Vegetable Crop Insects - Joanne Whalen, Extension IPM Specialist; firstname.lastname@example.org
Continue to sample fields for diamondback, cabbage looper, fall armyworm and beet armyworm. A treatment should be considered if you find 5% of the plants infested and before larvae move into the hearts of the plants.
Lima beans continue to be attractive to corn earworm moths. A treatment will be needed if you find one corn earworm larvae per 6 ft of row. Be sure to watch for soybean loopers as well – Lannate at 2.5-3pt/A will be needed to achieve soybean looper control.
Be sure to maintain a 5-7 day spray schedule for corn borer, corn earworm, beet armyworm and fall armyworm control. You should also continue to watch for aphid explosions.
Continue to spray snap beans from the bud stage through harvest for corn borer and corn earworm control. We have also heard reports of
beet armyworm in a few fields.
We can now find economic levels of webworms and beet armyworm in spinach fields. As a general guideline, controls should be applied when 5% of the plants are infested with small worms and before they have moved deep into the hearts of the plants. Also, remember that both insects can produce webbing on the plants. Since beet armyworms are more difficult to control, chemical selection is important. Confirm, Intrepid or Spintor will be needed for beet armyworm control. If webworms are the predominant species, permethrin, Confirm (8 oz/acre), or Intrepid (8-10 oz) should be used. Generally, at least 2 applications are needed to achieve control of webworms and beet armyworm.
You should also watch for an increase in aphid populations. Although still spotty, aphid populations are starting to increase in some fields. A combination of the cooler summer temperatures and a switch to a warm dry fall can result in population explosions. Since there is a zero tolerance for aphids in both processing and fresh market spinach, treatments should be applied before populations explode. Assail, dimethoate, Fulfill and Provado are labeled for aphid control in spinach. With aphid control, good coverage is essential. Although the addition of a spray adjuvant (not a sticker) can help to improve control with translaminar products (i.e. Assail, Fulfill and Provado), you will also need to watch for phytotoxicity and only use products that you know have not caused leaf burning in the past. The addition of a penetrating surfactant is recommended with Fulfill. Remember to check the label for days to harvest after the last application. NOTE -- After this fall, all new labels of dimethoate (starting as early as February 2005) will no longer have spinach on the label. Information from EPA indicates that there should be existing stocks of dimethoate available for use on spinach for the 2005 season. However, this could change so be sure to read labels carefully before applying.
All fresh market silking sweet corn should be sprayed on a 2-3 day schedule.
Vegetable Crop Diseases - Bob Mulrooney, Extension Plant Pathologist, email@example.com
Downy mildew continues to be found on C-Elite Select and now on
Field Crop Insects - Joanne Whalen, Extension IPM Specialist; firstname.lastname@example.org
At this time, the only fields that might still be at risk from soybean aphid damage are any very late double crop fields in the R1 to R3-R4 stage. Thresholds remain at 250/plant if plants are in the R1 to R3-4 stages. At this point, most of our double crop fields are in the R5 - R6 stages so it is unlikely that many fields will need a treatment. In most cases, fields will move quickly from the R5 to R6 stage. Ames Herbert from VPI called a few entomologists in the
As in most years, we all know that it is difficult to predict what will happen with insect populations. Cooler summer temperatures with adequate rainfall followed by a warm, dry fall are conditions that favor aphid development in small grains, especially in early planted fields. With the early corn harvest, more fields may be planted early and these fields could be susceptible to attack. Factors that increase the potential of a return from applying an insecticide to control aphids and to reduce barley yellow dwarf virus (BYDV) infection in wheat include: (1) normal-cool summer temperatures with adequate rainfall; (2) intensive wheat management including high fertility; (3) use of BYDV susceptible varieties; (4) planting before the Hessian fly free date; and (5) a late, warm fall. We are still using a threshold for fall treatment for aphids (except greenbug) of 15-25 aphids per foot of row in combination with a known history of BYDV. In states to our south where BYDV is more prevalent, they are using thresholds as low as 3 per foot of row or in some cases do not feel comfortable with any threshold.
Direct damage from greenbug aphid has also
been an issue in recent years. If you are able to scout, be sure you plan to
sample your fields at emergence. Although we do not have any thresholds developed
in our area for greenbug, thresholds from
the recent years, waiting to plant after the fly-free date (Oct 3 -
Field Crop Diseases - Bob Mulrooney, Extension Plant Pathologist, email@example.com
Be sure to plant treated seed. For loose smut and seed-born scab control, request seed treatment of Raxil/Thiram, Dividend Extreme at the 4 oz/cwt. rate, or Vitavax 200 plus LSP (thiabendazole) at 0.25 fl oz/cwt. They will perform the best for this disease combination. If you want early season powdery mildew control as well. Dividend at the 4 oz. rate will provide that. If scab is not an issue treat with Baytan 30 plus thiram or captan for early season powdery mildew, loose smut and a reduced level of control of seed born scab.
Septoria leafspot, downy mildew, and some Frog-eye (Cercospora) leafspot are still evident on late beans. Most levels that I have seen should not limit yield in any way.
Be sure to check corn fields for lodging potential by squeezing the lower nodes or pushing on the stalks. A simple way to do this is to walk through the field and, keeping your hands at chest height, push stalks 8-10 inches from vertical. If 10-15% of the stalks lodge, schedule the field for early harvest before a strong wind results in severe lodging.
Soybean Patterns of Maturity – Richard W. Taylor, Extension Agronomist, firstname.lastname@example.org
Many fields planted to earlier-maturing soybean varieties have either dropped their leaves or are beginning to yellow prior to dropping leaves. During this process, you may notice some unusual patterns. The yellow patterns can be the result of stress conditions (Photo 1) that may cause the plants to begin to shut-down prematurely (often on the sandy ridges or along field edges especially where tree roots invade the field soil). In other cases, the entire field may turn yellow except for areas of more favorable moisture conditions where plants remain green for an extra week or more before beginning to mature (Photo 2). Regular patterns often result from a man-made situation such as planting two or more varieties in a field, mixing varieties, or planting variety strip plots (Photo 3).
The first indication that a field is approaching maturity is a change in the color of the upper most trifoliate leaf (this one is usually smaller than most of the plant’s trifoliates) from green to a bright yellow to yellow-orange (Photo 4). Shortly after seeing a speckling of small yellow leaves across the field, the entire field will quickly turn yellow and then gradually drop individual leaflets as the crop approaches maturity. When most of the leaves have fallen from the plant, you should notice changes in pod color as the plant approaches maturity. Once 95 percent of the pods have reached their mature pod color, it takes about 10 to 14 days for the crop to dry to harvest moisture although the exact timing will depend on environmental conditions.
Photo 1. Pattern of soybean leaf yellowing/leaf Photo 2. Pattern of soybean leaf yellowing/
drop caused by stress conditions. Photo by R. Taylor leaf drop caused by soil conditions. Photo by R. Taylor
Photo 3. Man-made pattern of soybean leaf Photo 4. Leaf yellowing with maturity often
drop related to variety selection. Photo by R. Taylor begins with the smaller upper leaves on soybean plants. Photo by R. Taylor
Grain Marketing Highlights - Carl German, Extension Crops Marketing Specialist; email@example.com
Large Crops Have Tendency to Get Larger.
Corn and soybean futures markets traded higher on Wednesday this week due primarily to the potential for crop damage that may occur from the eventual path of Hurricane Ivan. Another factor that may be playing into corn and soybean price strength this morning is the Weekly Export Sales Report that came in above trader expectations for corn and soybeans at 47.5 million bushels and 23.3 million bushels, respectively. The corn number is nearly double last week's export level and about 20 million bushels higher than the high-end of pre-report estimates. The soybean export business, which also reported above pre-report expectations, was largely done with
Wheat exports were reported to be below the low end of trader expectations at 12.8 million bushels. Concerns remain over the size and quality of the spring wheat crop.
We are now into early harvest for the '04
The size of both the
Pasture and Hayfield Establishment Basics
Meet at farm buildings/grove area.
Registration: Phone (302) 730-4000 if you are attending.
If you are new to pastures or hay production, this workshop is for you.
Johnson, Agricultural Extension Agent, UD
Pumpkin and Sweet Corn Twilight
Place: Wye Research and
Come see the 2004 Pumpkin Variety Trials and see the results of two fungicide schemes: conventional and reduced risk. See how they performed, particularly in the face of this year’s downy mildew. See how 10 different cover crop regimes affected pumpkin production. Refresh your pumpkin disease identification skills.
Exciting new sweet corn possibilities too! See the new fresh market BT sweet corn hybrids and hear results of a variety trial looking at husk characteristics for resisting sap beetles.
***A light fare will be provided***
For information call (410) 313-2707 (Maryland Cooperative Extension,
Pre-registration is not necessary.
If you need special assistance to participate in this program, please contact Mrs. Carolyn Kulp at (410) 313-2707 by September 15.
Week of September
0.42 inches: September 15
Highs Ranged from 82°F on September 10 and September 16 to 73°F on September 15.
Lows Ranged from 67°F on September 15 to 55°F on September 12.
(Soil temperature taken at a 2 inch depth, under sod)
Web Address for the U of D Research & Education Center: http://www.rec.udel.edu
Compiled and Edited By:
Extension Associate – Vegetable Crops
Extension Education in Agriculture and Home Economics, University of Delaware,
Delaware State University and the United States Department of Agriculture
cooperating. Distributed in furtherance
of the Acts of Congress of May 8 and