Volume
11, Issue 2
April 4, 2003
Vegetables
Vegetable Insects
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New Registrations and Restrictions
Warrior.
The following uses
have been recently added to the Warrior label: apples and pears; edible podded, succulent shelled and dried shelled beans (included
but not limited to black-eye pea, garden pea, lima beans, and snap beans) and
peppers (bell and non-bell).
New 2ee Labels from Dupont:
(a) Avaunt –
For the control of Colorado potato beetle in potatoes. This label is in effect
in
(b) Vydate L - For control of leaf miners and
supplemental control of root knot nematode used in conjunction with other
marketed soil treatments as a Methyl bromide replacement program on the
following crops: tomato, bell and non-bell pepper, eggplant, pumpkin, cucumber,
cantaloupe, watermelon, honeydew melon, and squash using drip irrigation and
soil injection systems. This label is in
effect in DE, MD, NJ, PA, PR, and VA.
Definition of Coastal Counties - We often get the question regarding the
definition of coastal counties, especially as it relates to the use of Capture
on field corn and sweet corn in
Be sure to consider
seed corn maggot control, especially where a green cover crop is plowed under
close to planting, manure is used and/or a field is minimum tilled. A seed treatment containing diazinon or permethrin should be
used on early-planted sweet corn. Gaucho or Cruiser treated sweet corn seed
will also provide seed protection. In fields with a high potential for seed
corn maggot (combinations of the above conditions), a soil insecticide plus a
seed treatment will be needed. On all 3 crops, the use of diazinon
50W as a planter box treatment has provided good control in recent years. Seed
must be treated with a commercial fungicide; graphite may be needed to prevent
bridging and you should not treat more than you plan to plant in any one-day.
The diazinon 50W rate for seed corn maggot is 1/2 oz
per bushel of seed.
Sweet Corn.
Although winter
conditions have not been very favorable for overwintering
flea beetles, flea beetle management should be considered on early-planted
varieties susceptible to Stewart's Bacterial Wilt. If you are using a soil
insect insecticide for flea beetle control, the only labeled products providing
flea beetle control are Counter and Furadan. Regent
is not labeled on sweet corn. Another control option is Gaucho or Cruiser
treated seed. In 3 years of research trials, seed applied treatments have
provided very effective beetle control and management of Stewart's Wilt.
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Frozen Vegetable
Inventories –
The March 1 holdings of frozen peas
reflects the reduction in pack on a national basis.
The reductions reflect lower pack, increased movement, or some combination of the two. Moving product out of cold storage to consumers is good for the processors in keeping inventory costs down, and good for producers who want to keep these vegetable crops as part of their farm enterprise.
The other big item on Delmarva, sweet corn, is experiencing high inventory levels on a national basis right now. Cut corn is up nearly 14%, and cob corn is up 20% from inventories of the previous year. This is reflected in the acreage being contracted on Delmarva and other regions for 2003.
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Pea Production
Update –
Cold, wet weather has made pea planting a struggle so far this season. However, growers and processors have done a remarkable job of grabbing those opportunities for planting as they present themselves.
Many growers are using preemergence weed control programs that feature some combinations of Dual, Command, and/or Pursuit. However, wet weather may prevent applications being made until the peas have emerged.
In that case, growers will need to consider post-emergence applications of Poast or Assure for grass control; and post-emergence applications of Basagran for broad-leaf weed control. Scouting and checking fields for emerging weeds and grasses is critical, especially the broadleaf weeds. Basagran will provide better control if applied when the weeds are small. This is especially true for lambsquarter, but applies to all broadleaf weeds.
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Vegetable Diseases
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Be sure to rotate pea planting 4-5 years to avoid and reduce root rot. Ridomil Gold 4E applications broadcast after planting can be useful if Pythium control is needed.
Spinach.
Be sure to check overwintered fields for white rust. As soon as white rust is seen, apply Quadris as a foliar spray. If more sprays are needed, alternate with Actigard. Actigard is to be used at the rate of 0.75 oz/A. There is a 7-day preharvest interval for Actigard.
Phytophthora Blight and Fruit Rot.
Phytophthora Blight and Fruit Rot caused by the
fungus Phytophthora capsici is
still a concern for vegetable growers. The fungus is favored by wet conditions
and flooded soil. It was seen last season again on lima bean pods from wet
irrigated areas of fields in
The best control is to grow the plants on raised beds, especially
for peppers, to get them out of the water and to rotate for long periods of
time (3 years or more) away from susceptible crops. For vegetable growers this
is difficult because many crops are susceptible and irrigation availability
limits rotation intervals. But a combination of rotation and other
horticultural practices combined with fungicides may provide some relief.
Fungicides alone have not provided a solution as results from
Be aware that this soil borne fungus is out there and could become a problem if introduced or identified on your farm. It infects a wide number of vegetables including cucurbits (cucumbers, cantaloupes, watermelons, pumpkins and summer and winter squash), peppers, eggplant, tomatoes and now lima bean pods.
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Field Crop Insects - Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu
New Registrations and Restrictions.
See Vegetable
Insects page 1.
Alfalfa.
The first weevil
larvae can be found in
Field Corn.
In cooperation with
UAP Inc., we will again be running pheromone traps for black cutworm. The first
moths were caught last week in a number of locations (see table on last page of report).
Although no precise numbers are available, moth catches of 9 to 15 moths per
7-day period have been associated with a moderate to high potential for cutworm
outbreaks. Larvae will be large enough
to begin cutting when about 300 base-50 degree-days have accumulated since peak
moth activity and egg laying. By calculating cutworm
hatch and development over time, we can anticipate when to look for damage.
Pheromone trap catches help us determine when peak moth
flight and egg laying occurs; however, they cannot predict the amount or
magnitude of cutting that will occur. The presence of a major flight only means
that the potential for an outbreak exists. Adverse weather, lack of adequate
food for newly hatched larvae, predation, and disease can reduce larval
populations. You can use pheromone trap and degree-day information to estimate
or predict when first cutting will occur. Scouting of seedling corn near the
first cutting date is the best way to determine whether a problem exists. Just
a reminder, if you plan to tank mix a pyrethroid with
a herbicide for cutworm control, it should be done at
or immediately following plantings. Pyrethroids
combined with early burn-down applications, 2-3 weeks before planting, have not
provided effective control.
Timothy.
Reports from around
the region indicate that cereal rust mite populations are lower compared to
last season. However, as soon as fields green up you should begin checking for
mites and the early signs of infested leaves, especially in fields with
problems in 2002. These mites are microscopic, so the use of a 20x-magnifying
lens is necessary. If rust mites become a problem again in 2003, Sevin XLR Plus still has a 24C registration on timothy for
rust mite management. The following are the use directions for this label:
Apply 3 pts per acre (1.5 pounds ai per acre) using
ground equipment only with adequate water for complete coverage (20 or more
gallons by ground). One application
should provide enough suppression to prevent economic yield and quality losses.
Apply at approximately 3-4 weeks after green-up in fields with a previous
history of rust mites and/or when 25% of the plant tillers exhibit curled tips
of the new leaf blades. It has a 30 day wait until harvest.
Wheat.
At a recent meeting
of plant pathologist and entomologists in the Mid-Atlantic, the topic of the
potential for barley yellow dwarf this spring was again discussed. The
discussion focused on the fact that a great deal of small grain is still in a
vulnerable stage for possible transmission of the virus. It was agreed that for
most of us north of
Spring spraying for
aphids to prevent BYDV should only be considered if there has been a recent
history of BYDV in and around the field. Although Arv
Grybauskas from
Cereal leaf beetle
could also be a threat to the later planted wheat. Since cereal leaf beetle is
known to prefer small grain fields with thin canopies, many of our fields may
be at risk this year. We have just found the first signs of adult feeding in
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Field Crop
Diseases -
Soybean
Cyst Nematodes.
It is still not too late to check for soybean cyst nematode. Soil test bags can be purchased at the Extension offices. If you have a fax machine and need results quickly, tests results can be sent via FAX if you provide the number on the Nematode Assay Information Sheet.
Soybean Seed Quality.
The weather pattern last fall was not favorable for good seed quality in soybeans. Prolonged wet weather caused weathering and infection by the fungus Phomopsis. Seed lots tested in the Dept of Ag seed lab are testing lower than normal in general. Growers that have saved their seed are encouraged to get it tested with and without fungicide.
What to do if you have reduced germination seed?
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Reminders On Acetochlor
Use Restrictions -
Acetochlor is a preemergence herbicide for corn that controls annual
grasses and some broadleaf weeds. It is
in the following products: Harness, Harness Extra, Degree, Degree Extra,
Topnotch, and Fultime. There are restrictions that are important in
our area. The restrictions pertain to
groundwater quality. The restrictions
are based on depth of groundwater within one month of planting and the
combination of soil type and organic matter.
Do not apply acetachlor if the groundwater
depth is 30 feet and you have sands with less than 3% organic matter, or loamy
sands with less than 2% organic matter, or sandy loam with less than 1% organic
matter.
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New(er) Corn Products for
2003 -
Some of these products were available in 2002.
Callisto 4SC (Syngenta) has an active ingredient called mesotrione, with a new site of action. It is a pigment inhibitor and causes sensitive plants to turn white. It can be used either soil-applied or postemergence. It is a component of Lumax (see below). Postemergence are 3 fl oz/A, but other herbicides have it labeled for use with their product at lower rates. (If crabgrass is a weed you are targeting for control, I suggest you do not reduce the rate of Callisto.) There is excellent crop safety, up to 30-inch corn or 8 collars (whichever is most restrictive). There are numerous broadleaf weeds listed as controlled on the label, with large crabgrass as the only grass species listed. It is most effective with a little atrazine
(0.5 lbs/A or 1 pt/A
atrazine).
Replant is 4 months to small grains and 18 months for most other
crops. There are precautions for use
with Counter, refer to the label.
Lumax 3.95SC (Syngenta) is a pre-packaged mixture of Callisto, Dual II Magnum, atrazine, and a safener. Use rates are 2.5 or 3.0 qts/A, based on organic matter. At 2.5 qts/A of Lumax, it is 1.76 pt Dual II Magnum, 5.4 fl oz of Callisto, and 1.25 pt of atrazine. No label restrictions for use with Counter, provided