Contrary to what many people think, most insects are extremely useful to mankind and the environment. Our world could not be any better without insects.
Dr Abe V Rotor
Green Tree Ant colony, silhoute and closeup
Without them, we would not have honey and
silk, insect-pollinated fruits and vegetables, fish which feed on them, music
they create on a warm summer night. Nor can we see the Monarch butterfly that
meets us in the garden at sunrise in springtime.
On the other hand, we detest the presence
of their destructive kin: the disease-spreading cockroach, ticks that spoil a
dog’s lovely coat, caterpillars that defoliate our favorite trees, or simply
the buzzing of a pesky mosquito that interrupts our prayers or good rest.
If these negative traits are not enough
for us to take up arms against these pests, realize that the most ferocious
animal on earth is not the lion or rhino, but the mosquito. Disease-carrying mosquitoes have caused,
through the millennia, death and suffering to mankind. It is estimated that
deaths due to mosquitoes alone surpasses that which all wars in history have
caused.
The mosquito’s most prominent victim, Alexander the Great, died of
malaria at a young age on the banks of the Tigris-Euphrates Rivers, after a
conquest that would have formed the biggest empire in the world.
So here are strategies of war against our
insect enemies.
1.
Natural Resistance
There is no substitute for natural
resistance (those carried by the genes)
in combating the pest. Where do these genes come from?
Even before scientists came to the
conclusion that resistance (or susceptibility) is hereditary, farmers already
adopted selectivity in plant breeding and animal husbandry, as the foundation
of the first green revolution Black Stink Bug (Nezara viridula)
Evolution brought desirable genes together
in a species. “Survival of the fittest,”
Darwin’s general formula is the gradual pooling of these genes through time. It
also explains why varieties and breeds native to a place are more resistant
compared to their non-indigenous counterparts.
Wittingly or not, man has caused the elimination of resistance
genes. By making economically
advantageous agricultural decision, man unwittingly has eliminated
seemingly unimportant genetic characteristics. Many of the latter
characteristics are carried by indigenous species.
In order to gain from this knowledge, one
must look into the adoption of these two measures.
1. Choose plants and animals that are genetically
adapted to the place. They have the natural
resistance to pests and diseases, and can withstand unfavorable conditions
prevailing in the area.
2. Maintain physiologic (involving
healthy or normal functioning) resistance by enhancing soil nutrients and
proper cultural practices. Healthy
plants have less pest and disease problems.
The same is true with animals.
This leads us to the next practical technology.
2. Proper
Cultural Practices
It is not only the season’s calendar that
farmers plant or harvest their fields at the same. They have learned that by
working collectively with the seasons, crop loss due to pest and diseases is
minimized, since the damage they cause is thinly spread over larger area.
A colony of Aphids, major field and garden pest
The fields are fallowed in the
summer, giving the land time to “rest.” During this time the insect life cycle
is severed and the buildup of its population is remotely possible. This
practice is revived through cooperative farming, integrated with communal
irrigation, mechanization, and collective marketing to provide economies of
scale.
A key to control pests is to eliminate
their breeding places. This is done by uprooting infected plants, or pruning
affected parts, then burning them. To attract the potential pests, farmers
plant trap crops ahead of planting time. The trap crop is then rouged
and burned to eliminate the threat to the oncoming crop. Weeds need to be
eliminated since they serve as alternate hosts.
3. Biological
Control
As unsightly as cobwebs are, do not
remove them. Destroying them will take
away natural insect traps built by spiders. Inside warehouses, spiders prey on
weevils and moths that destroy grains and other commodities. Those webs also trap pesky mosquitoes and
flies at home. No echolocation device
can avoid the fine web, making it an indigenous trapping devise, indeed.
On plants, the preying mantis snatches
its victim with one deadly grasp. The spotted ladybug overruns a colony of
aphids and has its fill, unless the red ants guarding the aphids come to the
rescue. A nest of hantik ants up
in the tree is an army of thousands.
They swarm on intruders and large preys like caterpillars.
Under the microscope one can examine the
unsuspecting Trichogramma. Mass
production and dispersal of this parasitic wasp has benefited sugar and corn
planters since its discovery in the 1950s. The University of the Philippines at
Los Baños is mass-producing the parasite for dispersal in corn and sugarcane
fields throughout the Philippines.
Bacillus thuringiensis or Bt, has
become the most popular pathogens attacking Lepidopterous pests which
include rice stem borers and corn borers.
When the spores are applied as materials for inoculation, Bt can cause
widespread pests elimination on the field.
4. Practical
Pest Control at Home
Here are pest control techniques you can
adopt at home.
1.
To control furniture weevil and moths which destroy the
felt and piano wood, place a teabag of well-dried and uncrushed black pepper in
the piano chamber near the pedals. Paminta
is a good repellant and has a pleasant smell.
2.
Coconut trees whose shoots are destroyed by rhinoceros
beetle (Oryctis rhinoceros) can be saved with ordinary sand. If the trees are low, sprinkle sand onto the
leaf axils (angle between the leaf and axis from which it arises). Sand contains silica that penetrates the
beetle’s conjunctiva, the soft part of the body where hard chitinous
plates (hard outer membrane) are joined.
3.
To control bean weevil (Callosobruchus maculatus),
an insect that destroys stored beans, especially mungo), mix a little ash of
rice hull (ipa’) and spread it in a way that sand kills the rhinoceros
beetle.
4.
To get rid of nematodes (microscopic elongated,
cylindrical worms) in the soil, incorporate chopped or ground exoskeleton
(skin) of shrimps into the soil, preferably mixing it with compost. Chitinase
is formed which dissolves the cover of the egg and the body of the
nematode. Use poultry dropping to reduce
nematode population in farms and gardens.
5.
To control the cucurbit (plants of the gourd family)
fruit fly (Dacus cucurbitae), wrap the newly formed fruits of ampalaya
and cucumber with paper bag. Bagging is
also practiced on mango fruits. For ampalaya use newspaper (1/8 of the
broadsheet) or used paper, bond size.
Roll the paper into two inches in diameter and insert the young fruit,
folding the top then stapling. Bagged fruits are clean, smooth and light
green. Export quality mangoes were
individually bagged on the tree.
6.
To keep termites away from mud-plastered walls,
incorporate termite soil (anthill or punso). To discourage goats from
nibbling the trunk of trees, paint the base and trunk with manure slurry,
preferably their own.
7.
Raise ducks to eat snail pest (golden kuhol) on
the farm. Chicken and birds are natural
insect predators.
8.
An extra large size mosquito net can be made into a
mini greenhouse. Underneath, you can
raise vegetables without spraying. You
can conduct your own experiments such as studying the life cycle of
butterflies.
9.
Plants with repellant properties can be planted
around the garden. Examples of these are
lantana (Lantana camara), chrysanthemum, neem tree, eucalyptus, madre
de cacao (Gliricida sepium), garlic, onions, and kinchai (Allium
tuberosum).
10. To
scare birds that compete for feeds in poultry houses, recycle old balls,
plastic containers, styro and the like, by painting them with two large scary
eyes (like those of owls). This is the
reason why butterfly wings have “eyes” on them to scare away would-be predators. Hang these modern scarecrows in areas
frequented by birds. To scare off birds
in the field, dress up used mannequins.
In some cases, the mannequin may be more effective than the T-scarecrow. Discarded cassette tape ribbon tied along the
field borders scares maya and possibly other pests.
5. Insects as
Food
One practical means of insect control is
by harvesting them for food. This practice is not only confined among primitive
societies but is still one of the most practical means of controlling insects.
Anyone who has tasted kamaro’ (sautéed mole cricket – Gryllotalpa
africana) would tell you it is as tasty as shrimps, lobsters or other
crustaceans. After all, insects and
shrimps belong to the same phylum – Arthropoda.
Locusts may destroy crops but, in a way,
bring food to its victims. During a swarm, locust is harvested by the sacks and
sold for food and animal feeds. The same
goes for gamu-gamu (winged termites – Macrotermes) at the onset
of the rainy season, or the salagubang (Leucopolis irrorata), another
insect delicacy. Other food insects are
the grubs of kapok beetle locally called u-ok, eggs and larvae of
hantik (green tree ant), larvae of honeybee and cheese maggots.
When is a pest a
pest?
When we see an insect, instinct tells us
to kill it. We should not. A caterpillar
is a plant eater, but the beautiful butterfly that emerges from it is harmless,
efficient pollinator. Hantik ants make harvesting of fruits inconvenient
because of their painful bite, but they guard the trees from destructive
insects. Houseflies carry germs, but
without them the earth would be littered with dead, undecomposed
organisms. They are nature’s chief
decomposers working hand in hand with bacteria and fungi. Termites may cause a house to crumble, but
without them the forest would be a heap of fallen trees.
Cicada (molted skin); Leaf Insect
It is natural to see leafhoppers on rice
plants, aphids on corn, bugs in the soil, grasshopper on the meadow, borers on
twigs, fruit flies on ripening fruits. These organisms live with us under one
biosphere. If we can think we can
dominate them, we have to think again. They have been dominating the earth for
billions of years, even before man appeared. Just one proof: the total weight
of ants inhabiting the earth outweighs six billion human inhabitants.
There is no way to escape pesky
creatures. Conflict arises only when their populations increase rapidly to
overrun our crops, spoil our stored products, and threaten our health and
welfare.
We have set certain thresholds of our
co-existence with insects. As long as they do not cross that line, we can
cohabit this planet peacefully with them. By so doing, we can ponder at the
beauty of their wings, the mystery of the fire they carry, the music they make,
the magnitude of their numbers, or marvel at the mystery of their presence.
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