In 2007, the United States imported $55 billion in horticultural products which encompasses fruit and nuts, vegetables, greenhouse plants, nursery stock, essential oilseeds, cocoa, coffee, tropical products, sugar, beer and wine. This is expected to increase to $73.7 billion by 2017. The majority of U.S. imports come from Europe, Mexico, Canada, Chile and Brazil (USDA 2008).

Main crops	defined common name/genus and links
Tree crops
We have separated the tree crops into two categories, nut and fruit, for ease in manipulation of the key. Here we briefly discuss the types of nut and fruit trees that are imported and the thrips that are associated with these tree crops. There are 14 species directly associated with the tree crops listed herein and there are 23 thrips species in the key that are polyphagous, meaning that there are too many plant species to list. Therefore some polyphagous thrips species are included within the tree crops.
Nut trees
Thrips can be imported as eggs, larvae or pupae in the grains of cereal so it is not totally unlikely that thrips could be imported on much larger nuts such as cocoa, coconut, olive, and cashew which are currently imported into the U.S. from Europe, Africa, and the Mediterranean countries. Within this key we have provided web resources on nut tree production and crop management. There are four thrips species that are associated with the above crops as well as several polyphagous thrips that may prove to be pests of nut trees.
Cashew/Anacardium	Cocoa/Theobroma
Olive/Olae	Coconut/Cocos
Fruit trees
The U.S. currently imports apples, avocados, citrus, mangos, pears, peaches, and nectarines, from Central and South America, Mexico, Europe, Korea, Japan, Turkey, Canada, and Argentina. Thrips can be imported as eggs, larvae or pupae in the grains of cereal so it is not totally unlikely that thrips could be imported under the sepals or stems and leaves where the fruit is attached. Within this key we have provided web resources on fruit tree production and crop management. There are ten thrips species that are associated with the fruit crops listed here and we include those polyphagous thrips that may prove to be pests of fruit trees.
Nectarines/Prunus	Apple/Malus
Peach/Prunus	Avocado/Persea
Pear/Pyrus	Citrus
	Mango/Mangifera (2) (3)
Ornamentals/ Natives
We have separated the ornamental and native crops into two categories, flowers and foliage, for ease in manipulation of the key. Here we briefly discuss the types of flowers and foliage that are imported into the US and those thrips that are associated with the list of crops included here. There are 23 thrips species in this key that are polyphagous, meaning that there are too many plant species to list. Therefore some polyphagous thrips species are included within these ornamental/native crops.
Flowers
The U.S. currently imports roses, orchids, lilies, sunflowers, carnations, gladiolus, and others from the Europe, Southern and Central America, Japan, Canada, Mexico, China and Australia. Thrips can be imported as eggs, larvae or pupae in the leaf tissues and flowers of many of these plants and have found thrips inside of developing rose buds (Parrella et al. 2003). Within this key we have provided web resources on cut flower production and management. There are 14 thrips species that are associated with the flowers listed here and we include those polyphagous thrips that may prove to be pests of flowers.
Grasses	Roses/Rosa (2)
Verbascum (2) (3)	Orchids/Orchidaceae (2)
Marigolds/Tagetes (2)	Calla lily/Zantedeschia (2)
Neomarica	Sunflower/Helianthus (2)
Hollyhocks/Alcea (2) (3)	Carnations/Dianthus (2)
Hibiscus	Daylilies/Hemerocallis (2)
	Gladiolus (2)
Foliage
The U.S. imports numerous foliage plants as cut flowers and rooted crops from Europe, Southern and Central America, Japan, Canada, Mexico, China and Australia. Thrips can be imported as eggs, larvae or pupae in the leaf tissues and flowers of many of these plants and the horticultural industry has been highlighted as one of the primary avenues for exotic thrips introduction (Parrella et al. 2003). Within this key we have provided web resources on foliage production and management. There are ten thrips species that are associated with the foliage listed here and we include those polyphagous thrips that may prove to be pests of ornamental foliage.
Privit/Ligustrum (2)	Ficus
Pinus (2)	Dieffenbachia (2)
Maples/Acer (2)	Eucalyptus (2)
Olive/Olae (2)	Epipremnum (2)
Grasses	Syngonium (2)
	Myrtaceae
Cereal crops
There are several cereal crops that are imported into the U.S. each year ranging from animal feed, human consumption and crop seeds. The U.S imports tropical fruits from numerous countries throughout the world including Europe, Russia, Southern and Central America, Asia, Mexico, New Zealand and Australia. Within this key we have provided web resources on cereal production and management. Thrips are small insects and can travel easily feeding on the seed of cereal crops. Some exotic thrips have been introduced into countries by hiding under the sheath of seeds and cereal grains. There are seven thrips species that are associated with cereal crops and we include the 23 polyphagous thrips that may prove to be pests on cereal in the future.
Forage grasses (2)	Barley/Hordeum
Rice/Oryza	Maize/Zea
Rape/Brassica	Millet (many genera) (2) (3)
Oats/Avena	Rye/Secale
	Wheat/Triticum
Tropical fruit
The U.S. consumers are fond of bananas, coconuts, mangos, and annonas among other tropical fruits. The U.S imports cereal crops from numerous countries throughout the world including Africa, Canary Islands, Portugal, Spain, Southern and Central America, Asia, Mexico, and Australia. Within this key we have provided web resources on tropical fruit production and management. Thrips are small insects and can easily travel feeding on tropical fruits and their attached plant parts. Some exotic thrips have been introduced into countries worldwide as eggs, larvae and adults by feeding on the fruit or under the bracts of the flowers where the fruit develops. There are six thrips species that are associated with tropical fruit and we include the 23 polyphagous thrips that may prove to be pests on tropical fruit in the future.
Banana/Musa (2) (3)	Mango/Mangifera (2) (3) (4)
	Annona squamosa (2)
Legumes
The U.S. imports numerous legumes for the intent as forage for animals as well as human consumption.  The U.S imports legumes from Europe, Central and South America, India, Africa, and Asia. Within this key we have provided web resources on legume production and management. Thrips are small insects and can easily travel feeding on legumes. Some exotic thrips have been introduced into countries worldwide as eggs, larvae and adults by feeding on the legume or on/in the legume pod. There are six thrips species that are associated with legumes and we also include here the 23 polyphagous thrips that may prove to be pests on legumes in the future.
Forage legumes (2) (3)	Soybean/Cayjanus (2) (3) (4)
Beans	Peanut/Arachis (2)
Alfalfa/Medicago	Castor bean/Ricinus (2)
Pea/Pisum (2)
Other crops
We have included in this category crops such as grapes, cotton, sugarbeets, eggplant, cabbage, jicama, tomato, and squash among others which are imported into the U.S. from Central and South America, India, Europe, Asia, Turkey, Africa and Mexico. Within this key we have provided web resources on the production and management of most of these crops. Thrips can easily travel feeding on different parts of the plants listed here. Some exotic thrips have been introduced into countries worldwide as eggs, larvae and adults by feeding on the fruit or under the bracts of the flowers where the fruit/seed develops and as pupae on the dead plant material. In addition, thrips can be found living inside the clusters of grapes and leaves of cabbage. There are six thrips species that are associated with the other crops listed here and we have included the 23 polyphagous thrips that may prove to be pests on these crops in the future.
Cotton/Gossypium	Grapes/Vitis
Egg plant/Solanum (2) (3)	Sugarbeet/Beta
Squash/Cucurbita	Jicama/Pachyrhizus (2)
Tomato/Solanum	Flax/Linum (2) (3)
Cabbage/Brassica	Sunflower/Helianthus

Table 1: Crops and related links to important web pages

References to crop introductions

Parrella, MP; Murphy, B; O’Donnell, C; Casey, C (2003): Insects and other animals, pp. 437-443. In Roberts, AV; Debener, T; Gudin S [ed.], Encyclopedia of Rose Science. Elsevier Academic Press.
USDA, 2008: Summary of U.S. agricultural trade projections, fiscal years. In U. S. D. o. C. US Department of Agriculture and Bureau of Census [ed.]. USDA.