Frankliniella bispinosa (Morgan)

Florida flower thrips

Distribution

Frankliniella bispinosa (Morgan) is also known as the Florida flower thrips, although this common name has not yet been accepted by the Entomological Society of America. It is a common thrips species throughout southern Florida, and is increasingly common in northern Florida and southern Georgia.

Description (click here for drawing)

The female Florida flower thrips is about 1 mm long and her basic body color is yellow. The male is pale yellow or white and is smaller than the female. Females often have pale gray bands or blotches on each segment of the abdomen.

The postocular seta is about half as long as the interocellar seta. The pedicel of the third antennal segment has a sharp-edged flange.

The anteroangular and anteromarginal setae are well developed, with the anteromarginal shorter than the anteroangular.

The comb on abdominal segment VIII is incomplete.

Host Range

Frankliniella bispinosa infests a wide range of crops and uncultivated hosts. Major population peaks in vegetables coincide with or follow closely the blooming of such hosts as oaks, pines, and citrus, suggesting that immigration from these sources is a major factor in vegetable infestations (Glades Crop Care unpublished data). Vegetable crops infested include tomato, pepper, eggplant, potato, tomatillo, cucumber, watermelon, squash, beans. strawberry, and sweet corn. Cut flowers, such as chrysanthemum and baby's breath, are also favored, especially varieties with white or yellow flowers (Frantz & Mellinger 1990).

Economic importance and management specifics

Frankliniella bispinosa feeds primarily in blooms. It can infest the foliage or feed externally on the fruit when its population is high. Its feeding damage, either by itself or in conjunction with the fungal pathogen, Colletotrichum acutatum, can significantly reduce citrus yields (Childers 1992). Most problems with the Florida flower thrips in vegetable crops occur seasonally, when large numbers of thrips migrate from blooming citrus groves, or from other hosts, such as oaks.

In tomatoes, thrips oviposition wounds result in pin-prick dimples in the mature fruits. These are not a serious problem, unless the number of dimples is high. Feeding and oviposition damage to pepper fruits is also not a problem, unless very high numbers of thrips are present for an extended period.

High numbers of thrips migrating from citrus groves can inundate nearby vegetable crops. If these migrating populations are not accompanied by sufficient numbers of predators, such as the minute pirate bug, Orius insidious (Say), they can cause direct feeding damage to tender young foliage, fruits, or blooms. If scouting reports indicate F. bispinosa numbers less than 10/bloom in peppers, 2-3/bloom in tomatoes, or 10/growing point in cucurbits, crop damage should be tolerable. When counts exceed these levels, insecticide applications may be needed, unless predators are also present.

Generally, insecticide applications specifically for control of the Florida flower thrips are made sparingly. The reasons for this are:

  1. their damage is usually tolerable,
  2. they compete very well with more serious pests, such as melon thrips, for resources in the blooms of sensitive crops, such as peppers, and
  3. they serve as a very good food source for minute pirate bugs, which will contribute to control of this and other species of thrips.

When insecticides are used, the lowest rates of insecticides with short residual activity, such as methomyl, are usually efficient to bring Florida flower thrips under control. Follow-up applications may be needed during the blooming periods of oaks and citrus.

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