We had a great discussion at the cowpea curculio crisis meeting in Tifton. Unfortunately I don’t have great news to report about the meeting, but I have highlighted a few key points that I took away from the meeting:
1) Let’s discuss insecticides:
Many of you know that pyrethroids are only showing moderate suppression of the cowpea curculio. Therefore, many of you have asked me about the use of Vydate, a carbamate, as a control option. However, in field trials where the total clean pea (not stung peas) weight per 10ft was measured, the use of Vydate alone and Vydate in combination with HGW86 (a diamide) showed no better control then the Untreated Check.
Therefore, Vydate is not a viable option and a Section 18 is probably not worth pursuing at this point.
Diamide insecticides, a new chemistry, were also tested alone and showed not effective.
PBO a known synergist of pyrethroids was tested in research trials and was no more effective than a pyrethroid applied alone. Many growers at the meeting mentioned that they had already tried the addition of PBO and observed the same results as seen in field trials.
2) Is rotating an effective cultural control? Unfortunately, no. Although cowpea curculios are considered a flightless weevil, they do have the capability to fly, and have been found in fields that have not been planted to cowpeas for 50 years or more. This tells us that these insects are actively moving into fields in search of cowpea hosts. One grower mentioned that moving fields 2-3 miles down the road did not help him reduce his cowpea curculio numbers; however, when he moved fields 6-8 miles down the road with no cowpeas present within those 6-8 miles he saw reduction in curculio numbers. This however, is not a practical option for growers. There will always be other cowpea fields around!
Which brings me to my 3rd discussion topic
3) Regional control will be needed: If an effective control option is found we will need to attempt to control cowpea curculio on a regional basis. If 90% of growers perform effective control options it won’t be enough. We will need everyone to participate and attempt to eradicate this weevil in the southeast, as was done to the boll weevil.
4) Fall populations are higher! It was shown in research that some death of cowpea curculios is occurring during overwintering. Therefore spring populations are lower than fall populations.
5) Cowpea curculio likes yellow: An interesting point worth mentioning is that like most weevils the cowpea curculio is visually attracted to the color yellow. Therefore, it may worthwhile for a home gardener or small scale grower to put up yellow sticky traps and observe whether this aids in control.
6) Future research: Many of you have asked me about research being done on a soil treatment for the cowpea curculio. This research is currently being conducted, and UGA is investigating a soil treatment of Lorsban in the fall when grubs are dropping down to the ground to pupate. The window of opportunity to actually kill the grubs in soil is small and will take precise timing of application.
I wish that I had better news to report from this meeting. I ask from cowpea growers that while you’re out there investigating alternative controls and doing your own experimentation that you please let me know if you see a control option that seems promising. If you have any ideas or information that you would like to share please call me at 22-921-1992.