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How to Manage Pests

UC Pest Management Guidelines


Southern garden leafhopper nymphs.

Cucurbits

Leafhoppers

Scientific Names:
Western potato leafhopper: Empoasca abrupta
Southern garden leafhopper: Empoasca solana

(Reviewed 11/05, updated 6/08)

In this Guideline:


DESCRIPTION OF THE PESTS

Leafhoppers are small, light green, wedge-shaped insects that measure a little more than 0.12 inch (3 mm) in length. The western potato leafhopper is a pest throughout California whereas the southern garden leafhopper occurs mostly in the southern California desert areas. Adult females insert kidney-shaped eggs singly in the plant just below the surface. Eggs hatch and the nymphs pass through five instars. Nymphs are whitish to pale green and move rapidly (often sideways) when disturbed. They are found mainly on the underside of leaves.

DAMAGE

The leafhopper has sucking mouthparts and can cause severe white stippling and yellowing of the leaves, green spotting of the fruit, and premature leaf drop. Large populations can reduce quality as well as yield.

MANAGEMENT

Generally good field sanitation and crop growing practices are adequate for preventing damage by these pests.

Cultural Control
Melons and other cucurbits can tolerate fairly heavy feeding provided they are not stressed for moisture and possess six to eight healthy noninfested terminal leaves. Row covers placed over the seedbed after planting and removed at first bloom will keep leafhoppers off the plants. After harvest, destroy crop residue as soon as possible to eliminate breeding areas.

Organically Acceptable Methods
Cultural controls are acceptable to use in an organically certified crop.

Monitoring and Treatment Decisions
Treatment thresholds have not been established, but pesticide sprays are not usually required. If leafburn occurs or if leafhoppers are moving into an immature field from nearby harvested sugarbeet, potato, or other crops, a treatment may be needed.

Common name Amount/Acre R.E.I.+ P.H.I.+
(trade name)   (hours) (days)

When choosing a pesticide, consider information relating to water quality and impact on natural enemies and honey bees.
 
A. IMIDACLOPRID
  (Admire) 2F 16–24 fl oz 12 21
  MODE OF ACTION GROUP NUMBER1: 4A
  COMMENTS: Repeat applications of any neonicotinoid insecticide (imidacloprid-Admire; thiamethoxam-Platinum) can lead to resistance to all neonicotinoids. Alternate neonicotinoids with an insecticide that has a different mode of action to help delay the development of resistance.
 
B. ESFENVALERATE*
  (Asana XL) 5.8–9.6 oz 12 3
  MODE OF ACTION GROUP NUMBER1: 3
  COMMENTS: Repeat as necessary to maintain control. Do not exceed 0.25 lb a.i./acre/season. Highly toxic to honey bees.
 
C. OXYDEMETON METHYL*
  (MSR Spray Concentrate) 2 pt 72 see label
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: Apply in sufficient water for complete coverage, but not less than 1 gal/acre. No more than 1 application/season on squash and pumpkin, 2 applications/season on watermelons and cucumbers, and 3 applications on other melons. Repeated use of this material is very disruptive to beneficials. Moderately toxic to honey bees.
 
D. DIAZINON* Label rates see label see label
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: Not labeled for pumpkins and squash. Highly toxic to honey bees.
 
E. DIMETHOATE Label rates 48 3
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: Labeled for use on melons and watermelons only. Highly toxic to honey bees.
 
F. METHOMYL*
  (Lannate) LV 1.5–3 pt 48 1 (1.5 pt or less)
        3 (more than 1.5 pt)
  MODE OF ACTION GROUP NUMBER1: 1A
  COMMENTS: Labeled for use on cucumbers, melons and summer squash only. Use sufficient water for thorough coverage. Highly toxic to honey bees.
 
+ 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 to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
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/.
* Permit required from county agricultural commissioner for purchase or use.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Cucurbits
UC ANR Publication 3445
Insects and Mites
E. T. Natwick, UC Cooperative Extension, Imperial County
L. D. Godfrey, Entomology, UC Davis
C. G. Summers, Entomology, UC Davis/Kearney Agricultural Center, Parlier
J. J. Stapleton, UC IPM Program, Kearney Agricultultural Center, Parlier
Acknowledgment for contributions to Insects and Mites:
R. L. Coviello, UC Cooperative Extension, Fresno County
C. B. Fouche, UC Cooperative Extension, San Joaquin County
J. B. LeBoeuf, AgriData Sensing, Inc., Fresno
M. Murray, UC Cooperative Extension, Colusa/Glenn counties

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Statewide IPM Program, Agriculture and Natural Resources, University of California
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For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See How to manage pests, or in the U.S., contact your local Cooperative Extension office for assistance. /PMG/r116300811.html revised: June 30, 2008. Contact webmaster.