bean leaf beetle

(Cerotoma trifurcata)

Conservation Status
bean leaf beetle
Photo by Alfredo Colon
  IUCN Red List

not listed

     
  NatureServe

NR - Unranked

     
  Minnesota

not listed

     
           
           
           
 
Description
 
 

Bean leaf beetle is a small skeletonizing leaf beetle. It is common in North America east of the Great Plains. It is found in most soybean fields every year.

Adults are to ¼ long. The body is longer than wide and slightly convex. When viewed from above, the head and most of the legs are clearly visible.

The head is always black. The mouthparts project from the front of the head. The antennae are thread-like. The bases of the antennae are close together.

The upper thoracic shield (pronotum) and hardened wing covers (elytra) are usually yellow but may be red or any color in between. The pronotum is broad but slightly narrower that the base of the elytra. It has a distinct lateral margin and no black markings.

Each elytron has a black spot on the front (anterior) inner margin that joins with an identical spot on the opposite elytron forming a backward-pointing triangle. There are usually two large spots in the middle (mid-dorsal), one small spot near the tip (apex), and one stripe on the outer margin. The spots and stripes may be absent, but the triangle is always present.

The last part of each leg (tarsus), corresponding to the foot, has five segments but the fourth segment is minute, making it appear that there are only four segments.

 
     
 

Size

 
 

Total Length: to ¼

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

 

 
     
 
Biology
 
 

Season

 
 

One generation: Mid-May to late September

 
     
 

Behavior

 
 

 

 
     
 

Life Cycle

 
 

Adults overwinter in the soil. They become active in the spring when the plant seedlings first emerge and feed on the leaves that were preformed in the seed (cotyledon leaves). They remain active until the first new (neoformed) leaf unfurls. At that time the female lays small groups of orange eggs on the soil near the stems of host plants. The eggs hatch in about 11 days and the larvae begin feeding on host plant roots. In the next 35 to 55 days the larvae pass through three stages, pupate in the soil, and emerge as adults. These progeny of overwintered adults appear in the summer. They feed on mature leaves and on the green tissue of the pod wall, only occasionally eating through the wall to the bean. They do not occur in numbers large enough to cause serious crop damage.

 
     
 

Larva Food

 
 

Roots of legumes

 
     
 

Adult Food

 
 

Leaves of legumes

 
     
 
Distribution
 
 

Distribution Map

 

Sources

24, 27, 29, 30.

 
  10/4/2018      
         
 

Occurrence

 
 

Common

 
         
 
Taxonomy
 
 

Order

Coleoptera (beetles)  
 

Suborder

Polyphaga (water, rove, scarab, longhorn, leaf and snout beetles)  
 

Infraorder

Cucujiformia  
 

Superfamily

Chrysomeloidea (long-horned and leaf beetles)  
 

Family

Chrysomelidae (leaf beetles)  
 

Subfamily

Galerucinae (skeletonizing leaf beetles)  
 

Tribe

Luperini  
  Subtribe Diabroticina  
  No Rank Cerotomites  
 

Genus

Cerotoma  
       
 

Synonyms

 
 

Chrysomela trifurcata

 
       
 

Common Names

 
 

bean leaf beetle

 
       

 

 

 

 

 

 

 

Glossary

Elytra

The hardened or leathery forewings on an insect used to protect the fragile hindwings, which are used for flying, in beetles and true bugs.

 

Pronotum

The saddle-shaped, exoskeletal plate on the upper side of the first segment of the thorax of an insect.

 

Tarsus

The last two to five subdivisions of an insect’s leg, attached to the tibia; the foot. Plural: tarsi.

 

 

 

 

 

       
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Alfredo Colon
       
  bean leaf beetle    
       
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Other Videos
 
  Bean Leaf Beetle - Cerotoma trifurcata
adamitshelanu
 
   
 
About

Published on Sep 10, 2014

Bean Leaf Beetle - Cerotoma trifurcata

On the bank of the Deep River in Worthville, Randolph County, North Carolina, this farmers' pest with bright beautiful colors caught Uncle Steve's eye:

Bean Leaf Beetle
Cerotoma trifurcata
Family: Chrysomelidae; Subfamily: Galerucinae

Date: 26 AUGUST 2014

[vado-g3 avidemux]

   
       
  Soybean School - Bean Leaf Beetle
RealAgriculture
 
   
 
About

Published on Jun 12, 2018

Here's an interview with OMAFRA field entomologist Tracey Baute. We're talking the comeback of bean leaf beetle.

   
       
  Bean leaf beetle management in Ohio
The Ohio State University IPM Program
 
   
 
About

Published on Apr 24, 2018

In this video, Dr. Kelley Tilmon discusses the biology and proper way to scout for both foliar and pod injury caused by this pest in Ohio.

   
       

 

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Alfredo Colon
6/8/2018

Location: Woodbury, MN

bean leaf beetle


     
     
 
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