|
| I basically agree with Ron's post. If you are worried about them affecting pollination you can pull back the shucks carefully & shake the ear to see how many of the silks fall off an how many remain attached. The ones that remain attached have not pollinated but by this time, depending upon the stage of pollination, it's probably too late to spray. Seed agronomists around here say that as long as the ear has 1/2" of silk showing it will pollinate. I believe the threshold for around here is 3-5 beetles per ear, over that & you should be considering spraying if it's not too late.
My big concern would be with root damage. Those beetles had to come from somewhere & it was from larvae in the ground so damage is most likely done. From my experience if you have good soil moisture the plant will usually put down roots fast enough that there shouldn't be much damage. If you are in dry soil then there's a greater chance of lodging. Are you seeing any elbowing of the plant? If so that's a very good indication that you have rootworm damage.
Another thing that I have seen is that rootworms seem to like certain varities over others. I have had fields where one variety will be absolutely flat & the other will be standing with little indication of damage. Use to see this more before anyone thought about using insecticide on 1st year corn but had problems just a couple years ago in a field where 1/2 the planter had a rw resistant & the other was a conventional with granular insecticide. The corn that was flat was the rwr corn. | |
|
western corn rootworm beetles
