The following is a discussion about controlling adults (cucumber beetle) to ultimately prevent damage from southern corn rootworm in peanuts. Entomologists across the peanut belt are looking into this approach to prevent damage. However, there are no solid data sets demonstrating that this approach will be effective.
Royals:
I checked the SCR traps in Lewiston today and the numbers are good. In trap #1, there were 15 adults and trap #2 had 31. So, timing-wise I think we are getting close to treating. What are your thoughts?
Jordan:
There will be pegs and subsequent pods developing in early July. Not sure, of the life cycle of cucumber beetles but the adults right now could be responsible for worms in early to mid-July.
Brandenburg:
Steward has to be a preventive to stop the adults from laying eggs. Once the eggs are in the soil, the Steward will not have an effect. We need to be proactive with repeat apps to keep the adult numbers down.
Jordan:
Certainly agree. I am just wondering how soon to start based on life cycle. If an adult lays eggs on June 15, will the actual worm still be in the soil to feed on pods on say July 15 or will the worm have gone through its cycle?
Brandenburg:
Once the eggs are laid, we cannot touch them with Steward. The eggs will hatch in about a week, then the rootworms will feed for two weeks or so and then the pupae will be in the soil for about a week before the next adults come out. So an egg laid June 15 will complete the life cycle in typically just over a month during the summer.
Jordan:
Assume if you avoid the first generation worms (if there are no pods to feed on while they are living) you could still be hit by the second generation (along with the new adults coming into the field.)
Brandenburg:
I think the bulk of the eggs are probably laid in late June and the first three weeks of July. The next generation, actually the third of the year since the first is in corn, is rarely a problem in peanuts probably because pods are more mature and I am not sure the crops is very attractive to the adults.