The Queensland fruit fly (Bactrocera tryoni) is a species of tephritid fruit fly native to Australia. There are over 250 species of fruit fly in the family Tephritidae which occur in Australia but only about ten are pests. Adult flies are about seven millimeters long and are reddish-brown in color, with distinct yellow marking. QFF (Queensland Fruit Fly) is different from the small dark brown drosophila flies that hang around the ripe and decaying fruit. Drosophila flies are not agricultural pests but can be a nuisance where fruit and vegetables are stored. It is a widely acknowledged and feared pest in the agriculture and horticulture industry.
The fruit fly is native to eastern Queensland and north-eastern New South Wales. The ready availability of suitable hosts and habitat in urban and horticultural production areas in Queensland, Northern Territory, New South Wales and Victoria in Australia has enabled the fly to expand its natural range. It attacks a wide range of host plants, lowering production and making fruit inedible. This can have severe consequences for local and international trade.
The fruit fly causes damage in the larval stage as well as the adult stage. The female fly has a retractable, needle-sharp egg-laying organ (ovipositor) at the tip of her abdomen. Using the ovipositor she digs a flask-shaped chamber about 3 mm deep in the outer layer of the fruit where up to 12 eggs are laid at a time.
The fly lays eggs in maturing and ripe fruit on trees and sometimes in fallen fruit. The maggots (larvae) hatch and the fruit is destroyed by the feeding maggots and by associated fruit decay. The fly can attack a wide range of fruit, fruiting vegetables, and native fruiting plants. Evidence of the fly activity is sometimes seen as puncture marks in the skin of the fruit. The stings are where the female fruit fly has laid her eggs. Sting marks may appear as brown spots on persimmons, apples, and pears or small holes that may become small raised lumps in citrus and avocado. They are most active in warm humid conditions and after rain. The flies might be seen walking on the undersides of leaves or on maturing fruit. They readily take flight if disturbed.
There have been innumerable fruit fly outbreaks in the recent history. An outbreak however small in intensity spells huge losses for the horticulture industry as thousands of fruits growers are affected. They attack a host of fruit trees like apple, apricot, blackberry, cashew, etc. Bananas are said to be attacked only when overripe, and other fruits, such as grapes, are attacked only in peak years.
In Napa County a hub of olive growers, the meddling fruit fly has caused severe damage as reported in a leading newspaper. An ardent horticulturist Chris Craiker, the owner of Corlyone Olive Oyl in Browns Valley, said the infestation had hit his orchards hard in 2013, as he estimated a loss of 40 to 50 percent of his crop to the fruit fly infestation.
He said he usually grows about 1,000 to 1,500 pounds of olives, but had to discard the entire crop rather than sort the healthy fruit from the infected fruit.
Let us look at the following recent news article regarding the return of these devastating insects.
Fruit fly makes growers ‘nervous as hell’
By Mike Barrington – NORTHERN ADVOCATE
9:25 AM Friday, Jan 24, 2014
A single male Fruit Fly found in the Hatea Drive area of Whangarei. Photo / Ron Burgin
The discovery of a male Queensland fruit fly in Whangarei has sparked a major biosecurity alert.
Up to 50 Ministry for Primary Industries (MPI) staff was in the city and another 50 in Wellington were preparing yesterday to deal with the pest threatening New Zealand’s $4 billion horticulture industry.
The fly was found in the front yard of a home near the Whangarei Town Basin on Tuesday. It was collected from an insect trap MPI had placed there as part of its national fruit flies surveillance program involving 7400 traps around the country.
MPI staff yesterday put up signs banning people from taking whole fresh fruit and vegetables out of a 200m zone circling the place where the fly was found. Bins have been provided for residents to dump fruit and vegetables rather than disposing of them with other household rubbish.
Today MPI officials will begin putting about 200 pheromone traps into fruit trees in that zone and within a 1.5km radius of the discovery site extending up to the Regent, along Riverside Dr and into Parihaka.
An MPI mobile laboratory arrived in Whangarei yesterday for use analyzing fallen fruit and vegetables to be gathered from the two zones.
Queensland fruit fly is one of the most damaging fruit fly pests because it infests more than 100 species of fruit. Some countries will not import fruit and vegetables from sources where the fly is known to exist.
MPI deputy director general compliance and response Andrew Coleman said yesterday that New Zealand’s trading partners had been notified of the Whangarei find and measures were underway to find out if there is an infestation.
If no further evidence of fruit flies was found within a fortnight then overseas markets would accept the insect was alone, he said.
When the Northern Advocate asked whether the location of the fruit fly found in Whangarei indicated the insect had arrived in one of the many overseas yachts berthed at the Town Basin, Mr. Coleman said it may have done.
“But we may never know how it got here,” he said, explaining that the fruit fly life cycle involved a pupae development period on the ground.
The pheromone traps containing female fruit fly sex scent are expected to detect any males. If an infestation was found, ground spraying would be carried out to eradicate the invaders.
Minister of Primary Industries Nathan Guy and MPI chief executive officer Martyn Dunn were in Whangarei yesterday to see the fruit fly measures being imposed and for talks with Whangarei MP Phil Heatley, Mayor Sheryl Mai and top Northland Regional Council officials.
Mr. Heatley said later the minister had assured Whangarei people there would be no aerial spraying such as the Ministry of Agriculture and Forestry carried out with the insecticide Foray 48B over parts of Auckland from January 2002 to May 2004 to eradicate another exotic pest, the painted apple moth.
Kerikeri Fruit growers’ Association chairman Rick Curtis said growers in his area were “nervous as hell”.
“They are watching and hoping the male fly found was alone,” he said.
Fruit fly facts:
- The Queensland fruit fly is a native of Australia where it is considered to be the country’s most serious insect pest of fruit and vegetable crops.
- Air and sea passengers are prohibited from bringing fresh fruit and vegetables into New Zealand.
- Fruit flies eat ripened fruit and vegetables. Eggs which female fruit flies lay on fruit hatch into larvae which find dark places where they grow six legs and wings before emerging as adults.
- Larvae of fruit flies develop in moist areas where organic material and standing water are present. The entire life cycle lasts 25 days or more depending on the environmental conditions and the availability of food.
Thus these flies are notorious pests which affect the horticulture industry reigning in losses to the tune of billions of dollars. Let us see what has been done conventionally to deal with these pests. The fly has been the subject of extensive control regimes including a Fruit Fly Exclusion Zone where it is forbidden to take fruit, and post-harvest dipping of fruit in dimethoate and fenthion. Now dimethoate and fenthion are interesting chemicals. They are basically organophosphates. Dimethoate is a widely used organophosphate insecticide used to kill insects on contact. Fenthion is an organothiophosphate insecticide, avicide, and acaricide. Since both the above chemicals are extremely toxic and hazardous to the human life due to their mode of action targeting the central nervous system, their use was under review by the Australian Pesticides and Veterinary Medicines Authority (APVMA), with dimethoate suspended from use.
In effect, we still have outbreaks of fruit fly infestations with almost no means of controlling them. Termirepel™ a product by C Tech Corporation is a promising alternative solution. Termirepel™ is a non-toxic, non-hazardous insect and pest repellant. Primarily designed to be used as a termite aversive, it is highly effective against a host of other insects and pests. It works by the mechanism of repellence by which it ensures that the target insect or pest stays away from the application without resorting to killing it. Termirepel™ is available in liquid form which can be used in the form of a spray. Also, the masterbatch form can be incorporated in agricultural films.