N.V.
TECHNICAL SHEET
Heterorhabditis-System
Heterorhabditis-System provides a rapid, biological cure for vine weevil
larvae in containerised and outdoor crops. It is based on a unique strain
of the insect parasitic nematode Heterorhabditis megidis, which seeks out
and destroys vine weevil larvae in compost.
BLACK VINE WEEVIL (Otiorhynchus sulcatus)
Biology
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 as they are 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 do not occur here. The freshly emerged
females feed for about ten days, then commence laying
the unfertilised 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 Cshaped
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
or 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
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
the 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, Camellia, Taxus;
• Many herbaceous perennials, certain pot
plants, e.g. Cyclamen, Fuchsia and Primula;
• In arboriculture: conifers, ..;
• Strawberries.
HOW IT WORKS
Heterorhabditis-System is able to exert such rapid and
effective control of vine weevil because of the way in
which it works. When applied to the compost, the nema-
Biobest N.V. - Ilse Velden 18 - 2260 Westerlo (Belgium) - Tel : +32.14.25.79.80 - Fax : +32.14.25.79.82 - E-mail:info@biobest.be - www.biobest.be
BENEFITS
• Rapid curative control of vine weevil larvae;
• Practical and simple in usage;
• Compatible with other biological / IPMsystems;
• No pest resistance problems;
• Absolutely safe to users, consumers and the
environment;
• When using, no protective clothing required;
• No disposal problems.
todes seek out larvae already present in the root zone.
They enter the larvae through natural body openings or
by penetrating the cuticle directly. Once inside, they release
symbiotic bacteria.
A larva which is attacked will colour yellow to reddish
brown and will die after about two days.
The nematodes reproduce inside the insect and as it decomposes,
a new generation moves off in search of further
prey.
HETERORHABDITIS-SYSTEM
Heterorhabditis-System provides rapid and effective
control of vine weevil provided that:
a. it is used curatively, i.e. the larvae must be present at
the time of treatment,
b. the humidity of the compost is high and the compost
temperature does not fall below 12°C for 2 weeks
following treatment.
In practice, for most crops this means that there are two
periods in which Heterorhabditis-System is used:
• Treatment between August and late September will
be effective against larvae which have developed
from eggs laid earlier in the year, and before significant
damage is done.
• Treatment in April / May will be effective against
larvae which have escaped an autumn treatment
or against those resulted from eggs laid in late autumn.
Late spring applications will greatly reduce the numbers
pupating and emerging as well as the number of adult
weevils. It should be noted that Heterorhabditis-System
remains effective for about four weeks after application.
Larvae which result from eggs laid after this time will be
inadequately controlled. As in heated glasshouses all
stages of the vine weevil may occur at any time, it is
possible to control a whole year round.
PACKING
Heterorhabditis-System is delivered as a clay formulation.
Each pack contains minimum 50 million infective
juvenile nematodes.
By mixing with water, the nematodes form a suspension,
which can be applied easily to the compost surface.
Each pack of Heterorhabditis-System will treat 50 m²
open ground or 100 m² containerised crops. For individual
treatments (through e.g. drip irrigation) 10 000 nematodes
are used per liter potting compost.
Biobest N.V. - Ilse Velden 18 - 2260 Westerlo (Belgium) - Tel : +32.14.25.79.80 - Fax : +32.14.25.79.82 - E-mail:info@biobest.be - www.biobest.be
EN 030217
Biobest guarantees the quality of its products. However, Biobest has no control over how the product is used and therefore disclaims any liability for loss of function, or for damage that might occur from direct or indirect
use, transport or storage.