UC IPM: UC Management Guidelines for Black Pecan Aphid on Pecans

UC Pest Management Guidelines

Pecan

Black Pecan Aphid

Scientific name: Melanocallis caryaefoliae

(Reviewed 2/07, updated 2/07)

In this Guideline:

Description of the pest
Damage
Management

DESCRIPTION OF THE PEST

The black pecan aphid is the only black aphid that attacks pecan foliage. The adult may be various shades of green or black. Nymphs tend to be lighter in color than the adults, especially in spring when the first through fourth instars have little dark pigment. Antennae are pale yellow with small amounts of black on several segments. Eyes are dark red and cornicles are short. In the other two aphid species present on pecan, cornicles are absent or greatly reduced. Black pecan aphids have multiple generations each year beginning development in March and continuing into November. Populations generally peak in fall.

DAMAGE

Black pecan aphid feeding causes bright yellow, angular, 0.4 square inch spots to develop on the leaves between the veins. The spots die and turn brown, and just a few such spots cause a leaflet to shed. Premature leaf drop results in poor nut quality and reduced bloom in subsequent seasons.

MANAGEMENT

By choosing insecticides that preserve beneficial insects, aphid populations will decrease over time. The following guideline was developed in Texas and has not been proven in California. Usually control is not needed until late in the season, after mid-July. At that time, treat if levels exceed an average of one black aphid per compound leaf.

Common name

Amount to Use**

R.E.I.+

P.H.I.+

(trade name)

(hours)

(days)

The following materials are listed in order of usefulness in an IPM program, taking into account impact on natural enemies and honey bees and the environment.

IMIDACLOPRID

(Admire Pro)

7–14 fl oz

MODE OF ACTION: A neonicotinoid (Group 4A)¹ insecticide.

COMMENTS: Can be used from May 15 to July 15. This formulation of imidadoprid must be applied preventively before monitoring indicates a need; use if aphids have been a chronic problem in past years.

DIMETHOATE E267

1 pt/acre

MODE OF ACTION: An organophosphate (Group 1B)¹ insecticide.

COMMENTS: Ground application only.

CHLORPYRIFOS*

(Lorsban) 4E

2–4 pt/acre

MODE OF ACTION: An organophosphate (Group 1B)¹ insecticide.

COMMENTS: Use chlorpyrifos in combination with one of the other insecticides listed in this table. Avoid runoff and drift into surface waters.

NARROW RANGE OIL#

Label rates

MODE OF ACTION: Contact including smothering and barrier effects.

COMMENTS: Although research has not been done in pecans, in other tree crops oil is used to suppress populations of aphids, while preserving beneficials. In organic crops, check with certifier to determine which products are organically acceptable.

ENDOSULFAN*

(Thionex) 3EC

1 qt/100 gal

see comments

MODE OF ACTION: An organochlorine (Group 2A)¹ insecticide.

COMMENTS: Do not apply after shuck split. Do not exceed 2 application/year or 4 qt/acre/year. Cannot be applied in any situation where run-off may occur; check with county agricultural commissioner. May not be effective in all areas because of resistance.

**	For dilute applications mix with 330-400 gal water/acre; for concentrate application mix with at least 20 gal water/acre.
+	Restricted entry interval (R.E.I.) is the number of hours from treatment until the treated area can be safely entered without protective clothing. Preharvest entry interval (P.H.I.) is the number of days from treatment to harvest. 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.
*	Permit required from county agricultural commissioner for purchase or use.
¹	Modes of action are important in preventing the development of resistance to pesticides. 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. 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 is assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.
^#	Acceptable for use on organically grown produce.

UC IPM Pest Management Guidelines: Pecan
UC ANR Publication 3456
Insects
R. A. Van Steenwyk, Environmental Science, Policy, and Management, UC Berkeley
C. Pickel, UC IPM Program, UC Cooperative Extension, Sutter/Yuba counties
Acknowledgment for contributions to the insect section:
G. S. Sibbett, UC Cooperative Extension, Tulare County

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