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UC Pest Management Guidelines


Adult flea beetles and damage to a dichondra leaf.

Turfgrass

Dichondra Flea Beetle

Scientific Name: Chaetocnema repens

(Reviewed 9/09, updated 9/09)

In this Guideline:


DESCRIPTION OF THE PEST

Eggs are laid near the soil surface and require 3 days to hatch. The soil-dwelling larvae are white, with fine bristles and a light brown head capsule. Last (fourth) instar larvae are about 0.17 to 0.25 inch long. The white pupae are 0.05 inch long and are found in the same depths (up to 4 inches) in the soil as the larvae. Larvae require 22 to 25 days to complete development; pupation takes about 5 days. Adults are ovoid, about 0.06 inch long, and have greatly thickened hind femora for jumping. Newly emerged adults are white for 1 day, then turn a characteristic black color with a metallic reddish bronze tinge. The antennae, front, and middle legs are reddish yellow. Adults can be observed by passing a hand over affected dichondra. The disturbed adults will jump, some of them onto your hand or arm. Dichondra flea beetle overwinters as an adult.

SUSCEPTIBLE SPECIES

Dichondra and bermudagrass.

DAMAGE

Dichondra flea beetles seriously damage dichondra, causing many dichondra lawns to be replaced with grass turf. Larvae feed between May and October on small roots and the outsides of larger roots. This injury causes dichondra to wilt and die; often, large patches are affected. Adults feed on dichondra leaves, producing distinctive crescent marks on the upper surface. Severely skeletonized plants may wither; however, this symptom is most likely caused by larval root feeding. Larval populations can be assessed by placing turf soil cores in a Berlese funnel and extracting the larvae.

The dichondra flea beetle has also been found damaging common and hybrid bermudagrass in California. Symptoms include overall appearance of lack of water or fertilizer burn. First signs of damage appear in March and decrease in September as temperatures drop. Individual leaf blades have white linear banding along the length of the leaf blade. Occasionally the turf becomes bleached out in appearance.

MANAGEMENT

Treat for dichondra flea beetle if populations are high enough that damage may occur.

Common name Amount/1000 sq ft** Ag Use
R.E.I.+
NonAg Use
R.E.I.+
(trade name)   (hours) (hours)

  Calculate impact of pesticide on air quality
The following materials are listed in approximate order of usefulness in an IPM program, taking into account efficacy and impact on natural enemies and the environment. Not all registered materials are listed. Not all registered pesticides are listed. Always read label of product being used.
 
A. ACEPHATE
  (Orthene Turf, Tree, and 1–1.9 oz 24 until dry
  Ornamental Spray)
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: For use on golf courses and sod farms only. Odorous. Up to 2.4 oz material/1000 sq. ft. can be used for black cutworm on turfgrass.
 
B. DELTAMETHRIN
  (DeltaGard T & O) G 2 lb until dry
  MODE OF ACTION GROUP NUMBER1: 3
  COMMENTS: Not for use on sod farms or in commercial seed production. For best results, irrigate with an adequate quantity of water to thoroughly moisten grass and thatch and to dissolve the granules.
 
** Apply in 25 gal water/1000 sq ft unless otherwise noted.
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/.
+ 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. Agricultural use applies to sod farms and commercial seed production.
Indicates use is not listed on label.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Turfgrass
UC ANR Publication 3365-T
Insects and Mites
M. L. Flint, UC IPM Program, UC Davis
M. A. Harivandi, UC Cooperative Extension, Alameda County
H. K. Kaya, Nematology, UC Davis
Acknowledgment for contributions to Insect and Mites:
J. Hartin, UC Cooperative Extension, San Bernardino County
R. S. Cowles, Connecticut Agricultural Experiment Station, Windsor, CT
K. Kido, Entomology, UC Riverside
H. S. Costa, Entomology, UC Riverside
D. D. Giraud, UC Cooperative Extension, Humboldt/Del Norte counties

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