INFO-BUG

Crop Selected: Soybean
Crop Development: Pod-set to maturation
Pest Selected: Bean Leaf Beetle (BLB) Ceratoma trifurcata

Biology

Adults of the bean leaf beetle feed on soybean foliage from emergence through pod maturation. Late season injury to pods is most important.

The beetles range in color from greenish brown to rust red and generally have four black spots on their wing covers plus a black triangular spot behind the thorax (shoulder region).

BLB overwinters as an adult and passes through 2 generations per year. The larvae feed on the soybean root systems, but are not considered a problem.

Click to see larger picture:

BLB adults BLB adult on soybean leaf BLB on soybean pod BLB damage to soybean pod

Assessment

Prior to pod formation, decisions to apply an insecticide rescue treatment are based primarily on the observed defoliation caused by the total pest complex. In regard to defoliation, BLB may be causing all or part of the observed damage.

Rescue treatment is justified when defoliation exceeds:

40% prior to bloom
15% from bloom to pod-fill
25% after pod-fill to plant yellowing

and pest(s) causing defoliation are present.

When pod feeding is evident, treatment is warranted when 8% or more of pods show feeding damage and BLB adults are present.

| Click to see defoliation levels on leaves: |

Control

Recommended treatments for BLB include the following:

Ambush* 3.2 to 6.4 fl oz/A
Asana* XL @ 5.8 to 9.6 fl oz/A
Carbaryl (Sevin) @ 1 lb a.i./A
Dimethoate @ 1 pt/A
Lannate* 0.23 to 0.45 lb a.i./A
Larvin 3.2 @ 18 to 30 fl oz/A
Lorsban* 4E @ 1 to 2 pt/A
Mustang* @ 3.0 to 4.3 fl oz/A
Penncap-M* @ 4 pt of 2 lb flowable/A
Pounce* 3.2EC & 25WP @ 0.05 to 0.1 lb a.i./A
Warrior* 1CS @ 1.92 to 3.20 oz/A

Note: Post harvest limitation period varies considerably with the materials listed.

* Use is restricted to certified applicators.

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