Soybeans: Bean Leaf Beetle (Certoma trifurcata)


Pub 812: Field Crop Protection Guide > Pub 812: Soybeans > Bean Leaf Beetle

Field Crop Protection Guide 2011-2012, Order 2011-2012 publication

Table of Contents

  1. Description
    • Seed Treatment
      • thiamethoxam Cruiser 5 FS
      • thiamethoxam + metalaxyl-M + fludioxonil - Cruiser Maxx Beans
    • Foliar Treatment
      • cyhalothrin-lambda – Matador 120 E
      • cyhalothrin-lambda – Silencer 120 EC
      • dimethoate – Cygon 4 E, Lagon 480 EC
      • imidacloprid + deltamethrin - Concept
  2. Related links...

 

Description

The bean leaf beetle adult is around 5 mm in length (small) with four black spots usually found on the wing covers. Adult beetles can vary in colour but are most often yellow-green, tan or red. A small, black triangle is visible at the base of the wing covers (the prothorax - behind the head). The margins of the wing covers have a black border.

Image 1. Bean leaf beetle adults vary in colour, but always have a small black triangle visible behind the head. They may or may not have four spots.
Image 1. Bean leaf beetle adults vary in colour,
but always have a small black triangle visible behind the head.
They may or may not have four spots.

The bean leaf beetle is often confused with the spotted cucumber beetle. A small black triangle is visible at the base of the wing covers (behind the head) of the bean leaf beetle.


Integrated Pest Management Options

Seed Treatment

Seed treatment is recommended for those fields with a history of early-season infestation from overwintering adults. Fields in southwestern counties of Ontario in particular tend to experience injury to the seedling crop from early infestations of beetles.

 
Active ingredient thiamethoxam
Trade name Cruiser 5 FS
Rate (product) 83 mL per 100 kg seed
Comments For use in commercial seed treatment facilities only. To reduce early-season defoliation. Do not graze or feed livestock on treated areas for 45 days after planting.

 

 
Active ingredient thiamethoxam + metalaxyl-M + fludioxonil
Trade name Cruiser Maxx Beans
Rate (product) 195 mL per 100 kg seed
Comments For use in commercial seed treatment facilities only. To reduce early-season defoliation. Compatible with Rhizobium-based inoculants. Check with inoculant manufacturers for details prior to use. Do not graze or feed livestock on treated areas for 45 days after planting.


Foliar Treatment

For protection from overwintering adults, in areas with history of injury, consider using insecticide seed treatment for early-planted soybeans.

Bean leaf beetle populations rarely cause enough defoliation after the seedling stages to require a foliar insecticide application in Ontario. Defoliation thresholds during the R1-R5 stage are listed in the OMAFRA Publication 811, Agronomy Guide for Field Crops.

Food-grade and seed soybeans may require protection, especially during the later R5 and R6 pod stages to reduce pod disease development caused by beetle feeding. If 10% of pods have feeding damage, insecticide may be necessary. Pay attention to preharvest intervals when spraying during the R6 stage of soybeans.

 
Active ingredient cyhalothrin-lambda
Trade name Matador 120 E
Rate per hectare (product) 83-233 mL per ha
Rate per acre (product) 34-94 mL per ac
PHI* 21
Comments Ground and aerial application. For best results, apply during the early morning, before temperatures rise,or during the evening, past the heat of the day. Use 100-200 L water/ha for ground application, 10-40 L water/ha for aerial application. Maximum 3 applications/yr. 24-hr re-entry period.

 

 
Active ingredient cyhalothrin-lambda
Trade name Silencer 120 EC
Rate per hectare (product) 83 mL per ha
Rate per acre (product) 34 mL per ac
PHI* 21
Comments Ground application only. For best results, apply during the early morning, before temperatures rise, and during the evening, past the heat of the day. Maximum 3 applications/yr. 24-hr re-entry period.

 

 
Active ingredient dimethoate
Trade name Cygon 4 E
Rate per hectare (product) 0.7-1 L per ha
Rate per acre (product) 280-400 mL per ac
PHI* 30
Comments Ground and aerial application. Use sufficient water volume to ensure good coverage. Maximum 3 applications/yr.

 

 
Active ingredient dimethoate
Trade name Lagon 480 EC
Rate per hectare (product) 0.7-1 L per ha
Rate per acre (product) 280-400 mL per ac
PHI* 30
Comments Ground and aerial application. Use sufficient water volume to ensure good coverage. Maximum 3 applications/yr.

 

 
Active ingredient imidacloprid + deltamethrin
Trade name Concept
Rate per hectare (product) 325-650 mL per ha
Rate per acre (product) 131-263 mL per ac
PHI* 20
Comments Provides suppression only. Do not apply this product if following a seed treatment or soil application of a Group 4 insecticide (neonicotinoids) within that season. Ground application only. Use high rate for fastest knockdown and best residual control. Minimum of 5 days between applications. Maximum 3 applications/yr. 24-hr re-entry period.

 


Related links...

 


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca
Author: OMAFRA Staff
Creation Date: 2 May 2011
Last Reviewed: 11 May 2011