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About
the Author
Sample Entry from
"Bug"
Doug's
Computerized
Biological Control
A Computer Database
with Illustration Booklet
(c)
1988-1998 D.D.
Note:
Numbers in parentheses are code numbers
for
computerized cross-references (like modern-day hyperlinks)
as
well as for illustrations in the accompanying booklet.
Ladybird
Beetles, Lady Beetles,
Ladybugs,
or Aphidwolves
DESCRIPTION
Often
brightly colored and patterned. The
oval to almost ball-like body is very bulging on top but very flat below.
The short antenna has a 3- to 6-segmented club.
The head is at least partly hidden below the top of the thorax.
The pale- to
dark- or brightly-colored larvae look like little alligators.
RANGE
Widespread.
HABITATS
The adults
and larvae usually live around their prey (below).
FOODS
Ladybugs have
hefty appetites -- 1 larva [an "aphidwolf"] can eat over two
dozen aphids a day, and 1 adult can eat over twice that much!
Generally, reddish-orange ladybugs eat aphids; the darker ones more
often eat spider mites (6), whiteflies (41), and scale insects (46).
Overall, the
prey of ladybugs includes mites (5), spider mites (6), springtails (12),
thrips (23), lace bugs (28), chinch bugs (32), leafhoppers (37), perhaps
treehoppers (38), psyllids (40), whiteflies (41), aphids (42), gallmaking
and/or woolly aphids (43), pine and/or spruce aphids (44), scale insects
(46), mealybugs (47), such other ladybugs as the Mexican bean beetle (65)
[one of the few plant-eating species of ladybugs], asparagus beetles (70),
the Colorado potato beetle (72), perhaps flea beetles (73), the elm leaf
beetle (82), weevils (83), perhaps the diamondback moth (105), leafrollers
(112), the European corn borer (117), sphinx moths and/or hornworms (130),
cutworms and/or related caterpillars (138), the corn earworm (139), the
stalk borer (142), and webspinning and/or leafrolling sawflies (157).
DAMAGES/BENEFITS
Although a
very few are important pests (65), most ladybugs are among the most
beneficial of all insects. In
many avocado orchards in Southern California, ladybugs and other
beneficial insects control pests so well that virtually no chemical
controls have been needed. In addition, the brown and orange "vedalia" lady
beetle provided the first, classic example of modern biological control
(See scale insects (46).).
LIFE
CYCLES
There may be
a dozen or so generations a year (below).
PHYSICAL
CONTROLS
Plantings of
yarrow reportedly attract ladybugs. In
addition, there are commercially available aphid-scented lures to attract
such natural enemies as ladybugs!
Beneficial
species of ladybugs have often been intentionally imported into areas
plagued by insect pests. Typically, masses of the overwintering adults are
collected in Pacific Coast mountains and are then either distributed in
crop areas or kept in captivity for the rest of winter and sold in spring.
Although native ladybugs are usually the most efficient in a given
area, imported ladybugs often work well, especially against pests
accidentally imported from the same area.
See
"Biological Controls" for some commercial sources of ladybugs,
also available at many retail garden shops. How many ladybugs will you
need? Well, the answer varies
with the source you consult. Typical
answers are: 1/2 pint per 1 small garden or 1/4 acre; or 1 quart per acre;
or 30,000 ladybugs per 10 acres -- once again depending upon who you
consult, there are 9,000 ladybugs per pint; 135,000 ladybugs per gallon;
or 1,500 ladybugs per 1 ounce of weight.
Follow label directions. Prices
are typically reasonable.
There are
precautions to take in releasing ladybugs. To prevent starvation in or
migration from an area, do not put ladybugs out too early in the season.
It is best to keep ladybugs hibernating in their container in the
crisper compartment of the refrigerator (not the freezer) until there are
enough pests out to keep the ladybugs well fed. Each box of ladybugs
should be placed near plants and not too near other boxes of the beetles.
If you remove them from the boxes, handle the ladybugs gently, so
that they will not instinctively fly away in "fear".
To prevent ladybugs from flying away (as they often do, to burn-off
excess winter fat after finally being released from hibernation and
captivity), release ladybugs late in the afternoon or, better yet, at
sundown: They will not fly at
night, and many will become established in the release area by the next
day. Keep the soil moist, as
with a mulch, to give the ladybugs a safe place in which to hide.
Ladybugs can
reportedly be "preconditioned" to prevent their flying away.
For 5 days keep the ladybugs in a 4' x 6' x 4'-high tightly
screened cage in the release area and daily spray the plants inside with 1
pound of "wheast" (a high-protein byproduct of the cheese
industry, available as "Formula 57") and 1 pound of sugar in 1
gallon of water (This mixture will also attract native ladybugs and
lacewings, but perhaps also ants and, after the cage is removed, wasps and
bees -- this extreme method should be tested first.).
Another
method to prevent losses of ladybugs by their flying away is to release
them over wide areas: This,
of course, requires cooperation between neighbors or within garden clubs
or other community organizations, whose members should all benefit from
decreased pest control expenditures, especially in the long-run.
In warm,
sunny weather, released adults will mate and lay eggs in a day or two.
In about 2 weeks a new generation of larvae will hatch-out and
start eating their insect prey. Winter is spent in the adult stage,
usually in groups of up to a million individuals, wherever there is
shelter (especially from rain), usually in the mountains.
In and around such areas, they eat enough pollen, plant sap, and
the like to double their body weight before hibernation: This should be
considered before releasing masses of ladybugs near mountainous areas in
which valuable fall crops of such products as seed are grown.
Overall,
ladybugs are valuable garden friends, asking for no more than something to
eat -- namely, our pests.
CHEMICAL
CONTROLS
The use of
many insecticides, especially such chlorinated hydrocarbons as DDT, has
unintentionally killed many valuable ladybugs.
BIOLOGICAL
CONTROLS
Viruses
infecting ladybugs include Iridescent Virus.
Bacillus
thuringiensis, widely used vs. caterpillars (100), is reportedly nontoxic
to lady beetles.
Fungi
infecting ladybugs include Beauveria bassiana.
"Nematode"
round worms parasitizing ladybugs include Agamermis decaudata, Mermis
nigrescens, and Steinernema [Neoaplectana] carpocapsae.
Insects etc.
parasitizing or preying upon ladybugs include mantids (15), stink bugs
(24), damsel bugs (30), minute pirate bugs (31), assassin bugs (33),
lacewings and/or aphidlions (48), various beetles (50), tiger and/or
ground beetles (51), ladybugs (64), various (true) flies and/or maggots
(143), robber flies (146), flesh flies (154), tachinid flies (155),
braconids (159), perhaps "chalcidid" chalcids (161), "encyrtid"
chalcids (161), "eulophid" chalcids (161), "pteromalid"
chalcids (161), and ants (166) [In particular, those ants that carry and
"milk" such honeydew-producing insects as aphids (42) will ward
off some of the aphidwolves preying on their "livestock herd"!].
In a complex garden ecosystem, low levels of all these organisms
could co-exist, keeping pest levels likewise low.
SEE
ALSO
beetles,
including grubs and weevils (50) and the Mexican bean beetle (65).
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