pests
Vine weevil
Vine weevil (Otiorhynchus sulcatus)
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Adult weevils feed at night producing  telltale notches arround the edges of leaves and flowers. The damage is most severe when caused by the varacious larvae, feeding on roots Heterorhabditis-System provides rapid and effective control of vine weevil.

Biology
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Adult vine weevils are 8-12 mm long, have a grooved, dull black shell with patches of tiny yellow bristles. As they are well camouflaged and only active at night, they are seldom seen. If they are discovered, they play dead very convincingly.

Outdoors, adult vine weevils emerge from the soil from May onwards. They are wingless, but walk and climb exceedingly well. Male weevils have not been found. The freshly emerged females feed for about ten days, then commence laying the unfertilized eggs close to well-selected plants. Each female lays about 500 eggs, which are very small (0.8 mm diameter) and round. Initially, these eggs are white, but they turn brown as they mature. As adults are relatively long-lived, egg-laying can extend well until October.

Eggs hatch in 8-20 days, and the tiny emerging larvae burrow deep down into the compost. The larvae are C-shaped and legless. They have a creamy white colour with a shiny brown head. When fully grown, they are 10-14 mm long.

Vine weevils overwinter as larvae, which pupate in spring as temperatures rise. These pupae are cream-coloured and soft bodied. They are found in cavities several centimetres down in the soil. Adult weevils emerge some 3-4 weeks later. In heated glasshouses, the life-cycle is completed more rapidly and several different stages of vine weevil may be found at any time of the year.

Damage
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Adult weevils feed at night producing telltale notches around the edges of leaves and flowers. This is often the first sign of vine weevil activity. The damage is most severe when caused by the voracious larvae of the vine weevil. Emerged from the eggs, they feed on little roots. As they grow, they gradually attack bigger roots, tubers, rootstocks and even strip bark from woody stems. As a result, the damaged plant wilts and dies off.

Sometimes, it takes a long time before damage is determined. At that moment, the plant is often already severely weakened and beginning to die off. Slow growing plants, which are unable to compensate for loss of root tissue are most subject to damage.

 

 

Crops frequently attacked include:
 
  • Rhododendron, Azalea, Camelia, Taxus
  • Many herbaceous perennials
  • Certain pot plants, e.g. Cyclamen, Fuchsia and Primula
  • In arboriculture: conifers ...
  • Strawberries
Crop: Grape
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  • Dose: 1 milllion nematodes/m²
  • Pay attention: substratum must be moist during 14 days and the temperature must be higher than 12°C.
Crop: Public gardens
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  • There are two critical periods of application. The first period is April-May when larvae start pupating; the second around the end of August and beginning of September.
    The most important factors for application of this product are:
  1. A minimum soil temperature of 12°C
  2. The soil has to be kept moist during minimum 2 weeks.
  3. Active larvae must also be present.
     
  • Application rate: 1 million nematodes per m².
Crop: Strawberry
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  • Use at small damage of black vine weevil larvae, 0,5 million nematodes/m².
  • At a severe damage the dose has to be increased to 1 million nematodes/m².
Crop: Tree nurseries
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  • Use at small damage of black vine weevil larvae 0,5 million nematodes/m².
  • At a severe damage the dose has to be increased to 1 million nematodes/m².
  • The following quantities must be observed:
    • Preventive: 0,5 million nematodes/m² (5.000 nematodes per liter of pot soil)
    • Curative: 1 million nematodes/m² (10.000 nematodes per liter of pot soil)
Crop: Turf and lawn
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  • Dosage: 0.5 million nematodes / m² soil.
  • Available in packages of 50 million (for 100 m²) and 500 million (for 1.000 m²).
  • Time of treatment: from mid-July until end-September and at a minimum soil temperature of 12°C.
  • Apply the product thoroughly and keep the soil moist for at least 2 weeks.
  • If necessary repeat treatment next year.
pests
Contact Biobest
Biobest Belgium N.V.
Ilse Velden 18
2260 Westerlo
BE - Belgium
T: +32 14 257 980
F: +32 14 257 982