Dry Beans XIII-2

White Grubs

Gary L. Hein & Frank B. Peairs

White grub larva.

White grub infestations in dry beans are rare, but because of the difficulty in control, high risk situations should be avoided, if possible. 

Identification (and life cycle/seasonal history)

White grubs are large (1-1 ½ inch), white C-shaped larvae with a brown head and legs.  White grub life cycles range from 1-3 years.  Adult beetles are attracted to grasses for egg laying during mid summer.

Plant Response and Damage

White grubs feed on the roots of many types of plants, and they are particularly troublesome early in the season in row crop where the root mass is limited. 

Management Approaches

Problems from white grubs are most likely to occur when beans are planted after sod or grasses.  In some situations, grassy weed problems in alfalfa or corn may attract white grub adults to lay eggs.  Plant when conditions ensure rapid emergence of seedlings.  Few effective treatment options are available in dry beans for white grubs; therefore, avoid planting beans in fields with high risk of white grubs (e.g. after sod, grasses).

Product List for white grubs
Insecticide	Product	Preharvest Interval , remarks
Seed Treatment Cruiser 5FS	1.28 fl oz/100 lb seed	See treatment directions and precautions on label.
^RRestricted use pesticide ^1Labeled for chemigation
The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana.  Criticism of products or equipment not listed in neither implied nor intended.  Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein.  Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies.  State rules and regulations and special pesticide use allowances may vary from state to state:  contact you State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.

Categories:  Dry Beans, Insects, White Grubs

Date: 04/24/2006