Dry Beans XIII-11

Leafhoppers

Gary L. Hein & Frank B. Peairs

Potato leafhopper.

The potato leafhopper can be a devastating insect on dry beans; however, the leafhopper does not overwinter in the region and must migrate in from the Gulf Coast region.  This does not occur regularly, but because of the potential severity of damage from this insect it is important to be familiar with it.

Identification (and life cycle/seasonal history)

The potato leafhopper can be a serious problem in dry beans early in the season.  It overwinters in the Gulf Coast region, and migrates into areas of North America in the spring to establish summer populations.  Its migration into the High Plains region usually occurs in too low of numbers and too late in the season to cause serious damage.  However, in some years significant migration into the region can occur in June to create serious damage to dry beans.  Damage potential decreases from east to west in Nebraska, but severe damage has occurred as far west as the Panhandle.  The potato leafhopper is a wedge-shaped, lime-green insect with six white spots just behind the head.  The nymphs are also lime green, and are most often found on the underside of the bean leaves.  The nymphs are easily recognized because of their unusual habit of walking sideways very rapidly when disturbed.

Plant Response and Damage

The leafhopper injects a toxin during feeding that damages the plant and results in leaf discoloration and stunting.  Damaged leaves will turn yellow on the edges and tips, and later these areas of the leaf will die and turn brown.  Damaged plants also will be stunted and have short internodes.  Plants will be slow to recover from damage and may be stunted for the rest of the season.

Management Approaches

The most serious damage from the potato leafhopper will result when beans are infested at an early growth stage.  Sampling the beans from emergence through early July should be done to determine if leafhoppers are present.  A sweep net can be used to quickly determine the presence of the leafhoppers in the field.  If leafhoppers are present, a more specific sampling of individual plants should be done to determine the density of leafhoppers on the plants.  Twenty plants across a field should be examined for the presence of leafhoppers and for the number of trifoliates per plant.  On seedling (unifoliate) plants, the threshold for treatment is ½ leafhopper per plant.  Later, the threshold for treatment is one leafhopper (including nymphs and adults) per trifoliolate.

 

 

Product List for Leafhoppers:

Insecticide

Product

Preharvest Interval , remarks

Asana XLR1

5.8-9.6 oz./A

PHI 21 days; REI 12 hrs.

cyfluthrinR1

(Baythroid, generics)

See label for rates.

PHI 21 days; REI 12 hrs.

dimethoate1

multiple formulations

See label for rates

PHI see label; REI 48   hrs.

Di-Syston 15%R,

8R                                  

15%:6.0 oz./1000 ft

8:0.9-1.9 oz./1000 ft

PHI 60 days; REI 72 hrs.

Lannate  SP R, LV R

SP: 0.25-1.0 lbs/A

LV: 0.75-3.0 pts/A

PHI 14 days; REI 48 hrs.

Mustang MAXR1

2.72-4.0 oz./A

PHI 21 days; REI 12 hrs.

Orthene/acepahte multiple formulations

See label for rates

PHI 14 days; REI 24 hrs.                     

Penncap M

2.0 pts/A

PHI 15 days; REI 48 hrs.

Sevin/carbaryl1

Multiple formulations

See label for rates

PHI 21 days; REI 12 hrs.

Temik 15GR

7.0-14.0 lbs./A

                                 

 

Apply at planting. Potential for groundwater contamination.  See label for environmental
precautions and restrictions.  PHI 90 days; REI 48 hrs.

Thimet 20GR                          

4.5-7.0 oz/1000 row ft

Apply at planting; drill to side of seed, not in contact with seed; PHI 60 days; REI 72 hrs.

Phaser 3EC

See label for rates.

PHI 3 days: REI 24 hrs.

lambda-cyhalothrin R1

(Warrior, generics)

See label for rates.

PHI 21 days; REI 24 hrs.

Seed Treatment

Cruiser 5FS

 

1.28 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, Leafhoppers

 

Date: 04/24/2006