pests
Leafminer
Leafminer
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Miners inside the leaf
Leafminer damage can cause severe damage to several crops.
Biology
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Leafminers (Liriomyza spp.) are dipterous insects, just like the common housefly. In Europe three species of Liriomyza occur: the tomato leafminer (Lyriomyza bryoniae), the serpentine leafminer (L. trifolii) and the pea leafminer (L. huidobrensis). In these three species, adult females measure 2-3 mm. They are black with yellow, having a conspicuous yellow spot on their back. Only specialists are able to distinguish the three leafminer speces. Males are a little bit smaller (1.5 mm).
With her barbed ovipositor, a female leafminer pierces holes in the upper surface of the leaf to extract plant sap (feeding spots). Males do not have an ovipositor, so they make use of the feeding spots made by females for their food. In such e puncture a female can also deposit an egg. Feeding spots are round and egg spots are oval.
The egg hatches into a tiny fly larva (maggot), that immediately starts eating its way through the leaf. There are three larval stages. In the first stage, the larva is transparent, but later, depending on the species, it turns dirty-white to yellow-ochreous (L. trifolii). Just before pupation, the larva cuts a sickle shaped hole in the leaf cuticle and wiggles its way out. It usually lets itself fall off the leaf to pupate in the soil or between the folds of the plastic in case of substrate culture.
Sometimes, however, the pupae stay hanging on the leaf. Depending on the species, the pupa is yellow to (reddish) brown. The development time from egg to adult depends largely on temperature. For the serpentine leafminer, it takes 12-14 days at 30°C (86°F) and 54-61 days at 15°C (59°F). The first generations at the beginning of the cropping season often come in waves.
An adult female lives for 1-2 weeks. The number of eggs she deposits depends on the species, the host plant and on temperature. It can vary from several tens to some hundreds.
Damage
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Leafminer damage occurs on many vegetables and ornamentals. In ornamental crops, the feeding spots already reduce the aesthetic value of the plant. Leafminers do not only reduce photosynthesis of the leaves, but can also cause withering or early shedding of the leaves. Finally, feeding spots can also be an entrance for all kinds of diseases.
Crop: Cherry tomato
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- When the first leafminer infestations are detected, introduce minimum 0,30 Dacnusa / Diglyphus (90%-10%)/m² per week, until an equilibrium is reached.
- When the infestation increases, introduce 100% Diglyphus as from 1st of March at a minimum dose of 0,15 Diglyphus/m²/week during minimum 3 weeks or until a sufficient number of leafminers are parasitized.
- Remark:
- Samples of the leaf should be tested regularly to determine the percentage of parasitized leafminers. To have a sufficient control, the percentage must be 80-90%.
- Dacnusa as well as Diglyphus are active against Liriomyza bryoniae (Tomato leafminer), Liriomyza trifolii (American serpentine leafminer) and Liriomyza huidobrensis (Pea or South American leafminer).
- When the first leafminer infestations are detected, introduce minimum 0,30 Dacnusa / Diglyphus (90%-10%)/m² per week, until an equilibrium is reached.
- When the infestation increases, introduce 100% Diglyphus as from 1st of March at a minimum dose of 0,15 Diglyphus/m²/week during minimum 3 weeks or until a sufficient number of leafminers are parasitized.
- Remark:
- Samples of the leaf should be tested regularly to determine the percentage of parasitized leafminers. To have a sufficient control, the percentage must be 80-90%.
- Dacnusa as well as Diglyphus are active against Liriomyza bryoniae (Tomato leafminer), Liriomyza trifolii (American serpentine leafminer) and Liriomyza huidobrensis (Pea or South American leafminer).
Crop: Chrysant
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- Introduce 0,5-1 Diglyphus isaea/m²
- Remark: Samples of the leaf should be tested regularly to determine the percentage of parasitized leafminers. To have a sufficient control, the percentage must be 80-90%.
- Introduce preventive on a weekly base 2-4 tubes Dacnusa-Mix-System/ha.
- Remark: Samples of the leaf should be tested regularly to determine the percentage of parasitized leafminers. To have a sufficient control, the percentage must be 80-90%.
Crop: Eggplant
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- When the first leafminer are detected, introduce minimum 0,25 Diglyphys (90%-10%)/m² per week, until an equilibrium is reached.
- When the leafminer infestation increases, introduce 100% Diglyphus at a dose of minimum 0,1 Diglyphus/m²/week during minimum 3 weeks or until a sufficient number of leafminers are parasitized.
- Remarks: Samples of the leaf should be tested regularly to determine the percentage of parasitized leafminers. To have a satisfying control, the percentage must be 80-90%.
- When the first leafminer are detected, introduce minimum 0,25 Dacnusa/Diglyphus (90%-10%)/m² per week, until an equilibrium is reached.
- When the leafminer infestation increases, introduce 100% Diglyphus at a dose of minimum 0,1 Diglyphus/m²/week during minimum 3 weeks or until a sufficient number of leafminers are parasitized.
- Remarks: Samples of the leaf should be tested regularly to determine the percentage of parasitized leafminers. To have a satisfying control, the percentage must be 80-90%.
- When the first leafminer are detected, introduce minimum 0,25 Dacnusa/Diglyphus (90%-10%)/m² per week, until an equilibrium is reached.
- When the leafminer infestation increases, introduce 100% Diglyphus at a dose of minimum 0,1 Diglyphus/m²/week during minimum 3 weeks or until a sufficient number of leafminers are parasitized.
- Remarks: Samples of the leaf should be tested regularly to determine the percentage of parasitized leafminers. To have a satisfying control, the percentage must be 80-90%.
Crop: Gerbera
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- Introduce when the first leafminer infestation is detected.
- Spring & autumn: minimum 0,25 Dacnusa/Diglyphus (90%-10%) m² per week, until an equilibrium is reached.
- Summer (or at higher infestation): introduce 100% Diglyphus in a dose of minimum 0,1 Diglyphus/m²/week during minimum 3 weeks or until a sufficient number of leafminers are parasitized.
- Remark: Samples of the leaf should be tested regularly to determine the percentage of parasitized leafminers. To have an efficient control, the percentage must be 80-90%.
- Introduce when the first leafminer infestation is detected.
- Spring & autumn: minimum 0,25 Dacnusa/Diglyphus (90%-10%) m² per week, until an equilibrium is reached.
- Summer (or at higher infestation): introduce 100% Diglyphus in a dose of minimum 0,1 Diglyphus/m²/week during minimum 3 weeks or until a sufficient number of leafminers are parasitized.
- Remark: Samples of the leaf should be tested regularly to determine the percentage of parasitized leafminers. To have an efficient control, the percentage must be 80-90%.
Crop: Haricot bean
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- When the first leafminers are detected, introduce minimum 0,25 Dacnusa/Diglyphus (90%-10%) m² per week, until an equilibrium is reached.
- When the leafminer infestation increases, introduce 100% Dilgyphus at a dose ad minimum 0,1 Diglyphus/m²/week during minimum 3 weeks or until a sufficient number of leafminers are parasitized.
- Remark: Samples of the leaf should be tested regularly to determine the percentage of parasitized leafminers. To have a satisfying control, the percentage must be 80-90%.
- When the first leafminers are detected, introduce minimum 0,25 Dacnusa/Diglyphus (90%-10%) m² per week, until an equilibrium is reached.
- When the leafminer infestation increases, introduce 100% Dilgyphus at a dose ad minimum 0,1 Diglyphus/m²/week during minimum 3 weeks or until a sufficient number of leafminers are parasitized.
- Remark: Samples of the leaf should be tested regularly to determine the percentage of parasitized leafminers. To have a satisfying control, the percentage must be 80-90%.
Crop: Melon
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- When the first leafminers are detected, introduce minimum 0,25 Dacnusa/Diglyphus (90%-10%) m² per week, until an equilibrium is reached.
- When the leafminer infestation increases, introduce 100% Dilgyphus at a dose ad minimum 0,1 Diglyphus/m²/week during minimum 3 weeks or until a sufficient number of leafminers are parasitized.
- Remark: Samples of the leaf should be tested regularly to determine the percentage of parasitized leafminers. To have a satisfying control, the percentage must be 80-90%.
- Introduce when the first leafminer infestation is detected:
- Spring & Fall: minimum 0,5 Dacnusa/Diglyphus (90%-10%) m² per week, until an equilibrium is reached.
- Summer (or at a higher infestation): introduce 100% Diglyphus in a dose of minimum 0,1. Diglyphus/m²/week during minimum 3 weeks or until a sufficient number of leafminers are parasitized.
- Remark: Samples of the leaf should be tested regularly to determine the percentage must be 80-90%.
Crop: Sweet pepper
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- Introduce when the first leafminer infestation is detected:
- Spring & Fall: minimum 0,5 Dacnusa/Diglyphus (90%-10%) m² per week, until an equilibrium is reached.
- Summer (or at a higher infestation): introduce 100% Diglyphus in a dose of minimum 0,1. Diglyphus/m²/week during minimum 3 weeks or until a sufficient number of leafminers are parasitized.
- Remark: Samples of the leaf should be tested regularly to determine the percentage must be 80-90%.
- When the first leafminer infestations are detected, introduce minimum 0,25 Dacnusa/Diglyphus (90%-10%) m² per week, until an equilibrium is reached.
- When the damage of the leafminer increases, introduce 100% Diglyphus at a dose of minimum 0,1 Diglyphus/m²/week during minimum 3 weeks or until a sufficient number of leafminers are parasitized.
- Remark: Samples of the leaf should be tested regularly to determine the percentage of parasitized leafminers. To have a satisfying control, the percentage must be 80-90%.
Crop: Tomato
More info
- Hang up yellow sticky cards for detection of the first leafminers: 25-50/ha.
- Samples of the leaves should be tested regularly to determine the percentage of parasitized leafminers. Please contact your technical advisor in this respect.
- After detection of the first mines:
- introduce 0,25 Dacnusa/Diglyphus (90%-10%) per m² per week until a sufficient number of leafminers are parasitized. The exact strategy depends on the circumstances in the greenhouse.
- In case the number of leafminers increases, or from March 1st onwards, introduce 0,1 Diglyphus/m² per week for 3 weeks, or until a sufficient number of leafminers is parasitized.
- Correction: Trigard
- Remark: Both Dacnusa sibirica and Diglyphus isaea are very efficient against Liriomyza bryoniae (tomato leafminer), Liriomyza trifolii (American serpentine leafminer) and Liriomyza huidobrensis (South American leafminer).
- Hang up yellow sticky cards for detection of the first leafminers: 25-50/ha.
- Samples of the leaves should be tested regularly to determine the percentage of parasitized leafminers. Please contact your technical advisor in this respect.
- After detection of the first mines:
introduce 0,25 Dacnusa/Diglyphus (90%-10%) per m² per week until a sufficient number of leafminers are parasitized. The exact strategy depends on the circumstances in the greenhouse. - In case the number of leafminers increases, or from March 1st onwards, introduce 0,1 Diglyphus/m² per week for 3 weeks, or until a sufficient number of leafminers is parasitized.
- Correction: Trigard
- Remark: Both Dacnusa sibirica and Diglyphus isaea are very efficient against Liriomyza bryoniae (tomato leafminer), Liriomyza trifolii (American serpentine leafminer) and Liriomyza huidobrensis (South American leafminer).
pests
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Biobest Belgium N.V.
Ilse Velden 18
2260 Westerlo
BE - Belgium