Carrot fly
| Carrot fly | ||||||||||||
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Carrot Fly ( Chamaepsila rosae ) |
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| Scientific name | ||||||||||||
| Chamaepsila rosae | ||||||||||||
| ( Fabricius , 1794) |
The carrot fly or carrot fly ( Chamaepsila rosae ) is a fly from the family of nude flies (Psilidae). Synonyms for Chamaepsila rosae are Musca rosae ( Fabricius , 1794), Psila rosae (Fabricius, 1794) and Chamaepsila henngi (Tompson & Pont, 1994). It occurs primarily as a pest in umbellifers and is the most important pest in carrots that can lead to total failure.
description
features
The carrot fly is 4 to 5 millimeters long and shiny black. The head is yellow with red eyes, the legs and antennae are yellow and the wings are glassy and translucent. The carrot fly carries instead of the rear wing as well as other nude fly halteres . The eggs are 0.5-0.7 mm in size. They are long-oval with longitudinal grooves and are whitish in color. The larva with a length of 6-8 mm is shiny white-yellow and is segmented in the thorax and abdomen . The larva has no separate head and no legs. The pupa , which is 5 mm long, is brown-yellow in color.
Life cycle
The fly overwinters as a pupa (barrel) at a depth of 5 to 8 cm in the ground. After wintering, the winged animals hatch and look for windless spots in hedges and bushes. There they feed and are the first generation to fly into fields with host plants such as carrots from April to May. The larvae can also overwinter. The flies can hatch from a depth of 30 cm and more. The flight takes place within 2–3 days if the ground temperatures remain constant at 12 to 15 ° C. The flies use the late afternoon between 5 p.m. and dusk for this. You only stay in the field for a short time and then return again. The eggs are laid in small groups. Usually in the upper layer of soil very close to the root of the carrot. After a few days, yellowish, glassy maggots up to 6 to 8 millimeters long hatch. About 7 days pass between egg laying and hatching. The larva goes through three larval stages. The maggots of the first larval stage first eat the fine roots and the tip of the roots and soon afterwards bore into the central cylinder of the carrot. The second and often only the third larval instar eats inside the main root. In search of the root, the maggot can travel up to 60 cm. The corridors in the main root of the carrot are irregular. They pupate four to seven weeks after hatching and maturing to a 5 mm long light brown "barrel pupa". Humidity levels of 85–100% are favorable for good development. If the temperatures rise above 22 to 25 ° C, the development falls into diapause . The diapause can also be referred to as the "summer break". This protects the doll from dryness. Until a few years ago, only a second generation developed later with an arrival from August until the first frost. The spread of the second generation's entry is much stronger and causes the most damage. In the 1970s and 1980s, the third generation was considered rare or incomplete. At that time, the first generation flew from mid-May to early July, the second generation from mid-August to October (first frost). A full third generation has appeared almost regularly since the 1990s and flies in a little earlier each year. Their entry already takes place from September to October, while the flight of the second generation has been postponed to July to August. In Italy there is always a third generation. In general, the flight of the second and third generation can merge because the spread of the oviposition and thus the development increases with each generation. The hibernation takes place again as a pupa free in the ground or as a larva in the remains of infested plants.
Occurrence
The carrot fly occurs all over Europe. It was introduced to the USA and New Zealand. The animals mainly attack umbellifers. Carrots and celery are particularly affected. Parsley , root parsley , parsnip and angelica are also damaged . It also damages dill , fennel , caraway and wild carrot .
Enemies
Ground beetles such as Bembidion or rove beetles such as Aleochara sparsa are known to be beneficial insects. They eat eggs and larvae or parasitize the barrel pupae. Aphaerete spp., Adelura spp., Dacnusa spp. Also occur as parasites . and Loxotropa tritoma .
Plant damage
Symptoms
The first symptoms can be found around 15 days after the flight height. Then rust-brown root tips of the fine lateral roots can be found, which are caused by the first larval stage. If the seedlings are already attacked, they die. This infestation is also known as early infestation. When they eat ripening, the maggots excrete the droppings directly into the gutted passages behind them, which leads to a rust-red color. This is also called "iron fatigue". At the same time, due to the reduced water supply of the roots, the herb of the infected plant can wither, turn yellow to reddish and die off in the case of very severe infestation. If the roots are stored at milder temperatures after the harvest, the maggots will continue feeding. The second generation hatching in July is the most damaging. The lower third of the main root is particularly affected. In celery the tunnels cause purple discoloration in the otherwise white roots and tuber.
Countermeasures
Crop planning and management: If possible, the sowing date can be postponed, so that the flowering takes place before the sowing or after the harvest of the second generation. This means that the carrot fly cannot damage it by laying eggs and the maggots that hatch from them. In Italy, fields are sown in August for next spring harvest, which are rarely infested. If the culture is kept drier, the mortality of the eggs and younger larvae increases, which lowers the infestation pressure. If carrots are grown at the same location for several years in a row, the pressure of infestation increases from year to year. After 7 to 8 years at the latest, a very strong population has built up when, in addition to carrots, other umbellifers have been grown in neighboring fields for years. It is therefore recommended not to plant carrots in the same field more than twice in a row. Field hygiene is also an important measure. To make the survival of larvae and pupae impossible, infected plants should be completely cleared from the field.
Forecast models and field controls: The computer program SWAT V5.1 developed in Germany records the soil temperature and the air temperature in order to forecast the development. PSIROS is another forecast model that is used in Saxony-Anhalt. Instead of a forecast model, the strength of the flight can also be registered with yellow boards . The appropriate time for treatment can thus be determined. For this purpose, a separate trap is set up in each field, as the flight can take place at very different locations and with different times. Damage thresholds are used for assessment. The yellow board will be set up from mid-April. It should be attached at an angle of 45 ° to improve the catch result.
Variety Choice: There are some varieties that are not as susceptible to the carrot fly. Carrots of the 'Nantaise' type in particular often show a certain tolerance. A cultivar from Great Britain, the 'Flyaway' variety is known to be grown in the home garden with partial resistance. 'Sytan' also shows tolerance.
Choice of location: Windy locations are unfavorable for the carrot fly. Areas with a disproportionately large number of carrots should be avoided if possible because the pressure of infestation is usually higher there. Large fields are only infested at the edge. Cultivation on areas directly next to the plots infested in the previous year should be avoided. In the east of Austria, where dry and warm conditions prevail, the carrot fly is little known.
Mechanical: As a mechanical defense, culture protection nets have proven themselves for smaller areas that have to remain in place for a maximum of four weeks before harvest. The maggot takes that long until it begins to penetrate the beet body. The mesh size must not exceed 1 × 1 millimeter and the nets should be laid out at the latest at the start of the flight. Nets set up vertically as a fence to prevent entry have not yet been able to guarantee a safe defense against the carrot fly. This is due to the test areas being too small, which are not representative for professional cultivation, and the high susceptibility to wind, which causes damage to the fence. If nets are laid out immediately after sowing, the field dries out less quickly, which also encourages the carrots to germinate. In the case of early infestation, when the host plants are still seedlings, the oviposition can also be disturbed by frequent chopping.
Mixed culture: Sowing or planting carrots and onions next to each other also has a slight infestation-reducing effect .
Chemical treatment: Good effects can be achieved with granules containing the active ingredients chlorofevinphos , carbofuran or chlorpyrifos . The eggs and young larvae are sprayed with the active ingredients azactiractine , chlorfevinphos, cyhalothrin , dimethoate , tefluthrin and other active ingredients from the group of pyrethroids . Briefly raining in the active ingredient is advantageous. By using the same active ingredient over the years, an increased rate of degradation of the active ingredients of granules in the soil was found. Depending on the active ingredient, this now leads to reduced effectiveness. The control success is limited and lies between 50 and 70%.
supporting documents
Individual evidence
- ↑ a b c d e f g h T. Imhof: Pest in carrots - GVTS training from January 26, 2007 , lecture and presentation, education and advice center Arenenberg, 2007
- ↑ a b c d e f R. Fritzsche, R. Keilbach, H. Thiele: The plant, storage and material pests of Central Europe with references to countermeasures , Gustav Fischer Verlag, Jena, 1994, pp. 309 + 535
- ↑ a b c d e f g h A. Kahrer and M. Gross: Vegetable pests - detection, lifestyle, control , 1st edition, AV-Druck GmbH, Vienna, 2002, pp. 52–54, ISBN 3-7040-1569 -5
- ↑ a b c d e f g h i A. Pollini: Manuale di entomologia applicata , Edagricole, Milano, 2006, p. 105, ISBN 8-8506-3954-6
- ↑ a b c C.AB International Bureau of Crop Protections et al .: The Review of applied entomology , Volume 18, Commonwealth Agricultural Bureaux, 1831, p 536
- ↑ a b c d e f g h i G. Crüger et al .: Plant protection in vegetable cultivation , 4th edition, Ulmer Verlag, Stuttgart, 2002, pp. 97-98, ISBN 3-8001-3191-9
- ↑ a b c d A. Pollini: La difesa delle piante da orto - sintomi, diagnosi e terapia , 4th edition, Edagricole, Milano, 2008, pp. 86-87, ISBN 8-8506-5296-8
- ↑ a b c d e F. Villeneuve and J. Leteinturier: La Carotte guide pratiue - tome 1 , Ctifl, 1992, pp. 154–158, ISBN 2-8791-1021-1
- ↑ a b c d e f g h C. Sauer and S. Fischer: Die Möhrenfliege (Psila rosae) , leaflet, Agroscope Changins-Wädenswil ACW research station, 2007
- ↑ D. Gebelein, M. Hommes u. M. Otto: SWAT: A simulation model for small cabbage fly, carrot fly and onion fly , BBA (Federal Biological Institute for Agriculture and Forestry Institute for Plant Protection in Horticulture), 2001
- ↑ U. Sperling and Lopez: Notes on Plant Protection - Vegetables , No. 15, August 18, 2009, State Institute for Agriculture, Forests and Horticulture, Saxony-Anhalt, 2009
- ↑ E. Wyss and C. Daniel: Effect of U-shaped insect fences against the carrot fly Psila rosae in organic carrot cultivation , Research Institute for Organic Cultivation, No. 04 / 14e, Mittelprüfung, 2004