INFO-BUG

Crop Selected: Soybean
Crop Development: Bloom to pod-set
Pest Selected: Green Cloverworm (GCW), Plathypena scabra

Biology

The green cloverworm is a larvae of a moth that migrates from the south each year. Presumably, one generation occurs per year. But, two generations during a growing season are possible.

Depending on the weather and the activity of biological control agents, this pest may vary significantly in importance from one year to another. In Ohio, this pest is seldom a serious problem.

Larvae of GCW generally will begin to appear in soybeans in July and may cause serious defoliation in August or early September.

Click to see

Green cloverworm larva on soybean leaf

Assessment

Assessment of green cloverworm (GCW) depends on its additive impact together with the entire complex of insect defoliators of soybeans.
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

| Click to see defoliation levels on leaves: |

In regard to GCW, it is important to note stage of development and level of biological control that may be present, since the potential impact may vary with the stage of larval development and extent of activity by benefical parasites.

Control

Where cloverworm is a potential problem and a rescue treatment is warranted, the following materials are recommended:

B.T. (Bactospeine, Biobit, Dipel,Javelin, & Larvo-BT)
- these are microbial pesticides effective on moth larvae and exempt from tolerances.

Ambush* 0.05 to 0.1 lb ai/A
Asana* XL @ 2.9 to 5.8 fl oz/A
Lannate* @ 0.23 ai/A
Larvin 3.2 @ 10 to 16 oz/A
Lorsban* 4E @ 1/2 to 1 pt/A
Malathion @ 1-7/8 lb a.i./A
Malathion ULV @ 8 oz/A
Penncap-M* @ 2 to 3 pt/A
Pounce* @ 0.05 to 0.1 lb a.i./A
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 applicator

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