category of insect pest, major pest, minor pest, sporadic pest, epidemic pest, endemic pest, potential pest, key pest,

1. Course No. AENT – 5311
Course Title – Principles of Integrated Pests and Diseases Management

2. PESTS
 A pest is any organism whose population increases to the extent that it starts causing
annoyance, inconvenience or injury to man, his animals, plants and materials
possessions. A pest may be an insect, mite, nematode, bird, rodent, fungus,
bacterium, weeds or any other organisms.

3. Damage Concept
 Injury
 The physical harm or destruction to a valued commodity caused by the presence or activities
of a pest
 consuming leaves, tunnelling in wood, feeding on blood, etc.
 Damage
 The monetary value lost to the commodity as a result of injury by the pest
 spoilage, reduction in yield, loss of quality, etc.
 Any level of pest infestation causes injury, but not all levels of injury cause damage

4. Just how much damage can we tolerate?
 At some point, a pest begins to cause enough damage to justify the time and
expense of control measures
 But how does one know when this point is reached?
 How much financial loss is the pest causing?
 How much will it cost to control the pest?
 Economic Injury Level
 The pest density where economic value of the crop loss prevented by
the control action is equal to the cost of that control action
 Determined through extensive research

5. Economic Threshold
 Threshold
 Stimulus has reached a sufficient level to
provoke a response
 Must be qualified further
 Economic Threshold
 Pest density at which control action must be
taken to prevent the population from
increasing to the EIL
 ET occurs at a lower population that the
EIL…why?
 In weed science, the ET is equal to the EIL

6. Examples of thresholds??
 What are some of the thresholds written in our insect fact sheets?

7. Categories of pests based on occurrence
 Regular pest: Frequently occurs on crop - Close association e.g. Rice stem borer, Brinjal
(eggplant) fruit borer
 Occasional pest: Infrequently occurs, no close association e.g. Caseworm on rice, Mango stem
borer
 Seasonal pest: Occurs during a particular season every year e.g. Red hairy caterpillar on
groundnut, Mango hoppers
 Persistent pests: Occurs on the crop throughout the year and is difficult to control e.g. Chilli
thrips, mealy bug on guava
 Sporadic pests: Pest occurs in isolated localities during some period. e.g. Coconut slug
caterpillar

8. Categories of pests Based on level of infestation
 Epidemic Pest : Sudden outbreak of a pest in a severe form in a region at a
particular time e.g. Whitefly outbreak in Punjab, Sugarcane wooly aphid in
Karnataka
 Currently locust attack in India and pakistan in 2019-2020
 Endemic pest: Occurrence of the pest in a low level in few pockets, regularly and
confined to particular area e.g. Rice gall midge infestation in coastal Karnataka,
Red headed hairy caterpillar on groundnut (peanut) in Karnataka

9. (i) Key pest:-
 Most severe and damaging pests
 GEP lies above EIL always
 Spray temporarily bring population below EIL
 These are persistent pests
 The environment must be changed to bring GEP below EIL e.g. Diamond back moth
(ii) Major pest :-
 GEP lies very close to EIL or coincides with EIL
 Economic damage can be prevented by timely and repeated sprays e.g. Cotton jassid, Rice stem
borer
Pest categories according to EIL, GEP & DB

10.  (iii) Minor pest/Occasional pest
 GEP is below the EIL usually
 Rarely they cross EIL
 Can be controlled e.g. Cotton stainers, Rice hispa, Ash weevils
 (iv) Sporadic pests
 GEP generally below EIL
 Sometimes it crosses EIL and cause severe loss in some places/periods e.g. Sugarcane
pyrilla, White grub, Hairy caterpillar
 (v) Potential pests
 They are not pests at present
 GEP always less than ETL
 If environment changed may cause economic loss e.g. H. armigera is potentia pest on
alfalfa, S. litura