This weeks message will cover:

• Tomato update

• Potato late blight tolerance

• Corn earworm on the  increase

• Fall armyworm

• Peppers

• Powdery mildew on pumpkins

• No downy mildew yet

Tomato update
Well let's start with the good news.  Growers with tomato fields that were infected with late blight 2-3 weeks ago are finding that the recommended combinations of systemic and protectant fungicides seem to be holding the late blight spread reasonably well.  That includes farms that have used Previcur Flex with a maneb or Manzate type product, Tanos with copper or Bravo, or  Presidio and Bravo.  Be aware that Presidio has some rotational restrictions where many crops can not follow a spray for 18 months.  Also, Presidio is recommended on a 10-day schedule, so should be applied with a protectant like Bravo which can last for up to 10 days.  You should make another application of a different systemic/protectant combination 5 days after applying Tanos and 7 days after applying Previcur Flex.  

Late blight will only survive the winter in potato tubers, so it is critical that all volunteer potato plants that come up next spring be destroyed to avoid repeating this whole late blight disaster a second year.  Also, sanitation is an important part of controlling this disease.  You should inspect your tomato and potato planting every few days and remove any leaves, stems or whole vines that appear to have late blight symptoms.  You want to minimize the number of spores that your crop is exposed to help give it a fighting chance with the fungicides.  There may come a point that there is just too many infected plants to remove.  At that point you are down to chemical warfare, but the odds of a successful outcome decrease.  If most of the plants in your tomato or potato block are already dead, it may be time to give up the battle and kill the remaining plants by spraying them with paraquat to reduce disease spread to other farms.

There are now many other diseases we are finding on tomatoes, both in the field and in the greenhouse.  Many growers seem to have blocks with bacterial canker.  This disease starts at the bottom of the plant and infects the edge of the leaf through natural openings.  The margins of the leaves turn brown or black and may have a inner area of yellow discoloration.  It is hard to rid your farm of this disease as the bacteria often seems to survive the winter.  Cultural controls include rotating plantings to new ground next year, dunking stakes in a chlorine bath, and sanitizing greenhouse benches and flats.

Some growers also have one or both of the most common fungal diseases: early blight and Septoria leaf spot.  Again, both diseases start on leaves at the bottom of the plant and make there way up the plant as the season progresses killing leaves as it goes.  The tight fungicide programs that we are suggesting for late blight should be providing good control of both of these diseases as well as Anthracnose ripe rot.

Some growers also have bacterial spot and/or spec which just love this wet weather.  Copper may be the most effective bactericide we have to combate these problems, although some growers have had good luck with Oxidate in the past. 

In the greenhouse we have seen high levels of Botrytis grey mold, leaf mold and even Sclerotinia white rot in one house.  These first two are related to high humidity, which is almost impossible to correct this summer, but can be minimized by removing infected leaf tissue on a regular basis.  Sclerotinia is also related to excess water and can be controlled by carefully removing infected plants to prevent the spread of the disease.  Sclerotinia produces white fungal growth and black sclerotia within the stem, which are the long term resting spores that last up to 7 years in the soil.  Sclerotinia usually first attacks dead tissue such as dead or dying flower petals.    

This tomato has a disease called White Mold, caused by Sclerotinia sclerotium.  It is charactized by the growth of white mycelium and black sclerotia form inside infected stems. click on image to see a larger view Photos:  Joan E. Allen, Assistant Cooperative Extension Educator in Residence, Home & Garden Education Center, University of Connecticut

Potato late blight tolerance
For those of you wondering what you can plant for potatoes that may stand up to late blight, here are a few varieties that are more tolerant than many others: Elba, Sebago, Co83008, Kennebec, Fl 1625, Fl1859, Castile, Allegany, Rosa, FL1869, Katahdin.  Also, pathologists are suggesting that you mow, flame or kill the vines two weeks before digging your potatoes if they have late blight this season.  The disease only infects living tissue and the theory is that the UV light will break down any spores in the field that are on the dead vines within the two week time so that you do not spread it to the tubers.  Also, do not store tubers that look diseased.   

Corn earworm increasing
The number of corn earworm moths increased at all locations throughout the state this past week.  Pheromone traps in Shelton, Northford, East Lyme, Berlin, South Windsor, Ellington, Somers and New Milford all captured between 1 and 6.4 moths per night this week which puts those farms on a 4 day spray schedule on fresh silking corn.  The high captures were in New Milford with 3.7 moths per night and Northford with 6.4 moth.  East Hartford and Ellington captured 0.6 and 0.9 moths per night, respectively, and are on a 5 day spray schedule on fresh silking corn, although the traps were emptied in East Hartford on Monday before the two storms.

Most farms should be on a 4 day spray schedule on fresh silking corn at this time.

 Here are the CEW thresholds: 

Fall armyworm
We failed to capture FAW moths in pheromone traps in Northford, East Hartford, South Windsor, New Milford or Somers.  We captured a single moth in Ellington after capturing 2 last week, and the trap in Shelton had 9 moths that could not be identified because the trap was flooded with water. 

Ellington had 8% of midwhorl stage plants infested with FAW larvae and Shelton had 1 %.  Scout your young whorl stage plantings and spray if 10-15% of the plants are infested.  Based on past experiences with this insect, SpinTor and Avaunt may provide better control than Warrior.

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	1% FAW	MW	0 ECB, ? FAW	3 =  4 day schedule
Northford		PT	ECB, 0 FAW	6.4 = 4 day schedule
East Lyme I	0%	PT-MW	1 ECB	1 = 4 day schedule
Berlin		PT	0 ECB, 0 FAW	1.2 = 4 day schedule
East Hartford	0%	MW	0 ECB	0.6 = 5 day schedule
South Windsor			0 FAW	1 = 4 day schedule
Ellington	8% FAW	MW	1 FAW	0.9 = 5 day schedule
New Milford	8%	PT	0 FAW	3.7 = 3 day schedule
Somers			0 FAW	1 = 4 day schedule

Peppers
Growers with a history of heavy pepper maggot damage should be applying their second and final Orthene or dimethoate spray this coming week, 8-10 days after the first spray.  One grower had most of the peppers in their planting severely damaged this week by bacterial leaf spot.  It was either a very potent strain of the disease, all the nitrogen had leached out of the field, or maybe the plants were in a very week state due to all the adverse weather.  At any rate, it caused more damage, faster than any BLS outbreaks I can remember.  Fortunately, it was a small planting.  Be sure to scout your peppers for irregular shaped brown to black spots on the leaves.  This disease can defoliate plants and cause raised wart-like spots on the fruit.  Use BLS resistant plants when ever possible, keep the level of nitrogen from falling, rogue out infected plants if you find the disease in its early stages and use copper sprays to limit disease spread.

European corn borer moths are still between generations, so peppers do not need to be treated for borer at this time.   

Powdery mildew on pumpkins
We found powdery mildew on pumpkins in East Lyme and one other farm this week. Most farms had pumpkins that were just beginning to run this week that were free of all major diseases including powdery mildew.  Scout the underside of 50 leaves per field on a weekly basis and spray if you find even a single small spot of powdery mildew.  The best place to check is along the eastern edge of the field if there are trees that will shade the plants along that border, and cause the dew to linger, so that the leaves stay wet in the morning.  Do not use a systemic on pumpkins until you find the first powdery mildew.  If you need to spray for Plectosporium blight because the plants are setting fruit and it has been so wet, we suggest you start your program with a product like Bravo that contains chlorothalonil as the active ingredient.