Cotton Aphids Showing Up

We have a pretty wide range of ages in our cotton with the oldest around 10-11 leaves.  Squaring should start in older fields before too long.

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Thrips are no longer an issue due to the size of the plants and Jeremy Greene pointed out in last week’s Cotton/Soybean Insect Newsletter that spraying for them at this point is a waste of money.  Not much is bugging us right now, maybe a few plant bugs here and there and some cotton aphids are starting to show up.

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Usually, we don’t have to treat for aphids.  Natural enemies like parasitic wasps, lady bugs, and the pathogenic aphid fungus, Neozygites, do a pretty good job of holding down populations.  Last season we saw Neozygites come through in late July and wipe the aphids out.

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Neozygites on cotton aphids.  The dark colored aphids are infected.  (From 2015 season)

When scouting, shiny, sticky leaves are a pretty good indicator that aphids (or whiteflies) are present.  The shiny residue is the honeydew that is excreted as the feed.  Ants love it.  You can see a few in the second photo above.  Again, you probably won’t need to make any treatments unless you can’t see the plants for the aphids.  The products that are labeled for aphids are pretty rough on your natural enemies, so don’t be too quick to act.

For reference, check out the Cotton Insect Section of the 2016 SC Pest Management Handbook.  Thresholds are in a table at the top of page 105 and if needed, products labeled for aphids are on page 107.

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