• Early blight fungicides

• LATE BLIGHT ALERT

• European corn borer

• Corn earworm moths found

• Aphids on everything

Early blight fungicides
As predicted, we found the first couple of early blight lesions on the lower leaves of a few plants at ever single farm I visited this week: over a dozen different sites throughout the state.  Strangely enough the TomCast model down in Gales Ferry did not reach threshold and did not recommend a spray.  However, the best time to begin spraying for this disease is when the first lesion is found in your field.  Based on what I found this past week, I believe you now have early blight in your field and should make your first fungicide application on tomatoes if you haven=t done so already.  Normally, I recommend starting with maneb or Manzate before fruit begin to ripen if early blight is detected, and then we alternate between Cabrio and Bravo about every 10 days after fruit begin to color. Remember that we tighten that schedule to as little as 7 days when we get constant rain, like we are experiencing now.  I usually like to recommend using the systemic product Cabrio first to make sure you have complete coverage on those lowest leaves where the disease starts.  However, this year we have a real threat from late blight. Pathologists say that the stobiluron fungicides in group 11 such as Cabrio, work on late blight, but there are much more effective materials that could be used, such as Bravo, maneb and Manzate. I just talked with Meg McGrath, the pathologist at Cornell=s LI research Station about all our choices for early blight and late blight and she suggested an alternate early blight program in years when late blight is not a threat.  For growers using a plastic mulch and staked or trellis systems, where fruit are up and away from anthracnose ripe rot that can splash up from the soil, you can alternate between Endura and Bravo. She said the boscalid active ingredient in Endura is very effective on early blight, but may not provide protection from ripe rot if a grower had ground tomatoes.  For this year, a better alternative would be to alternate between Tanos and Bravo.  The Tanos is a pre-mix of the AI in Curzate, which is very effective on late blight, and a newer stobiluron fungicide that hasn=t been exposed to early blight spores for as many years as Cabrio.      

LATE BLIGHT ALERT
Just to refresh your memories, late blight is the disease that caused the Irish Potato famine. It is capable of spreading throughout a potato or tomato planting in just a couple days if daytime temperatures are between 60-75 degrees and the leaves are continually wet due to rain, mist, fog, and cloudy weather.  I last found this disease in Connecticut about 15 years ago in a potato field in Putnam and it killed the entire field in less than 1 week.  Late blight tends to be more of a problem in states that grow a lot of potatoes because it often originates on volunteer plants that seed themselves from prior years or from old cull piles.  However, even the potato growing regions of New York, such as Long Island, have experienced the disease in only 3 out of the last 20 years.  The strain that hits tomatoes is usually less common than those commonly found on potatoes. So why are the pathologists so excited about this disease this year, other than the fact that the weather has been ideal for the spread of late blight all month and for the foreseeable future?  Well, it turns out that just like with the downy mildew on basil plants that I warned you about earlier this season, the big box stores have been acting as the Johnny Appleseed of disease spreading by selling homeowners throughout the East Coast late blight infected tomato plants. When this was announced, Tom Zitter, the pathologist at Cornell, went to the three largest local big box stores, and found the disease on plants at all three of the stores and it has been found on plants from Maryland to Presque Isle, ME.  USDA APHIS has been notified and is having the stores involved pull all infected plants from their shelves, but the cat is out of the bag, so to speak. This disease spreads rapidly on the wind and usually one of the main controls is to destroy all plantings that are determined to be infected with late blight. Obviously, this can not be done when it comes to home gardens due to the sheer magnitude of the problem and the likeliness that many garden plantings would not be destroyed. Commercial fields of tomatoes and potatoes in states to our west and south have already been diagnosed with the disease.  So, now that the disease has been spread throughout the countryside and probably to a home garden near you, the odds of your tomatoes or potatoes becoming infected have just risen substantially, especially with the wet 7-day forecast. 

What are you looking for when scouting?  Look at the stems and leaves deep in the canopy where leaves dry slowly.  The classic leaf symptom is a half-dollar or silver-dollar-sized  dark brown or olive green lesion, which sometimes has water-soaked margins.  If dark lesions appear on the stem the vine beyond the lesions often die. Fruit can also be infected. Remove infected plants from the farm.

All tomato and potato plantings should be treated with protective fungicides before the disease develops.  Bravo is very effective on late blight, and so are the EBDC fungicides such as maneb or Manzate, but Ridomil is no longer effective due to resistance problems.  Curzate or Tanos, which contains the active ingredient in Curzate, can burn out lesions that are up to 48 hours old, but does not provide residual protection for more than a few days, so should be followed with a protectant fungicide within 5 days. Other options include Previcur Flex and Ranman which should be mixed with a protectant fungicide.  The new product Revus Top has two active ingredients to control both early and late blight but is not available this year due to supply shortages.   

European corn borer
For the third year in a row we are experiencing very low corn borer pressure.  ECB trap catches fell to 0 or 1 moth at three of the sites where we have been monitoring their population and the last site was checked after 2 weeks and contained 26 moths or an average of 13 moths per week.  That was the high catch this year from the four sites, when we often catch up to 150 moths per week in the first generation. The high larval infestation for the week was in Somers where 52% of the pre-tassel stage corn plants were infested with larvae.  East Hartford was also over threshold with 18% of the plants infested.  Whorl and pretassel infestations are unusually low at some farms and this may be due to a disease that infects corn borer in some wet years. 

Since moth numbers have fallen at most sites this week, you should spray any silking corn that has been pushed ahead by row covers because peak egg hatch is occurring right now.

Also spray any pre-tassel stage corn that has more than 15% of the plants infested.  Continue to scout pre-tassel and late whorl stage plantings for at least another week or two. 

Remember that you can control borer larvae with selective materials such as SpinTor, Avaunt or Intrepid just as well as you can with Warrior or any of the other synthetic pyrethroids.  These selective materials cost you a few more dollars per acre, but will spare the predators in the corn which can help you control pests on all your other crops when they spread out throughout the farm.  If you are certified organic, you can control borer with Entrust or an OMRI-approved B.t. product like XenTari or Dipel DF. 

Here is a list of infestations found at different sites while scouting sweet corn this past week. *means that the planting is over threshold and should be sprayed.  MW=mid-whorl, LW= late-whorl, PT=pre-tassel, S=silk.

Town	% infested plants	Stage of planting	ECB moths trapped	CEW moths/N
Shelton	4% 2%	PT LW	91 moths	1.5=4-day schedule*
E. Lyme	4% 10%	PT LW	13 moths	0=no spray
Berlin			90 moths	0 = no spray
E. Hartford	18%* 14%	PT LW	90 moths	--
Ellington	0%	MW		set up trap
Somers	52%*	LW
Falls Village	0%	MW

Corn earworm moths found
Corn earworm pheromone traps in East Lyme and Berlin were empty this week, but in Shelton the grower picked up an average of 1.5 moths per night and is now on a 4-day spray schedule on fresh silking corn.  Farms along the coast or in the Connecticut River Meadows are usually the first sites to pick up CEW moths because the moths migrate along the coastline and up the major rivers.  So, it is not surprising that we detected this moth first in Shelton within sight of Long Island Sound. You should have pheromone traps set up in your first silking corn to detect these moths and determine if you should be spraying silking corn for this pest.  Empty the traps every 3-4 days.  Spray every 6 days if you find an average of 0.2-0.5 moths per night.  Spray every 5 days if you find between 0.5 and 1 moth per night.  Spray ever 4 days if you find between 1 and 13 moths per night.   

Aphids on everything
Aphid populations are booming.  The UMass newsletter reported outbreaks of black aphids on Swiss chard, spinach, beets, lettuce, and  radishes.  They have identified them as chickpea aphids that usually only inhabit weeds such as lambsquarters and pigweed and also may be found on beans and peas. Other growers also have light green aphids on peppers, eggplant and tomatoes or a combination of light green and dark aphids on cucurbit crops like squash and cucumbers.  These are most likely green peach aphids with a few melon aphids thrown in for good measure.  We usually think of aphids associated with dry weather, but there must be something out there in all this rain that is reducing the population of their natural enemies and causing these aphid outbreaks. Fulfill is usually one of the more effective materials on aphids and it is registered on many crop, but not all crops, so check the label.  Other very effective aphidicdes include the neonicotinoids such as Provado or Assail.  Again, check the label or the New England Vegetable Management Guide to see which products are labeled for the crops you need to spray.  The web site address for the NEVMG, in case you do not have a copy, is www.nevegetable.org.

That's enough for this week.  This message will next be updated on Friday afternoon July 2.