Vegetables

Vegetable Insects - Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu

Cabbage.

Continue to watch cabbage plants for increases in diamond back and cabbage looper populations. Despite the cooler weather, levels have increased well above threshold levels (5% if present in the hearts). Spintor, Proclaim, or a Bt will provide control of both species. If diamond back populations are light and cabbage looper is the predominant species, Confirm will provide good control.

Peppers.

At the present time, all peppers should be sprayed on a 7-day schedule for corn borer, pepper maggot control and corn earworm. In the Harrington and Frederica areas, sprays should be applied on a 5-7 day schedule. As of this newsletter, you are still only allowed to apply 2-lbs. ai/acre of acephate on peppers (new label change on peppers reported in earlier newsletters). EPA has denied our Section 24C request to increase the rate to 4-lb. ai/acre. The reasons provided related to FQPA issues, primarily worker exposure.

Lima Beans.

Continue to sample fields with blossoms and pods for earworm, lygus and stinkbugs. Leafhoppers can still be found in later planted fields so continue to sample fields for adults and nymphs.

Snap Beans.

Processing snap beans should be sprayed at the bud stages with acephate for corn borer control and with acephate plus Capture or Asana at the pin stage for corn earworm and corn borer control. With the recent cool weather and lighter trap catches, sprays are needed on 5-day schedule from pin until harvest except in the Milford and Harrington areas where sprays are needed on a 4-day schedule. Fresh market snap beans should be sprayed on a 7-day schedule as soon as pin pods are present.

Sweet Corn.

All fresh market silking sweet corn should be sprayed on a 3-day schedule.

Lima Bean Disease, Insect, and Crop Management Workshop - Gordon Johnson, Extension Agriculture Agent, Kent County, gcjohn@udel.edu

Date: Thursday, August 31, 2000

Time: 10:00 AM - 1:00 PM

Lunch: Will be provided

Place: Fifer Orchards, Wyoming, DE

Meet at the farm market parking lot.

Who Should Come: Lima Bean Growers and their Employees, Processors & Fieldmen, Consultants & Scouts, and Agribusiness Personnel.

The University of Delaware Extension Office in Kent County is offering a special invitation to lima bean growers and those who work with lima beans to attend a disease, insect, and crop management workshop at Fifer Orchards on Thursday, August 31, from 10:00 AM to 1:00 PM. We will scout nearby lima bean fields; explore disease, insect, and weed biology; and discuss control strategies. In addition, we will examine cultural practices and other crop management considerations for successful lima bean production. On hand will be University of Delaware Specialists including Bob Mulrooney, Kate Everts, Ed Kee, Joanne Whalen, and Mark VanGessel to answer questions. A light lunch will be provided.

Phone (302) 697-4000 if you will be attending.

Vegetable Diseases - Bob Mulrooney, Extension Vegetable Pathologist, University of Delaware; bobmul@udel.edu and Dr. Tom Evans, Associate Professor, University of Delaware, tomevans@udel.edu

Downy Mildew Alert.

Downy mildew caused by Phytophthora phaseoli is widespread in baby lima bean fields. Fields should be scouted frequently to detect insect pests as well as for downy mildew. The unusually cool August weather with ample rainfall has been very favorable for downy mildew. The fungus is evidently surviving very well from season to season. When you have the pathogen (the disease causing fungus), favorable weather for infection and a susceptible host you will get disease, in this case downy mildew.

Races D and E are both present in Delmarva fields. Race E is the newest one to which very few varieties have any resistance. The following table is the result of field observations and greenhouse tests performed here with race D and E by Dr. Tom Evans, Daryl Whittington, and Carley Davidson.

Cultivar	Reaction to race D	Reaction to race E
Eastland	Tolerant	Susceptible
Packer	Tolerant	Susceptible
M-15	Tolerant	Susceptible
8-78	Resistant	Susceptible
184-85	Susceptible	Resistant
328	Not Tested	Susceptible
C-elite Select	Not Tested	Resistant

‘Tolerant’ means that mildew can be present but infection progresses more slowly than if they were susceptible. Infection levels (fewer pods infected) are also lower than a susceptible cultivar.

‘Not tested’ means that they were not tested here with race D and E isolates from DE fields.

This information can help determine what race you may have. In order to know better what races are present we are asking that growers, fieldmen, and Extension personnel collect as many downy mildew samples from infected fields as possible for laboratory race determination. We are requesting that you collect 20-25 infected pods, wrap them in a dry paper towel, place in paper bag, indicate the variety and nearest town, and refrigerate until we can collect them. Please deliver them to the county Extension offices or call Carley Davidson at 302-831-2548 and we will arrange to pick them up.

As mentioned in the last Crop Update the only effective fungicide at the present time is copper hydroxide, either Kocide 2000 or Champ. Coppers like Bravo, Dithane and other familiar fungicides are protective in their mode of action. They work best when applied before symptoms can be seen. This is true for most of the systemic fungicides as well. Depending on the weather the fungus can infect the beans and it can take up to a week before you see the disease on the plants. By the time you see the disease much more can be infected that you cannot see at that time. The fungicide will not control any of that infection, which can make it look like the fungicide is not working. The key to control is prevention, not waiting for symptoms to appear. If downy mildew is present in the area and you have a susceptible variety with flowers and/or pods with no disease symptoms, preventative sprays are suggested. Remember that downy mildew only infects the pods, racemes, and petioles of limas. The first application of fungicide should be no earlier than blossom. Several well-timed preventative sprays 7 days apart should reduce or eliminate downy mildew if the weather is not too severe for downy mildew.

Vegetable Diseases - Kate Everts, Extension Vegetable Pathologist, University of Delaware and University of Maryland; everts@udel.edu

Downy Mildew On Cucurbits.

Downy mildew on cucurbits is present here on the Delmarva Peninsula. The disease can be recognized by brown to gray sporulation that occurs on the underside of leaves. The sporangia can be seen with a 10X hand lens and appear as barely distinguishable black or purple spots. When you observe this disease, continue application of chlorothalonil plus Nova plus a copper fungicide alternated with Quadris or Flint plus a copper fungicide. Ridomil Gold/Bravo or Ridomil Gold /Copper are also effective against Downy mildew and can be applied every other week (alternate with one of the above fungicide combinations).

Melcast for Watermelons

EFI Values (Environmental Favorability Index)

Do not use MELCAST if there is a disease outbreak in your field, it is a preventative program. Any questions please call Phil Shields at (410) 742-8788 or e-mail: ps136@umail.umd.edu

Location	8/16	8/17	8/18	8/19	8/20	8/21	8/22	8/23
Bridgeville, DE	5	1	2	3	1	1	1	0
Laurel, DE (Collins Farms)	5	1	2	2	1	0	0	1
Galestown, MD	5	1	1	2	1	0	1	0
Georgetown, DE	0	2	1	3	0	0	0	0
Hebron, MD	2	1	2	3	1	1	1	0
Salisbury, MD	1	0	2	2	1	1	1	1
Vienna, MD	2	1	1	2	1	1	1	0
Laurel, DE (Vincent Farms)	2	2	2	3	1	1	1	1

The first fungicide spray should be applied when the watermelon vines meet within the row. Additional sprays

should be applied using MELCAST. Accumulate EFI (environmental favorability index) values beginning the

day after your first fungicide spray. Apply a fungicide spray when 30 EFI values have accumulated by the

weather station nearest your fields. Add 2 points for every overhead irrigation. After a fungicide spray, reset

your counter to 0 and start over. If a spray has not been applied in 14 days, apply a fungicide and reset the

counter to 0 and start over. The first and last day listed above can be partial days so use the larger EFI value

of this report and other reports for any specific day.

If, for some reason, a serious disease outbreak occurs in your field, return to a weekly spray schedule.

More detailed information concerning MELCAST and sample data sheets are available on the web at http://www.agnr.umd.edu/users/vegdisease/vegdisease.htm or http://www.udel.edu/IPM/ v

Field Crops

Field Crop Insects - Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu

Alfalfa.

Potato leafhoppers can still be found in fields, especially since cutting was delayed in many cases. If fields were yellow before cutting, in most cases it was a result of leafhopper damage. Fields should be sampled soon after harvest and treatments applied if you find 20 leafhoppers per 100 sweeps on alfalfa 3-inches or less in height. The threshold increases to 50 per 100 sweeps in alfalfa 3-6 inches tall. We are also seeing an increase in webworm activity in alfalfa. Early harvest and diseases can often reduce population, As a general rule, a treatment may be needed if you find webbing on 25-30% of the terminals and you are 2 or more weeks from harvest. Most insecticides labeled for leafhopper, except dimethoate, will provide webworm control.

Soybeans.

We have encountered above threshold levels of corn earworm in soybeans planted behind wheat in Kent and Sussex counties (3-5 per 25 sweeps not the high levels found in 1999). However, it is still only an occasional field, larvae are still small and feeding is light. In most cases, treatment should be delayed until you start to see pod feeding and 1/3 of the larvae are 3/8 inch long. You should also watch for diseased larvae since the weather has been favorable for diseases that are able to reduce populations in less than one week. Small amounts of pod feeding can still be found on full season beans and occasional larvae can be found (1-2 per 25 sweeps). The treatment threshold is 3 per 25 sweeps in narrow-row fields and 5 per 25 sweeps in wide-row fields. If the weather turns warm and/or weather fronts move additional moths front, we could see an increase in populations. Although lower than 2 weeks ago, corn earworm trap catches remain highest in the Milford, Harrington, and Frederica areas. Trap catches have also increased in the Greenwood area.

Attention All Kent County Farm Operators Pre-Harvest Planning Workshops - Gordon Johnson, Extension Agriculture Agent, Kent County, gcjohn@udel.edu

Sponsored by the Farm Service Agency and University of Delaware Cooperative Extension Office in Kent County

Topics Will Include:

Making the Best Use of Farm Programs in Marketing

Review of the LDP program and new eligibilities.

Marketing Assistance Loans

Payment limitations review

Loan repayments with Commodity Certificates

Farm Storage Facility Loans

Review of other available farm programs

Temporary grain storage and handling

Marketing strategies for harvest and the coming year

You are welcome to attend this workshop in one of 3 locations and times:

Workshop 1

Date: Wednesday, September 6, 2000

Time: 7-9 PM

Place: Lake Forest High School Vocational Agriculture Classroom

Workshop 2

Date: Monday, September 11, 2000

Time: 8-10 AM

Place: UD Kent County Extension Office, Rt. 113, Dover, next to DelDOT

Workshop 3

Date: Wednesday, September 13, 2000

Time: 7-9 PM

Place: Snow Farms Meeting Place, Whitehall

Crossroads, North of Leipsic

All Kent County grain producers and farm operators are encouraged to attend one of three pre-harvest workshops sponsored by the Farm Service Agency and UD Cooperative Extension Office in Kent County.

Personnel from the Farm Service Agency will be on hand to review LDP’s, marketing assistance loans, commodity certificates, and farm storage facility loans. Participants will work through examples involving LDP’s, payment limitations, storage, loans, and certificate use. The session will then be opened up to questions. Other farm programs will also be reviewed.

Extension personnel from UD will be on hand to talk about temporary grain storage and handling, provide designs, and discuss critical considerations for temporary storage. The UD Extension Marketing specialist will provide information on marketing considerations for the harvest season and the coming year.

Call the Extension Office at (302) 697-4000 or the FSA Office at (302) 697-2600 x 2 if you are planning to attend one of these sessions. Anyone interested is welcome to attend. For further information or special consideration in accessing these workshops contact Gordon Johnson at 697-4000 or Greg Hudson at 697-2600 in advance

See you there.

Expectations for Corn Dry Down This Season - Richard W. Taylor, Extension Agronomist; rtaylor@udel.edu

I contacted a number of corn specialists to obtain their opinions of how fast corn dry down occurs in a growing season similar to the one we’ve experienced this year. What follows is my interpretation of their opinions and my own original opinion.

The onset of black layer in corn could be slightly delayed this year since growing conditions have been so favorable and daily high temperatures often have been below the 85°F maximum used to compute growing degree day accumulation for corn. However, except for the temperatures, maturity should proceed similar to that which you usually experience in irrigated corn since dryland corn this year has had growing conditions similar to irrigated corn.

Once black layer is reached, corn has finished accumulating dry matter (yield) and continues the process of drying down. Work from Iowa estimates that it takes about 20 growing degree days (GDD) to remove one point of moisture from the grain. In early-to mid-September, only one to two days might be needed to reach 20 GDD. As temperatures fall in late September and into October, GDD accumulate more slowly so it will take longer and longer to dry corn. Depending on conditions in a given year at some point, it would take so long to dry that the best choice is to go ahead and harvest the corn and pay the drying costs.

Another factor in how fast corn dries, is how the corn matures. When ears mature normally, the husk generally will loosen and allow moisture loss at a fast rate. If the ear is shut down early by an early frost, drought conditions, or some other problem, the husk often will be tighter on the ear and moisture loss will be inhibited or restricted to some degree. In this latter case, dry down may be delayed by several days to several weeks. For dryland corn, late-season drought followed by a moist fall often causes this type of problem. Delayed dry down is often a problem under these conditions.

The amount of green leaf area left in corn also impacts dry down rates. If green leaf area is left, corn will dry down faster even when rainfall is experienced since the leaf area can transpire a large amount of water. In this case, even if black layer is delayed, growers would need to plan for a quick harvest since the grain would dry faster in the field.

So, what about this year? The factors that will be hard to gage are the effect of frequent rainfall, high humidity within the canopy, the effectiveness of each hybrid’s disease resistance characteristics and the impact these will have on disease incidence and therefore the amount of green leaf area left after black layer occurs. You’ll need to watch each field carefully to judge how fast dry down will occur but at least at this time I expect a slightly delayed black layer but a rapid dry down of corn that is not severely impacted by disease incidence. This should hold true for most of our corn crop regardless of whether it was dryland or irrigated. Only in isolated areas where rainfall amounts were lower than normal for much of the season will dry down be slower than for rest of the state.

Finally, many thanks to the corn specialists across the country who took time to send me information used in this report. Any mistakes in interpretation are mine and not theirs. Have a safe and good harvest!

Grain Marketing Highlights - Carl German, Extension Crops Marketing Specialist; clgerman@udel.edu

Weak Basis Levels and Low Commodity Prices Give Rise to Caution

Weak basis levels and low commodity prices give rise to using caution in fall harvest marketing decisions. In overnight trade on August 23rd December corn futures closed at $1.86 and November soybeans closed at $4.68 per bushel. When taking current basis levels into account these prices equate to $1.86 for forward cash price offerings for new crop corn and $4.38 for new crop beans. The current basis for new crop corn is even (0) and 30 under for new crop soybeans. From an historical perspective the basis for corn is about 20 cents weaker than normal and about 10 cents weaker than normal for soybeans. All things considered, this is not a good time to be thinking about advancing new crop sales. The uncertainty level in the market right now is running quite high. Although there are some reports of crop problems in some areas in the U.S., many in the grain trade believe that commodity prices could drop lower and basis levels could weaken further from their current levels. In the event the latter scenario develops, many farmers will need to consider storing unpriced grain at harvest and the varying alternatives involved in the storage decision.

A series of meetings to assist with new crop marketing strategies will be held at three locations in Kent County in order to provide technical assistance with the Farm Service Agency farm program and planning grain marketing strategies for harvest time. The meetings entitled "Making the Best Use of Farm Programs in Marketing" will be held in three locations and times: Wednesday, September 6 from 7 to 9 pm at the Lake Forest High School Vocational Agriculture Classroom; Monday, September 11 from 8 to 10 am at the UD Kent County Extension Office, Rt. 113 Dover, next to DelDOT; and Wednesday, September 13 from 7 to 9 pm at Snow Farms Meeting Place, Whitehall Crossroads, North of Leipsic. Topics to be covered include: Review of LDP Program; Marketing Assistance Loans; Payment Limitations Review; Loan Repayments with Commodity Certificates; Farm Storage Facility Loans; Temporary Grain Storage and Handling; and Marketing Strategies for Harvest. All Delaware farmers are invited to attend.

Weed Control in Seedling Alfalfa -Mark VanGessel, Extension Weed Specialist ; mjv@udel.edu

Getting seedling alfalfa off to a good start is critical for a long term quality stand. The following herbicide suggestions are for pure alfalfa stands. Gramoxone or Roundup can be used prior to planting to kill emerged weeds. Balan or Eptam can be used pre-plant incorporated for control of small-seeded broadleaves such as pigweed or lambsquarters and most annual grasses. Residual control of either Balan or Eptam is only a few weeks. Fall postemergence treatments include Butyrac 200 (2 to 4 alfalfa trifoliates), Buctril (at least 4 trifoliates), Kerb, Poast Plus, Select, or Pursuit (at least 2 trifoliates). Pursuit provides the broadest spectrum of control, and can be tank-mixed with Buctril or Butyrac to improve control. The addition of Buctril to Pursuit will improve German moss, lambquarters, and henbit control. Kerb will provide the best common chickweed control, but it must be applied when soil temperatures are 50 degrees or less and requires rainfall for activation. Applications to small weeds is critical for effective control. Poast Plus and Select are effective only on grasses, and cannot be used on alfalfa/grass seedings. Most of the labeled herbicides can cause some crop injury.

Weed Control for Grass or Mixed Pastures -Mark VanGessel, Extension Weed Specialist ; mjv@udel.edu

Weed control options are very limited for establishing a grass or mixed stand pasture. There are no products to use pre-plant incorporated or preemergence that will provide residual control and not injure the crop. Early postemergence options are also very limited. Ally, Banvel, Crossbow, or 2,4-D can be used for pure grass seedings (they will kill clovers and alfalfa) but grasses need to be well established at time of application. Ally can injure fescue and ryegrass. Fescue injury can be reduced if Ally is tankmixed with 2,4-D. Pursuit is labeled for established mixed pasture stands (broadleaf plus grass pastures).

Resist the Temptation To Treat Annual Weeds In The Fall -Mark VanGessel, Extension Weed Specialist ; mjv@udel.edu

Fall herbicide applications for control of annual weeds needs to be considered carefully. Most of the yield loss due to the weeds has already occurred. Most of the time it is best to accept the fact the weed control program was not acceptable; find out why your weed control was not acceptable; and wait until next year to take action. The temptation is often to spray in the fall to kill the weed seed. To have a significant impact on reducing weed seed production, the herbicide must be extremely effective on the specific weed and applied at or shortly after flowering. The further after flowering that the herbicides are applied the greater the percentage of viable seed that is produced. Fall herbicides to dry down weed biomass to reduce fore