Japanese beetle threshold

[wood1954]

Whats your threshold for spraying for these buggers? After handpicking them for a week i got out the pyrethrin as they were swarming my elderberry bushes and too a lesser degree my vines, couldn't take it anymore. I find it odd that after spraying i dont even see them flying around, it's almost as tho the insecticide changes how the plants look or smell so the bugs dont even come near. the elderberry flowers really attracted them, now none.

 

[salcoco]

start spraying immediately. should be good if spray at 7-10 ,day interval two spays should do it.

 

[BigH]

https://blog-fruit-vegetable-ipm.ex.../japanese-beetle-management-and-choosing.html
Walked the vineyard yesterday and collected a mason jar of JB by hand. Noticed that swarms were forming in rows that I had just walked 5 minutes prior. Decided to make my second and final application of assail. I probably waited a bit too long long to be honest, but the prior day wasn't all that bad.

The general advice I tend to see is to hit them before those big swarms start forming, so you can keep most of the pheromones out of your vineyard.

H