Volume 12, Issue 7
May 7, 2004
Volume 12, Issue 7
May 7, 2004
Vegetables
Sinbar and Reflex
Receive Section 18 Emergency Labels – Ed
Kee, Extension Vegetable Crops Specialist; kee@udel.edu
Reminder, Sinbar has been approved by the EPA for a
Section 18 Emergency Label for pre-emergence use on watermelons. Sinbar has been approved annually for several
years, and has provided excellent broadleaf weed control.
Reflex has been approved for a Section 18 label for
post-emergence use on snap beans. Reflex
has also been approved annually for several years, and has also provided
excellent broadleaf control in snap beans.
It has become a standard, with Dual used preemergence, followed by
Reflex applications approximately 18-21 days after planting to control
broadleaf weeds.
Always read the label completely for application
directions.
Pickle Planting
Will Begin Soon - Population Rates and Herbicide Programs –
Ed Kee, Extension Vegetable Crops Specialist; kee@udel.edu
Growers of pickling cucumbers will begin planting
in May. Some will begin as early as the
first full week of May. Population
studies have indicated that 55,000 plants per acre is the most advantageous
population. In 30 inch rows, this is a
plant every 31/2 to 4 inches apart.
Pickling cucumber seed is now over $1.55 per thousand. There may be real merit in reducing the
population to 50,000 plants per acre.
Reducing the seed used by 5,000 per acre is a saving of $7.75 per acre,
over 500 acres this saves $3,875. While
it is not known for sure if yield would be consistently affected by this
reduction, it may be worth the trouble for growers to run several tests on
their farms.
Herbicide options have improved over the
years. The commercial standard seems to
have evolved to a tank-mix of Curbit 3E at 1.5 pint/acre plus Command 3ME at
3-4 ounces per acre. The Curbit 3E rate
can be raised to 2 pints/acre as temperatures rise through the planting
season. Typically by the time of June
plantings, the rate can be raised to 2 pints per acre. Keeping the lower rate during the cooler
period of early planting will help avoid any stunting or “growth
checking.” Raising the rate later will
provide a little extra control.
These materials are now sold as a jug-mix product
labeled as Strategy. 1.5 pints of
strategy is roughly equal to 1 pint of Curbit 3E and 4 ounces of Command
3ME. 2 pints of Strategy is equal to 1.2
pints of Curbit 3E and 6 ounces of Command 3 ME. While the 2 pint rate of Strategy is a little
light on the Curbit portion of the mix, it’s still acceptable for good weed
control in most situations.
The other material is Sandea, which has been
labeled for two seasons. It may be used
premergence at 0.5 to 1 ounces to control cocklebur, redroot pigweed, smooth
pigweed, ragweed and galinsoga.
Perhaps the best use of Sandea is as a
post-emergence material. It can be applied at 0.5 to 0.66 ounces per acre to
suppress or control yellow nutsedge in addition to the weeds listed above. It’s control of breakthrough redroot pigweed
is especially important to mechanical harvest operations, especially with the
pinch-roller type of harvester.
Always read the label for complete details on use
and application.
Vegetable Crop Insects -
Melons.
As soon as plants are
set in the field, you should begin scouting for cucumber beetles, aphids and
spider mites. Foliar products can provide good cucumber beetle control;
however, multiple applications of a pyrethroid or Sevin may lead to spider mite outbreaks later in the season,
so be sure to scout fields and only treat if populations are causing damage. In
2003, dimethoate provided very good cucumber beetle control. As indicated in a previous newsletter,
Furadan, Admire and Platinum can all be applied as at-planting materials.
Admire, Platinum and Vydate can be applied through the drip irrigation and all
provided good cucumber beetle and aphid control in 2003 trials. As a reminder,
the rates for all products applied through the drip are expressed as a
broadcast rate/acre; however, you should check the labels and calculate the
rate per 1000 foot of row based on your bed spacing
(e.g for Vydate at 2 qts/acre: for a
6 foot bed spacing the rate is 8.8 oz/1000 ft of row; at the same rate/acre for
a 7 foot bed spacing the rate is 10.28 oz/1000 ft of row.)
There have been reports of low levels of aphids on
plants in the greenhouse as well as plants recently set in fields. If plants
are ready to set out, the best option is to check plants for aphids as soon as
they are set in the field. Be sure to watch for beneficial insects as well. In
recent years, they have helped to crash populations. The treatment threshold for aphids is 20
percent infested plants with at least 5 aphids per leaf. Actara, Fulfill, Lannate and Thionex are labeled
on melons and will provide melon aphid control. These materials should be
applied before aphids explode.
Peas.
As the earliest peas
bloom and set pin pods, be sure to sample for aphids. Although levels have been
generally low, we are starting to see an increase in populations. Warmer weather could result in a rapid increase
in populations. On small plants, you should sample for aphids by counting the
number of aphids on 10 plants in 10 locations throughout a field. On larger
plants, take 10 sweeps in 10 locations. A treatment is recommended if you find
5-10 aphids per plant or 50 or more aphids per sweep. Dimethoate
or Lannate will provide aphid control. Be sure to
check the labels for application restrictions during bloom.
Potatoes.
The first Colorado
potato beetle adults and egg masses have been found in the earliest emerged
fields. Actara, cryolite, Spintor or Provado will provide
control. To avoid the development of resistance to the neonicotinoid
insecticides, fields treated with Admire, Platinum or Tops MZ Gaucho at
planting should not receive foliar treatments of Provado
or Actara. Corn borer moth catches are below one-per-night
in most areas except in the Bridgeville area were catches increased to 4-per-night.
We can expect to see an increase in moth populations as soon as temperatures
increase after the recent period of cool, rainy weather.
Sweet Corn.
In fields where plastic was used as
a row cover, be sure to begin sampling for European corn borer
larvae as soon as the plastic is removed. A treatment should be applied
if 15 percent of the plants are infested. The best timing for a treatment is
just as the tassels are emerging from the whorls. In recent years, Avaunt
(labeled for whorl stage only), Baythroid, Mustang
MAX, Penncap, Spintor or Warrior have
provided effective control. Intrepid was labeled last year and provided good
corn borer control in whorl stage corn.
You should also continue to watch for black cutworm and flea beetle
activity. Damage from both insect pests has been observed in early-planted
sweet corn.
Vegetable Diseases –
Growers frequently ask “What chemicals can I use in
the greenhouse on my transplants?” The
following article, written last winter by Dan Egel and Fred Whitford for a
PESTICIDES IN THE VEGETABLE GREENHOUSE: LAWS, LABELS, AND LESIONS- (Dan Egel and
Fred Whitford) – Forget the cold snow outside. Imagine it’s April. You walk into your transplant greenhouse only
to discover that you have a pest problem.
Perhaps you find spider mites on tomatoes. Or perhaps you notice gummy stem blight on
watermelons. Later, in your pesticide
storage shed, you reach for the same pesticide that was affective against the
pest last year in the field. Suddenly,
you find yourself wondering, is it OK to apply this pesticide in a greenhouse?
It’s a good question since insects and diseases
tend to flourish inside the hot, humid environments that greenhouses
provide. The answer to this question is,
to coin a well-known extension phrase, it all depends! It depends on what the label says or doesn’t
say as to how the question can be answered.
(Of course, telling growers to read the label first is nothing
new.) In general (another well-worn
Extension phrase) the answer is 1) yes, 2) no; it’s illegal, or 3) we can’t
recommend it, but you can use at your own risk.
Let’s look at our answers based on different scenarios.
Scenario 1. Our yes answer is supported by language found
on the Kocide 2000 label. Kocide 2000 is
a fixed copper compound that vegetable growers might use to combat bacterial
diseases such as tomato bacterial spot and bacterial fruit blotch of
watermelon. The twelve-page label, with
instructions for use in the field and in the greenhouse, clearly states “Kocide
2000 may be used in greenhouses and shadehouses to control diseases on any crop
on this label where physiology allows greenhouse or shadehouse culture. Specific directions are presented for Citrus,
Cucumber, Eggplant, Pepper, and Tomato.”
This is found on page 3 of the label.
You can then turn to page 9 and find the heading Greenhouse and
Shadehouse Crops, and find specific instructions on disease control for citrus,
cucumber, eggplant, pepper and tomatoes.
Again, the answer to the question, can this pesticide be used in the
greenhouse is yes.
Scenario 2. The label language found
in Bravo WeatherStik will be used to clarify the no answer. Under the section of the label titles
“General Precaution and Restrictions” the label says, “Do not use on
greenhouse-grown crops.” In this case,
the manufacture is quite clear that they do not want this specific brand name
product to be used in the greenhouse.
Case closed!
Now that we have the easy yes and no answers out of
the way, lets try and tackle the more difficult situations.
Scenario 3. The label of Dithane F45 clearly states
“Dithane F45 fungicide is a broad-spectrum fungicide recommended for outdoor or
greenhouse grown crops.” You look up
what vegetables this fungicide can be applied to and you find asparagus, all
types of corn, cucumbers, fennel, gourds, all types of melons, onions,
potatoes, and squash. That’s wonderful,
except when you read how to mix up the product for greenhouse use, you only
find rates per acre.
In a situation such as the one above, it is
critical to follow the label to the letter.
If it is not possible, follow the applications instructions for
greenhouse use, do not use the product in the greenhouse.
Scenario 4. You have a crop that is found on the label,
but the words greenhouse is nowhere to be found. A good example would be the information found
on the Thiodan 3EC label for cucumbers.
This label does not prohibit nor does it recommend its use for cucumbers
in the greenhouse. The label is what is
termed “silent” on the subject of use in the greenhouse.
The examples provided in scenarios 3 and 4 are
difficult for us in Extension to answer.
We really have three answers and we allow you to pick the one you want.
Answer 1. Unless the label prohibits the use in the
greenhouse (scenario 2), if you find your crops on the label then you can
legally use the product. However, you
have to follow all of the recommendations intended for the field in your
greenhouse applications. Following label
instructions is critical. Remember, the
first sentence under the “Directions of Use” indicates “It is a violation of
Federal law to use this product in a manner inconsistent with its
labeling”. What that means is that you
are held liable by the Office of the Indiana State Chemist and EPA for not
following instructions.
Answer 2. Contact the manufacturer home office to see
whether the product can be used in the greenhouse. However, you better write the names down of
the persons who allowed the use since most product warranties do not pay for
damages even when their representatives say you can use it in violation of the
label instructions.
Answer 3. This is where we in Extension say from our
perspective of erring on the side of safety that the product cannot be
used. It’s not a legal answer, but one
that we feel very comfortable making since the research to support its use is
lacking or the manufacturer is not willing to put this on the product label. In fact, the label for Kocide 2000 makes it
clear that it’s buyer beware when using their product on vegetables that do not
have specific greenhouse use instructions.
It states, “Kocide 2000 may be used in greenhouses and shadehouses to
control diseases on crops which appear on this label and specific instructions
have been developed for crops listed.
The grower should bear in mind that the sensitivity of crops grown in
greenhouses and shadehouses differs greatly from crops grown under field
conditions. Neither the manufacturer nor
seller has determined whether or not Kocide 2000 can be used safely on all
greenhouse and shadehouse grown crops.”
What the above label does provide are instructions
to the grower to determine if Kocide 2000 can be used safely prior to
commercial use. The label states, “In a
small area, apply the recommended rates to the plants in questions and observe
for 7 to 10 days for symptoms of phytotoxicity prior to commercial use.” It also provides excellent information such
as “Apply Kocide 2000 according to specific rates given for those crops in
pounds per acre. One level tablespoon of
Kocide 2000 per 1000 square feet is equivalent to 1 pound per acre”. This is an excellent label with clear
instructions to the grower. We wish they
were all this good.
And lastly, can we use this pesticide in the
greenhouse is always a no with extension specialist if the crop is not listed
on the label. As most of you are aware,
any pesticides we apply to crops must have a tolerance established with
EPA. For use in extension, it doesn’t
matter if you know it works against an insect or disease. If the crop is not on the label, then it’s
illegal to use.
What we’ve presented so far is in the best interest
of us in Extension. We want to make sure
that our recommendations work, and that you will come back to us with
questions. We want to give you the best
answers possible, and be right 100 percent of the time. We won’t go out on a limb when your
greenhouse transplants and vegetables-your investment, source of income, and
livelihood are at stake.
But what’s in your best interest as the
grower? It seems obvious that you want
to protect your crops against the insects and diseases that are all too common
in the greenhouse. And we understand that
your livelihood depends on producing quality and abundant crops. Yet, on the other hand, if you experience any
negative effects from the use of the product, you rightfully expect the company
of the product to stand behind their products.
But companies would only guarantee their products if used according to
label directions. In the event that you
applied a product that says do not use in the greenhouse, then their obvious
answer is no. What we will never know is
whether they will stand behind their product when the greenhouse is not listed
on the label. In this case, it is buyer
beware.
As always, you the grower must make up your own
mind on how much risk you are willing to take.
The decision to use a product is an important consideration. Be safe and use products labeled for
greenhouses, labeled for the transplants or vegetables that you will grow in
the greenhouse, and with instructions written for greenhouse use. If you do this, then we can help clarify any
questions that you might have on the specific products, and it will be a
pleasure serving you.
Field Crop Insects -
We can now find economic
levels of alfalfa weevil in numerous fields. In some cases, fields are
approaching harvest so an early cutting may be the best control option.
However, remember that cutting should only be used if you can cut within 5 days
of finding an economic infestation. In addition, if economic levels are present
before cutting, be sure to check regrowth within a week of cutting. Although
populations are not as high as in 2002, damage to regrowth can be significant.
In recent years, cool conditions after first harvest has not resulted in
“stubble heat” to control populations. If fields are close to harvest and you
spray instead of cut, be sure to use a chemical and rate with a short residual.
Field Corn.
We are starting to find
the first cutworm leaf damage and cut plants. Even if a field was treated for
cutworm before or at planting, be sure to sample all fields as soon as corn
emerges. A treatment in 1-2 leaf stage
should be applied if you find 3% cut plants or 10% leaf feeding. The threshold
in 3-4 leaf stage corn increases to 5% cut plants. A pyrethroid
or Lorsban will provide the best control. Fields
should be scouted through the 5th leaf stage for cutworm damage. If
cutworms are feeding below the soil surface, it will be important to treat as
late in the day as possible, direct sprays to the base of the plants and use at
least 30 gallons of water per acre.
Small Grains.
We continue to find low
levels of cereal leaf beetle eggs and low levels of larvae have been found in
wheat and barley in
Soybeans.
As you make plans to
plant your first no-till full season beans, be sure to consider a treatment for
seed corn maggot. In no-till fields, seed corn maggot will remain a problem
through May. Flies continue to lay eggs and maggots
will be present at the time of seed germination. Kernel Guard Supreme and KickStart VP are both labeled on soybeans. The active
ingredient in both products is permethrin.
Grain Marketing Highlights - Carl German, Extension Crops Marketing Specialist; clgerman@udel.edu
General
Comments.
The next USDA supply and demand report will be released on Wednesday, May12th.
We can expect sideways to neutral trading patterns in the commodities markets
until the release of the report. Traders will be looking for adjustments in the
demand numbers, particularly for an upward revision in USDA's projected corn
exports number.
Weather will become increasingly important to the markets as we enter critical
crop development stages this summer. Any weather problems developing in the
corn belt once the crop is planted will send corn and soybean markets rocketing
up. Conversely, in the event that we achieve 'ideal' growing conditions these markets
are likely to go down fast and hard. For corn, with an 856 million bushel carry
over projection for the current marketing year, the supply and demand situation
becomes even more critical in the '04/'05 marketing year. Currently, parts of
the western corn belt are reporting very dry planting conditions. This was
being discounted in this morning's market comments by the old adage 'plant in
the dust, the bins will bust'.
Weekly export reports continue to be price supportive, with a recent report
indicating that the monthly crush for soybeans must drop by about 25 million
bushels below the norm before USDA's stock figure of 115 million bushels can
become a reality. Weekly exports for
Market Strategy.
July '04 wheat futures are currently trading at $4.08 per bushel. The current
price offering is within 20 to 22 cents of the life of contract high
established in April. The new crop wheat harvest is beginning in the Southwest.
This might be a good time to consider increasing new crop wheat sales.
Soil-Applied Herbicides to Emerged
Fields - Mark VanGessel,
Extension Weed Specialist; mjv@udel.edu
There are times (like this year) that corn has been
planted and is emerged without residual herbicides being applied; or to reduce
the risk of crop injury, the residual herbicides are applied as the corn begins
to emerge. The greatest risk of failure
comes with trying to control annual grasses such as foxtail and panicum after
they emerge. However, several products
are available to control emerged grasses (e.g., Accent, Basis, Basis Gold,
Celebrity Plus, Option, Steadfast (ATZ), glyphosate on Roundup Ready corn only,
Lightning on CL/IMI-corn only, and
|
Herbicide |
Maximum
field corn height |
Maximum
weed size |
|
Atrazine
# ^ |
12" |
1.5” broadleaf |
|
Princep |
do not apply to emerged corn |
before emergence |
|
Python |
20" |
before emergence |
|
Prowl # ^ |