INFO-BUG

Crop Selected: Soybean
Crop Development: Pod-set to maturation
Pest Selected: Mexican Bean Beetle (MBB) Epilachna varivestis

Biology

Mexican bean beetle is a relatively new pest problem affecting soybeans in Ohio. Economic infestations of MBB have been primarily in the southern half of the state.

Both the 16 spotted copper colored adult and the spiny larvae feed on bean foliage leaving a skeletonized form of foliage injury.

Overwintering adults cause some injury in the early summer. First and second generation larvae and adults cause increasing levels of foliar injury as the season progresses into the late summer.

Click to see

MBB adults MBB larvae

Assessment

Decisions to apply a rescue treatment to control insect pest defoliators are based on the total level of observed defoliation caused by the total pest complex. Thus, the impact of MBB must be judged as part of all insect defoliators present. Rescue treatment is warranted when defoliation exceeds the following:

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

and defoliating pests are present.

| Click to see defoliation levels on leaves: |

If MBB is the primary cause of defoliation, special attention should be paid to MBB stage present since the pupal stage is not affected by insecticide treatments.

Control

Rescue treatments recommended for control of MBB infestations include the following:

Ambush* @ 3.2 to -6.4 oz/A
Asana* XL @ 2.9-5.8 oz/A
Dimethoate 2.67 @1-3/8 pt/A,267 @ 1-1/3pt/A, 4E or 400 @1pt/A
Dimilin 2L @ 2 to 4 fl oz/A
Furadan* 4F @ 1/2 to 1 pt/A
Lannate* @ 0.23 lb a.i./A Larvin 3.2 @ 18 to 30 fl oz/A
Lorsban* 4E @ 1 to 1.5 pt of 4 lb/gal/A
Malathion 57EC or 5 @ 2 1/2-3 pt/A and ULV @ 8oz/A
Mustang* @ 3.0 to 4.3 fl oz/A
Pounce* 3.2 EC & 25 WP @ 0.05 to 0.1 lb a.i./A
Carbaryl (Sevin) @ 1 lb a.i./A
Scout X-Tra @ 1.71 to 2.28 fl oz/A
Warrior* 1CS @ 1.92 to 3.20 fl oz/A

* Use is restricted to certified applicators.

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