About the Fruit Fly: Species & Biology
Understanding the biology and environmental dynamics of the fruit fly is an important step in order to know how to better control it and manage the application of our bait in the field. Although there are many different kinds of fruit flies, we chose to focus and present four major fruit fly pecies of significant global economic importance, which we also have broader experience and knowledge in dealing with.
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Eggs of the Chinese Fruit Fly (CFF) are 1.2-1.5 mm long. They are laid under the skin of mature green and ripening fruit. Upon hatching, the larvae are 15-19 mm long, whitish maggots. They begin to feed within the fruit, causing it to ripen prematurely, rot and drop to the ground, damaging the fruit and rendering it inedible.
Eggs are 0.8 mm long and 0.2 mm wide, white to yellow-white in colour, with the micropyle protruding slightly at the anterior end. The chorion is reticulate. The third-instar, which has a typical maggot appearance, is about 10 mm in length and creamy white.
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The eggs of the melon fly are slender, white in colour, and measure 1/12 inch in length. Eggs are inserted into fruit in bunches of 1 to 37, and hatch within 2 to 4 days. There are 3 larval stages for this insect. The larvae, or maggots, are typical fruit fly shape: cylindrical-maggot, elongated, narrowed and somewhat curved downward at the end, with mouth hooks at the head. These maggots reach approximately 1/2 inch in length upon maturity.
The eggs of the melon fly are slender, white in colour, and measure 1/12 inch in length. Eggs are inserted into fruit in bunches of 1 to 37, and hatch within 2 to 4 days. There are 3 larval stages for this insect. The larvae, or maggots, are typical fruit fly shape: cylindrical-maggot, elongated, narrowed and somewhat curved downward at the end, with mouth hooks at the head. These maggots reach approximately 1/2 inch in length upon maturity.
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The economic importance of the Medfly cannot be evaluated entirely from the standpoint of the actual damage to the various crops affected. It must also be considered from the standpoint of quarantine. Quarantine laws aimed at preventing the entry and establishment of flies in areas where it does not occur have been established and are vigorously enforced.
Larval feeding damage 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 tap roots, and stems and buds of host plants.
The economic importance of the Medfly cannot be evaluated entirely from the standpoint of the actual damage to the various crops affected. It must also be considered from the standpoint of quarantine. Quarantine laws aimed at preventing the entry and establishment of flies in areas where it does not occur have been established and are vigorously enforced.
Chinese Citrus Fly - Bactrocera minax (Enderlien):
The Chinese Citrus Fly is a major pest of economic importance and is devestating to citrus fruits, attacking citrus crops including orange, grapefruit, tangerine, lemon and kumquats. Eggs are laid just beneath the skin of the fruits. From June onward oviposition spots (punctures with a little resin) can be observed on the upper half of fruit. Later, fruits show round, brownish, hard spots of 1-2 mm diameter, just under the skin. The larvae (maggots) feed on the pulp and develop inside the maturing fruits. A small group of larvae starts feeding in one segment and can later spread to a few adjoining segments. As a result of their feeding activity, the fruits turn prematurely yellow around the feeding site and eventually drop. When the maggots are mature they leave the fruit by making an exit hole, and enter into the soil to pupate.
Oriental Fruit Fly - Bactrocera dorsalis (Hendel):
The Oriental Fruit Fly is a very serious pest of a wide variety of fruits and vegetables throughout its range, and damage levels can as high as 100% in unprotected fruit.
Bactrocera dorsalis has been recorded from more than 150 kinds of fruit and vegetables. As a result of its widespread distribution, pest status, invasive ability, and potential impact on market access, B. dorsalis is considered to be a major threat to many countries. The adult, which is noticeably larger than a house fly, has a body length of about 8.0 mm; the wing is about 7.3 mm in length and is mostly hyaline. The colour of the fly is very variable, but there are prominent yellow and dark-brown to black markings on the thorax.
Melon Fruit Fly - Bactrocera cucurbitae (Coquillett):
The Melon Fruit Fly is considered the most destructive pest of melons and related crops, and it has greatly curtailed the production of melons, cucumbers and tomatoes in Hawaii. The melon fly can attack flowers as well as fruit, and additionally will attack stem and root tissue.
Females prefer to oviposit in new plant growth, such as young seedlings, growing tips, and developing ovaries of all cucurbits except young cucumbers. Ripe fruits are preferred; green fruits are sometimes used. Because of their high egg laying capacity and mobility, each female is capable of destroying large numbers of fruit in her lifespan.
The damage to crops caused by melon flies result from 1) oviposition in fruit and soft tissues of vegetative parts of hosts 2) feeding by the larvae, and 3) decomposition of plant tissue by invading secondary microorganisms.
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Mediteranean Fruit Fly (Medfly) - Ceratitis capitata (Wiedemann):
The Medfly is one of the world's most destructive fruit pests. Because of its wide distribution over the world, its ability to tolerate cooler climates better than most other species of fruit flies, and its wide range of hosts, it is ranked first among economically important fruit fly species. This pest attacks more than 260 different fruits, flowers, vegetables and nuts. Thin-skinned, ripe, succulent fruits are preferred. Host preferences vary in different regions. Plant hosts include avocado, banana, bittermelon, carambola (star fruit), coffee, guava, mango, papaya, peppers and persimmon. It may also transmit fruit-rotting fungi.
The damage to crops caused by Ceratitis capitata result 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.