That varies depending on what chemical you are spraying and what pest you are going after.

 

Heliothis caterpillar in Chickpea crop.
Chemical choice is either Indoxacarb or Alpha-cypermethrin.

 

cooler day temps

 

STO, could you elaborate on that.
I should probably elaborate too.
What I`m trying to say is: Is it better to spray in the cool of the early morning, with a hot day to follow, or is it better to spray immediately before dark where you have 12 hours of cooler night time temps where the grubs are possibly more active, or does it make no difference to the result.