I put opaque covers on 2 of my 4 hives last week,I also put out 5 million nematodes out.I do have screened bottom boards and try to keep a daily count on dead beetles.I normally have 8-10 dead bugs every day.The 2 hives with opaque covers also get 5 hours full sunlight,I put sun blockers on top so the sun would not cook them but they still get the light.The last 2 days I have had 0 dead bodies in one and 2 in the other.This is after 1 week.I put opaque covers on my other 2 yesterday.The hives are 10 frame medium 2 deep,the ones I did yesterday are 3 deep and are in more shade,I hope they do as well.I am in central Florida so you know we have plenty Beetles.