forecasting model for insect pests

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Forecasting Models for major Insect pests
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Forecasting involves all the activities in
ascertaining and notifying the growers of
community that conditions are sufficiently
favourable for certain insect pest, that
application of control measures will result in
economic gain or on the other hand and just as
important that the amount expected is unlikely
to be enough to justify the expenditure of time,
energy and money for control.

Miller and
OBrien (1952)
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Crop Pests - Weather Relationship
Crop
Weather
Pests
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Pre-requisites for developing a Forecast
System

• The crop must be a cash crop(economic yield)
• The insect must have potential to cause
  damage(yield losses)
• The Insect pest should not be regular
  (uncertainty)
• Effective and economic control known (options to
  growers)
• Reliable means of communication with farmers
• Farmer should be adaptive and have purchase power

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National Consultation on a Framework for Climate
Services in Belize
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Criteria for successful Insect pest forecasting
system

• Reliability -use of sound biological and
  environmental data
• Simplicity - The simpler the system, the more
  likely it will be applied and used by producers
• Importance -The insect pest is of economic
  importance to the crop,
• Usefulness -The forecasting model should be
  applied when the insect can be detected reliably
• Multipurpose applicability -monitoring and
  decision-making tools for several diseases and
  pests should be available
• Cost effectiveness -forecasting system should be
  cost affordable relative to available insect pest
  management tactics.

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Experimental pest and disease data
Sensitivity studies
Observed weather
calibration
calibration
Pest and disease models
Weather generator Re-sampling approach
Future hourly weather data
Climate change scenarios
Future pest/disease scenarios
Schematic overview of the Forecast model for
Insect and disease
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Forecast Model- Types

• Between year models
• These models are developed using previous years
  data.
• The forecast for pests and diseases can be
  obtained by substituting the current year data
  into a model developed upon the previous years.
• Within year models
• Sometimes, past data are not available but the
  pests status at different points of time during
  the current crop season are available.
• In such situations, within years growth model
  can be used, provided there are 10-12 data points
  between time of first appearance of pests and
  maximum or most damaging stage.

(Amrender,2006)
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Forecast Models Developed in the Past for insect
pests

• Techniques used were essentially Statistical
  (Correlation and Regression Analysis)
• T.P. Trivedi had proposed a regression model to
  predict the pest attack.
• Model seems to work only for some years
  (1992-1994)
• Correlation analysis was used by C.P. Srivastava
  to explore the relationship between the rainfall
  and pest abundance in different years.
• The technique is not effective as the attributes
  dont follow normal distribution

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Model based on Regression method
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Weather Related Forecasting Model

• Observations-
• Crop data Phenological development, Growth, Leaf
  area and Variety
• Insect pest Pest population
• Weather Data Required (hourly for ten or more
• years)
• Precipitation
• Temperature
• Sunshine/cloudiness
• Relative humidity
• Leaf wetness
• Wind direction and speed

National Consultation on a Framework for Climate
Services in Belize
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Degree-Day Models

• Degree-days (DD) are used in models because they
  allow a simple way of predicting development of
  cold-blooded organisms (insects, mites, bacteria,
  fungi, plants).
• Degree-day models have long been used as part of
  decision support systems to help growers predict
  spray timing or when to begin pest scouting.
• 1 degree-day (DD)-DD is way of measuring of
  Insect growth and development in response to
  daily temperature
• http//www.ipm.ucdavis.edu/MODELS

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Calculating degree-days

• Degree days (Maximum temperature minimum
  temperature)/2 - Base Temperature
• Accumulated growing degree days was derived by
  using the formula
• ????????
• Where,
• Tmax maximum temperature (C)
• Tmin minimum temperature (C)
• Tb base temperature (C)
  (Iwata,1984)

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Degree-Days Models types
Simulation model
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Phenology Models

• Phenology models are driven by several weather
  parameters on hourly basis.
• Relationships between temperature and stage
  specific development rates of the insect life
  cycles are established in through laboratory
  experiments under controlled conditions.
• For validation, implemented model predictions are
  compared with independent field observations from
  several years.

(Stinner et al., 1974)
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Two Methods to Manage Codling moth Larvae

• Calendar Approach
• Treat 3 weeks after full bloom

• Degree Day Model
• Monitor adult flight with pheromone traps
• Biofix 1st consistent catch of moths in traps
• Treat at 250 DD after Biofix

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IPPC weather data homepage (http//pnwpest.org/wea
)
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IPPC weather data homepage (http//pnwpest.org/wea
)
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GDD approach

• This method is based on the assumption that the
  pest becomes inactive below a certain temperature
  known as base temperature
• GDD ? (mean temperature base temperature)
• Not much work on base temperature for various
  diseases and insect pest. Normally base
  temperature is taken as 50 C
• Under Indian conditions, mean temperature is
  seldom below 50 C
• Need for work on base temperature and initial
  time of calculation

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Limitations of Degree-Day Models

• Insect response to temperature is not linear
• Lower Thresholds Temperature known for very few
  species.
• Measured temperatures not the same as those
  experienced by the pest.

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Models developed at IASRI

• Mustard
• Aphid
• Cotton
• American boll worm
• Pink boll worm
• Spotted boll worm
• Whitefly
• Groundnut
• Spodoptera litura
• Onion
• Thrips

• Sugarcane
• Pyrilla
• Early shoot borer
• Top borer
• Pigeon pea
• Pod fly
• Pod borer
• Rice
• BPH
• Gall midge
• Mango
• hoppers
• fruit-fly

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Forecasting model for H. armigera
S. No. Parameters Pest infestation in 10-14 standard week Pest infestation in 10-14 standard week Pest infestation in 10-14 standard week
S. No. Parameters High Medium Low
1 Sudden rise in the minimum temperature by gt50C around 7-8 standard week - - -
2 Rainfall during 1-9 standard weeks - - -
3 Base adult moth population gt15 per week during 5-7 standard week - - -
(Indian Institute of Pulses Research)
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Forewarning model given by National research
Center for Rapeseed Mustard
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• Potato aphid
• Potato aphid (Myzus persicae) is an abundant
  potato pest and vector of potato leaf-roll virus,
  potato virus Y , etc.
• Potato aphid population Pantnagar (weekly
  models)
• Data used 1974-96 on MAXT, MINT and RH
• X1 to X3) lagged by 2 weeks
• Model for December 3rd week
• Y 80.25 40.25 cos (2.70 X12 - 14.82)
• 35.78 cos (6.81 X22 8.03)

Trivedi et al 1999
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Potato Aphid population in 3rd week of
December at Pantnagar
Trivedi et al 1999
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(Yadav and singh,2015)
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Deviation method

• Useful when only 5-6 year data available for
  different periods
• Week-wise data not adequate for modeling
• Combined model considering complete data.
• Not used for disease forewarning but in pest
  forewarning
• Assumption pest population in particular year
  at a given point of time composed of two
  components.
• Natural cycle of pest
• Weather fluctuations

(Mehta et al,2001)
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• Mango
• Mango fruit fly Lucknow (weekly models)
• Data used 1993-94 to 1998-99 on MAXT, MINT and
  RH X1 to X3
• Model for natural pattern

t Week no. Yt Fruit fly population count
at week t
Mehta et al.(2001)
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Mango fruit fly population prediction model based
on deviation method in Lucknow
Mehta et al.(2001)
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Pest simulation models

• Pre requisites for Simulation models
• Mathematical descriptions of biological data.
• Computer programs or software to run these
  models.
• Application of these models in understanding
  population dynamics and dissemination of pest
  forecasts for timely pest management decisions.
• (Coulson and Saunders, 1987 )

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EPIPRE

• EPIPRE (EPidemics PREdiction and PREvention) is a
  system of supervised control of diseases and
  pests in wheat.
• The participating farmers do their own pest
  monitoring, simple and reliable observation and
  sampling techniques.
• Farmers send their field observations to the
  central team, which enters them in the data bank.
  Field data are updated daily by means of
  simplified simulation models. Expected damage and
  loss are calculated and used in a decision
  system, that leads to one of three major
  decisions
• treat
• don't treat
• make another field observation
• Ex-Rhopalosiphum padi

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Organization scheme for EPIPRE in relation to
farmers and research organizations
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Generic Pest Forecast System (GPFS)

• Combination of multiple weather variables and
  biological processes into a single predictive
  model Temperature, relative humidity, leaf
  wetness (hourly)
• Growth, mortality, infection
• Predict timing and abundance of specific life
  stages
• Estimate damage to specific host plants based on
  pest and host phenology

Hong et al,2013
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GPFS Model Modules

• Development Response to temperature
• Simple linear model (Tmin, Topt1, Topt2, Tmax)
• Mortality factors Heat, cold, aging, soil
  moisture, food availability

• Case Studies
• Insects
• Bactrocera dorsalis (oriental fruit fly)
• Epiphyas postvittana (light brown apple moth)
• Helicoverpa armigera (boll worm)

Hong et al,2013
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Oriental Fruit Fly

• Highly polyphagous and extremely invasive
• Development is temperature driven
• Available data sets of distribution records and
  seasonal observations available for validation
• Model validation in three locations India, USA
  (HI), China
• Comparisons made with CLIMEX-compare locations

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Case Study I Bangalore, India
Of fruit fly
(Jayanthi and Verghese, 2011)
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Ordinal logistic model model for qualitative
data

• pest / disease outbreak can be taken even if the
  information on the extent of severity is not
  available but merely the epidemic status is
  accessible
• models have added advantage that these could be
  obtained even if the detailed and exact
  information on pest count / disease severity is
  not available but only the qualitative status.
• where z is a function of weather variables.
• Forecast / Prediction rule
• If P .5 more chance of occurrence of epidemic
• If P lt .5 probability of occurrence of epidemic
  is minimum

(Mehta et al. 2001 Mishra et al. 2004 Johnson
et al. 1996 Agrawal, et al. 2004)
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Forecasting outbreak of pest using Ordinal
Logistic model
Crop (Location) Pest Important variables Time of Time of Workers
Damage Forecast
Cotton (south India) Whitefly MAXT,MINT,RH I RH II Mid Dec. Mid Nov. Agrawal et al. (2004)
Sugarcane (Muzaffarnagar) Pyrilla MAXT RHM Oct.-Nov. May Mehta et al. (2001)
Mango (Lucknow) Fruit fly MAXT,MINT RH I May-June 2nd week of March Misra et al. (2004)
MAXT maximum temperature, MINT minimum
temperature, RH 1 relative humidity
(morning),RHIIrelative humidity (evening) and
RHMmean relative humidity
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Uses of ANN(artificial neural network technique)

• ANN provides an efficient alternative tool for
  forecasting.
• Neural Networks dont make any distributional
  assumption about the data.
• It learns the patterns in the data, while
  statistical techniques try to do model fitting.
• ANNs can often correctly infer the unseen part
  of a population even if data contains noisy
  information.
• This makes neural network modeling a powerful
  tool for exploring complex, nonlinear biological
  problems like pest incidence.

(Agrawal et al. 2004 Dewolf et al. 1997, 2000
Kumar, et al. 2010)
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Remote Sensing

• Remote sensing technologies are used to gather
  information about the surface of the earth from a
  distant platform, usually a satellite or airborne
  sensor
• The integration of remote sensing, GPS and GIS
  are valuable tools that can enable resource
  managers to develop maps showing the distribution
  of insect infestations over large areas
• Site-specific data, such as type of insect, level
  of damage, stage of attack, yield loss are
  collected from different sources, stored and
  managed in spatial database , either contained
  within the GIS or connected to the GIS from an
  external source.

(Wu et al., 2008)
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Predicting the potential geographical
distribution of sugarcane wooly aphid

• Prediction of potential geographical distribution
  of sugarcane wooly aphid using its current
  distribution and data on range of environmental
  parameters.
• Two approaches for the purpose
• GPS (Global Positioning System)
• GIS (Geographic Information System)

(Prabhakar et al., 2012)
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Infrastructure to calculate risk maps
step1
met. data
Geo.data
step 2
combine with GIS
Interpolation
step 3
Calculation of forecasting models with
interpolated input parameters
step 4
Presentation of results
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The forecasting models database

• The CIPRA (Computer Centre for Agricultural Pest
  Forecasting) software allows the user to
  visualise forecasts of insect development .
• Within CIPRA, there is forecasting models for a
  total of 35 pests (25 insects and 10 diseases).
  In vegetables ( cabbage, carrot, onion, potato,
  tomato), fruits(apple, grape, strawberry), and
  cereals (wheat, barley, corn).
• Each crop has its own independent computer
  programs file, known as DLL (Dynamic Link
  Library), which makes possible their integration
  in other specialized software.
• (Bourgeois et al., 2008)

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DEGREE-DAYS MODELS AVAILABLE IN CIPRA

• Mathematical models vary from simple degree-days
  approach based on air temperature to more
  detailed epidemiological system based on air
  temperature, relative humidity and duration of
  leaf wetness.

• Crop
• Apple
• Crucifers
• Potato
• Tomato
• Cotton

• Insect
• Codling moth
• Diamond back moth
• Colorado potato beetle
• Tomato fruit borer
• Spotted boll worm

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Computer Software Model for Prediction for Insect
pest

• PEST-MAN is a computerized forecasting tool for
  apple and pear pests-Canada
• MORPH is predictive computer model for
  horticultural pest-UK
• SOPRA is applied as a decision support system for
  eight major insect pests of fruit orchards
  -Switzerland and southern Germany
• The SIMLEP decision support system for Colorado
  potato beetle (Leptinotarsa decemlineata)-Germany
  and Austria

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mainstream technology of computer software for
forecasting
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Insect pest forecasting concept
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success of a forecasting

• The success of a forecasting system depends,
  among other things, on
• The commonness of epidemics (or need to
  intervene)
• The accuracy of predictions of epidemic risk
  (based on weather, for example)
• The ability to deliver predictions in a timely
  fashion
• The ability to implement a control tactic
  (Insecticide application, for example)
• The economic impact of using a predictive system

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Uses of insect pest forecasts

• Forewarning or assessment of insect pest
  important for crop production management
• for timely plant protection measures
• information whether the insect pest status is
  expected to be below or above the threshold level
  is enough, models based on qualitative data can
  be used qualitative models
• loss assessment
• forewarning actual intensity is required -
  quantitative model
• For making strategic decision-
• Prediction of the risks involved in planting a
  certain crop.
• Deciding about the need to apply strategic
  control measures (soil treatment,
  planting a resistant cultivar etc)

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• For making tactical decision-
• Deciding about the need to implement insect pest
  management measure
• Entomologist and meteorologists have often
  collaborated to develop insect pest forecasting
  or warning systems that attempt to help growers
  make economic decisions for managing insect.  
• These types of warning systems may consist of
  supporting a producers decision making process
  for determining cost and benefits for applying
  pesticides, selecting seed or propagation
  materials, or whether to plant a crop in a
  particular area.
• forecasting models in order to optimize timing of
  monitoring, management and control measures of
  insect pests

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Limitations of forecasting Models-

• Statistical models are simple in their usage and
  less parameter-intensive, but they are limited in
  the information they can provide outside the
  range of values for which the model is
  parameterized.
• Crop simulation models are rather hard to use and
  parameterize. The need for calibration can be
  quite data extensive and not applicable to some
  developing countries.
• The major limitation in use of satellite-borne(rem
  ote Sensing) data in pest forewarning is the
  timely availability of cloud-free data with the
  desired spatial and spectral resolution

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Thank You