato tuber moth or tobacco splitworm, is a moth of the family Gelechiidae. It is an oligophagous insect that feeds on the plant family Solanaceae and is especially known for being a major pest of potato crops. Currently farmers utilize insecticides, parasites, and sprinkler irrigation in order to prevent P. operculella from infesting their croplands. The potato tuber moth also has a rare oviposition process where the ovipositor contains sensors that pick up on chemical signals given off by the host plant. Therefore, the adult female moth only needs to be within the vicinity of a host plant to lay her eggs. The potato tuber moth has a body length of about 10mm and a wingspan of about 12mm. Adult moths have a narrow, light brown body with grayish-brown wings containing a variety of small dark spots. The moth contains two sets of wings, both having frayed edges. Females are distinguished from males by having a black “X” pattern on their forewings when their wings are closed. P. operculella can be found worldwide but prefer subtropical, tropical, and mediterranean climates. In the United States, P.operculella have been spotted in at least 25 states, especially along the Atlantic and Pacific coast. The potato tuber moth is also commonly found in Africa, Asia, Europe, South America, and Oceania. In total, the moth has been reported in more than 90 countries. The potato tuber moth typically lives in areas near potatoes or within the vicinity of their host plant family, Solanaceae. Temperature is an important factor in the survival rate and development of P. operculella, and so they are typically found in warmer climates, preferring subtropical and tropical habitats. Potato tuber moth larvae are known for feeding on the tubers, roots, and foliage (on which they are leafminers) of potato plants (Solanum tuberosum). However, larvae are only able to locate potato tubers if the tubers are exposed or within 1 cm of the soil surface. There is no evidence that newly hatched larvae would burrow down and locate tubers using the root system. On foliage, the larvae mainly feed on the mesophyll, leaving brown or white spots in the leaves, known as blotch mines. The potato tuber moth has been found to feed on various members of the Solanaceae family such as tobacco plants (Nicotiana tabacum), eggplants (Solanum melongena), tomatoes (Lycopersicon esculentum), and bell peppers (Capsicum annuum). The ovipositor of the P. operculella is approximately 1.5mm in length and 0.3mm in width. On either side of the ovipositor are approximately 30-40 tapering hairs that range from 0.03-0.3mm in length. At the tip of the ovipositor are more smaller hairs that are spaced evenly over the area. The female potato tuber moth does not require to be on top of or inside a host plant in order to mate and lay eggs. However, full fecundity is only achieved when the moth is in the vicinity of a preferred host plant. Female adult moths look for surface depressions (cracks) that are just large enough to contain her eggs, typically 0.2-0.5 mm squared. Hairy and textured surfaces are preferred over smooth and waxy surfaces. Females also strongly prefer dry places to lay her eggs and studies have shown that total number of eggs laid is reduced in the presence of moist surfaces. Shade is also preferred over bright light.