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Hypoaspis [Stratiolaelaps (=Hypoaspis) miles] Fungus Gnat Predator by Applied Bio-nomics PO Box 1555,
Ventura, CA 93002 800-248-2847 *
805-643-5407 * fax 805-643-6267 e-mail
bugnet@rinconvitova.com |
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Target
Pests
Fungus
gnats (Bradysia
spp.) –larvae only
Western
flower thrips (Frankliniella occidentalis) – pupal instars only
Larval
stages of other soil borne pests, including springtails (Collembola),
nematodes, mold mites, spider mites, cactus root mealybug, strawberry root weevil,
and black vine root weevil in the soil
Description
Hypoaspis
is a native species of soil-dwelling mite, which feeds on small insects and
mites, but prefers fungus gnat larvae. It has a swarming behavior on all larval
stages of pests. Adults are tan in color, less than 1/20th inch long
(1 mm). They move rapidly over the soil surface.
Use
as a Biological Control
·
Hypoaspis are used primarily to control young larvae of
fungus gnats in the soil. Fungus gnats cause feeding damage to roots and
transmit Pythium, Phytophthora
and Fusarium that cause root rot
diseases. They are also a nuisance to people. Identification is important
because they look like shore flies, but their antennae are long and bead-like,
with long legs and a prominent Y shape in the wing veins. Fungus gnats are poor
flyers.
·
They also help control soil stages of thrips and may account
for up to 30% of Western flower thrips control. Hypoaspis do not control shore
flies or moth flies, but will feed on other soil organisms, such as springtails
and root mealybugs.
·
They have been used successfully in bedding and potted plant
production, seedling and cutting propagation, and poinsettia stock.
·
They adapt well to the various growth media and capillary
mats used in plant production, but do not survive freezing or flooding
conditions.
Monitoring
Tips
Use
a headband magnifier or 10-15 X hand lens to look for the mites in the top inch
(1-2 centimeters) of soil or growth media and at the base of plants.
Life
Cycle
The
complete life cycle takes 18 days at 68o F (20o C) and as short as 13 days at warmer
temperatures.
·
The sex ratio is equal, 1:1 females to males. The males are
much smaller and hard to see.
·
Eggs hatch in 2-3 days into young nymphs
·
Each Hypoaspis consumes 1-5 prey per day. It can also survive
for very long periods as a scavenger, living on algae and plant debris.
Populations
will naturally fluctuate throughout the growing season.
Product
Information
Hypoaspis
is supplied in a pasteurized peat/bran mixture in a one liter container with a shaker
lid for distributing the mixture over the soil.
There
are 25,000 predators per liter, or about 25 predators per cc. The mixture also
contains another species of mite as a food source for the predators.
To
check the product for live mites, inspect under 10-15 X magnification. The
predators are tan and move quickly compared to the food source mites, which are
white or translucent, and move slowly.
Apply
soon after receipt. If necessary, containers can be held, out of direct
sunlight, at 60-70o F (16-21o C) for up to 7 days. Do not
refrigerate.
Introduction
Rates
Hypoaspis
is most effective when applied before fungus gnat populations become
established or while numbers are still low.
In general one application of from 6 to 60 Hypoaspis per container or
ft2 per crop cycle is sufficient, if used early in the season.
·
Soil Culture – Apply 1 L/1000 ft2 (100 m2) to the soil at the
time of planting. Be sure to treat wet, exposed areas of soil, where fungus
gnats are likely to breed.
·
Sawdust bag or Rockwool culture – Apply 3-6 L/acre (8-16 L/ hectare) to at least one plant in
every bag or rockwool slab. Vegetable transplants may be treated 1 week before
planting out.
·
Pot Culture – Apply
1 L/ 1000 ft2 (100 m2) of bench area. Treat the floor of the greenhouse if it
provides conditions for fungus gnats to breed and occasionally treat the
perimeter of the greenhouse.
It
is not necessary to apply mites to every flat of bedding plants if applications
are done early, at full rate, to allow them time to spread to all flats. Mites
can also be applied to propagation media before striking cuttings.
For
Best Results
·
Do not mix predators into the growth media before potting
because they do not survive.
·
Hypoaspis will eat beneficial nematodes; Atheta will eat
Hypoaspis.
·
Apply Hypoaspis shortly after planting as a prophylactic
treatment, before fungus gnat levels reach more than 20 adults/trap/week and
continue
·
To control high numbers of fungus gnats (above 75 flies per
card), apply Bacillus thurinigiensis israelensis (Bti) (Gnatrol or
Vectobac®) or the beneficial insect parasitic nematode Steinernema
feltiae for fastest control. Both control the larval stage of fungus
gnats. Neither Bti nor beneficial nematodes harms Hypoaspis.
Conventional
Pesticides
·
In general, do not apply Hypoaspis to soil that has been
treated with lime or pesticides (particularly soil treated with diazinon). Cygon, Decis, Dursban, Intercept, Lorsban,
Malathion, Sevin, Trumpet and Vydate pesticides create residual damage for over
a month. Plant Fume (Sulfolep) remains harmful for 70 days.
·
It is likely that foliar sprays are less harmful than soil
drenches, depending upon how much pesticide reaches the soil surface.
·
Fungicide drenches containing benzimidazoles are known to
reduce reproduction of Hypoaspis.
·
See our Pesticide Toxicity Chart that shows expected effects
of pesticides on Hypoaspis.
Pesticides Compatible with Hypoaspis
Insecticides Pirimor (pirimicarb) Vendex (fenbutation
oxide) Dipel (Bacillus
thuringiensis) Enstar (kinoprene) |
Fungicide Sprays Daconil
2787 (chlorothalonil) ExothermTermil
(chiorothalonil) Karathane
(dinocap) Meltatox
(dodemorph acetate) Rovral
(iprodione) |
Growth Regulators B-Nine
(daminozide) Cycocel
(chlormequat chloride) |
ã Rincon-Vitova Insectaries, Inc. 2008