percentages—implications for treatments in soybean
At the time of this report, we have tested 109 corn earworm moths this week. These moths represent the ‘front edge’ of the large second generation flight from corn. The results are not good. The first batch of 49 moths had 49% survivorship and the second batch of 60 moths had 53% survivorship. We have another 150 moths in vials to be assessed tomorrow (Friday). What does this mean? This confirms what I thought we might see based on previous year’s patterns—with survivorship percentages peaking in late July/early August. If corn earworm flights are heavy and large worm infestations set up in soybean fields, non-pyrethroids will need to be tank-mixed with pyrethroids (which are still recommended to control whatever stink bugs may be present). We have had success with several pyrethroid tank mix options including with Belt, Steward, and Orthene. I was asked about Lannate. Lannate is an effective product against corn earworm but I have not tested whether it will tank mix with a pyrethroid. If you choose this option, you should jar-test the mix before loading your spray tank. Also, although effective, Lannate has a very short residual activity period—24 hours, unless it rains. If the worm infestations do not develop to high levels, the pyrethroids will probably still do a decent job—apply them only at the highest labeled rate.