Ceratitis capitata (insect)

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Taxonomic name: Ceratitis capitata (Wiedemann, 1824) Synonyms: Ceratitis citriperda MacLeay , Ceratitis hispanica De Brême, Paradalaspis asparagi Bezzi, Tephritis capitata Wiedemann , Trypeta capitata Wiedemann, 1824 Common names: medfly (English), Mediterranean fruit fly (English) Organism type: insect Ceratitis capitata is considered a major tephritid fruit fly pest of economic importance attacking more than 300 different hosts, primarily temperate and subtropical fruits. The medfly as it is commonly called has invaded many countries and caused major economic losses for fruit farmers. C. capitata has the ability to tolerate cooler climates better than most other species of fruit flies. It lays its eggs under the skin of fruit, usually around already broken skin. Due to this reproduction habit, C. capitata thrives in agricultural areas where fruit is left out and becomes damaged. It spreads to new locations via exports and the local sale of fruit that contains eggs. Description The adult medfly is 4 to 5mm [1/6 to 1/5 inch] long, (about two-thirds the size of a housefly). The general colour of the body is yellowish with a tinge of brown, especially the abdomen, legs, and some of the markings on the wings. The oval shaped abdomen is clothed on the upper surface with fine, scattered black bristles, and has two narrow, transverse, light coloured bands on the basal half. The female can be distinguished by its long ovipositor at the apex of the abdomen.The larval phase consists of three instars. The size of the larvae depend on their diet. The larvae are typically elongate, cream coloured, cylindrical maggot-shaped. Their anterior end narrows and is somewhat recurved ventrally, with anterior mouth hooks, and a flattened caudal end. The length of the first larval stage is 1mm [1/25 inch] or less, and the body is mostly transparent; the second larval stage is partially transparent with the fruit in the gut visible; the fully grown third larval stage is 6 to 8mm [1/4 to 1/3 inch] long, with a body fully opaque white or the colour of ingested food. The pupae are cylindrical, approximately 3mm [1/8 inch] long, and dark reddish brown in colour (Mau and Kessing, 1992). Please see PaDIL (Pests and Diseases Image Library) Species Content Page Mediterranean fruit fly for high quality diagnostic and overview images. Occurs in: agricultural areas Habitat description Medfly has the ability to tolerate cooler climates better than most other species of fruit flies (Mau and Kessing 1992). Thomas et al. 2001, state that some adults may survive up to six months or more under favourable conditions of food (fruit, honeydew, or plant sap), water, and cool temperatures. General impacts C. capitata is a serious pest to many crops. Damage to crops caused by C. capitata results from 1) oviposition in fruit and soft tissues of vegetative parts of certain plants, 2) feeding by the larvae, and 3) decomposition of plant tissue by invading secondary microorganisms. Larval feeding in fruits is the most damaging. Mature, attacked fruits may develop a water soaked appearance. Young fruits become distorted and usually drop. The larval tunnels provide entry points for bacteria and fungi that cause the fruit to rot. These maggots also attack young seedlings, succulent taproots, and stems and buds of host plants. Trapping for detection of populations; excluding populations by using foliage baits and chemical sprays and release of male sterile medflys to reduce populations require a great deal of resources and can have significant economic implications. Medflies are serious quarantine pests that also affect global trade. The presence of medflies often requires host crops to undergo quarantine treatments or other disinfestation procedure of certification of flyfree areas. The costs of such activities and phytosanitary regulatory compliance can be significant. Geographical range Native range: The Mediterranean region and north Africa (Mau and Kessing, 1992) Known introduced range: North America, South America, and Australia (Thomas et al. 2000) The climate matching model CLIMEX was used to infer the climatic requirements of the medfly using observed geographical range in the Mediterranean region. The study indicated that the distribution of the medfly was restricted by climatic factors - dryness in the south of Spain and Portugal and northern Africa; and by the cold to the north in Europe. The model was then used to map the potential areas of distribution in Argentina and Australia. The results demonstrated agreement with observed distribution in Argentina and historical distribution in Australia. There was however disagreement with current distribution in eastern Australia, this was attributed to displacement of the medfly by another frutfly species Bactrocera (Dacus) tryoni (Froggatt) ( Vera et al. 2002 ). Introduction pathways to new locations Agriculture: Insects lay their eggs under the skin of fruit (Mau and Kessing, 1992). Ignorant possession: Insects lay their eggs under the skin of fruit (Mau and Kessing, 1992). Local dispersal methods Agriculture (local): According to Mau and Kessing (1992), the fly lays it's eggs under the skin of fruit and usually in a spot where the skin is already broken. So more damaged fruit is associated with more flies. C. capitata also spreads by local sale of infested fruit. On animals (local): Ceratitis capitata can fly short distances, but winds may carry it a mile or more away (Mau and Kessing, 1992). Management information Preventative: Early detection is very important to prevent establishement of populations. Detection programmes using lures and attractants and constant monitoring are required to ensure early detection. Countries which export fruit have to make sure that a comprehensive detection programme is maintained and that strict quarantine procedures are in place to prevent the spread of the pest to flyfree zones. Control options should be started early in spring when temperatures start rising and overwintering adults become active and new adults emerge from the ground (medfly can overwinter as adults, as eggs and larvae in fruit or in their pupal form in the ground). Chemical: An important measure to be taken to ensure success of any chemical control is the disposal of unwanted and medfly infested fruit. Several methods suggested for disposal are: soaking fruit in water topped by a layer of kerosene( to cut off oxygen supply); freezing fruit for a few days; cooking or pureeing fruit. Burial is not recommended at depths of less than 18 inches as medfly can survive a burial . The two main control methods recommended are foliage baiting and cover spraying. The female medfly requires a source of protein for the maturation of her eggs which she sources from fruit juices, bacteria etc from nature. The foliage bait combines a source of protein with an insecticide and is attractive for both the male as well as the female medfly. The bait is usually applied in the morning hours and applies as a spot application aimed at the middle of the trees. Cover spraying controls all life stages through contact and penetrative action. Spraying is carried out when fruits are half or two thirds in size. Depending on the level of infestation the two methods can be used together. Physical: Trapping is not recommended as a control option but is useful for detection. The three types of traps used are those used to trap the male medfly which consists of a parapheromone plus insecticide, a trap for the female medfly using a lure and a wet trap used for both the male and the female medfly which consists of a food source ( a sugar or protein) plus an insecticide. It is good to remember that other insects can also be caught in these traps. Biological: A technique called the sterile insect technique (SIT) is used to contain and exclude populations of medfly. The goal of SIT is to release sterile males to mate with any introduced wild females, resulting in the production of infertile eggs. In California, the SIT program is changing from the release of both male and female sterile flies (bisexual strains) to the use of sterile flies from “male-only” strains (Jang et al. 2003). Nutrition The medfly is known to attack over 300 different hosts, primarily temperate and subtropical fruits (Liquido et al. 1991 ). Reproduction Newly emerged adults are not sexually mature. Males often show sexual activity four days after emergence, and copulation which can occur at anytime has been observed five days after emergence. Most females are ready to mate from 6 to 8 days after emerging from the pupa. Eggs are very slender, curved, 1mm [1/25 inch] long, smooth and shiny white. They are deposited under the skin of fruit that is just beginning to ripen, often in an area where some break in the skin has already occurred. Several females may use the same deposition hole with 75 or more eggs clustered in one spot. Each female will deposit 2 to 10 eggs. Eggs hatch in 1.5 to 3 days in warm weather. Females lay 1 to 10 eggs in a cavity 1mm [1/25 inch] deep. She may lay as many as 22 eggs per day and as many as 800 eggs during her lifetime (usually about 300) (Mau and Kessing, 1992). Lifecycle stages Larvae begin feeding almost immediately after hatching. Tunnels are formed, but the larvae often feed together in the same vicinity until they are nearly fully grown. Larvae pass through three larval stages, or instars before they emerge from the fruit. They may emerge in large numbers just after daybreak and pupate in the soil or whatever is available. Minimum duration of the pupal stage is 6-13 days when the mean temperature ranged from 24-26 C [76-79 F]. Pupae usually develop in soil an inch or two below the surface. Adults emerge from the pupal cases in large numbers early in the day during warm weather and more sporadically in cooler weather. Females usually die soon after they stop ovipositing. The length of time required for C. capitata to develop from egg to adult is about 21-30 days under tropical conditions. According to Thomas et al. (2001), “adults die within four days if they cannot obtain food. Usually about 50% of the flies die during the first two months after emergence. Some adults may survive up to six months or more under favourable conditions of food (fruit, honeydew, or plant sap), water, and cool temperatures. When host fruit is continuously available and weather conditions favourable for many months, successive generations will be large and continuous. Lack of fruit for three to four months reduces the population to a minimum.” Reviewed by: Eric Jang Research Leader U.S. Pacific Basin Agric. Res. Center Principal sources: Ceratitis capitata (Wiedemann) (Mau and Kessing 1992) Compiled by: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG) To contribute information, please contact Shyama Pagad. Last Modified: Tuesday, 23 June 2009