Frankliniella occidentalis (Pergande, 1895)

Cvetkovska-Gjorgievska, Aleksandra, Dedov, Ivailo, Hristovski, Slavcho, Langourov, Mario, Lazarevska, Stanislava, Prelik, Dana & Simov, Nikolay, 2019, New records of allochtonous, invasive and pest invertebrate species from the Republic of Macedonia, Ecologica Montenegrina 20, pp. 56-70 : 64-65

Frankliniella occidentalis (Pergande, 1895) - Western Flower Trips ( Thysanoptera , Thripidae )

Record: CABI/EPPO, 1988

Origin: Southwestern US ( Waterhouse & Norris 1989).

Comments: F. occidentalis is native to Nort America. The western flower trips was first described in California in 1895, and since 1970s, it had invaded much of the word and became dominant population in most of the areas where it had been introduced ( Kirk & Terry 2003).

The western flower thrips is widespread from sea level to sub-alpine altitudes. It is the most common thrips species. This thrips has spread to the Canary Islands, Europe, Hawaii, New Zealand, northern South America ( Waterhouse & Norris 1989).

During the decades of 1970 and 1989 it spread to Europe and other countries in the world. In 1983 F. occidentalis was accidentally introduce in Netherland and later became main problem in field crops and orchards ( Loomans 2003). In 1985 it was recorded in Danmark and Germany ( CABI 2014), in 1987 the pest is recorded on chrysanthemum in Belgium ( Clerco & Casteels 1992), in Czech Republic, Finland, France, Ireland, Italy, Poland ( CABI 2014), in 1988 is recorded in Austria, Sicilia, Sardinia and Macedonia ( CABI 2014). Today, this species is widespread in Macedonia in open field and greenhouses.

F. occidentalis is poor flier, but easily transported passively by the wind. It has been spread with international trade throughout subtropical and temperate regions of the world. In colder climates it is frequently a serious pest in greenhouses. The international spread of the western flower thrips occurred predominantly by the movement of horticultural material, such as cuttings, seedlings and potted plants. Within Europe, an outward spread from the original outbreak in the Netherlands is discernible. The speed of spread was 229± 20km /year ( Kirk & Terry 2003).

F. occidentalis is a polyphagous species with hosts in 65 families, including more than 250 species of vegetables and ornamental crops. Some examples of host plants are alfalfa, apricots, artichoke, carnations, chrysanthemum, corn, cotton, cucumber, eggplant, gerbera, gladiolus, grapefruit, grapes, impatiens, melons, nectarines, peaches, peanut, peas, pepper, plums, Spanish needle, strawberry, tomato, watermelon, and wild radish ( CABI 2014).

Thrips cause both direct and indirect injury to crops. Direct damage occurs when the thrips cause injury by feeding or oviposition. F. occidentalis is prevalent in flowers, but it can also be found on crop foliage and fruit, which reduce photosynthetic capacity (Shipp et al. 2000) and cause fruit surface dimpling. Indirect damage refers primarily to the transmission of viruses (Tomato spotted wilt virus (TSWV), Tomato chlorotic spot virus (TSCV), Impatiens necrotic spot virus (INSV), and Groundnut ring spot virus (GRSV). F. occidentalis is considered to be the predominant vector of TSWV worldwide, a serious virus for wide range of crop and non crop hosts and causes billions economic losses worldwide ( Riley et al. 2011).

In warm regions or in greenhouses F.occidentalis develops 12-15 generation per year. Otherwise, adults and pupae will overwinter in sheltered places like under lumps of soil, tree bark, in grass and weeds, and only 1 or 2 generations may be completed. In spring, the adults migrate to flowering plants and start with oviposition. The female lays about 40- 50 eggs, 1-2 per day. Each is inserted singly into the plant tissue.