Texas: Cotton Squaring; Soybeans at Pre-Bloom – Calhoun, Refugio & Victoria Counties

Debra Ferguson
By Stephen Biles, Pest Mangement News - Calhoun, Refugio & Victoria Counties , Texas AgriLife Extension June 14, 2013 19:17

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Texas: Cotton Squaring; Soybeans at Pre-Bloom – Calhoun, Refugio & Victoria Counties

Cotton

Cotton fields range from squaring to mid-bloom. Blooming cotton has from 7-9 nodes above white flower. We are finding cotton fleahoppers and verde plant bugs in cotton fields and I expect to begin seeing evidence of stink bug feeding in cotton fields that have been blooming for a couple of weeks.

  • Monitor squaring cotton for cotton fleahopper and verde plant bug. Treat when numbers exceed 15 per 100 plants.
  • Blooming cotton is generally considered safe from cotton fleahoppers.
  • Begin looking for evidence of stink bug feeding in cotton 10 days after first bloom using an economic threshold of 20% bolls with evidence of feeding. Soybeans Soybean fields range from pre-bloom to early pod fill. Fields with pods should be checked for stink bugs suing either a drop cloth or sweep net. I use a sweep net when checking soybeans because I find it covers more ground and is quicker but either method is similar in locating stink bug populations. Treat soybeans when they exceed 36 stink bugs per 100 sweeps or 1 per foot of row with drop cloth. Reduce the threshold to 24 per 100 sweeps or 2 per 3 feet if red-banded stink bug is a majority of species found.

Grain Sorghum

Sorghum fields range from pre-bloom to soft dough stage. Blooming fields should be monitored for sorghum midge. The populations of this insect should be increasing as the season progresses. Continue to scout fields for stink bugs and headworms using a bucket.

We are finding low to above threshold populations of stink bugs and headworm in local fields. The Economic Threshold for sorghum insects is dependent of the cost of control, crop value and number of heads per acre. I have found the number of sorghum per acre in fields along the Texas Coast range from 40,000 to 90,000 per acre.

Check your field to determine how this affects the ET for pests in your sorghum. If you assume $8 cost of control, $7/cwt and 60,000 heads per acre, the ET is 0.98 medium worms, 0.19 large worms and 0.58 stink bugs per sorghum head.

Soybeans

Soybean fields range from pre-bloom to early pod fill. Fields with pods should be checked for stink bugs suing either a drop cloth or sweep net. I use a sweep net when checking soybeans because I find it covers more ground and is quicker but either method is similar in locating stink bug populations. Treat soybeans when they exceed 36 stink bugs per 100 sweeps or 1 per foot of row with drop cloth. Reduce the threshold to 24 per 100 sweeps or 2 per 3 feet if red-banded stink bug is a majority of species found. Minute Pirate

Minute Pirate Bug

If you beat a few sorghum heads into a bucket, you will likely find some very small black and white insects. Minute Pirate Bugs are tiny (1/8 inch) black bugs with white markings at the base of the front wings (hemelytra), resulting in a band-like appearance across the body when wings are at rest. Wingless immature stages (nymphs) are orange and similar in size and shape to cotton fleahopper nymphs. These are some of the more voracious predators we find in our crops and are considered to be very beneficial.

Current field projects include:

• Sorghum planting rate in Refugio and Calhoun Counties

• Aflaguard use in corn for reducing aflatoxin in Refugio County

• Thrips control with foliar insecticides in Victoria County

• Fungicide use in grain sorghum in Victoria County

• Cotton Fleahopper control with foliar insecticides in Calhoun County

Looking for locations for the following trials:

• Stink bug and headworm control in Sorghum

• Fall armyworm control in bermudagrass pastures

I am interested in conducting research to solve pest management issues on your farm. Call me if you have something I should look into. 361-920-1138

Debra Ferguson
By Stephen Biles, Pest Mangement News - Calhoun, Refugio & Victoria Counties , Texas AgriLife Extension June 14, 2013 19:17

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