UConn Extension Vegetable IPM Pest Message & Reports from the Farm, Friday, Aug 19th, 2016 [Comments/answers in brackets/red by Jude Boucher, UConn Extension].

Jude Boucher – UConn Extension

A L ER T – All cuc u mb e rs a n d m e l o n s sh o u l d be p r otec t ed from d o w ny m il d ew ( D M ) at th i s t i m e . Several farms didn’t bother to spray their cucumbers last week, but risk losing them if they are not protected. Organic growers can apply copper or Double Nickel. See the New England Vegetable Management Guide (NEVMG) for more choices (ww w .n e v e g etab l e.o r g ). Alternate between two effective materials for resistance management. If DM occurs after spraying for it, or if it continues to get worse, then apply a different fungicide, because the first may not work on this strain of the disease. DM was also found on cantaloupe on Long Island this week, so both melons and cucumbers should be protected. Other cucurbit crops do not need to be treated for this disease at this time, but continue to scout for small “squarish” brown spots on the leaves that are contained by the tiny leaf veins. We suggest you save your Presidio for some time we have late blight or for Phytophthora control, because there have been reports of it not being effective on DM in recent years.

P um p k i ns and w i nter s q u ash – I encountered many fields of orange pumpkins this week, and some winter squash have matured too. The extreme temperatures this season have pushed many crops towards harvest faster than usual. It is asking a lot for fungicides to protect these ripe fruit in the field until October, especially if the late season turns rainy. Those who have protected the foliage with effective powdery mildew (PM) applications will have a better canopy to protect the fruit from damage by sunscald. Ripe squash fruit should be harvested and cured ASAP. Continue to make PM and fruit rot fungicide applications at 10 day intervals for crops left in the field. If you have already applied Vivando and Torino or Quintec for PM, then you can go with a resistance group 3 material in your 4th application: Proline, Procure or Luna Experience. These should be mixed with something to protect the fruit from black rot, Plectosporium and other fruit rot diseases - examples include: Bravo, Cabrio or Quadris, and Dithane.

A L ER T - C orn e a r w orm (C E W ) moths in pheromone traps ranged from 0.4 to 24 moths per night this week and increased quickly on Tuesday night. All growers are now spraying silking corn on a 6, 5, 4 or even a 3-day schedule.

M oths p e r n i g ht S pray i nter v al

0-0.2 no spray

0.2-0.5 6-days

0.5-1 5-days

1-13 4-days

>13 3-days

F a l l ar m y w or m s ranged from 0-18 moth in traps. Some farms have no pressure while others are under heavy pressure. You should scout your pre-tassel stage corn for caterpillars as this is the last chance to catch an infestation of this pest before the caterpillars move down to the ears. One grower reported that Besiege (mix of Coragen and Warrior) did not control the FAW larvae,

even many days after spraying. He was successful with Radiant. Other products that have worked well on this pest in the past include Avaunt and Intrepid, or Entrust for organic growers. We also saw one B.t. corn ear that had a large larvae in it this week, so while B.t. corn usually stops ECB and FAW, it is not perfect on the latter.

E urope a n c o rn b o rer ( E CB ) trap captures ranged from 0-6 moths this week. Pepper fields do not need spraying for this pest at this time. Time will tell if we have a third generation that requires control.

UC o n n R es ea rch F a rm – 5 CEW moths per night calls for a 4-day schedule on silking corn. Zero FAW moths, and just 2 ECB moths.

Steve Bengtson, Cold Spring Brook Farm, Berlin, CT

CEW counts rose suddenly this week. Now averaging 4 moths per night, putting me on a 4 day spray schedule on fresh silking corn.

One ECB moth (Z) caught this week, up from 0 last

week. 0 FAW caught this week.

Cucumbers sprayed with Ranman to hold off downy mildew. Winter squash sprayed with Torino for powder mildew.

Nelson Cecarelli, Cecarelli Farm, Northford, CT

CEW moths increased from 2.5 on Sunday to 8 per night late in the week. I’m still on a 4-day schedule, but they are increasing fast.

Dave [private consultant/scout] captured 18 FAW moths in the trap and all young corn fields have more than 10% infestation. I have sprayed most young corn twice. The Besiege did not work on FAW, even many days later, so I had to go back in with Radiant.

We captured 6 ECB moths.

The tolerant variety Eleanora, finally succumbed to basil downy mildew this week, but I’d have to say that I was happy with how it performed. I did spray it once with Ranman.

Jamie Jones, Jones Family Farms, Shelton, CT

Sorry I missed the update last week. I just took this picture, a couple interestingobservations. Something is eating all the red root pigweed, I’ve seen so much of it skeletonized across different fields [see if you can catch one, I’d like to know what it is].

The pumpkin leaf dying back, I don’t see any obvious disease and assume it may be senescence from the hot dry weather we’re having [could be black rot]. And the pumpkin in the background is starting to turn orange. Seems everything is at least a week ahead of usual. Our blueberry season has ended and some grape varieties are starting verasion (rapidly gaining sugar and nearing harvest).

I now know what a margined blister beetle is. I have noticed them devouring our beets. I’ve never noticed any insect eat a beet like that before.

Dan Slywka, Daffodil Hill Growers, Southbury, CT

Jude, I'm at the corn right now [8/17], 24 CEW in the trap [in one night]. Yikes! Spraying now.

Photo by Dan Slywka, Daffodil Hill Growers

No FAW moths in the Southbury trap. Zero FAW larvae in pre-tassel stage corn, 4% in late- whorl stage corn and 1% in mid-whorl stage corn. Threshold is 10%.

Pumpkins and winter squash – still no powdery mildew in this late-planted block. We will scout again next week. Dan may be the only one who has pumpkins that turn orange at the right time this year because he planted so late!

Randy Rogowski, Laurel Glen Farm, Shelton, CT [reported by J.B.]

Sweet corn – 4 CEW moths per night in trap means a 4-day schedule on silking corn.

Peppers - 4 ECB moths for this week in the traps. Peppers do not need to be sprayed.

Cucumbers – We didn’t find any downy mildew but we did find Anthracnose. Randy will spray his young cukes with Ranman to prevent DM, and Cabrio to stop the spread of the Anthracnose.

Anthracnose on cucumbers.

Winter Squash – no DM. He will apply another application of sulfur (for PM) and chlorothalonil(i.e. Bravo) for fruit rot organisms.

Owen Jarmoc, CT Valley Growers, Enfield, CT [reported by JB]

Cucumbers - Owen had the cucumbers sprayed for DM by Crop production Services. There was no additional spread this week. We did find a little Anthracnose, so he may need to add some Cabrio or Quadris on the next application.

Peppers – We failed to find any bacterial leaf spot and only 1 ECB moth was captured so no action was needed.

Pumpkins and winter squash – Pumpkins in his earliest planted fields were turning orange. Some winter squash was sized too. The leaf canopy in his fields is healthy so should provide good shade from the intense sunlight we will get in the next month before pumpkin harvest season starts for real. The fields are almost ready for the 3rd PM/fruit rot application. He has already applied Quintec and Torino for PM, so will apply Vivando with Bravo or Cabrio this time around. No sign of DM on these crops in the region, so we are not adding anything for that disease at this time.

Josh Bristol, Bristol’s Farm Market, Canton, CT [reported by JB]

Sweet corn – We finally captured 0.4 CEW moths per night, which puts Josh on a 6-day schedule on silking corn. This is the first time he has had to spray silking corn all year.

Peppers – only 2 ECB moths were captured this week. No action needed.

Brussel sprouts – the plants were still clean after a spray for caterpillars two weeks ago. The first Alternaria spots were present. I recommended that he plant only Alternaria-resistant sprout varieties next year. This is especially important for organic growers.

Tomatoes – Were sprayed for early blight. Copper will go on next for the bacterial canker. More plants died this week, but we are still curious about why the plants are not showing signs of canker. Colleagues at Cornell suggested that the test strip used in the lab to confirm the presence of bacterial canker may have produced a false positive. We will continue to explore the cause of the plant death, so that we can figure out the proper management strategy.

Colin Burson, Pinecroft Farms, Somers, CT [reported by J.B.]

Sweet corn – CEW traps in Somers, Enfield and Long Meadow, MA captured 4, 11, and 13 moths per night, respectively. That calls for a 4-day schedule in Enfield and Somers and a 3-day schedule of fresh silking corn just over the border in Long Meadow. Some corn in Enfield that they couldn’t get irrigation to in early silk stage was lost to drought damage as it failed to make usable ears. Another field of whorl stage corn in Somers was just sprayed for FAW larvae, but we captured 7 moths this week, so it may need an additional application if more larvae hatch and 10% of the plants are infested when it reaches pre-tassel stage. Keep scouting your pre- tassel stage corn for FAW larvae.

Peppers – Only 2 ECB moths were captured in traps again this week. No action needed.

Cucumbers – This crop has been sprayed twice for DM, but the consultant that scouts theircrops weekly found the first DM on cucumbers this week. A different fungicide may be neededin the next application, because the strain we have this year may be tolerant to the last product they applied.

Lars and Eric Demander, Clover Nook Farm, Bethany, CT [reported by JB]Sweet corn – Lars captured 0.6 moths per night on Tuesday, but the catch may have increased the next day as it did on many other farms. 0.6 moths calls for a 5-day schedule on silking corn.No FAW moths were captured this week.

Brassica – They were opening their new stand last week and didn’t get to the Brassica caterpillar control. The infestation increased to 70% infested plants this week. On one leaf, I counted 37 tiny cross-striped cabbageworms that had just hatched form a single yellow egg batch. Time to treat! He will treat the kale with Assail for cabbage whitefly. At the UConn Research Farm I have plots with and without a perimeter trap crop of kaletts surrounding a mix of Brassica crops. Unfortunately, we have no white flies yet to test the system – the entomological curse strikes again!

Winter squash and pumpkins – They are due for a second application of sulfur (i.e. MircrothiolD) and Bravo. We did not find any DM.

Eggplant – On vegetable farms, tomato and tobacco hornworms (THW) are usually found on tomatoes or peppers, but we found this big boy on eggplant! Eric said that years ago he learned from an old Italian fellow that you can hand pick THW easily at dusk because they all

come to the top of the plants to feed on the new growth at night – so you don’t have to search the whole plant for them. During the day they retreat to the shady parts of the plant. You often see the top leaves removed by hornworms first, so the theory makes sense, and Lars says that picking hornworms at dusk has been one of their chores since they were little kids.

THW on eggplant (4” long). Note fecal pellets in background on leaf below that can give away their hiding place.

Cole Van Seters, Freund’s Farm Market, E. Canaan, CT [reported by JB]Sweet corn – We captured 1 CEW moth per night which calls for a 5-day schedule on silking corn. No FAW or ECB moths were captured at this site this week.

Winter squash and pumpkins – Cole has applied only one application of sulfur and Bravo so far. He will make a second application in 10 days. We didn’t find any DM.

Steve and Ben Berecz, The Farm Woodbury, CT [reported by JB]Sweet corn – They captured 4 CEW moths per night, which calls for a 4-day spray schedule on silking corn, but this may have increased by now.

Peppers – we captured only 1 ECB moth, and the bacterial leaf spot we though we found a couple of weeks back has disappeared (without any copper sprays). Harvest is in full swing.

Cucumbers – we did not find any DM but they will apply Tanos to prevent this disease from defoliating their cukes.

Pumpkins – we scouted several fields. We didn’t find any DM, so they will just be spraying for PM and fruit rots. Their next (2nd) application will be Torino + Cabrio.

Lee Pinny, Elm Knoll Farm, Enfield, CT [reported by JB]

Lee has quite a bit of early blight (EB) in his tomato greenhouse – with really big lesions. I have seen this a couple of times before, but it is rare enough that it is not even listed in the NEVMG. Usually EB requires several hours of leaf wetness time for spores to infect leaves, so it is not a common problem in a GH where there is no rain or overhead irrigation. However, with the humidity hovering above 90% for many days or weeks, the disease seemed to have had enough moisture to cause infection. The only product I could find that is registered to apply for EB in the greenhouse is copper (i.e. Kocide 3000). The re-entry is just 24 hours for GH tomatoes, instead of the usual 48 hours, but you need to make sure workers have access to an eyewash station of some type and are informed about the application. See label restrictions.

Large early blight lesion on tomato leaf in greenhouse

Meg McGrath, LIHREC, Cornell University, Riverhead, NYThere is a new virus that I want you to be aware of. TCSV (tomato chlorotic spot virus). It is related to tomato spotted wilt virus (TSWV) and impatiens necrotic spot virus (INSV) (all tospoviruses), sufficiently closely that a plant with TCSV can falsely test positive with an immunostrip assay for one of theothers. Symptoms are similar.

I have an article plus photos posted at:

h tt p : // vege t a b le m d o n l in e . pp ath . c o r n ell . ed u / N e wsAr t icles / T o ma t o _ C h lo r o ti c _S p o t_V i r u s. ht ml

Please let me know if you see virus symptoms especially on tomato (M T M 3@ c o r n ell . ed u , 631-727-3595, ext 20). I have a colleague studying TCSV who is eager for possible samples. I’ll cover the cost of FedEx. Thanks, Meg

That’s all for this week. The next IPM pest message will be sent on Friday afternoon August 26th.