Drosophila suzukii

Cherry fruit fly (Drosophila suzukii ), male

The cherry fruit fly (Drosophila suzukii ) is a species of the family of fruit flies ( Drosophilidae ) and is closely related to Drosophila melanogaster. It is native to Southeast Asia and was first described in 1931 by Shonen Matsumura. In Japan, it has been reported in 1916 by T. Kanzawa. In the 1930s, Drosophila suzukii was detected in Japan, Korea and China, 1980 in Hawaii, in August 2008 in California, Oregon, Washington, British Columbia and Florida, 2010 in South Carolina, North Carolina, Louisiana, Utah, Michigan and Wisconsin. During the same period has also been observed in several European countries; 2009 in Spain, France, Italy and Slovenia, 2011 in Switzerland, Austria and Germany.

The species is in agriculture as a pest because it damages the ripening fruit of cherries, blueberries, raspberries, blackberries, peaches, plums, nectarines, apricots, grapes and others. Due to their enormous rapid multiplication, great damage can be caused. The short generation cycle of the cherry fruit fly makes it a difficult combated with today's insecticides insect

Features

Like other members of the family fruit fly, Drosophila is suzukii small, about 2 to 3.5 mm in length and 5 to 6.5 mm in span and looks very similar to their relatives. Your body is yellow to brown in color with darker stripes on the belly and she has red eyes. The male has a distinct dark spot near the tip of each wing. The females do not have spotted wings. The female has a long, sharp, serrated egg-laying apparatus. With this, they scratch on the fruit and put into the eggs.

The larvae are white and cylindrical and are 3.5 mm long. In contrast to the related fruit fly, which is attracted primarily by rotting or fermenting fruit, live larvae of Drosophila suzukii of fresh, ripe fruit. Eggs are laid under the soft skin and the larvae hatch and develop into the fruit.

• Cherry fruit fly '' Drosophila '' suzukii

Drosophila suzukii - females

Serrated egg-laying apparatus of the female.

Anatomical differences of Drosophila simulans Drosophila suzukii to

Way of life

The cherry fruit fly preferred temperate climate. Temperatures of 30 ° C and not limit the activity above 32 ° C and a multiplication. For large parts of Europe are eligible for a settlement. One limitation of development, there should be only in very hot areas of southern Europe and in parts of northern Europe. The life span of Drosophila suzukii varies greatly among the generations; a few weeks up to 10 months. Every year can be observed up to 15 generations in Japan. In Central Europe it is not expected with such a high number of generations.

The mated females looking for ripe fruit for oviposition. You have a busy with thorn-like teeth Raspelapparat at the end of the abdomen, with the damage the fruit skin to lay their eggs and then into the fruit. Can lay 7-16 eggs a female per day. The fruit are 1-3 eggs, a total of 300 - 400 eggs laid, which suzukii Drosophila has a huge potential for development. From the high number created enormous proliferation rates and a quick settlement, which make a strong damage of the fruit in a short time possible. After two days, the larvae begin to feed inside the fruit. The completion of a generation is already possible within 8 to 14 days. Pupation may take place in or outside of the fruit.

The cherry fruit fly overwinters ( the majority of females ) than adult insect in a frost-free shelter. In the spring, the animals are active at about 10 ° C.

Host plants

The fly infests fruits of wild and cultivated species of fruit with a thin skin and therefore represents a significant risk for soft fruit species such as stone fruit and soft fruit dar. Mainly the sweet cherry is affected, but also peach, nectarine, apricot, plum, blueberry, gooseberry, blackberry, raspberry, strawberry and grape. Other possible host plants are elderberry, mulberry, dogwood, persimmon, fig, melon, apple and nashi pear. Apples and Nashi pears are only affected by the cherry fruit fly, when the cup is already damaged. Due to the high growth rate and good adaptability to the host plant spectrum can still expand.

Distribution and economic importance

The Asian region is the original home of Art is only in recent years (from 2008) to occur in North America and Canada and in Europe in Spain, France, Italy and in 2011 was found in Switzerland, Austria and Germany. The large-scale distribution presumably occurs through the import of infested fruit. A local spread of a few kilometers is possible through the screen itself.

From the European and Mediterranean Plant Protection Organization ( EPPO), Drosophila has been classified suzukii as a harmful organism from which a large plant-damaging threat to the European orchards and vineyards. Drosophila suzukii place in Europe for the establishment of far-reaching ideal habitats, although this depends in northern areas, the presence of wintering grounds in the vicinity of human dwellings.

Damage

The infestation of the fruits is manifested by small damages and indented soft spots on the surface. The damage is caused by one or more maggots ( larvae) that feed the flesh. Infested fruit very quickly begin to decay the feeding site around. Due to the very rapid development, for example, can pass on cherries from infestation after oviposition until the collapse of the fruits of only two to three days. In addition, secondary infections by fungi or bacteria to a further deterioration ( rot) can contribute after infestation.

In Southern France (with strawberries to 80 %), Switzerland and Italy considerable damage was caused suzukii by Drosophila already in different cultures ( in Trentino in cherries (up to 90 %) and table grapes and in South Tyrol to the varieties Verna and Lagrein ).

Combat

Drosophila suzukii is able to infect healthy fruit just before harvest. This peculiarity makes it a difficult to combat insect. Immediately before the crop can not be used more insecticide, so that only direct hygiene remain such as the removal and destruction of all the fruit from the plant by means of deep burial (30 cm) in the soil so as to reduce said population. To destroy composting is not suitable. The timely complete close-knit Back of the Net is another measure, if that is possible in the culture. To reduce the fly population can catch traps filled with a safety catch liquid ( apple cider vinegar as attractant and in addition a yellow panel on the inside of the container ) are used. They are also used for attack detection. Chemical pesticides are not currently available.