WEEK 7:  Flea beetles above, rootworms below, loopers everywhere

Let me explain:
  • Flea beetles invade fields rapidly, and can cause substantial damage to newly emerged leaves. Scouting is simple, thanks to the characteristic leaf damage. See photos and learn more here.
  • Rootworm is the common name for larval Diabrotica beetles. They feed underground, but can be distinguished from maggots by the presence of thoracic legs and a brown sclerotized plate just behind the head.
Rootworm. PHOTO CREDIT: Ken Gray, OSU
  • Cabbage Looper moths continue to be very abundant in the landscape. There is no diapause in this species, so 6-7 generations per year are possible if environmental conditions are suitable. Although trap counts are way above normal, the effect on crops has yet to be determined, and depends on a variety of factors. We will be discussing some of these in the weeks to come.

Read the full pest report HERE and subscribe to receive alert updates.

WEEK 6: Read the full report HERE

* Continued pressure of cabbage loopers. An outbreak occurred in the Valley in 2008, when trap counts reached 100+ per day. Review last week’s post for details, interpretation of looper flights, and recommendations for scouting.

* A diamondback moth ‘point-concern’ for the Corvallis location. More data will be available in the coming weeks.

* True armyworms (M. unipuncta) are not traditionally monitored by VegNet, because damage is most notable in grasses and forage crops. However, feeding on peas, beans, and brassicas can occur in outbreak years. Visit the armyworm page for more info.

WEEK 5: First of two looper flights. Read the full report HERE.


The most notable trend this week is the sharp rise in looper activity. As seen in the graph below, 2016 levels (blue bars) were well above the historical norm (gray shaded line), and they remained that way throughout the season. This early 2017 peak (orange dot), while alarming, just means we’ll need to keep an eye on activity. It is the 2nd flight (Jul-Aug) that causes the most damage, because larvae and pupae contaminate crops headed for the processor. A contaminated crop can mean load rejection.

Home gardeners should be wary of looper levels, because larvae feed on a variety of crops including lettuce, tomatoes, peas, and other garden favorites. If you are concerned about defoliation, begin scouting between May 18th and 23rd. Look for ‘windowpanes’ or ragged holes, depending on how big the larvae are.

Processed vegetable growers are mostly concerned with looper flights near button-stage, as the main concern of this pest is contamination.

Looper larvae are light green with a white lateral stripe down each side, and display characteristic movement¬† – ‘looping’ along the leaf surface by gathering the rear legs to meet the front legs and then extending forward. More info on loopers is available here.

WEEK 4: Moth movement is low, rootworms in the landscape.

Don’t worry if you’re getting a late start to the planting season. So are the bugs. Many of the pest moth species we track are LOWER than normal for this time of year.

You may start to notice those familiar 12-spot beetles around, particularly on the dandelions in your yard or garden. These are the overwintered females, looking for suitable egg-laying sites (seedling corn, cucumbers, beans).

Check out this week’s full report HERE, and subscribe to receive VegNet highlights straight to your inbox!

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