Camden Crop News: August 2023

2023 Wheat Variety Trial Data

Downloadable results from our 2023 NE AG Expo Wheat Variety Trials are now available. Production information, as well as rainfall totals for each site, can be found on the second page. Yields were ranked individually at each location, and averaged across the locations to give an overall ranking.

National Corn Yield Contest Entry Deadline: 8/16

Entry & Harvest Rules for the 2023 National Corn Yield Contest can be accessed online. Per this publication entry and contest fees must be completed online by 4:30 pm Central Time no later than August 16, 2023.

Soybean Insect Management

Last week I captured the first corn earworm moths of the year in the blacklight trap I operate in Camden. As moth catches increase in this local trap, the likelihood of moths flying into and laying eggs in your soybean fields that will become worms increases as well. Trap data is published every Monday on the Camden Extension Center website under the Camden Crop Data tab on the left side of the page. Furthermore data from traps across the state will be reported on the NC State Extension Trap Data site.

Dr. Dominic Reisig noted in a 7/21/23 article: Start scouting for corn earworm in soybeans at R3 (beginning pod). We have several resources on scouting. Scouting for Insects on the NC State Extension soybean website has a section dedicated to corn earworm sampling. On this page, you can find a link to a

to see how to scout using a sweep net, drop cloth, and how to use the online threshold calculator for corn earworm. We also have the NC Soybean Scouting Guide, with tips for corn earworm scouting on page 82. Finally, this

describes how to scout for mid-season soybean insect pests. Keep in mind that we can tolerate very very high levels of corn earworm in blooming soybeans (R1 and R2). So it’s not a good idea to tank mix insecticides with fungicides for a few corn earworms. Let biocontrol agents do their job! Also, be sure to scout for stink bugs- they are most damaging from R3 (beginning pod) to R5 (beginning seed).

Thresholds


  • For foliage feeders (soybean looper, green cloverworm, armyworms, and bean leaf beetle) the defoliation threshold is 30% defoliation up to two weeks prior to bloom, and 15% defoliation from two weeks prior to bloom until the pods have filled(R7-R8). Note that this includes a defoliation estimate throughout the entire canopy, not just the top visible leaves. Also, loopers tend to defoliate from the bottom up. See defoliation images below.

Leaves at varying stages of destruction

  • Stink bug threshold is 5 stink bugs per 15 sweeps of a sweep net for beans planted in 7-21inch wide rows (with the exception of edible or seed soybeans being 2.5/15 sweeps).
  • Our Corn earworm threshold is based on our corn earworm economic threshold calculator, which utilizes information you input concerning control cost, soybean price, row width, and sampling method to develop tailored thresholds.