loopers « VegNet

While none of us have a crystal ball, especially in agriculture, I thought it might be fun to offer some thoughts / warnings of how this year might look for insect pests of vegetables. I predict* ……

“Flea beetles will be rampant.” In the spring, adult flea beetles emerge from overwintering, and are already causing some problems in radish. We’ve been told by both local and regional sources that it’s going to be a hot and dry summer = flea beetles’ favorite weather. I suggest early and often scouting in brassica crops. Starting now, begin to scout weedy areas around fields. Once the crop emerges, or shortly after transplanting, focus efforts on field edges. It may be necessary to scout daily – yes, daily. Be aware that these insects are easily disturbed (they jump), sticky traps placed ~10″ off the ground can help assess activity – place them near edges. You’ll recognize the distinctive ‘pitting’ on cotyledons and true leaves. Check stems for signs of damage as well, just above the soil surface. For more information, see the flea beetle pest profile page.

“Wireworms are a cryptic foe we should get to know.” They are a common problem in grass and potato production. Adult click beetles do not live for very long and do not cause damage. Larvae (wireworms), on the other hand, live for 2-6 years and damage can be extensive. Before planting, especially if you are coming out of a grass rotation, take my advice and place a few bait traps to assess larval activity. Instructions and more information is available at the wireworm pest profile page.

“Every other year, cabbage loopers cause fear.” Ok, I admit, this one is just a stretch to fit the rhyme scheme. However, it is true that in the Willamette Valley, we have had major looper outbreaks in 2017 and 2019… so 2021 is a possibility. Trap count data will be available soon.

* PLEASE NOTE: these are merely educated guesses. In fact, part of the fun of monitoring insects is that they are truly so unpredictable!

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Over the past few days, I have seen 300+ cabbage looper moths in traps next to fields that aren’t even out of the ground yet, and been texted twice about flea beetle damage. It seems it will be a busy year for brassica pests!

cone trap with about 60 visible looper moths inside — First indication of probable outbreak – May 8th 2019: too early to see this many

All the more reason to subscribe! Stay informed by clicking here. We do not share your information, and many of the pests we report on have wide host ranges, which means the data are relevant for home gardens, nurseries, and many commodity crops.

An example pest report can be seen here: https://mailchi.mp/f504f1497d5b/pest-report-week-4

Update: May 16th

WEEK 18 – Diamondback moths are exploding, and I try my hand at interactive maps!

Read the full report here: http://bit.ly/VNweek18 and subscribe on our homepage to receive weekly newsletters during field season. Thanks!

We monitor for cabbage loopers because they are pests of brassica crops. Feeding can occur on a wide variety of vegetable hosts including: beet, celery, cucumber, lettuce, pea, pepper, snap bean, spinach. Not all hosts are suitable for complete development of the insect, but feeding is feeding, from a grower or gardener’s perspective.

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.

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.

Loopers are latent and storms are splendid!

Windy gusts of up to 30 MPH and nearly 1″ inch of rain this week. Yes, believe it or not, it’s bug season!

Check out the full report HERE, and subscribe to receive next week’s pest report straight to your inbox!

**Thanks for your patience as I continue to build the rest of this site**

VegNet

your regional insect pest monitoring resource!

Category Archives: loopers

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Let me explain:

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