UC IPM: UC Management Guidelines for Western Boxelder Bug on Pear

UC Pest Management Guidelines

Pear

Western Boxelder Bug

Scientific name: Boisea rubrolineata

(Reviewed 2/07, updated 3/8)

In this Guideline:

Description of the pest
Damage
Management

Western boxelder bug may be more damaging in North Coast districts near riparian vegetation. Adults are slender and gray brown to black, with conspicuous red lines on the thorax and wing coverings. The body beneath the wings is orange red and very noticeable in flight. Immature bugs are bright orange-red until they are half grown. Eggs are laid in groups and resemble miniature red kidney beans. The adult bug overwinters on boxelder, maples, and cottonwoods in a riparian corridor. There is one generation a year.

The adults aggregate in the winter months in riparian vegetation where they overwinter. On warm March days, adults are active, they mate and move to the edge of the orchard. Egg laying begins in late March and continues through April. Eggs are laid on riparian vegetation (blackberry, cottonwood, maples leaves) and on leaves and fruit of pear trees close to the riparian corridor. Nymphs develop from April through July. Adults begin to emerge in mid-July.

Adults and nymphs feed on fruit causing dimples very similar to stink bug damage. A small dark depression is formed where they feed producing a hard pithy area under the skin.In orchards, the highest boxelder feeding damage is seen in the first 10 to 30 rows adjacent to riparian vegetation. Damage incidence decreases as you move away from the river and can be seen throughout the orchard but in low incidence. Fruit damage incidence increase starting in mid-June when nymphs are larger an as fruit softens.

Western boxelder bugs may become more important pests in orchards where mating disruption is used for codling moth control. Monitor weeds in spring and trees in early summer to determine need for treatment.

Monitoring and Treatment Decisions
In orchards next to riparian corridors with a history of boxelder bug, monitor pear trees at the edge of the orchard. Monitor during April by inspecting leaves in flower clusters for eggs. (For more information, see SAMPLING AT BLOOM.) Also examine nearby maples, cottonwoods, boxelder, and blackberries near rivers for adults. Beginning in April, continue monitoring fruit clusters for presence of nymphs in the first 20 to 40 rows adjacent to the riparian corridor. Monitor fruit damage beginning in May (see SAMPLING DURING FRUIT DEVELOPMENT for more details).

No treatment thresholds have been developed for boxelder bug. In an orchard with a history of damage treating the first 20 to 40 rows adjacent to the riparian corridor may be warranted. Control is most effective when the nymphs are small in May.

Harvest fruit sample. At harvest, assess your IPM program by monitoring fruit in the bins for western boxelder bug damage. Sample 200 fruit per bin from 5 bins per orchard (or 20-acre block in large orchards). (For more information, see HARVEST FRUIT SAMPLE.)

Common name

Amount to use**

R.E.I.+

P.H.I.+

(trade name)

(conc.)

(dilute)

(hours)

(days)

The following materials are listed in order of usefulness in an IPM program, taking into account efficacy and impact on natural enemies and honey bees. When choosing a pesticide, also consider information relating to environmental impact.

MAY/JUNE TO PREHARVEST

FENPROPATHRIN*

(Danitol) 2.4EC

16–21.33 fl oz

4–5.3325 fl oz

MODE OF ACTION GROUP NUMBER¹: 3

COMMENTS: Harmful to beneficial insects and mites; will suppress spider mites. Take care to avoid spray runoff or drift when spraying adjacent to riparian corridors because of water quality concerns.

LAMBDA-CYHALOTHRIN*

(Warrior with Zeon)

2.56-5.12 fl oz

—

MODE OF ACTION GROUP NUMBER¹: 3

COMMENTS: Do not apply more than 0.2 lb a.i. (1.6 pt product)/acre/year. Do not apply more than 0.16 lb a.i. (1.28 pt product)/acre/year after bloom. Harmful to beneficial insects and mites; will suppress spider mites. May cause outbreaks of pear rust mite. Take care to avoid spray runoff or drift when spraying adjacent to riparian corridors because of water quality concerns.

THIAMETHOXAM*

(Actara)

4.5-5.5 oz

1.125-1.375 oz

see comments

MODE OF ACTION GROUP NUMBER¹: 4A

COMMENTS: Allow a minimum of 10 days between applications; do not exceed 8 oz/acre/season. Preharvest interval is 14 days when 2.75 oz/acre or less is used and 35 day when more than 2.75 oz/acre is used.

IMIDACLOPRID

(Provado) 1.6 F

10 fl oz

2.5 fl. oz

MODE OF ACTION GROUP NUMBER¹: 4A

COMMENTS: Effective against boxelder and lygus bugs, but not stink bugs.

DIMETHOATE

Label rates

MODE OF ACTION GROUP NUMBER¹: 1B

COMMENTS: May kill beneficial mites and pear psylla predators.

FORMETANATE HYDROCHLORIDE

(Carzol) SP

1 lb

4 oz

see comments

MODE OF ACTION GROUP NUMBER¹: 1A

COMMENTS: Most disruptive to beneficial mites and psylla predators. Do not apply after petal fall. See label for second application restrictions. Restricted entry interval (R.E.I.) is 4 days if during the dormant season, 10 days for hand labor activities, and 16 days for harvest.

**	Dilute rate is the rate per 100 gal water; use 400 gal solution/acre. Apply concentrate in 80-100 gal water/acre, or less if the label allows.
+	Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment until the harvest may take place. In some cases the R.E.I. exceeds the P.H.I. The longer of these two intervals is the minimum time that must elapse before harvest may take place.
*	Permit required from county agricultural commissioner for purchase or use.
¹	Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode of action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.

UC IPM Pest Management Guidelines: Pear
UC ANR Publication 3455
Insects and Mites
L. G. Varela, UC IPM Program, UC Cooperative Extension Sonoma Co.
R. B. Elkins, UC Cooperative Extension Lake Co.
R. A. Van Steenwyk, Insect Biology, UC Berkeley
C. Ingels, UC Cooperative Extension Sacramento Co.
Acknowledgment for contributions to the insects and mites section:
C. Pickel, UC IPM Program, UC Cooperative Extension Sutter/Yuba counties
P. W. Weddle, Weddle, Hansen & Associates
P. Chevalier, United Ag Products, Ukiah; B. Knispel, United Ag Products, Kelseyville
T. Lidyoff, Purity Products, Healdsburg; G. McCosker, AgroTech, Kelseyville
B. Oldham, Ag Unlimited, Ukiah
D. Smith, Western Farm Service, Walnut Grove
J. Sisevich, AgroTech, Kelseyville
B. Zoller, The Pear Doctor, Inc., Kelseyville

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How to Manage Pests

UC Pest Management Guidelines

Pear

Western Boxelder Bug

Scientific name: Boisea rubrolineata

DESCRIPTION OF THE PEST

DAMAGE

MANAGEMENT

PUBLICATION