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OSU Extension

College of Food, Agricultural, and Environmental Sciences

CFAES

FARM #1: RIPLEY-A

Plant Date: April 28, 2021


Report Date: June 6, 2021 - Waterhemp/Pigweeds

Growing Degree Day since planting: 407

Total Growing Degree Day since 01/01/21: 732

Growth: V1

Pest: Waterhemp & Redroot/Smooth Pigweed - Pigweed species are beginning to emerge. Be on the lookout and control as soon as possible before height reaches over 6" tall. Seedlings are very small and can easily be missed. See images below for aid with identification. 

A. The impact of this much seed—doing the math, From: Palmer Amaranth and Waterhemp Management: It’s All About the Seed

  • Single female plant produces 1 million seeds
  • Assume 20 percent of these are viable
  • Assume only 25 percent germination following year equals 50,000 plants
  • Even assuming 99 percent control that equals 500 plants (assume half are female) and…… 
  • 250 female waterhemp plants produce 250 million seed
  • Following year—equals 12.5 million plants
  • Even with 99 percent control, that can mean 125,000 plants

B.Chemical Control: From Waterhemp Management in Soybeans - Take Action Fact Sheet

  • Soon before or after soybean planting, apply a full rate (according to label guidelines for soil type and organic matter content) of an effective pre-emergence, soilresidual herbicide.
  • Depending on the herbicide resistance profile, effective soil-residual herbicides may include: Authority® First, Authority Assist, Authority MTZ, Authority XL, Boundary®, Dual II Magnum(or other metolachlor products), Enlite®, Envive®, Fierce®, Gangster®, Outlook®, Prefix®, Sencor®, Sonic®, Treflan®, Valor®, Valor XLT, Warrant® and Zidua

C. Visit the following links to find more information on waterhemp/pigweeed control. Contact the Brown County Extension Office if you have additional questions or need help with identification. 

Waterhemp seedling

Image above: watehemp seedling

waterhemp seedlings

Image above: Waterhemp seedling sizes 06/04/21. 

Pigweed

Image above: Redroot/smooth pigweed seedling. 


 

Report Date: May 26, 2021 - Bean Leaf Beetle

Growing Degree Day since planting: 310

Total Growing Degree Day since 01/01/21: 646

Growth: VE-V1

Pest: Bean Leaf Beetle damage conitues to progress. Estimated 10-20% leaf defoliation with small pockets of more sevre feeding. Again, earlier panted soybeans can be a trap crop. Damage normally doesn't reach thresholds of 40% defolaition this early in the season as overwintering adults will likely die in the next 7-10 days. 1st genreation adults will begin feeding again around July and 2nd generation adults will begin feeding in the fall (late August  - September). Pod damage can occur in the fall and thresholds are lower. 

The Corn, Soybean, Wheat, and Forages Field guide (shown below) has guides to assist with defolaitions estimates. Contact the Brown County Extension office to purchase a copy. 

See May 10 update for more details on control. 

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Report Date: May 20, 2021 - Bean Leaf Beetle

Growing Degree Day since planting: 198

Total Growing Degree Day since 01/01/21: 534

Growth: Wide Variety of seedling stages (non-emerged to VC). Some seeds still in the soil were rotten and others were still viable and germinating. 

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Pest: Bean Leaf Beetles (BLB) and foliar damage present.

Source: Hammond, et al. Bean Leaf Beetle on Soybean, Ohioline.osu.edu

  • Description: BLB can overwinter in the adult stage and will pass through 2 generations in Ohio. Overwintering adults are found now feeding of soybean foliage. 1st generations are typically found in late June and early July. 2nd generations appear around August and September. 
  • Early Seaon Scouting and Damage: As with this field, early planted fields can become a trap crop for the first generation, especially if minimal soybeans are emergend in surrounding areas. However, economic injury is rare at this stage. "Severe leaf feeding can cause significant damage and should be stopped if defoliation goes over 50%, plants are being stunted, and beetles are still actively feeding."  The foliar damge foud in this field ranged from 5-10%. 
  • Late Season and Scouting: Later planted soybeans that are still green in September can also serve as a trap crop if others nearby have reach physiological maturity. "Scouting, sweeping for population or for defoliation assessment, pull 20 plants and estimate damage among entire plant. Rescue treatment is justified when defoliation exceeds: 40% prior to bloom, 15% from bloom to pod-fill, and 25% after pod-fill to plant yellowing." BLB can slaco vector bean pod mottle virus (BPMV.) "Infection by this virus results in plants that remain green well past harvest maturity, with seeds that often are severely mottled"
  • More details on identification and management:  
    1. Ohio Sate Bean Leaf Beetle Fact Sheet | https://ohioline.osu.edu/factsheet/ENT-23

 

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Report Date: May 10, 2021 - Emergence

Description: Emergence started. 

Growing Degree Day since planting: ~100

Total Growing Degree Day since 01/01/21: 435