Dear Mr.Murthy,

Your letter has prompted me to share my views on temperature degree days and growth.

The concept of accumulation of degree days as related to growth and deveopment of organisms (be it plants or insects) usully holds good for the temperate World, where temperature is the predominant limiting factor and not the water availabilty.

That is why the scientists workiing in the cooler environments had laid more empahsis rightly on the temperature. But for the Tropical World water availabilty becomes the is the main driver of growth and development and not temperature.

Most of these models based predominantly on growing degree days do not accurately predict the role of water stress on phenology in a tropical situation.

Some studies by Prof.S.K.Sinha group i(IARI) have clearly shown that there exists a better relationship between wate stress (like accumulated water potential) than tempeature degree days.

One has to understand what combinations of the given local envronmental, agronomic and genotypic factors trigger the observed spurt in the population of the insect popultions.

The sure method of model imporvement lies in understanding how they work. Only then we can devise experiments and put the appropriate quotients for various interactions in the models.

if you are in India I would stongly suggest you to interact with Dr.Y.S.Ramakrishna group in the Central Research Institute for Dryland agriculture in Hyderabad whihc is having a net work project on modelling insect and pest.

Gangadhar


vasiraju murthy <[log in to unmask]> wrote:
Dear INSAM,DSSAT,AGROMET-L members,

Regards and wishes,

In the WMO's "Lecture notes for training agricultural meteorological
personnel"preared by Jon Wieringa and Jakob Lomas,Second edition,2001, as
WMO-no.551 ,under Chater 8 --Oerational agrometeorology--in page no 129 it
is mentioned as followed.

The need for --------.Another insect pest which can only be controlled by
close cooperation between meteorologists and entomologists is the codling
moth-----when the catch becomes significant ,'Biofix day',is decided for the
area around the station,as the starting day for accumulating degree days
with base temerature 10 degrees C,and ceiling temerature 32 degrees C.First
pesticide spray alert is at when accumulated growing degree days reach 640
from "biofix'----.

My question is--- where is such research as also operational
agrometeorological service /forecast is going on in the world now ?

I shall be happy to interact with him/them if the exact address as also
E-mail ID's of scientists /extension workers is provided to me.

Murthy.

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