A strain of A. suspensa, believed to have been established in Florida for many years prior to its discovery there, was first identified as occurring in Florida from adults collected at Key West in 1931. On November 6, 1930, two larvae, identified as being Anastrepha sp., were found infesting hog plums in Key West. Two additional larvae were collected from hog plums on November 12, and five pupae were obtained on November 12 and 14 by sifting soil. Larvae and adults of a closely related species, Anastrepha obliqua (Macquart) Sén, were reared at Key West from hog plums in September 1931. Adults of A. suspensa were reared from guavas soon thereafter. Guava subsequently proved to be the preferred host of A. suspensa in the Key West area. An eradication program for A. obliqua and A. suspensa in Key West was established jointly by the State Plant Board of Florida and the United States Department of Agriculture on August 1, 1933. These measures consisted primarily of the maintenance of host-free conditions on the island, plus the application of tartar emetic sprays at two-week intervals. Traps were used to obtain an indication of the progress of eradication.
Meanwhile investigations were conducted to determine what hosts might be attacked under caged conditions, as well as under field conditions, to determine the results of the crossing of several species of Anastrepha under laboratory conditions, to work out the life histories of the species found to occur in the Florida Keys, and to develop control and eradication techniques. An expanded detection system of trapping eventually showed both A. suspensa and A. obliqua to occur throughout the Keys and on the mainland over a fairly extensive area in southern Florida. This resulted in a discontinuation of eradication efforts in January 1937. During this period A. suspensa was never found in a field host on the mainland and was reared under field conditions only from guava in the Florida Keys. Under laboratory conditions at Key West, A. suspensa was reared from nearly a dozen other hosts. In every case the preferred host, guava, was present in the cage with other hosts which were attacked. In no case was orange, grapefruit, or mango attacked. Only 19 A. suspensa adults were recovered from traps on the mainland from Dade, Broward, and Palm Beach County, one in Lee County on Pine Island, and less than 200 on the Florida Keys.
It may be significant that the strain of A. suspensa known to be established in Florida during the 1930s was never found infesting citrus, or any other fruit, on the mainland. In contrast, a strain found in Puerto Rico occurs there in large numbers and attacks a number of tropical and subtropical fruits, including citrus.
Another indication that the A. suspensa of Puerto Rico has different "tastes" than the Florida strain is indicated by the fact that in Puerto Rico this insect has been found in tropical almonds during every week of the year. At Key West, where there are many tropical almond trees, thousands of almonds were examined over a period of years without finding A. suspensa. This raises the question as to what assurance there is that the Puerto Rican strain, with "some developed taste" for citrus, if established in Florida, would not become a major pest of citrus in the absence of its preferred hosts.
Although no eradication measures ever were applied on the mainland other than inspection in South Dade County, the native populations of A. suspensa and A. obliqua apparently died out some time after 1936, as not a single specimen of either species was collected anywhere in Florida in the field after 1936 until 1959, when two adults of A. suspensa were taken from a trap at Key West. One larva identified as A. suspensa was found in 1964 in oranges imported from Haiti at a juice plant in central Florida.
No positive conclusions can be drawn on the prevalence of A. suspensa in Florida subsequent to 1936, when the detection program was discontinued. No significant trapping was carried on for the detection of fruit flies until 1957, following the rediscovery of the Mediterranean fruit fly (Ceratitis capitata (Wiedeman)) in 1956 and its subsequent costly eradication. During the early 1950s, O.D. Link, a special inspector for the State Plant Board of Florida, operated 20 McPhail traps in the Florida Keys. This limited trapping program was not sufficient to provide conclusive evidence as to the occurrence, or lack of occurrence, of A. suspensa during that period, nor was the bait used in those traps a highly effective lure for A. suspensa.
Since 1965, however, a new introduction of the pest into Florida has continued to spread and it now occurs in most of southern peninsular Florida, commonly north to Citrus and Volusia counties, with isolated records north to Jacksonville (Ibrahim, 1980). Within the first three months following the discovery of A. suspensa in Florida in 1965, more than 14,000 adults were trapped in Dade County and identified by state entomologists. It has now developed into the main fruit fly problem for citrus and several other crops in Florida.
On April 23, 1965, Anastrepha larvae were discovered in fruit of Surinam cherry by a Miami Springs homeowner near the Miami International Airport. Four days afterward, adults of Anastrepha suspensa were collected at this site. Intensive trapping and fruit cutting during the next several weeks indicated an alarming buildup of what appeared to be a localized population of A. suspensa. Trapping and fruit cutting indicated extensions of this population as far northward as Riviera Beach and as far southward as Homestead by mid-July. Many thousands of adults were taken in traps within a few weeks, with the heaviest concentration around the original find in Miami Springs. An intensive field survey showed that the larvae were attacking a fairly extensive list of host plants similar to the hosts of the Puerto Rican strain of A. suspensa. There were several strong indications that this was a recently introduced strain of A. suspensa, rather than a reappearance of the old Key West strain. The Division of Plant Industry of the Florida Department of Agriculture (formerly the State Plant Board of Florida) and the United States Department of Agriculture expanded the detection program to obtain more information on the distribution and abundance of this strain of A. suspensa in Florida, and to determine what additional kinds of fruit might be serving as field hosts. Spray operations were instigated to try to check the further spread and increase of this fruit fly. With the further cooperation of the Department of Entomology and Nematology of the University of Florida, field experiments were set up to try to obtain more accurate information on the seriousness of the threat this "strain" of A. suspensa might constitute to Florida citrus, mangoes, and dooryard tropical fruit plantings, and to investigate improved methods of detection, control, and eradication.
Trypeta suspensa (Loew),
(Trypeta) Acrotoxa suspensa (Loew),
Anastrepha unipuncta Séin,
Anastrepha longimacula Greene.
Stone further stated that "in the national museum collection are 19 specimens, the offspring of two A. suspensa females and two A. obliqua males. The cross was made at Key West, Fla. These specimens show characters of both parents and a wing pattern with the V band rather widely separated from the S band and therefore scarcely agreeing with either. There is also a specimen reared by I.W. Berryhill at San Juan, Puerto Rico, in August 1938, which is the result of the crossing of the two species. The writer has never seen any specimens collected in the field that agreed with these hybrid specimens, and it is rather doubtful that such crossing takes place in nature." The ovipositor of the female, in comparison with some other species of Anastrepha, is short, stout, the base widened, the tip distinctly narrowed beyond the oviduct, with serrations rather rounded and occupying the apical two-thirds of the tip.
Larva: White with typical fruit fly larval shape (cylindrical, elongated, anterior end usually somewhat recurved ventrally and with mouth hooks, flattened caudal end) but with 10 fusiform areas visible; last instar about 8 to 10 mm in length. Anterior buccal carinae normally 8. Cephalo-pharyngeal skeleton with relatively large mouth hook (length 2 X width) with hypostome of nearly equal width; dorsal bridge enlarged; pharyngeal plate longer than dorsal wing plate and with a long pharyngeal support. Anterior spiracles slightly asymmetrical, with a median depression; 12 to 13 tubules present. Caudal end with paired dorsal (D1 & D2) and intermediate (I1 & I2) papillules, plus a distinct I3; prominent L1; indistinct V1 (rarely somewhat prominent); D1 & D2 acutely angled (ca. 45°) and closer together than 11 & 12 (ca. 1/2 distance); I1 & I2 almost in a horizontal line (ca. 10-15°); I1, I3, and L1 approximately in a straight line (at ca. 30°) and I3 twice as distant from I1 as from L1. Posterior spiracles elongated (ca. 3-3.5 X width), with dorsal 2 angled upward and ventral one angled downward on each side of median; most interspiracular processes (hairs) usually not branched distally. Anal lobe always entire. [Described from USNM and FSCA lots from Puerto Rico and Florida.]
Accurate larval identification of A. suspensa and other species of Anastrepha is difficult. Mexican fruit fly, Anastrepha ludens (Loew), and Caribbean fruit fly larvae (last instars) may be separated as follows:
The larval descriptions herein were made from reared and verified specimens from the U.S. National Museum of Natural History (USNM), Washington, and from other identified lots of larval specimens at the Florida State Collection of Arthropods (FSCA). Nonetheless, these specimens did not result in a configuration of the cephalo-pharyngeal skeleton exactly as published in illustrations of Phillips (1946) and Pruitt (1953). Various populations of each fruit fly species evidently exhibit variations in this and other characters that need to be taken into account. The main characteristics, however, of each species appear to be constant and allow relatively easy identification. The cephalo-pharyngeal skeleton is not usually examined in routine identifications because the larval specimen must be dissected before this character can be examined.
Preferred hosts include Psidium guajava (common guava), Eugenia uniflora (Surinam cherry, Pitanga, or French cherry) , Syzygium jambos (roseapple), Prunus persica (peach), and Terminalia catappa (tropical almond)
Field hosts in Florida before 1965: Psidium guajava (common guava)
Caged hosts in Florida before 1965: Psidium spp. (guava), Fortunella sp. (kumquat), Spondias purpurea (mombin), Eugenia uniflora (Surinam cherry), Citrus mitis (calamondin), Syzygium jambos (roseapple), Annona cherimoya (Jamaica apple), Prunus sp. (wild plum), Carissa grandiflora (natal plum), and Carica papaya (papaya)
Field hosts in Miami in 1965: Eugenia uniflora (Surinam cherry), Syzygium jambos (roseapple), Psidium guajava (common guava), Psidium cattleianum (Cattley guava), Citrus mitis (calamondin), Fortunella sp. (kumquat), Malpighia glabra (Barbados cherry), Prunus persica (peach), Momordica balsamina (balsamapple), and Mangifera indica (mango) (larvae only in mango)
Greater Antilles field hosts: Terminalia catappa (tropical almond), Psidium guajava (common guava), Psidium cattleianum (Cattley or strawberry guava), Psidium guineense (Brazilian guava), Syzygium jambos (roseapple), Syzygium (=Eugenia) malaccensis (ohia, Malayapple, or mountainapple), Citrus grandis (pummelo or shaddock), Citrus paradisi (grapefruit or pomelo), Citrus aurantium (sour orange, bitter orange, or Seville orange), Citrus sinensis (sweet orange or Kona orange), Fortunella margarita (oval or Nagami kumquat), Chrysobalanus icaco (Icaco cocoplum), Spondias mombin (yellow mombin, jobo, or hogplum), Chrysophyllum cainito (starapple or cainito), Achras zapota (sapodilla or chicle tree), Malpighia glabra (Barbados cherry), and Garcinia sp. (garcinia)
Insect Management Guide for fruit
adult Diachasmimorpha longicaudata (Ashmead)
Another biological control method involves the release of large numbers of laboratory-reared sterile flies. This program is known as the Sterile Insect Technique (SIT). Mating between the sterile lab-reared flies and fertile wild flies interrupts the native population because offspring are not produced. SIT also holds promise for effective reduction of the Caribbean fruit fly in Flortda. Millions of flies are produced each week at the Caribbean fruit fly mass rearing facility in Gainesville.
There are two basic features to this protocol. First, areas must be maintained under certain sanitary conditions, including the removal of preferred hosts from in and around the designated area. Second, trap surveys must be routinely conducted to make sure there are no Caribbean fruit flies in the area.
If certification is based on negative trapping in early season (August 1-December 20), the area must be at least 300 acres and located 1.5 miles (3 miles for shipments to Japan) from residential or other areas containing preferred hosts (common guava, Cattley guava, Surinam cherry, rose apple and loquat). If certification if based on negative trapping in standard season (December 21- end of harvest season), the area must be at least 300 acres and located three miles from residential or other areas containing preferred hosts. It is the responsibility of the grower/participant to negotiate with the property owner for host removal.
If certification is based on aerial bait sprays, a minimum of 40 acres will qualify as a designated area. There are several methods available for certification under bait-spray provisions: early season: 300 feet from areas containing preferred hosts with bait spray applications; standard season: 300 feet from areas containing preferred hosts with bait spray applications every seven to 10 days for 28 days; and standard season, one- half mile from areas containing preferred hosts with bait-spray applications.
There are other conditions concerning designated areas, buffer zones, control of preferred hosts, trap surveys, certified packinghouses, etc. For details contact the Division of Plant Industry in Fort Pierce, Florida, at (561) 468-4092.
Authors: H.V. Weems, Jr. (retired), J.B. Heppner, Florida Department of Agriculture and Consumer Services, Division of Plant Industry; T.R. Fasulo and J.L. Nation, University of Florida
Originally published as DPI Entomology Circulars 38 and 260. Updated for this publication.
Graphics: Division of Plant Industry
Photograph: Jeff Lotz, Division of Plant Industry
Project Coordinator: Thomas R. Fasulo, University of Florida
Publication Number: EENY-196
Publication Date: March 2001
Copyright 2001 University of Florida
Featured Creatures
Department of Entomology and Nematology
Division of Plant Industry
Electronic Data Information Source
distribution map
adult female
ovipositor comparison
buccal carinae
pharyngeal skeleton
caudal end of larva