TECHNICAL SHEET
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
Steinernema-System provides the perfect biological solution to the pro blem of
glasshouse sciarids. It is based on a uni que strain of the insect parasitic nematode
Steinernema feltiae, which seeks out and destroys sciarid larvae in compost. Also,
this nematode is a natural enemy of thrips and leafminer.
Steinernema-System
GLASSHOUSE SCIARID
Biology
Glasshouse sciarids belong to the family of the Sciaridae. They
are small (3-5 mm) dark fl ies with long, slender antennae and long
legs. They are usually seen in warm and humid environment in the
proximity of plants. That’s why they can occur the whole year round
in the greenhouse.
After mating, the female fl y lays 50-200 eggs, which hatch in 2-3 days.
The emerging larvae develop through four instars over 2-3 weeks.
By that time, they are about 5 mm long, translucent white in color
with a distinctive black head. They then pupate in the compost and
emerge as adult fl ies 3 days later. At temperatures in excess of 24 °C,
breeding is continuous and the life cycle takes 3-4 weeks.
Damage
The larvae of the glasshouse sciarids can cause a lot of damage. They
not only feed on decaying organic matter in the compost, such as algae
and mould, but also on living material such as root and stalk tissue.
They pierce into the root and/or stalk of cuttings, seedlings or young
plants. As a result of this, secondary plant diseases such as Pythium,
Phytophthora, Botrytis, Fusarium and Vertici lium can be spread.
The most common symptoms of such an attack are the wilting and
the slowing down of the plant growth. In the worst case, this might
even lead to the death of these plants.
The following crops frequently suffer severe sciarid attack:
• seedlings, cuttings and young plants, especially if heated and under
mist;
• certain pot plants, e.g. ferns, Poinsettia, Azalea, Cyclamen,
Kalanchoë, Exacum, Gerbera, Begonia, ...;
• some long term rockwool grown crops;
• mushrooms
HOW IT WORKS
Steinernema-System owes its consistent, effective control of sciarids
to the way in which it works.
Applied to the compost, the nematodes actively seek out sciarid
larvae. They enter each larva through natural body openings. Once
inside of the larva, they move to the intestinal canal and drill through
the intestinal wall of the larva. A specifi c bacterium which lives in
symbiosis with the nematode is released and will eventually cause
the death of the larva.
The nematodes reproduce inside the sciarid larva. As it decomposes,
a new generation of nematodes moves off into the compost in search
of further prey.
CONTROLLING GLASSHOUSE SCIARIDS
WITH STEINERNEMA-SYSTEM
The key to success is applying routine, preventative treatments. That
way, sciarid populations are not allowed to build up, and crop damage
is prevented.
Compost should be treated as soon as possible after sowing seed
or inserting cuttings. Many crops are susceptible to sciarid damage
during the fi rst six weeks, and a single Steinernema-System treatment
is already suffi cient. The dose that needs to be applied is always 1
million of nematodes/m². For very slow growing crops, it may be
desirable to reapply Steinernema-System at six week intervals in order
to maintain protection. If Steinernema-System treatment is delayed
until sciarids are established in the crop, it will take 2-3 weeks before
the numbers of adult fl ies are noticeably reduced.
Steinernema-System works best in moist, warm compost (15 °C-
20 °C). If compost temperatures fall to less than 10 °C or rise to 30
°C or higher, the nematodes become inactive. Wet spots as well as
the growth of algae are best to be prevented, as they could promote
the number of glasshouse sciarids present.
THRIPS
(Frankliniella occidentalis – Western fl ower thrips)
Biology
Adult thrips are small, elongated insects with typical fringed wings.
They measure about 1 mm, and have a greyish or yellow to brown
colour. The female thrips deposits eggs in the leaf tissue. The eggs
hatch within a few days into very mobile larvae which immediately
start to feed. After the second instar they let themselves fall on the
ground to pupate. The total development time from egg to adult
takes from 20 days at 20 °C (68°F) to 12 days at 30 °C (86°F). At
suffi ciently high temperatures one female thrips can produce up to
100 descendants.
EN 080219
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.
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
ADVANTAGES
• No re-entry time;
• No residue on the crop;
• Can be integrated in resistance management;
• No pest resistance problems;
• Can be applied during bloom (e.g. strawberry);
• Indifferent to most chemical crop protection means
(tankmix);
• Controls the problem before it appears
• Practical and simple usage
• Compatible with other biological or integrated
systems
• Absolutely safe to users, consumers and the
environment
• No disposal problems.
Damage
Thrips damage the crop by withdrawing the plant cell fl uids. Empty
cells are fi lled with air, causing a silvery appearance, on which dark
spots (the excrements) are visible. Moreover, there exist many more
damage symptoms depending on the crop. For instance, thrips can
cause deformed fruits. In several ornamentals, fl ower damage through
discoloration or deformation occurs. Only a few individual thrips are
enough. Moreover, thrips are important vectors of several viruses
(e.g. tomato spotted wilt virus or TSWV and impatiens necrotic spot
virus ).
EFFECTS OF STEINERNEMA FELTIAE
Through spraying of the leaves, the nematodes come in contact with
thrips. They enter the host through natural body openings. Once
inside, the nematodes move to the intestinal canal and drill through
the intestinal wall of the larva. The Xenorhabdus bacterium, that lives
in symbiosis with the nematode, is released and will eventually cause
the death of the larva.
Steinernema-System can be used for all cultures to control the thrips
population, without having any negative infl uence on biological
adversaries. If used in alternation to thrips pesticides, it reduces the
resistance of thrips to chemical agents. No perceptible residue remains
after the treatment. The use of Steinernema-System as part of a thrips
control program seems obvious.
CONTROL
There’s both a precautionary and curative control strategy. For the
precautionary strategy 125.000 nematodes/m² are sprayed weekly. For
the curative treatment a dose of 250.000 nematodes/m² is applied 2 up
to 3 times. Each time, the nematodes are dissolved in approximately
1000 liter of water per ha. It is important to obtain a consistent
coverage, with no spray solution leaving the crop. Otherwise the
nematodes would not end up on the crop but on the soil. To guarantee
a good consistent coverage and to increase the penetration in the head
of the crop, it is recommended to add a wetting agent to the solution.
After some applications the situation needs to be reassessed. The
thrips damage can be easily monitored by means of blue Bug-Scan
traps. The nematodes control all life stages of thrips except eggs. The
nematodes are very effi cient against the females in the population. This
way exponential growth of the thrips population is impossible.
Since the nematodes are susceptible to dehydration, it is important
that the leaves remain wet for at least 2 hours. We recommend to
perform the treatment in the evening with the ventilation closed.
These nematodes experience little or no hindrance of most of the
chemical pesticides (excepting nematicides) and can therefore be used
in a tankmix. To make sure, you can always consult our side-effects
manual on www.biobest.be.
LEAFMINER
Leafminer damage occurs on lots of vegetables and ornamentals.
In ornamental crops, the feeding spots already reduce the aesthetic
value of the plant. Leafminer 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.
To control leafminer with these nematodes the timing of application
is very important.
In case of synchronous population, one application is suffi cient. When
the population of leafminer grows asynchronously, it is necessary to
repeat the treatment weekly. Doses and application techniques are the
same as for thrips control.
PACKING
Steinernema-System is delivered as a gelformulation. Depending on
the pack size, they contain a minimum of 5, 50 or 250 or 1250 (5x250)
million juvenile nematodes. During mixing with water, the nematodes
form a suspension, which can be applied to the compost surface.