Soybean Yield Loss to Insects in the Midsouthern US

Survey-based soybean yield losses to insects are estimated annually in several southern US states. These estimates are collected through informal telephone or written survey queries to crop consultants and extension personnel who actively scout soybean fields and assist growers in making insect control decisions. Production losses are based on estimates of yield in the absence of insects.

Insect loss and cost data for insect management are from No. 1 issues of 2012-2019 Midsouth Entomologist. Acreage, production, and price data are from NASS.

Below are summary results from the 2011-2018 surveys in the midsouthern states of Ark., La., Miss., and Tenn.

•    Economic losses attributed to insects (yield lost to insects + insect management costs) during the 2011-2018 period in the combined four states (calculated using the commodity prices shown in Table 1) ranged from $407.7 million in 2013 to $695.2 million in 2017.

•    During the 2011-2018 period, Arkansas had the largest percentage yield loss to insects of the four states. Of the four states, insect control costs/acre were the highest for Arkansas in 2011, 2012, 2014, 2017, and 2018, and for Louisana in 2013, 2015, and 2016 (Table 1). Tennessee had the lowest economic loss/acre (yield loss + control costs) to insects in all years.

•    During the 2011-2018 period, annual yield losses to insects in Mississippi ranged from 2.77% (2014) to 5.11% (2017). Economic losses attributed to insects (yield lost to insects + insect management costs) in Mississippi ranged from $46.45/acre in 2014 to $79.77/acre in 2017 (Table 1).

•    During the 2011-2018 period, economic losses to insect damage plus costs for applied control measures in Mississippi ranged from $100.8 million in 2011 to $173.1 million in 2017.

The following following statements summarize data shown in Table 2.

•    In Arkansas, armyworm complex, corn earworm, and stink bugs were prominent damaging insects in all years. Bean leaf beetle was prominent in 2013-2018, and soybean looper was prominent in 2011-2013 and 2016-2017. Redbanded stinkbug (RBSB) was the dominant stinkbug only in 2017.

•    In Louisiana, soybean looper and stink bugs were prominent in all years. Corn earworm was prominent only in 2011. Threecornered alfalfa hopper was prominent in 5 of the 8 years, while either green clover worm, velvetbean caterpillar, or both were prominent in 2013-2018. Soybean looper was prominent in 2016-2018. RBSB was the dominant stinkbug in 2017 and 2018.

•    In Mississippi, corn earworm and soybean looper were prominent in all years. Stink bugs were prominent in 2012-2018, especially in 2017-2018. RBSB was the dominant stinkbug only in 2017. Either green cloverworm, velvetbean caterpillar, or both had a significant presence in all years.

•    In Tennessee, stink bugs and green clover worm were prominent damaging species in all years. Corn earworm was prominent only in 2011, and soybean looper was not prominent in any of the 8 years. The green stinkbug was the dominant stinkbug in 2017 and 2018. Slugs were a prominent pest in 2017 and 2018. Dectes stem borer was the major pest in 2018.

The above estimates and summary points support the following important tenets for insect management in the Midsouth soybean crop.

•    Insects pose a constant threat to soybean production in the region, and cause significant economic losses each year.

•    Each Midsouth state had consistently prominent species across all 8 years, but all years had varied pests that were problematic in a given year and required management to prevent yield losses to those insects in those specific years.

•    The emerging importance of the RBSB in 2017 will warrant special attention in future years’ soybean crops.      

•    The consistent presence of several of the damaging insect species across all years underlines the importance of resistance management when control measures are selected each year. Where possible, insecticidal chemistries should be rotated when targeting the same pest year after year. Click here for additional information.

Composed by Larry G. Heatherly, June 2019, larryheatherly@bellsouth.net