Soya Pests

Soybean looprSoybean Looper
Source: Clemson University - USDA Co-op Ext Slide Series

Common Names: Includes Soybean Looper, Velvet Bean Caterpillar, Green Clover Worm, Webworm, Armyworms
Latin Names: Pseudoplusia includens, Anticarsia gemmatalis, Plathypena scabra
Order: Lepidoptera
Family: Noctuidae; Plathypena: Erebidae (formerly Noctuidae)

Main Host(s): Soybean and other legume crops, but for some species also large variety of other host plants including cotton, tobacco and vegetables.

Life Cycle

Velvet bean caterpillarVelvet Bean Caterpillar 
Source: Clemson University - USDA Co-op Ext Slide Series

The Velvet Bean Caterpillar is tropical and subtropical with wide distribution, occurring from the southern U.S. to Argentina. It is considered an important pest in the U.S., Brazil, Mexico, Colombia, Venezuela and Argentina. Soybean Looper occurs from the U.S. to southern South America. In the northern U.S., growers can find Alfalfa Caterpillars. The pest mix can include not only the Soybean Looper and Velvet Bean Caterpillar, but also the Green Clover Worm, Webworm and Armyworm species.

Many of these pests migrate, and in a variety of combinations they impact most soybean regions in North and South America. The adults move into soybean fields in mid- to late summer, and some species (Loopers) will lay eggs singly with many hundreds of eggs per female. Egg hatch is between 3-7 days depending on temperature. The number of larval stages may vary per species and field conditions but is usually around six. The Velvet Bean Caterpillar has green and dark colored forms. Many of the soybean pest caterpillars are defoliators and especially the older larvae in large numbers can defoliate plants. Some species such as the Soybean Looper start feeding on the lower half of the crop and move upward.

Impact & Damage

At the early stages of crop growth, beneficial insects and fungal diseases can bring down some caterpillar populations before insecticide treatments are warranted. At the vegetative growth stage of soybeans, the amount of leaf damage tolerated is a bit higher than at more mature crop stages. Late in the season, however, the impact from these pests, if left unchecked, can be severe, decreasing yield.

Recommended Control

DiPel Logo 

DiPel® is highly effective on both of the important soybean pests, Soybean Looper and Velvet Bean Caterpillar. For greatest efficiency, DiPel should be applied at preflowering with low pest pressure to control the first to third larval stages. It can be applied both by ground application or by airplane. DiPel can be mixed with a knockdown chemical insecticide, such as a pyrethroid, organophosphate or carbamate. Use of DiPel in combination with these other insecticides can maximize control.

References & Sources:

www.biorationalapproach.com
www.ksre.ksu.edu/library/entml2/s116.pdf 
cropwatch.unl.edu/web/cropwatch/archive?articleID=4236335
www.mdcrops.umd.edu/UMDextension/AgronomyNews20100902.pdf
pubs.ext.vt.edu/444/444-770/444-770.html 
msucares.com/insects/soybeans/pubs/insect_management.pdf
 

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