How to Manage Pests

UC Pest Management Guidelines

Bermudagrass Seed Production

Bermudagrass Mirid

Scientific Name: Trigonotylus tenuis

(Reviewed 1/07, updated 6/09)

In this Guideline:


This plant bug may be abundant on bermudagrass florets and leaves. Trigonotylus tenuis is a small, light green, narrow, stilt-legged seed bug. Adults and immatures may be found in bermudagrass at any time from spring through fall.


Trigonotylus tenuis is of greatest concern during spring and fall seed-production seasons from regrowth through bloom. Its feeding can reduce plant vigor, stunting growth and delaying the development of florets. Adult feeding on developing seeds also reduces seed yields.


Monitor seed fields with a sweep net for Trigonotylus tenuis from regrowth through bloom. Treat if Trigonotylus tenuis counts reach 100 per sweep. When fields are developing seed, monitor for adult bugs only, as nymphal mouthparts do not appear to be large enough to attack developing seed. One adult mirid per 90° sweep 2 weeks before summer harvest can reduce uncleaned seed yields by almost 20 pounds per acre.

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

Calculate impact of pesticide on air quality
Bee precaution pesticide ratings
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  (Orthene) 75S 1.33 lb 24 0
  COMMENTS: Available for use under a 24(c) registration. Do not feed crop residue to livestock or allow animals to graze treated areas. Do not apply this product through any type of irrigation system.
+ 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 interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of the two intervals is the minimum time that must elapse before harvest.
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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



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Bermudagrass Seed Production
UC ANR Publication 3472

Insects and Mites

E. T. Natwick, UC Cooperative Extension, Imperial County
V. M. Barlow, UC Cooperative Extension, Riverside County
M. D. Rethwisch, UC Cooperative Extension, Riverside County

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