pest control with the help of Growing degree days

1. USING GROWING DEGREE-DAYS
FOR PEST MANAGEMENT
Presented by
P.MANIKANDAN
M.Sc.,(Ag.)Entomology
Chaiman: Dr.R.Kannan
Assistant Professor in Entomology
Annamalai university

2. GDD/GDU
 Growing degree days (GDD)/growing degree
units (GDUs): a heuristic tool in phenology.
 GDD are a measure of heat accumulation
 Used by farmers to estimate the growth-stages of crops,
weeds, and life stages of insects;

3. GDD CALCULATION
 GDD are calculated by taking the average of the daily
maximum and minimum temperatures compared to a base
temperature,(usually 10°C).
 Maximum temperature is usually capped at 30°C
 If the mean daily temperature is lower than the base
temperature then GDD=0.

4.  When pest management is based on calendar timings,
Daily temperature is not taken into account.
 This can result in misleading information regarding
current insect activity.
 Insects, plants and many other organisms, are
dependent on temperature to develop

5.  Insects are cold-blooded animals, temperature plays a
major role in their growth and development.
 Species specific threshold temperature
 Depending on weather conditions, insect development
may vary from year to year by a few weeks, consequently
predicting the proper time for control measures is difficult.

6. DEPENDING ON THE DEVELOPMENT OF INSECTS
AT DIFFERENT TEMPERATURE LEVELS

8. PEST CONTROL WITH GDD
 Insect development and growing degree days are used by
farmers for use pest control methods.
 Applying the pest control methods or treatment at the point
that the pest is most vulnerable.
 For example:
 Black cutworm larvae have grown large enough to start
causing economic damage at 165 GDD
 Azalea Lace Bug emerges at about 130 GDD
 Boxwood leaf miner emerges at about 250 GDD
 This system can be more accurate than the calendar method
for estimating insect development and timing management
strategies.