Not Just for Corn: European Corn Borer in Snap Beans, Peppers and Potatoes by Julie Kikkert, Judson Reid, Carol MacNeil

Although European Corn Borer (Ostrinia nubilalis) is a major pest of corn, it also feeds on over 200 plant species. Vegetable producers in New York are most concerned with this pest in sweet corn, snap beans, peppers and potatoes. Growers can find information on this pest in the weekly WNY Sweet Corn Trap Network Report as found on page 9 of this newsletter.

European corn borers (ECB) overwinter as fully grown larva in the stalks and stems of the host plant. The larvae pupate in early spring and the emerging adults mate. Females lay their eggs on susceptible crops. Masses of 5 to 50 eggs can be found on the undersides of leaves of their food crops. Eggs hatch in 4-9 days depending on the temperature. Young larvae feed on leaf tissue before boring into stalks, stems and pods.

Snap Beans Larvae that bore into pods are the main concern, be-cause the resultant holes render the beans unmarket-able and no one wants to find a “worm” while cook-ing their snap beans. There is especially low tolerance for this in processing beans. Properly timed insecti-cide sprays are an effective tool for ECB management in snap beans. Both timing and number of applica-tions is influenced by (1) moth activity during early bloom and (2) history of ECB damage in that field or area. If moth activity in pheromone traps (see the weekly sweet corn report) is increasing or high in a field during early bloom OR if the field has a history of high ECB damage, the field is at high risk and should be sprayed 2 times. The first application should be made during full bloom (21 d before harvest) and then followed by another application 6 to 8 d later. If moth activity is low and numbers of moths caught in pheromone traps are not increasing OR if the field has a history of very low corn borer damage, the field is at low risk

Volume 7, Issue 15 July 6, 2011

Cooperative Extension Cornell Vegetable Program

Cornell University

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Contents General

Not Just for Corn: European Corn Borer ................. 1 Cover Crops for Mid-Late Summer ......................... 6 2011 Federal Market Prices .................................... 6

Dates .......................................................................... 3

Sponsors ................................................................... 11

Weather Charts ........................................................ 11

Crops Crops: Tidbits & Insights .......................................... 7 Cabbage & Cole Crops: Managing Clubroot ............ 8 Onions: Rotation for Inspire Super & Quadris Top . 9 Sweet Corn: Trap Network Report, 7/5/11 ............. 9 Tomato Concerns: Late Blight in NY ........................ 3 Tomatoes & Potatoes: LB Severity Values .............. 4 Tomato Fungicide Roster & Ratings ........................ 4 Vine Crop Concerns ............................................... 10

Continued on page 2

ECB in snap beans. Photo courtesy of Iowa State University

July 6, 2011 Volume 7, Issue 15 Veg Edge Weekly

Page 2

Continued from cover

and only 1 application is needed. In this situation, the application should be timed during late bloom to early pin stage, say around 17 d before harvest. In many cases these insecticide sprays will coincide with fungicide applications, but not always. All of the products listed in the Cornell Vegetable Guidelines for ECB control on snap bean are effective.

Peppers ECB larvae bore into pepper fruit. Attack that occurs when fruits are small results in fruit that are rotten by harvest. Attack on lar-ger fruit may be unnoticed on the outside, but the peppers are deteriorated on the inside as larvae feed on the central seed mass, in the ribs and in the wall of the fruit. Usually, infested pep-pers have a small hole near the edge of the cap that is sur-rounded by sawdust-like frass.

It is best to locate fields away from corn. A variety of natural ene-mies such as lady bugs, minute pirate bugs, lacewings, and parasi-toids help suppress ECB infestations. If you’ve had problems with this in the past, there are several insecticides labeled for control (see page 254-255 of the Cornell Vegetable Guidelines). Insecti-cide treatments should coincide with peaks in adult activity as determined by pheromone traps (see the weekly sweet corn re-port). Do not spray before fruit begins to form.

Potatoes Small ECB larvae tunnel into potato stems within several days of hatching. Many varieties have a high tolerance for borer tunnel-ing and by itself up to 35% infestation may be tolerated. How-ever, in wet weather, or when seed was infected with blackleg, bacterial infection of the damaged stem tissue causes rotting of the vines. The mid-season destruction of the vines can severely affect tuber size.

There are a number of risk factors for ECB infestation in potatoes. Fields are at higher risk if: there’s a history of serious ECB dam-age; if potatoes were planted very early and corn planting in the area was delayed; if potato fields are near or following non-Bt corn, especially if the stalks weren’t chopped last fall. In addition, volunteer corn in the potato field attracts corn borer moths so control them with a selective grass killer like Poast or Select Max (follow the label regarding proper use of adjuvants or oil). Fields near or following Bt corn are at lower risk. In trials ECB larvae survived best on Sebago, followed by Monona, then Superior, and survived most poorly on Katahdin. Under field conditions Sebago, Monona and Norchip have been observed to be susceptible to attack by ECB's and to infection by aerial blackleg.

If you’ve had problems with this in the past, there are several insecticides labeled for control (see page 293-295 of the Cornell Vegetable Guidelines). Choose a material based on whether Colorado potato beetle and/or potato leafhopper also need control as many materials are not effective against all three pests. Insecticide treatments should coincide with peaks in ECB moth catches as determined by pheromone traps (see the weekly sweet corn report).

Additional photos and information can be found at: http://www.nysipm.cornell.edu/factsheets/vegetables/swcorn/ecb.pdf or http://web.entomology.cornell.edu/shelton/veg-insects-ne/pests/ecb.html

ECB in peppers. Photo courtesy of OMAFRA

ECB larvae in potato stem. Photo courtesy of University of Maine IPM

July 6, 2011 Volume 7, Issue 15 Veg Edge Weekly

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Dates... July 12 - Farm IT: You Probably Still Need a Farm Website 7-9pm, Cornell Food & Agricultural Technology Park, Geneva. $10. To REGISTER: Call Nancy Anderson at 585-394-3977 x427 or send name, address and phone number to nea8@cornell.edu

July 13 - 2011 Cornell Vegetable Weed Science Field Day Thompson Research Farm, Freeville, NY (10 miles Northeast of Ithaca, Fall Creek Rd, Rt. 366 Extension, 8:00 am Registration, 8:30 am – 11:30 am Vegetable Crop Weed Control (with Dr. Bellinder). $8. Pre-Register by July 11 to Maxine Welcome, 607-255-5439 or mw45@cornell.edu

July 25 - PowerPoint and Your Farm, 7-9pm, Cornell Food & Agricultural Technology Park, Geneva. Learn how to use PowerPoint software to plan and create a basic digital slideshow. Will also cover how to make posters or signs for your farm or farm stand using this software. $10. To REGISTER: Call Nancy Anderson at 585-394-3977 x427 or send name, address and phone number to nea8@cornell.edu

August 2 - Annual Elba Muck Onion Twilight Meeting Mark your calendars!

August 9 - Protecting & Improving Your Crops From the Soil Up 4-7pm, Mud Creek Farm, McMahon Rd, Vic-tor. Crystal Stewart, CDVSFP, will focus on best management techniques for organic farmers trying to eliminate or prevent garlic bloat nema-tode and soil-borne pests and pathogens. Learn the management techniques that promote soil physical health, reduce soil compaction and encourage healthy soil microbia. To register, visit NOFA-NY Shopping page or by call (585)271-1979 ext 512.

August 9-11 - Empire Farm Days, Rodman Lott & Sons Farm, Seneca Falls. For more info: 877-697-7837 or mwick-ham@empirefarmdays.com

August 12-14 - NOFA Summer Conference UMass Amherst. 225 workshops on organic farming, gardening, land care, draft animals, homesteading, sustainability, nutrition, food politics and more. Beginning Farmer Scholar-ships available. Deadline for application is July 11. Go to: http://www.nofasummerconference.org/beginningfarmer.php

Bacterial spot on tomato.

Tomato Concerns: Late Blight in NY

J. Reid, CVP: Cornell Plant Pathologist Meg McGrath discovered Late Blight on June 28 in 3 separate tomato fields and 2 potato fields on the South Fork of Long Island where long periods of morning fog make conditions favorable for the disease. Symptoms were found at a very low level North Fork of Long Island during scouting on 6/30 and 7/1. One of the affected farms had a severe outbreak with several rows of at least 75% of plant tissue affected. The origin of these outbreaks has not been determined.

Is it time to break out the spray rig? Not yet, at least not for Late Blight in Western or Central New York. Predominant weather patterns are unlikely to spread the disease in this direction. Vigilance is recommended and the CVP takes (almost) all Late Blight concerns seriously. There are several other diseases that require diligence.

For example, Bacterial Spot and Early Blight (see photos) can be found on local farms this week. These diseases overwinter in the soil and on used tomato stakes (see previous issue for stake sterilization). We recommend a 2 year rotation away from tomatoes and potatoes for Early Blight preven-tion and 3 years for Bacterial diseases. Quite simply the longer a field is out of solanaceous and cucurbitaceous crops the less problems we have. Other preventative techniques include using plastic mulch and timely trellising of tomatoes. Having taken these measures there are some sprays to consider.

For bacterial diseases copper products are regarded as the most effective materials. Note that high pressure sprays can increase bacterial problems, so back off the PSI on this one. For Early Blight the list is longer, with chlorothalonil continuing to be the backbone protectant. An alternation of chlorothalonil and copper hydroxide will also be a first step in protecting against Late Blight. Materials with action against Late Blight are highly spe-cific. See Tom Zitter’s 2011 Tomato Fungicide Roster & Ratings chart for LB and EB (page 4).

Early blight in tomatoes.

July 6, 2011 Volume 7, Issue 15 Veg Edge Weekly

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2011 Tomato Fungicide Roster and Ratings (in order of preference – Best to Poorest) with specific emphasis on Late Blight (LB) (Phytophthora infestans), as well as Early Blight (EB)

(Alternaria tomatophila), and Septoria leaf spot (SLS) (Septoria lycopersici). TEP = Tomato, Eggplant, Pepper

Tom Zitter, Dept. of Plant Pathology and Plant-Microbe Biology, Cornell University, June 23, 2011

Late Blight Severity Value Accumulations

C. MacNeil, CVP: No late blight (LB) severity values (SV) were accumulated in the past week at any of the weather stations except Lafayette where two were accumulated. This indicates low risk of LB development. Pockets that received rain, had long dew periods or fog would have a higher risk. Unless you’re using the new Late Blight Decision Support System (LB DSS) stay on a 7 day interval. For information on using this advanced online LB forecast system contact C. MacNeil at 585-313-8796.

Late blight (LB) has now been detected at low levels on the North Fork of Long Island in addition to several tomato/potato fields on the South Fork. The source of initial infection is likely infected potato seed in a nearby field, or potato culls that over-wintered. (from M.

McGrath, Cornell, LIHREC)

Tomato fungicides (Eggplt. or Pep.)

MOA for LB (Protectant/Curative/

Antisporulant)/ Mobility

1FRAC Group

2Risk mtg

REI (hrs.)

PHI (days)

No. applic./ amt/season

3Usage rate for tomato

4 Efficacy 5Special comments & Resistance Mtg. measures

LB EB SLS

Ridomil Gold Bravo (mefenoxam + chlorothalonil) (T); also RG/MZ or CU

P, C, A/Systemic 4 + M5 Hr for Gp 4; mix =

M

48 5 Don’t exceed 11.25 lb a.i. /S of chloro.

2.5 pt (rate = 1 lb a.i. chloro.)

++++ US-22

++ ++ mefenoxam is effective for US22, but not for most other isolates of LB; Alternate with different MOA between each spray

mefenoxam - effectiveness based upon isolate – i.e.

US22

*Previcur Flex (propamocarb) add Contact (T,P)

P, C, A/Systemic 28 L-M 12 5 7.5 pt per season

LB @ 0.7-1.5 pt. + contact

++(+)

++ TM

++ TM

TM with contact fungicide; Suggest alternating diff. MOA with each spray; also GH for Pyth & Phytophthora spp. Damping-off.

Good upper movement to stems

and leaves

*Presidio SC (fluopicolide) add Contact (TEP)

P, C, A/Translaminar/Sys.

43 H 12 2+ by TM

partner

4 applic./12 fl oz/season

LB @ 3-4 fl oz + contact

+++ ++ TM

++ TM

TM with contact fungicide; no more than 2 consecutive applic. before alternating to diff. MOA; Also for Phytophthora blight.

Preventative; some curative reach-back

activity

Revus (mandipropamid) add Contact (TE?P)

P, c, a/ Translaminar 40 L-M 12 1 4 applic./32 fl oz/season

LB @ 5.5-8 fl oz +

contact

++ ++ TM

++ TM

TM with contact fungicide; no more than 2 consecutive applic. before alternating to diff. MOA; addition of spreader/adj. recomm.

Locks into waxy layer (rainfast), then moves

through leaf

Revus Top (mandipropamid + difenoconazole) (T)

P, c, a/Translaminar 40 + 3 L-M 12 1 4 applic./28 fl oz/season

LB @ 5.5-7 floz

++ ++ ++ No more than 2 consecutive applic. before alternating to diff. MOA; See adjuvant recomm.

Added broad spectrum component

Ranman 400SC (cyazofamid) add Contact (TEP)

P, -, -/Contact 21 H 12 0 6 applic./ 16.5 fl oz/

season

LB @2.1-2.75 fl oz +

contact

++ ++ TM

++ TM

TM important; No more than 3 consec-utive applic., then switch to 3 sprays of diff. MOA; GrHs use for Pythium Damping-off

Limited systemic activity

*Gavel 75DF (zoxamide + mancozeb) (T)

P, -, -/Contact 22 + M3

L-M 48 5 8 applic. or 16 lb/sea.

LB @ 1.5-2 lb

+(+) ++ +(+) Suggest alternating diff. MOA with each spray. Not sys., vapor activity

reported

*Zoxium 80WSP (zoxamide) add Contact (T)

P, -, -/Contact 22 L-M 48 5 8 applic. or 2 lb/season

LB @ 2.5-4.0 oz/A

+(+) ++ TM

+(+) TM

Product alone will only control LB; Do not make more than 2 consecutive applic.

Same as above w/o mancozeb

1, 2 FRAC = Fungicide Resistance Action Committee Group No. and Risk for fungicide resistance development; 3 Usage rate for LB as range or highest value; 4 Foliar blight ratings where 0 = no effect or not labeled; 0(+) = some effect; + = poor; ++ = OK-good; +++ = very good; ++++ = excellent. 5 Special comments: TM = tank mix with another fungicide for resistance management and control of other diseases like early blight; MOA = mode of action means selecting a

fungicide from a different Fungicide Group *= Restricted applicator use in NYS per DEC requirements; † = Not for use on Long Island.

July 6, 2011 Volume 7, Issue 15 Veg Edge Weekly

Page 5

Tomato fungicides (Eggplt. or Pep.)

MOA for LB (Protectant/Curative/

Antisporulant)/ Mobility

1FRAC Group

2Risk mtg

REI (hrs.)

PHI (days)

No. applic./ amt/season

3Usage rate for tomato

4 Efficacy 5Special comments & Resistance Mtg. measures LB EB SLS

Forum (dimethomorph) add Contact (TEP)

P, c, A/Translaminar 40 L-M 12 4 + 30 oz/season LB @ 6 oz/A + contact

++ ++ ++ TM suggestion and addition of spreading/penetrating adjuvant; alternate with diff. MOA.

Use as preventative

Curzate 60DF (cymoxanil) add Contact (T)

P, C, a/Translaminar 27 L-M 12 3 + No more than 30 oz /

season

LB @ 3.2-5.0 oz/A

+(+) ++ TM

++ TM

TM required; Alternate sprays with fungicide with diff. MOA; Kick back activity is only 2 days if cool and zero if above 80F.

Short residual, stronger curative

properties

Tanos 50DF (famoxadone + cymoxanil) + Contact (T,P)

P, C, a/Translaminar 11 + 27

M-H 12 3 + 72 oz/season LB @ 8 oz + contact

++ TM

++ TM

++ TM

See the limitations above for Curzate 60DF; treat essentially like a preventative spray.

Needs to be applied before infection

occurs

Strobilurin Fungicides (ex. Quadris F) (TEP)

P, -, a/Translaminar 11 H is used alone

4 0 Limit to 37 fl oz/season

LB @6.2 fl oz; others

at 5.0-6.2 fl oz

+(+) TM

+ Res.

++ Res. to Group 11 fungicides exists in NYS; Other Gp.11 = Cabrio0, Flint3, Heritage0(GrHs), †Reason14

TM with or choose Product better for LB

Quadris Opti (azoxy + chloro.)(T)

P, -, -/Translaminar 11 + M5

M 12 0 15.0 lb a.i. of chloro.

LB @1.6 pt/A

+(+) ++ +++ No more than 1 applic. before rotating.

Quadris Top (TEP) P, -,-/Translaminar 11+3 M 12 0 47 fl oz 8 fl oz 0 +++ +++ No more than 2 consec. sprays.

Catamaran (chlorothalonil + K phosphite) (T)

P, -, -/Contact M5 + 33

L 12 0 50 pt/A/season

5-7 pt/A +(+) ++ ++ Apply highest rate at shortest interval under severe disease conditions. Broad spectrum

chlorothalonil (ex. Bravo Weather Stik) (TEP)

P, -, -/Contact M5 L 12 0 20 pt (15 lb a.i.) /season

LB @ 1 3/8-2.75 pt

++ ++ +++ Good TM partner; Other formulations and generics exist; BravoWS is most complete label.

Broad spectrum

mancozeb (ex. *Dithane DF Rain Shield) (T)

P, -, -/Contact M3 L 24 5 Limit 22.4 lb (16.8 lb a.i./

season)

LB @ 0.75-1.5 lb/A

++ ++ ++ Good TM partner; rate can be adjusted depending on plant; Other formulations exist; see Manzate P-S, or Penncozeb 75DF.

Broad spectrum – for LB and EB

Endura (boscalid) (TEP)

P, -, -/Contact 7 12 0 6 applic. (21oz) @ low

rate

EB @ 2.5-3.5 oz

0 + 0 Also higher rates for Botrytis; could be combined with Cabrio for better control of EB and SLS.

Ziram (ex. Ziram 76DF) (ziram) (T)

P, -, -/Contact M3 L 48 7 Limit to 24 lb/season

EB & SLS @ 3-4lb/A

0 ++ ++ See also Ziram Granuflo

Scala (pyrimethanil) + Contact (T)

P, -, -/Contact 9 M 12 1 Limit to 35 fl oz/season

EB & Botrytis 7 fl

oz

0 ++ TM

0 TM with chlorothalonil; Alone can be used in well-ventilated tunnel or GrHs.

Requires TM with a protectant fungicide

copper (ex. Champ WG, since OMRI) (copper hydroxide) (TEP)

P, -, -/Contact M1 L 24 0 No limits listed

LB @2-4 lb /A

+ + + Other OMRI coppers: Basic copper 53; Cueva; Nu-Cop 50WP; Many other Con-ventional coppers avail.

Broad spectrum, only Fungicide Group

available for Organic Production

2011 Tomato Fungicide Roster and Ratings (continued)

July 6, 2011 Volume 7, Issue 15 Veg Edge Weekly

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Cover Crops for Mid-Late Summer

C. MacNeil*, CVP: This year many growers are going to leave fields un-planted over the summer. Rather than leave the ground open to grow weeds, the land can be improved by holding it with a cover crop. Reducing weed seed production is an obvious advantage that will be appreciated the following year. Using the great growing condi-tions of late summer also allows you to address soil health issues by choosing a cover crop that directly targets proper-ties that are a concern. Hard surface soil and subsurface compaction are both common vegetable production limitations. Cover crops inhibit weed growth directly and create unfavorable conditions for soil-borne diseases by improving water percolation. Late sum-mer cover crops also scavenge leftover nitrogen and add organic matter. Note! Be sure that soil moisture is ade-quate for good germination of the cover crop to assure the crowd-ing out of weeds.

Buckwheat and sudangrass are at their best when sown in July, and can be sown into early August. (For information on sudangrass see the article Su-dangrass on Unplanted Ground in the June 15 Veg Edge Weekly.) Buckwheat works in a short window (40 days), is ex-cellent against weeds, and leaves the soil mellow and ready to plant. It doesn’t estab-lish well in compacted soil,

added fertilizer and is good at scaveng-ing phosphorus. It is an excellent ref-uge for beneficial insects.

Medium red clover is a short-lived per-ennial used to supply nitrogen. (Do not substitute Mammoth red clover.) Unlike other legumes, it fixes a lot of nitrogen even in high-nitrogen soils. This crop is well-adapted to a wide range of soil types and conditions. It can be planted anytime from April to Sept, or frost-seed in Feb-March. Since red clover seedlings tend to be slow growing and shade tolerant, it benefits from a nurse crop, such as oats or an-other small grain. It forms tap roots and is useful for remediation of com-pacted soils. Red clover is also good for weed suppression. If you’d like to grow some nitrogen this is a good crop to try. Since it is a legume, however, it shares the same diseases as legume crops such as beans, peas, soybeans,

etc. and if you have a short rotation between legumes then red clover should probably not be used. Red clover supports aphid predators such as ladybeetles, green lacewing larvae and hoverfly larvae. Incorpo-rate red clover in the spring when it flowers.

(*Info from Thomas Bjorkman’s Cornell Cover Crops for Vegetable Growers website at: http://covercrop.net. See more details there on seedbed prepara-tion, planting methods, seeding rate,

seed sources, etc.)

however. The short cycle lets you use buckwheat between crops. It works especially well before fall grains but allow a few weeks from buckwheat incorporation and wheat planting to avoid negative allelopathic effects. Buckwheat seeded in July and early August sets seed quickly. Make sure to stop the cover crop at the right time. If it is mowed too early (30 days from seeding), it will regrow and make seed in less than a month. If it is mowed or incorporated too late (45 days), it will already have viable seed that will sprout in the spring. Buckwheat volun-teers tend not to be a problem with row crops that have early cultivation or post-emergence herbicide programs. Mow 35-40 days after seeding or incor-porate 35-45 days after seeding to avoid volunteers. The right time is when the field has just turned white with flowers. Buckwheat doesn’t need

Buckwheat seed is already set

2011 Federal Market Prices The USDA Fruit and Vegetable Market News Service provides information on current supplies, demand, and prices for over 400 fresh fruit, vegetables, and other specialty crops updated on a regular basis during the sea-son. Reports for both conventional and organic fruits and vegetables are provided. Information can be accessed by visiting the website at www.marketnews.usda.gov/portal/fv.

Market price reports for organic fruits and vegetables can be accessed by visiting the New Farm Organic Price Report website at http://rodaleinstitute.org/Organic‐Price‐Report, or the Maine Organic Farmers and Gardener’s Association puts out a report reflecting prices charged by Maine farmers and this information can be accessed at http://www.mofga.org/Publications/OrganicCropPriceReports/tabid/260/Default.aspx.

July 6, 2011 Veg Edge Weekly

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Volume 7, Issue 15

CROPS Tidbits & Insights

BEETS/CARROTS Later planted fields have uneven germination and emergence. This is making herbicide application tricky especially in carrots. Weeds are already getting ahead of the carrots in some fields. Some entire fields are still in the germination stage. Irrigation may help, but also tends to cause soil crusting. Try to keep the soil uniformly moist. Keep scouting for leaf diseases on older plantings.

DRY BEANS Bean planting continues. Emergence is delayed in some fields planted late last week due to dry soils. Emergence in earlier fields is good. The first Western bean cutworm moth in the CVP area was caught in a trap in a Mendon dry bean field in the past week.

As the first trifoliate leaf approaches full expansion it’s time to scout your fields for weeds which have escaped your pre and incorporated herbicide applications. All broadleaf weeds are most susceptible when they’re very tiny, having just their cotyledons or first true leaf(ves). Basagran plus Re-flex plus a non-ionic surfactant will control most problem annual broadleaf weeds if they’re small. Reflex must be applied before bloom and the season maximum rate is 1.25 pts/acre. Raptor is better against the nightshades but should be mixed with Basagran to avoid a delay in maturity. This combination is weak against Galinsoga. Poast, Assure II/Targa, and Select are effective against many annual grasses, and all but the first will also provide control of quackgrass. Allow 3 – 7 days between applications of the grass killers and Reflex. Read the product labels for rates for the spe-cies/size weeds you have, and for the recommended adjuvants/additives for these post-emergence materials.

Check out Herbicides for Snap & Dry Bean Weed Control in the April Veg Edge, which lists problem weeds and rates labeled bean herbicides for effectiveness against them, or view it online at the CVP website at http://blogs.cce.cornell.edu/cvp/files/2010/05/2010-Bean-Herbicide-Chart.pdf

When temps are 85°+ , or if weather has been cloudy for a couple of days, post-emergence herbicide applications may cause more bean injury.

ONIONS Transplanted onions and early direct seeded varieties have been bulbing very nicely. Early varieties of transplants started to lodge this week. The crop could use some rain. Critical timing for onions to have a steady water supply is during bulbing. If it does not rain this week, onions should be irrigated, if possible.

Onion thrips (OT) increased this past week, but remain well below the spray threshold for Movento of 3 OT per leaf in the muck areas. Save on in-secticides by waiting to spray until the threshold is reached. At this time, OT are entering into onion fields from outside sources. Therefore, it is very common to observe an “edge effect” where OT are higher along field edges, while remaining very low in the rest of the field. We recommend that you do not spray an entire field based only on high numbers of OT along the edge of the field. Make sure to walk into the field when scouting to determine whether or not you have an edge effect. In some cases, it makes sense to spray only the field borders for OT, if feasible. Also, at this time, not every plant in the field has OT, but others can have 10 to 50 or more OT per plant. It is very important to inspect several plants to deter-mine the actual OT pressure in the field, because several plants with very low OT counts will compensate for a few plants with high OT counts, and you do not need to spray. When scouting, count the number of OT per plant on a least 20 plants per field, and divide the total number of OT per plant by the average number of leaves per plant to get the number of OT per leaf. A spray threshold of 3 OT per leaf is equivalent to 20 plants at the 10-leaf stage having 30 OT per plant. See issue #13 for OT control recommendations.

In transplanted onions, Botrytis leaf blight (BLB) continues to drop and is now below the spray threshold of 1 BLB lesion per leaf in Elba. Purple blotch (PB) remains undetected this week. With OT also below the spray threshold, this could be an IPM opportunity to skip a spray in transplanted onions this week. BLB continues to exceed the spray threshold in most direct seeded fields in Elba and Wayne muck areas, and should now be get-ting regular BLB fungicide sprays. Keep in mind that in the absence of rain, night time dew and cool temperatures can provide favorable conditions to drive BLB. Although I can’t explain it, I have often observed large transplants grow out of BLB, while it continues to increase in direct seeded on-ions. I suspect that this is at least in-part a function of plant age. For growers who are using the newly registered fungicides, Inspire Super and Quadris Top, there are several rotation strategies to consider (see page 9).

PEAS Harvest of processing peas has begun. Many pea fields suffered from too much water early in the season. Root development is poor due to compac-tion and/or root rot. Plants are likely to yellow and wither in the hot dry weather this week.

POTATOES In many areas soils are getting dry for the relatively shallow rooted potato plant. This is of particular concern because tubers are setting and begin-ning to develop. This is also a critical time for potential scab development, which is favored by dry soils. Even though you may feel some moisture in the soil down in the tuber zone if you can’t make a soil ball from the soil which will hold together the soil is too dry and potatoes are beginning to be stressed. The next approximately 6 weeks are critical for building yield and size, and for reducing scab. Maintain good/moderate soil moisture with irrigation if necessary. Potato varieties most susceptible to scab include: Adirondack Blue and Red, Katahdin, Norwis, Norwis, Snowden and Yukon Gold, but many other varieties get scab if conditions are favorable for it. See the section on European corn borer (ECB) in the article in this issue “Not Just for Corn: European Corn Borer in Snap Beans, Peppers and Potatoes.”

SNAP BEANS If you are still planting, try to get the bean seed down where there is moisture, as most of our region is very dry. Sunscald is evident in fields this week. This is especially true in fields where root development was limited by wet and compacted soils earlier on. The plants just can’t keep up with the moisture requirements of the young growing tissue in this hot, dry weather.

Soybean aphids are active in soybean fields. They will also move through snap bean fields. The feeding doesn’t usually damage snap beans dir ectly. However, soybean aphids are the major vector of viruses in beans in NY. We are interested in obtaining virus infected beans again this year. Call Julie if you suspect infested fields.

VINE CROPS Bee activity has picked up in many fields. Cool nights and hot days may have slowed down pollination over the past couple of weeks. Harvest yields seem to have picked up in summer squash, zucchini, and cucumbers with less poor pollinated fruit being culled. See page 10 for vine crop concerns.

July 6, 2011 Volume 7, Issue 15 Veg Edge Weekly

Page 8

Considerations for Managing Clubroot in Cabbage & Cole Crops

C. Hoepting, CVP: The wet spring was very favorable for clubroot and the recent dry weather has caused this disease to show up over the past couple of weeks. Unfortunately, there is nothing that can be done to manage clubroot this year, but here are some manage-ment strategies for next year.

What is clubroot? Clubroot is a fungal disease of cabbage and other cole crops that causes club-like spindle-shaped swellings on individ-ual roots or on the whole root system. These distorted roots are unable to absorb nutrients and water, and are often invaded by secon-dary organisms like maggots causing death of the plant. Above-ground symptoms include stunted and wilted plants (which may recover at night), which can easily be confused with heat and draught stress or water-logged soil conditions.

What causes Clubroot? Clubroot is caused by a water-loving fungus, the spores of which can persist in the soil for up to 18 years. It is favored by wet, acidic soils (pH < 7.0). The optimum soil temperature is 67–73˚F with a minimum of 61˚F. It is introduced by drainage water, soil that clings to farm equipment, shoes, infected transplants, and contaminated manure and irrigation water. Repeated crucifer production leads to a rapid build-up of the clubroot fungus in the soil.

Above-ground symptoms of clubroot.

How to control Clubroot:

1) Rotate out of crucifers for 5-7 years. Cruciferous weeds such as mustards and Shepherd’s purse also serve as hosts to clubroot, so it is important to control these weeds within the rotational crops.

2) Avoid the movement of soil and plant material from infected fields to non-infected areas - Do not plant clubroot-infested transplants into a clean field.

3) Maintain a soil pH of 7.2 to 7.5 by liming. This high pH does not kill the fungus, it just reduces its ability to cause infections. Clubroot will still occur in heavily infested soils despite an elevated pH. For fields that have cole crops in their rotation, pH should be maintained at 6.8. In the year that you are planting cole crops, apply 1500 lbs/acre of hydrated lime to get the pH between 7.2 and 7.5. Hydrated lime is more expensive than ground limestone, but it can change the pH easily with an early spring application. It should be applied at least 6 weeks prior to planting. Balance nutrients in high pH soil: When pH is greater than 7.2, boron, manganese, zinc, copper and phosphorous can become tied up and deficient to the cole crops. The most important nutrient to cole crops, especially cauliflower, is boron. Boron can be applied pre-plant incorporated with NPK at 1-2 lbs actual boron per acre (= 10 lbs Borax). A good amount of phosphorous should also be applied in the transplant solution.

4) Fungicides with active ingredient, pentachloronitrobenzene (PCNB) and trade names Terrachlor 75WP, Terrachlor F and Blocker, have historically been used to provide some control of clubroot. Unfortunately, they have been discontinued and not sold due to a “Stop Sale, Use or Removal Order” from EPA. Fortunately, the fungicide Ranman (a.i. cyazofamid) now has a supplemental label that includes clubroot in crucifers (as well as downy mildew). Cyazofamid does not kill the overwintering spores that last for more than 10 years, but it does reduce the number of clubs so that the crop is nearly normal size. Ranman has been effective in several evaluations conducted at the Muck Crops Agricultural Research Station in Ohio where conditions are very favorable (acidic soil) and clubroot is severe. Severity was reduced by up to 56% with Ranman at the highest rate tested and plant vigor was greatly improved in these experiments. A PCNB fungicide was not included in these experiments, but Ranman was more effective than other fungicides tested. According to the manufacturer, FMC Corporation, good incorporation and maintaining moist soil are key to maximizing control of clubroot with Ranman, because Ranman becomes inactive when soil dries. Soil should be moist when Ranman is applied at planting and kept moist afterwards. Till Ranman into moist soil or drench into soil with ample water. The label states to apply as a transplant drench or in at least 50 gallons of water and incorporate 6‐8 inches deep.

Clubroot

July 6, 2011 Volume 7, Issue 15 Veg Edge Weekly

Page 9

WNY Sweet Corn Trap Network Report, 7/5/11

Abby Seaman, NYS IPM Program

European corn borer E and Z race moth counts remain low this week. Although trap counts are low this week, ECB and CEW larvae from eggs laid by moths during the peak flight will still be found in emerging tassels. Continue scouting emerging tassels (threshold 15% infested plants) for larvae, and the ear zone in silk stage fields for small larvae and egg masses. Corn earworm were caught at less than half the reporting locations this week, and numbers at a couple of sites are high enough to determine the spray schedule in silk stage fields. See the chart below for recommended spray intervals where CEW are being caught. No fall armyworm or western bean cutworm were caught this week at sites in the sweet corn trap net-work.

Onions: Suggested Rotation Sequence for Inspire Super & Quadris Top

C. Hoepting, CVP: Due to the label requirements of newly registered fungicides, Inspire Super and Quadris Top to rotate to different chemical classes after 2 and 1 application(s), respectively, and due to these premixes belonging to the same chemical classes as several other onion fungicides, it is important to know how to use them properly for resistance management.

Inspire Super: Active ingredients, difenoconazole (FRAC group 3) + cyprodinil (FRAC group 9). No more than 2 sequential applications before switching to a dif-ferent mode of action*. Scala (9), Switch (9 + 12), Vangard (9), Tilt(3), Quilt Xcel (3 + 11) and Quadris Top (11 + 3) all belong to the same chemical classes as Inspire Super and cannot be used as rotation partners.

Quadris Top: Active ingredients, azoxystrobin (FRAC group 11) + difenoconazole (FRAC group 3). No more than 1 application before switching to a different mode of action*. Quadris (11), Quilt Xcel (3 + 11), Pristine (7 + 11), Cabrio (11), Inspire Super (3 +9) and Tilt (3) belong to these chemical classes and cannot be used as rotation partners.

*FRAC group indicates chemical class; different numbers belong to different classes and therefore have different modes of action.

Suggested Spray Sequence for Inspire Super and Quadris Top in Onions: 1) Bravo (M5) for BLB when onions

are small for the first 1-2 sprays. 2) Inspire Super (3 + 9) for BLB + PB

for 2 consecutive sprays. 3) Bravo (M5) for BLB or Rovral (2)

for BLB + PB for 1 spray. 4) Quadris Top (11 + 3) + 1.5 pts

Bravo (M5) for PB + BLB for 1 spray.**

5) Rovral (2) for BLB + PB for 1 spray. 6) Inspire Super (3 + 9) for BLB + PB +

suppression of black mold for up to 2 consecutive sprays.*

* saved for the last spray for BM sup-pression. **If spray season is short, skip #4 and #5 and go straight to #6 in sequence.

ECB ECB

Location -E -Z CEW FAW WBC

Baldwinsville (Onondaga) 3 0 5 0 0

Batavia (Genesee) 3 1 0 0 0

Bellona (Ontario) 1 0 3 0 0

Eden (Erie) 0 0 0 0 0

Farmington (Ontario) 0 0 0 0 0

Great Valley (Cattaraugus) 0 0 0 0 0

Hamlin (Monroe) 2 8 0 0 0

LeRoy (Genesee) 2 5 0 0 NA

Lockport (Niagara) 0 1 2 0 0

Penn Yan (Yates) 0 4 1 0 0

Spencerport (Monroe) 0 0 0 0 0

Waterport (Orleans) 0 0 0 0 0

Williamson (Wayne) 0 0 7 0 0

WNY Pheromone Trap Catches: July 05, 2011

July 6, 2011 Volume 7, Issue 15 Veg Edge Weekly

Page 10

Vine Crop Concerns

R. Hadad, CVP: Below are several diseases and a pest you might encounter in your vine crops.

Downy Mildew DM has been confirmed in a pickling cu-cumber field in Kent County, Ontario Can-ada. There have also been reports out of PA of the disease showing up there in the last few days. Despite the hot and breezy dry weather we have, the nights have been cool and dews have been present on cucumber fields. This will offer an opportunity for the disease to get started. Preventative applica-tions should be sprayed as soon as possible.

Alternaria Leaf Spot This disease has been found in several loca-tions. Symptoms first appear on the upper surface of crown leaves as small, circular spots 1/4 inch in diameter and later enlarge to show a target-like pattern of rings.

Angular Leaf Spot This disease has also been seen in a couple of fields in the last week. Angular leaf spot - brown, water-soaked spots are 1/25 to 3/25 inch in length and angular in shape. Bacterial leaf spot - spots are similar in color and size to angular leaf spot, but cir-cular. Under moist conditions, small drop-lets of ooze come from the water-soaked areas and dry as white residue.

Powdery Mildew Again, despite the dry weather, PM has been found in small sections of summer squash, zucchini, and gourd plantings. Found on the lower leaves under the can-opy, there seems to be enough early morn-ing humidity to keep this disease around.

All of these diseases are not treated the same. PM being one that does not have control products that overlap with DM. Reading labels is essential. There is a com-parison chart in the Cornell Vegetable Guidelines for vine crop chemical products.

Squash Vine Borer Because larvae are protected from insecticides once they have bored into the stem, adult activity should be used to time insecticide applications where squash vine borer is a perennial problem. Adult activity may be monitored using pheromone traps or predicted using base 50° F degree-day accumulations. The following information is from the University of Wisconsin: Pumpkin and squash crops should be monitored once 900DD50 have accumulated. Two to three insecticide treatments, 5-7 days apart during the three week egg-laying period around 1000DD50 will control most of the larval borers before they become protected by the vines. Organic growers may use floating row covers to protect plants until the adult flight period is over.

Several of the chemical products available are also used for other pests. Assail, Brigade, Asana XL, and Warrior II are just some that are available.

Squash vine borer adult

Volume 7, Issue 15 Veg Edge Weekly

Page 11

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Weather Charts

*Airport stations ** Data from other station/airport sites is at: http://newa.cornell.edu/ Weather Data, Daily Summary and Degree Days.

July 6, 2011

J. Gibbons, CVP:

Rainfall (inch) Temp (°F)

Location Week Month Max Min

Albion 0.00 0.00 87 52

Appleton, North 0.00 0.00 83 45

Baldwinsville 0.61 0.00 86 56

Buffalo* 0.00 0.00 84 55

Ceres 0.07 0.00 83 44

Elba 0.00 0.00 88 51

Farmington 0.50 0.00 89 52

Geneva 0.07 0.00 86 58

Himrod **** **** 88 49

Lafayette 0.00 0.00 85 49

Lodi 0.20 0.00 88 49

Lyndonville 0.00 0.00 87 48

Ransomville 0.01 0.00 85 49

Rochester* 0.00 0.00 86 52

Syracuse* 0.23 0.00 87 58

Williamson 0.05 0.00 88 54

Weekly Weather Summary: 6/28 - 7/04

Location 2011 2010 2009

Albion 902 1015 767

Appleton, South 793 925 677

Buffalo 943 1026 802

Elba 840 1023 638

Farmington 919 1001 736

Geneva 1023 1219 818

Himrod 978 1029 774

Lafayette 982 956 763

Lodi 1054 1142 ***

Lyndonville 884 1019 752

Ransomville 884 1012 743

Rochester 977 1079 759

Syracuse 1173 1096 853

Williamson 908 1055 730

Accumulated Growing Degree Days (AGDD) Base 50°F: Jan. 1 — July 04, 2011

Cooperative Extension Cornell Vegetable Program

Cornell University Serving Allegany, Cattaraugus,

Erie, Genesee, Monroe, Niagara,

Onondaga, Ontario, Orleans,

Seneca, Wayne and Yates Counties

Veg Edge Weekly is a seasonal weekly publication of the Cornell Vegetable Program providing information about crop development, pest activity and management, pesticide updates, local weather conditions, meetings and resources.

Veg Edge is published 28 times annually, monthly from October-May and weekly from May-September. If you have any questions about this publication, contact Julie Kikkert at 585-394-3977 x404 or jrk2@cornell.edu. Visit the Cornell Vegetable Program website at http://cvp.cce.cornell.edu/ for information on our research, upcoming events and enrolling in our program.

Cornell Cooperative Extension provides equal program and employment opportunities.

Robert Hadad 585-739-4065 Cell rgh26@cornell.edu

Christy Hoepting 585-721-6953 Cell cah59@cornell.edu

Julie Kikkert 585-313-8160 Cell jrk2@cornell.edu

Carol MacNeil 585-313-8796 Cell crm6@cornell.edu

Judson Reid 585-313-8912 Cell jer11@cornell.edu

Cornell Vegetable Program Extension Specialists

John Gibbons, 716-474-5238 Cell

Katie Klotzbach 585-732-2545 Cell

CVP Assistants

This publication contains pesticide recommendations. Changes in pesticide regulations occur constantly and human errors are possible. Some materials may no longer be available and some uses may no longer be legal. All pesticides distributed, sold or applied in New York State must be registered with the New York State Department of Environ-mental Conservation (DEC). Questions concerning the legality and/or registration status for pesticide usage in New York State should be directed to the appropriate Cornell

Cooperative Extension specialist or your regional DEC office.

Cornell Cooperative Extension and its employees assume no liability for the effectiveness or results of any chemicals for pesticide usage. No endorsement of products or com-panies is made or implied. READ THE LABEL BEFORE APPLYING ANY PESTICIDE.

Yates County Cornell Cooperative Extension 417 Liberty Street Penn Yan, NY 14527