Economic classification of insects and Pests surveillance

1. L-1 Economic classification of
insects

2. • Based on their relation to man, insects may be
classified into two general groups, beneficial and
injurious

3. Beneficial insects: Commercial products
derived from insects
A. Honey
Honey is used extensively as food and in the manufacture of
many products.
B. Beeswax
• Bees wax is used extensively by industry in making candles,
sealing wax, polishes and certain type of inks, models, dental
impressions, cosmetics and other products.

5. Cont…
C. Silk
• The silk industry is an ancient one
• Several types of silkworms are utilized for production of
commercial silk, but the most important is Bombyx
mori (Mulberry silkworm).
D. Shellac
• Produced from the secretions of the lac insects Laccifer
lacca, a type of scale insect occurring on palas, ber, kusum
banyan, etc.
• These insects form encrustations of 6 to 13 mm thick on the
twing of the host plant. These are collected, ground and
processed to get shellac.

7. Cont…
E. Dyes and other materials
• Several insects have been used in the manufacture of dyes.
• The cochineal insect, Dactylopius coccus, a scale insect
somewhat similar to mealy bugs, is used for the production of
cochineal dyes.
• These insects feed on Opuntia cacti (prickly pear).
• The dye obtained from these insects is crimson in colour and
is produced from the dried bodies of insects.
• Dyes have also been made from other types of scale insects
and from certain cynipid galls.

9. Cont…
F. Insects as medicine
• Allantoin is a substance isolated from secretions of fly
maggots and it has properties of healing deep wounds
• Cantharidin is a substance found in the blister beetle, Lytta
vesicatoria and is useful internally treating certain urinary
diseases and externally as a vesieeant and counter – irritant
• ‘Specific Medicine Apis’ is extracted from honeybees by
diagnosing the excited bees in alcohol, and is used against
certain disease like urinary irritation, diphtheria etc
• Bee venom cures rheumatism and arthritis and is available for
hypodermic injection.

11. Cont…
G. Use of insect galls
• Some of the galls are of medicinal value: Aleppo gall of oak
has astringent and tonic properties and has been used for
about 25 centuries in Europe and West Asian Countries
• Other insect galls contain dyes and give inks of permanent
nature
• Aleppo gall is used for dyeing wool and hair and ink from it
had been used for writing important records in Manasteries in
Western Countries.

13. Other useful insects
1. Insects and pollination
• Majority of higher plants are cross-pollinated (depend on
wind and insects for pollination)
• While wind pollination may be a chance, insect aided
pollination is somewhat a sure proposition.
• Wind pollinated crop produces large quantities of dry pollen
while the insect pollinated crop produces less pollen, which is
usually sticky and adheres to the bodies of insects that visit
for the flower.

14. Cont…
• Some species of plants depend solely on a single of species of
insect or type of insect for pollination e.g.
a. Smyrna fig pollination by fig wasp
b. Rosaceous plants (apple, pear, cherry, strawberry) chiefly
depend on honeybees
• Many orchard fruits are mainly insect pollinated
• Most important insect pollinator is honeybee
• Every time the bees collect Rs. 100 worth of honey, they
make Rs.2000 worth of seeds and fruits by pollinating the
flowers

15. 2. Entomophagous insects
• The check (control) exerted upon insect pests by
entomolophagous (or insect eating animals) insect is very
important factor in keeping down the population of pest
species
• A classical example of successful control of an insect pest by
a predator is the cottony cushion scale, Icerya purchasi, a
serious pest of orchard in California, by a lady bird beetle
(Vedalia beetle) Rodolia cardinalis introduced from Australia
• In less than 2 years the scale insect was completely controlled
• Several parasitoids and predators, which check the pest
population

17. 3. Insect as weed killers
• Many insects feed and destroy noxious weed plant e.g.
1. Prickly pear (Opuntia spp.) was introduced into Australia
and by 1925 had spread over 25mil acres.
• In 1925, the larvae of moth, Cactobalastis cactorum were
introduced into Australia from Argentina. Now it is almost
eradicated with about just 1% of the area it occupied in 1925.
2. Hypericum perforatum L., Klamath weed or goat weed was
introduced into California in 1900 and by 1940 spread over 2
1/2 mil acres. Chrysomelid, Chrysolina quadringemina proved
effective and now it is a minor problem

19. 4. Insects as scavengers
• Insect scavengers are those that feed on decomposing plants
or animals or dung. They convert these materials into simpler
substances, which are returned to the soil
• Also help to remove the unhealthful materials from man’s
surroundings
• Wood boring beetles, termites, carpenter ants and other wood
feeders convert fallen trees and logs to soil
• Dung beetles (Scarabaeidae) and dungflies enhance the
decomposition of dung.
• Carrion-feeding insects (blowflies), skin beetles (Dermestids)
are helpful in removal of carrion from landscape.

21. 5. Insects improve soil fertility
a. Soil enriched by the excretions and dead bodies of
insects
b. Soil insects improve the physical properties of soil
and add its organic content eg. Spring tails, ants, mole
crickets, cicadas (nymphs), termites, beetles, flies etc.

22. 6. Insects as food of man and animals
• Many animals utilize insects as food. Man himself is sometimes
insectivorous.
• Many fresh water fish feed on mayflies, stoneflies, caddish flies,
mosquito larvae, various aquatic beetles etc.
• Birds that feed largely or entirely upon insects have practical value as
predators of insect pests. Eg. Gulls (aquatic bird) checked a cricket
outbreak in Utah. Other vertebrates’ are toads, frogs; lizards, bats etc.
• Man in many parts of the world utilizes insects as food. Grasshoppers,
locusts, crickets, cicadas, large ants, eggs of some large water bugs,
grubs of cockchafer beetles, caterpillars of some Saturnid moths, and
larvae and pupae of bees and wasps are eaten by man in different parts
of the world
• Termites are consumed in some parts of our country

23. 7. The use of insects in scientific research
• The fruit flies, Drosophila spp. have been extensively used in
genetic studies
• These insects have 1. Short life cycle. 2. Large chromosomes
– salivary chromosomes. 3. Great number of easily
recognizable hereditary variations and 4. Drosophila sp can
be easily reared in large number at low cost
• Insect have been used as experimental animal in studies of
behavior. Studies on social insects have provided much
interesting and valuable information on social organization
and behavior

25. 8. The aesthetic value of insects
• For many people, study of insect provides a stimulating
hobby as the study of birds, flowers etc. Artists, jewelers and
designers have utilized the beauty of insects for patterns
• Some of the butterflies, moths and beetles have provided
basic patterns in many types of art

26. Harmful insects
1. Injury by feeding
• Phytophagous insects cause damage resulting in defoliation
(eg. Leaf eating caterpillars), desapping (sucking pests e.g.
aphids, thrips, leaf and planthoppers) etc.
• Injury by oviposition: e.g. Periodical cicadas cause wilting of
twigs when the eggs are aid. Cowbug on many plants.
• Injury by disease transmission: More than 200 plant diseases
are transmitted by insects. e.g. Bhendi yellow vein clearing
transmitted by whitefly

27. 2. Insects attacking stored products
• Many insects damage stored produce by feeding, tunneling or
contaminating them.eg. rice moth, potato tuber moth, red
flour beetle
• Pests of wood: All sorts of wooden structures, such as
buildings, furniture, fence; insects damage posts etc. e.g.
termites
• Pests of fabrics: Fabric pests such as dermestid beetles and
clothes moths cause damage to furs, clothing, blankets, rugs
etc.

29. 3. Insects attacking man and animals
• Annoyance: Bot flies and face flies cause great annoyance to
man and cattle.
• Venomous insects: Many insects inject toxins into man and
animals that cause irritation, swelling, pain and sometimes
paralysis. e.g. Bees, Wasps
• Parasitic insects: Many parasitic insects live in or on the
bodies of man or animals causing irritation, tissue damage or
even death. e.g. Chewing lice of birds, sucking lice on
mammals

30. Cont…
• Disease transmission: Many insects borne disease have a
high mortality rate in man and animals. Insects transmit
diseases in two
• A) As mechanical vectors (houseflies, blowflies-typhoid,
cholera etc)
• B) As biological vectors (Anopheles – Malaria)

31. L-2 Pest Surveillance

32. Pest Surveillance: Meaning, Objectives
and Steps
1. Meaning of Pest Surveillance
2. Objectives of Pest Surveillance
3. Steps

33. 1. Meaning of Pest Surveillance
• An insect pest survey is a detailed collection of insect
population information at a particular time in a given
area
• The regular surveys of same place or locality at
consistent intervals to assess changes in pest species
over a time is called ‘surveillance’

34. Cont…
•The basic components of pest surveillance include
identification of pest, determining the stage,
population density of pest and natural enemies,
estimating loss the pest species may cause the
economic and other benefits that pest control will
provide
•Survey may be done in a small field, a pond, or it may
be as extensive as a state or region of the country
•Carried out at certain critical periods in the insect life
cycle

35. Pest surveys can be grouped into following
categories
(1) Qualitative Survey:
• Generally aimed at pest detection and provides list of pest
species present along with reference to density like common,
abundant, and rare
• Employed with newly introduced pests to understand the
extent of infestation
• Surveys are mostly adopted at international borders where
agricultural commodities are inspected to avoid invasion of
any new species

36. (2) Quantitative Survey
• Survey defines numerally the abundance of pest population in
time and space
• Provides information on the damaging potential of a species
and data can be used to predict future population trends
• Surveys provide the basis to decision making for adopting
control measures for a pest by the farmers
• Survey/surveillance can also be classified as fixed plot and
roving

37. (3) Fixed Plot Survey
• In fixed plot survey, the pest population or damage due to insect pests
is assessed from a fixed plot selected in a field
• Data are recorded regularly from sowing till harvest of the crop from
the same fixed plot in a particular field
• Data collected in these surveys are used to develop forecasting models
• Direct counting of population on plant, light traps, sticky trap,
pheromone traps, etc., are techniques which can be used to monitor
population in this survey
• Counting total tillers and number of tillers affected by stem borer from
10 randomly selected plants from fixed five spots of 1m2 in one ha is
an example of fixed plot survey

38. (4) Rapid/Roving Survey
• Survey includes assessment of pest population or damage from
randomly selected spots in a short period of time over a large area
• Provides information on pest level which helps in determining the
timing of adopting appropriate control measures
• Surveys are made to monitor the initial development of pests in
endemic areas in the beginning of crop season
• Based on these surveys, the farmers are instructed to monitor the pest
incidence in their respective fields by the agriculture extension
specialists and take interventions to manage the pests accordingly
• Counting of whitefly adults from lower surface of leaf from randomly
selected cotton plants on a predetermined route after a definite period
of intervals is an example of roving survey

39. Objectives of Pest Surveillance
i. To monitor, when pest population/ damage at different
growth stages of crop reaches the economic threshold levels.
ii. To estimate the crop losses caused by pests.
iii. To study changing pest status from minor to major in a
given crop ecosystem, this enables to determine the research
priorities.
iv. To monitor the development of biotypes, resistance to
insecticides, resurgence, etc.

40. Cont…
v. To monitor the invasion of new pest species in a local
ecosystem and determining the rate of spread of exotic pest
that has already been established.
vi. To study the influence of weather parameters on pest by
recording the changes in density of pest population throughout
the year.
vii. To assess natural enemies population and their influence in
a particular cropping system and in different seasons.

41. Steps for Pest Surveillance
1. Identification of Pest
2. Determination of Pest Population Stage:
• This involves two considerations. First, the life stage (egg,
larva, pupa or adult) at which counting can be made most
advantageously; and secondly, the actual process of counting
3. Estimation of Abundance of Natural Enemies
4. Estimation of Yield Loss
5. Direct Loss Surveys
6. Surveys of Infestation/Pest Damage