UConn Extension Vegetable IPM Pest Message & Reports from the Farm, Friday June 10th, 2016

[Comments or answers in brackets/color are provided by Jude Boucher, UConn Extension]

Jude Boucher, UConn Extension[Welcome back for another growing season of the IPM Pest Message and Reports from the Farm. Growers who are 100% certain of their pest identification are welcome to send reports in to me on a weekly or occasional basis for publication. Most of the growers you will hear from in this report have either been trained on UConn’s IPM Program or are currently being trained and are familiar with the pests they are reporting and the control options that will work to manage them. We reserve the right to fact check and edit reports from the farms for both clarity and accuracy.

Growers wishing to run pheromone traps for sweet corn pests or for squash vine borer or other pests can purchase traps and lures at one of the following suppliers among others: Great Lakes IPM, Alpha Scents, or Gemplers. To trap the following pests, you should purchase this number and brand of traps and lures:-European corn borer: purchase two white, nylon Scentry Brand Heliothis Traps and 7 of both the IA and NY type lures. Trece or Scentry brand lures will do. Place traps in the weeds along sweet corn or pepper fields, change the lures every two weeks, and empty the traps to count moths weekly.-Fall Armyworm: purchase one or more green, canister-type, Universal Moth traps and 4-5 Scentry or Trece FAW pheromone lures for each trap. You’ll also need one Vaportape (DDVP toxicant) strip for each trap to kill the moths that enter. Place the trap in young whorl stage sweet corn in early July and empty weekly. Change lures and move traps to new young whorl-stage corn every two weeks.-Corn earworm: Purchase two or more Scentry Heliothis traps and a package of 10 Hercon brand lures for each trap. UConn’s moth thresholds for this pest only work for the Hercon brand lures. Set traps in silking corn at ear height and change lures every 2-3 weeks. Move traps to fresh silk when silk turns brown. Empty traps every 3-4 days and use UConn thresholds to determine if and how frequently corn needs to be treated. -Squash vine borer: Purchase one Scentry Heliothis trap and one SVB lure for the season. Set trap up at plant height in a cucurbit field in mid-June (now). Protect squash starting one week after catching 5 or more SVB moths.-There are dozens of pests you can monitor if you want to, just talk to a rep at one of the supply houses for details.] Frist generation European corn borers and Colorado Potato beetles are flying and laying eggs – more on these pests next week.

Nelson Cecarelli, Cecarelli Farm, Northford, CTFlea beetles were exceptionally heavy on Brassica crops and eggplant earlier, but have been treated and seem to be under control now.

Spinach is showing some kind of nutrient or abiotic disorder. No disease was found on plants that were sent to the CT Ag Experiment Station. We tried a fertilizer with micro nutrients and they are starting to look better, but…

Ian Gibson, Well Stone Farm, Durham, CT Flea beetles on potatoes were much higher than in previous years.

I used BeetleGone [a new subspecies of B.t.] to protect my carrots and had much less damage from this pest this year. We’ll see what that means for later in the season.

I also used BeetleGone at the 2 oz. per gallon rate on my Brassica crops for white grubs and most types of Brassica suffered no loss to grubs. I didn’t treat my kohlrabi and lost about one third of the planting.

Seduce [solid spinosad bait] worked pretty well on the cutworm problem I had earlier.

Joan Allen, Plant Diagnostician, UConn

I have a case of potato blackleg at a farm in Southbury. She’s planted and now has some plants dying with typical symptoms (root rot, dark discoloration up the stem internally). I did have samples to confirm. [The UMass Newsletter Vegetable Notes reported this week that blackleg has been showing up around the region this year and that the “varieties Reba, Superior and Norwis from Maine seed have been identified as containing blackleg.” The Long Island Fruit & Veg Newsletter also reported that blackleg is being reported in “many of the fields being examined.”]

Blackleg and related diseases of potato are caused by bacteria in the genus Erwinia. Blackleg symptoms occur at any stage of development. They progress from decay in the seed piece. Affected tissue is soft and water-soaked under humid conditions and becomes shriveled under dry conditions. The stem pith is often decayed beyond the boundary of the external lesion and the vascular tissue is commonly discolored well in advance of the lesion. (These symptoms were noted on the sample.)

Bacteria that cause blackleg are introduced in or on tubers, primarily in lenticels and in wounds. They can be spread to healthy tubers during seed cutting, handling, and planting. Blackleg is favored by cool wet soils at planting followed by high temperatures after plant emergence, conditions that occurred this spring.

Management practices include clean seed potatoes, sanitation of equipment during cutting and between seed lots, planting well-suberized seed potato pieces, and planting in well-drained soil with soil temperatures at 50-55°F at planting depth. Irrigation before plants emerge increases the likelihood of losses.

Crop rotation away from potato is recommended to reduce pathogen populations in soil.

Blackleg (photos by Joan Allen)

Bill Syme, Crop production Services, E. Windsor, CT

photo by Bill SymeJude i believe this is slug damage. I found some in the field in the middle of the afternoon. I believe they feed mostly at night - there is a slug in picture 23.[Yes, definitely a slug in picture 23 and that is definitely slug damage. I have seen it so bad on one no-till planting in the distant past that the plants were stripped up to waist high. He probably will need a slug treatment…i.e. Deadline Bullets if it is field corn. So far, we have not seen slugs as a problem in deep zone till fields.

I heard yesterday that some dairy folks in the East are seeing some true armyworms, so keep an eye out for that pest.]

We have sprayed 50 acres of armyworm in Lebanon, and 90 acres in Coventry. I know another 100 acres in Salem that were sprayed. Every lot that I have found them in heavy is surrounded by hay fields. I did not spray some corn that had them because i felt that they were not at an economical threshold. [True armyworm attacks young seedling corn and other grasses and can strip the leaves and even kill the plants if in high populations – watch your sweet corn fields in Eastern CT.]

Randy Rogowski, Laurel Glen Farm, Shelton, CT [reported by JB]

Yellow nutsedge has become an increasing problem over the years and is now pushing up through the black plastic mulch and is thick between the rows of plastic on parts of this farm. Try to control nutsedge when it is still in a small area on your farm. Nutlets separate from the rhizomes at the beginning of August to make next year’s plants, so it needs to be controlled before then to reduce stands in the field. Use summer fallow periods with repeated cultivation to reduce stands. This can be done between cover crops or after early season crops are harvested. Sandea (halosulfuron) is registered on asparagus, beans, cucurbits, eggplant, peppers, tomatoes and sweet corn. Use a nonionic surfactant for best results. Basagran is also labeled for peas, beans and sweet corn. Two applications of either product may be needed for good control. Roundup (glyphosate) with liquid ammonium sulfate can be used after early crops and before planting fall crops.

We scouted Randy’s Brassica plantings and failed to find any caterpillar pests.

The weeds in his asparagus field need to be cleaned up so the plants can store energy in the young crowns. We also found just a few spotted and common asparagus beetles – not enough to warrant treatment – they could be hand crushed on some farms. Treat the ferns after the last harvest if more than 50-75% of the plants are infested with adults or slug-like larvae to prevent defoliation. SAB can be controlled simply by removing female plants from the stand so that only male plants remain.

Top left: spotted asparagus beetles Top right: common asparagus beetle

Bottom left: CAB larva Bottom right: fern stripped of leaves

Dan Slywka, Daffodil Hill Growers, Southbury, CT [reported by JB]

This is Dan’s first year growing sweet corn and pumpkins so I’m helping him get started with these crops and he got help planting from a local dairy farmer who owns planting equipment. Old hay fields were plowed and harrowed to prepare the ground. However, quack grass is coming back up. The best procedure would have been to apply glyphosate about a week before plowing to allow the product to reach the roots and kill the quack grass, otherwise you can fight this perennial grass in the field for years to come. His best option now may be to spray Roundup in unplanted sections of the field as the quack grass re-emerges, before planting his sweet corn or pumpkins. In the planted sections of the sweet corn field, Accent Q is labeled for quack grass control, but does present some risk to some sweet corn varieties. For organic growers, summer fallow with repeated cultivation, to run the quack out of energy is the best way to clean up the field of perennial weeds the year before planting.

Ben and Steve Berecz, The Farm, Woodbury, CT [reported by JB]

Most crops looked great. No caterpillars on their Brassica planting and the tomatoes, peppers and squash were clean, etc.

This is their first year growing tomatoes in a high tunnel and they were wondering how you get the abundant flowers to pollinate. The standard method is to purchase a hive of bumble bees for the tunnel and you will find that they are the hardest workers on the farm. Unlike traditional honey bees that get disoriented inside a plastic covered greenhouse/tunnel, bumble bees have no problem orienting themselves without being able to see the sun directly and work just fine.

Cole Van Seters, Freund’s Farm market, E. Canaan, CT [reported by JB]

Asparagus plants needed weeding. Tomatoes in high tunnels just getting red. Other crops just planted.

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

Tomatoes: plants look great, but we found the first early blight lesion of the season on one plant. Normally, this would signal the start of a fungicide program. However, since he is trying to grow organically, he will remove all lower leaves that show infection and either bury the leaves or bag them for the garbage. Next week we will scout again and determine if he needs to start an organic fungicide program. Scout tomatoes weekly for early blight lesions on the lowest leaves.

EB lesion (note concentric rings and yellow around spot).

We scouted his Brassica planting and again found no caterpillars on this farm.

Early sweet corn plantings require hilling in rows to cover young weeds. Sweet corn can be grown without herbicides by using tight row spacing and a tine cultivator to do “blind cultivations” before the weeds and crop is up while weeds are still in the white thread stage and very susceptible to drying out. This can be repeated when the corn is at spike stage. A rolling cultivator (Lilliston-type) can then be set in a non-aggressive way (no angle) to weed between the corn rows. Once the corn is 5 inches high, the rolling cultivator can be set more aggressively (more angle) to throw soil and hill the corn to smother weeds in the row. Prolonged wet periods can foil the best plans when relying on cultivation.

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

This farm has been growing tobacco, pumpkins and a small garden to support a small farm stand, but is making a stab at wholesale vegetable production this year. They have 27 acres of pumpkins with a similar amount of winter squash planted, and 8 acres of peppers, cucumbers and summer squash planted thus far. Those last 8 acres are all on black plastic and everything looks great.

We found just a few cucumber beetles in their 12-acre butternut field. Seedling winter squash, watermelons and pumpkins should be sprayed when you find 1-2 cucumber beetles per plant. Seedling cucumbers and melons, which are much more susceptible to bacterial wilt than other cucurbits, should be protected when one beetle is found on every two plants.

A better way to protect cucumbers, melons, and squash is to use perimeter trap cropping with a single row of Blue Hubbard squash (or another highly attractive Cucurbit maxima squash) in the outer row all the way around the field. Treat just the trap crop when the first beetle of the season shows up or you detect feeding on the underside of the codyledon leaves. One to three applications on 5-7 day intervals may be needed to control first generation beetles, depending upon population levels at your location. Rotating to fields ½ mile away help lower the number of beetles that find and colonize your plantings.

Becky Sideman & Heather Bryant – UNH, Mark Hutton & Bruce Hoskins – UMaine, Margaret Skinner & Cheryl Frank Sullivan – UVM, Eric Sideman – MOFGA, John Spargo - PennStateAs part of our new Northeast SARE project “Improving nutrient and pest management in high tunnel production”, we want to learn more about the practices used and challenges faced by growers using high tunnels. We ask you to help us by please responding to our survey, found at the link below.

https://unh.az1.qualtrics.com/SE/?SID=SV_5sZDRnBReS9vxNH

Your responses are crucial to help us design our research & outreach programs to provide the best resources for improving nutrient and pest management in high tunnels. All responses will be kept confidential. We greatly appreciate your time and input

That’s all for this week. The next IPM pest message will be sent on Friday afternoon June 17th.