Welcome to the University of Connecticut Cooperative Extension System's
Vegetable Pest Message

2009

This message is being recorded on Thursday afternoon July 2 by Jude Boucher.   

This weeks message will cover:

  • Can the weather get any worse?

  • More on late blight

  • Corn borer

  • Corn earworm

  • Set up your fall armyworm traps

  • Pepper maggot traps

Can the weather get any worse?
Tornadoes in Wethersfield, hail in East Hartford and Southington, floods in many different towns...  I drove through Wethersfield yesterday and it was a mess, the crops on one of the large vegetable farms there were shredded from the wind and hail all through town, right down to the river.  The grower I'm working with in East Hartford also had his crops completely shredded and flattened by hail.  The Ellington area has been underwater from heavy storms the last two nights, and the southeast corner was way underwater.  Can you believe this is July!   

More on late blight
When it comes to tomatoes and potatoes production, this may be the toughest year the Northeast has ever seen.  After I finished recording the pest message last Friday I visited our local big box stores and every one of them were selling late blight infested plants.  I bought a couple of plants with symptoms and the diagnosis was confirmed by the pathologist at the UConn diagnostic lab. The distributor of the plants is taking all tomato plants off the shelf at all sites, but clerks at one of the stores told me they had already sold thousands or tens of thousands of the infected plants. What's worse is that every Extension agent and pathologist that checked stores anywhere in the Northeast found late blight infested plants.  That means we have thousands of home gardens from Maryland to Ohio and north to Maine and Quebec that are acting as sources of late bight spores and perfect weather for late blight development (cool and wet). This situation is unprecedented. This is also the earliest that late blight has ever been detected, so there is a whole lot of season left for the infections to spread. Because this disease is airborne, like powdery or downy mildew, we are not expecting unsprayed tomatoes and potatoes in home gardens or on organic farms to survive the season.  So, you can expect the customers who purchased transplants from you this spring to report back that their tomatoes died.  You can pretty safely tell them that the disease responsible did not come on the plants that they purchased from your farm, but rather spread through the air from surrounding gardens that used transplants purchased at big box stores.  Pathologists throughout the Northeast have been checking for infections on garden center plants that were supplied by local producers and have not found any late blight. 

Now here is the bad news!  If the weather doesn't get dryer soon, even plantings on commercial farms that are using the most effective fungicides may not survive the season, because this epidemic will start to snowball, bathing the plants in more and more spores as the season progresses.  There are already commercial farms in southern Quebec, up-state NY and PA where late blight has been confirmed. We expect many more infected farms to be reported next week and it will get worse as we go along. 

All tomato and potato plantings should be protected with effective fungicides.  Maneb or Manzate can be used prior to the fruit turning pink. After fruit begins to ripen, you can alternate every 5-7 days with applications of Bravo and Tanos + copper. You are required to use a protectant fungicide, such as copper, when applying Tanos.  If the weather turns dry later in the season, you can then begin to stretch the interval between sprays to 10 days.  Other products that have proven to be very effective against late blight include Ranman and Previcure Flex.  If you find plants that are infected in your field, dispose of those plants off farm to limit the amount of spores produced.       

European corn borer
Corn borer pheromone traps in Shelton, Berlin and East Hartford captured between 0 or 2 borer moths, which means that egg laying is over.  There will be a few eggs left to hatch this week so continue to scout pre-tassel stage corn for live borer larvae. Pre-tassel stage plantings ranged from 10-24% infested plants this week, and farms in Shelton, Northford and Berlin had fields that exceeded thresholds at pre-tassel and required treatments. If you find more than 15% of the pre-tassel plants infested you should spray twice about 3-5 days apart.  Fields that have infestations right about at the threshold level can be sprayed a single time, when the first few tassels in the field open fully.  Selective products such as SpinTor, Avaunt, Intrepid and B.t will control the borer and spare predators that will migrate into your mixed vegetables to help provide some control of pests.  

Corn earworm
We captured 0.5 CEW moths per night in pheromone traps in Shelton, down from 1.5 per night last week.  Shelton is now on a 6 day spray schedule on fresh silking corn. CEW traps in East Lyme, Berlin, East Hartford and Ellington were all empty and those farmers are not spraying silking corn at this time.  If you have silking corn on your farm, you should set up a Heliothis pheromone trap and bait it with a Hercon brand CEW lure.  You can purchase these supplies at greatlakesIPM.com.

Set up your fall armyworm traps
It is also time to put up your small green IP trap in very young whorl stage plantings to capture FAW moths.  Don't forget that you need to add a Vapona killing strip to the bucket of the trap and bait it with a pheromone lure in the top, for these traps to work.  If you, catch the adult FAW moths, with purple hind wings, then it simply means that you need to start scouting whorl and pre-tassel corn again.  

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

36%*
18%
14%
10%

GT
PW
LW
PT

1 moth

0.5=6-day schedule

Northford 16%*
10%
GT
PT
   
E. Lyme       0=no spray

Berlin

24%*
4%

PT
LW

0 moths

0 = no spray

E. Hartford 12% PT 2 moths 0 = no spray
Ellington 0% LW   0 = no spray
Falls Village 10% LW    

Pepper maggot traps
For those of you who have know pepper maggot problems on your farms, it is now time to set up your pepper maggot traps.  Use a yellow sticky AM trap, baited with a vial of strong ammonia solution, and hang it 20 feet up in a maple tree beside your pepper field. Check the traps weekly for the PM flies which have banded wings and 3 bright yellow lines on their backs.  If you find a PM fly, wait about 7 days and then apply 1 or 2 dimethoate or Orthene applications on an 8-10 day schedule.  If you don't want to climb a tree or a ladder, the easy way to monitor for pepper maggots is to plant cherry pepper plants around your field and check the fruit weekly through July for small dimples and a tiny, round, white scar that indicates the flies are laying eggs in the fruit.  If you plant a row of cherry peppers all the way around your field, instead of just using one plant ever 25 yards or so to monitor the pest, then you can just spray the cherry peppers to stop the fly from infesting the unsprayed portion of the field.   

That's all for this week.  This message will next be updated on Friday afternoon July 10.

Jude Boucher


 Previous Vegetable Pest Messages - 2009

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The information in this material is for educational purposes. The recommendations contained are based on the best available knowledge at the time of printing. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension system does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.All agrochemicals/pesticides listed are registered for suggested uses in accordance with federal and Connecticut state laws and regulations as of the date of printing. If the information does not agree with current labeling, follow the label instructions. The label is the law.Warning! Agrochemicals/pesticides are dangerous. Read and follow all instructions and safety precautions on labels. Carefully handle and store agrochemicals/pesticides in originally labeled containers immediately in a safe manner and place. Contact the Connecticut Department of Environmental Protection for current regulations.The user of this information assumes all risks for personal injury or property damage.Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Kirklyn M. Kerr, Director, Cooperative Extension System, The University of Connecticut, Storrs. The Connecticut Cooperative Extension System offers its programs to persons regardless of race, color, national origin, sex, age or disability and is an equal opportunity employer.

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