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Welcome to the University of Connecticut
Cooperative Extension System's
Vegetable Pest Message.
This message is being recorded on Friday afternoon August 22 by Jude
Boucher.
Upcoming Educational programs
Downy mildew in Connecticut
Corn/pepper pests
Tomato fruit worms
Bacterial canker and powdery mildew on tomatoes
Upcoming Educational
programs
On Thursday, September 18, there will be a day-long session
on using Biological Control in Greenhouses at the Sturbridge
Host Hotel. The session will cost $35 and have 4 pesticide
re-certification credits. Contact Leanne Pundt at 860-626-6240 for
more information.
On Monday, December 1, there will be another opportunity for you to learn more about Zone Tillage and How it Affects Soil Health. This meeting will also be conducted at the Sturbridge Host Hotel. We will have researchers from Cornell and growers who are using zone tillage speak and I will present the results of the soil survey I have been conducting around CT this summer. Cost has not yet been determined. Contact, yours truly, Jude Boucher, for more information at 860 875-3331.
On Thursday, December 4, there will be a day-long conference on Renewable Energy for Farms and Greenhouses. This will also be at the Sturbridge Host Hotel. For more information contact Tina Smith at 413-545-5306.
Finally, on Thursday January 22, we will host the Annual Connecticut Vegetable and Small Fruit Growers Conference here at the Tolland County Extension Office. Contact Jude for more information.
We'll also get you more information on these December and January Meetings in the next issue of Crop Talk.
Downy mildew in
Connecticut
On Wednesday, August 20, we found
downy mildew on cucumber plants in Berlin and East Hartford,
CT. It was also detected the same day on butternut squash in East
Windsor. This must have arrived on Monday=s
storm. Since DM will usually defoliate plants in as little as 7-10
days, all growers should protect their cucumber, melon and winter
squash crops with an effective fungicide at this time. As of yet,
there has been no report of DM on pumpkins, and I scouted quite a
few acres this week, so this crop may not need protection. The
materials that seem to be working the best in neighboring states
include Ranman, Previcur Flex and Tanos. However, we had a strain
that only affected cucumbers and melons last year and many
inexpensive materials such as ProPhyt and maneb were effective.
There is a 5 day-to-harvest restriction on maneb products. Remember
to re-scout your field 4-5 days after treatment to be sure that the
material you applied is working. If not, switch to a different
material and spray again immediately. DM is easy to spot on
cucumbers and melons. It first affects the oldest leaves before
moving to young leaves, and appears as yellow or brown squared-off
lesions about 1/4-1/2 inch in size, that are restricted by the small
leaf veins. Organic growers may be limited to using copper
sulfate. The UMass folks report that both the products Basic Copper
53 and NuCop 50WP are OMRI approved for organic growers. For more
information, check the
New England
Vegetable Management Guide
Corn earworm
The number of CEW moths in
pheromone traps ranged from a low of 1.5 per night in East Lyme to a
high of 33 per night in Shelton. Most folks captured high counts on
Monday, but by Tuesday the traps at these sites had settled down to
moderate levels putting most growers on a 4-day spray schedule on
fresh silking corn this week. Between 1.5 and 9 moths per night were
captured in East Lyme, Northford, Berlin, Glastonbury and Storrs,
and at a second trap across town in Shelton. East Hartford was just
over the 3-day schedule threshold at 13.5 moths per night. The trap
with 33 moths/night in Shelton was checked last Monday, so is
probably at lower levels now.
Here are the CEW thresholds:
| moths per night | recommended spray interval | |
| 0-0.2 | No spray | |
| 0.2-0.5 | 6 day schedule | |
| 0.5-1 | 5 day schedule | |
| 1-13 | 4 day schedule | |
| >13 moths | 3 day schedule |
Fall armyworm
infestations
Traps in Shelton and East Lyme captured 3 and 5
FAW moths for the third week in a row,
while the trap in East Hartford was empty. Both whorl and
pre-tassel stage plantings in Shelton and East Lyme required
treatment this week as pre-tassel stage fields had 14-16% of the
plants infested with FAW caterpillars, and mid-whorl stage plantings
were at 50%. Continue to scout your young corn for this pest and
treat if pretassel stage fields are over 10% infested. This week I
was able to show two growers who did not spray a pre-tassel stage
field on-time, that the caterpillars had moved from the expanded
tassel down to the ear and infested the end, just like corn
earworm. However, unlike corn earworm, it is too late to get the
FAW larvae out with silk sprays. One grower had poor control with
Warrior at pre-tassel and also had a FAW infestation at silk.
Remember that SpinTor, Avaunt and Intrepid will provide consistent
control of this pest and spare natural enemies.
European corn borer
Trap counts for ECB crashed at all
locations this week. Traps in Shelton, Berlin, Northford and East
Hartford all captured less than 3 moths. I think the second
generation corn borer flight is over and it is safe to stop spraying
peppers at this time.
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 & FAW moths / week | CEW moths/N |
| Shelton |
14%* FAW 24%* FAW 50%* FAW |
PT LW MW |
|
33
= 3-day schedule 3 = 4-day |
| Northford |
|
6 = 4-day schedule | ||
| East Lyme II |
16%* FAW 16%* FAW |
PT LW |
5 FAW | 7 = 4-day schedule |
| Berlin | 0% | PT |
|
7 = 4-day schedule |
| Glastonbury | 9 = 4 day schedule | |||
| East Hartford | 0% | PT |
|
13.5 = 3-day schedule |
| Storrs | 8 = 4-day schedule |
Tomato fruit worms
The corn earworm is also known as
the TFW. Normally it only bothers our tomatoes when we are capturing
over 30 moths/night in our corn traps and there are no corn plantings
with fresh silk left around our tomatoes. However, this week we found
TFW in the tomatoes on several farms around the state with fresh silk
close by and relatively low moth numbers in traps. The caterpillar has
a light tan head capsule and light colored stripes down the side of its
body. The higher rates of selective materials such as SpinTor, Avaunt,
Intrepid, Proclaim or a Bt product will control TFW on tomatoes, without
getting you into problems with aphids.
Bacterial canker and
powdery mildew on tomatoes
Bacterial canker appears on
lowest leaves first as dark lesions along the margins of the leaves.
Several farms have tomatoes with canker at this time due to all the wet
weather. This disease is usually seed borne but can survive between
years on stakes, old crop residue and reused plastics. It can be tough
to rid a farm of this disease once you have it, even when taking the
proper sanitary precautions, such as dunking all stakes in a chlorine
bath, switching tomato varieties and sanitizing greenhouse surfaces. At
this point in the season, growers with canker on their tomatoes should
add copper to their early blight or leaf spot sprays.
I found the first case of powdery mildew on tomatoes this year on the All-America Selection Trial garden up at the research farm in Storrs this week. Yes, researcher=s plants get diseases too! Materials that help manage powdery mildew on tomatoes include Nova, Cabrio, Rally and sulfur products like Microthiol Disperse. These products can all be used on the day of harvest.
That=s all for this week. This message will next be updated in on Friday afternoon August 29.
Jude Boucher
Previous Vegetable Pest Messages - 2008
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