Rhode Island Apple IPM
2003 - Current Pest Report - Visual
Tree Stage for McIntosh trees:
4/14/03- green tip
4/21/03 - half inch green
4/28/03 - tight cluster
5/5/03 - full pink
5/9/03 - bloom
5/18/03 - petal fall
Starting August 12, the phone message will
be available between 5pm & 8am!
Phone message available 24 hours a day: 949-1456. Updated
8/7/03 - Apple maggot flies are still
being caught on red sticky spheres. Apply an insecticide every 14 days
until around August 20th.
-White apple leafhopper nymphs are beginning to hatch. It may be necessary
for some growers to control them. The biggest problem with leafhoppers
is they are a nuisance to pickers. Leafhoppers also get excrement on the
fruit that looks like small black/brown spots called tar spots. The spots
are larger than flyspeck spots.
- Speaking of flyspeck. I saw my first apple with flyspeck today, and
my first apple with sooty blotch on 8/4/03. This could be a bad year for
summer diseases! Keep protected with a fungicide.
7/29/03 - I finally got the apple maggot chart made for 2003. Here
it is. I'm only catching apple maggot flies where there are unsprayed
trees nearby. In most orchards I'm catching very few apple maggot flies.
We should be at peak apple maggot fly time now. If it has been 2 weeks
since your last insecticide application, apply one soon.
-Rose leafhoppers are starting to become adults now. There are also nymphs
present. It may still be useful to spray an insecticide against rose leafhoppers.
There will be another generation of rose leafhoppers before they leave
apples and return to roses for the winter. Leafhoppers can be controlled
with Thiodan, Provado, or Sevin.
- White apple leafhopper second generation nymphs should begin to hatch
around August 10th.
- I'm finding more orchards with mite problems. Some have European red
mites and others have two spotted spider mites. The red mites cause apple
leaves to turn bronze colored, where as the two spotted mites cause the
leaves to turn pale, or off color. Two spotted mite damage looks like
the tree is lacking nitrogen. At this time of year, Pyramite works best
to control red mites. Two spotted mites can best be controlled with Savey
or Vendex plus Tactic.
- I haven't seen any fly speck or sooty blotch damage yet, but I think
I will soon. Be sure to keep to your summer fungicide schedule.
7/22/03 - Until my final orchard yesterday, I was finding not many
apple maggot flies out yet. Out of 20 traps I caught only 5 apple
maggot flies. Then at my final orchard I caught 9 apple maggot flies on
only 5 traps. At this same orchard I set up 7 traps in an unsprayed Red
Astrachan tree. On these 7 traps I caught a total of 577 apple maggot
flies!!!! That's an average of 82 per trap. Now these flies were caught
in an unsprayed setting, so it doesn't really compare to what is happening
in a sprayed orchard. Still, many orchards have abandoned trees very close
by, so the chances are that apple maggot flies will move into your orchard.
Red Astrachans are especially attractive to apple maggot flies. The fruit
is nearly ripe, and the maggot flies just love them. If it has been 2
weeks since your last insecticide application, I recommend you apply another
-Rose leafhopper nymphs are much easier to see this week since
most of them are larger. Now is a very good time to scout your leaves
for the small, white nymphs. Look on the underside of many leaves. I like
to turn a whole branch over and look at many leaves in one location. The
spray threshold is 25 nymphs per 100 leaves. Thiodan, Sevin or low rates
of Provado will control leafhoppers well at this time. I see rose leafhoppers
in only a few orchards. They tend to be in orchards with a lot of wild
roses on the edges.
I want to start planning for leaf tissue analysis samples. If you
want me to take a sample in your orchard, please call or email me. The
cost is about $20 per sample. In most situations, one sample is plenty.
874-2750 or firstname.lastname@example.org.
7/15/03 - I checked 21 apple maggot fly traps this past week and
only caught 4 apple maggot flies. So they are around, but not in great
numbers. The spray threshold is an average of 1-2 flies per trap. I expect
most growers will apply an insecticide this week against apple maggot
flies. Remember half or even quarter rates of insecticide will control
apple maggot flies.
7/8/03 - I haven't checked many apple maggot fly traps, but I have
not caught any. Hudson Valley, NY reported catching their first apple
maggot fly last week. We are usually pretty similar to Hudson Valley.
If you don't have red sticky spheres to check for apple maggot fly, you
may want to apply an insecticide soon. Early maturing varieties should
be protected with an insecticide soon. Use half rates of Imidan or Guthion.
If you are using red sticky traps you can wait until you have an average
of 1-2 apple maggot flies per trap.
- Green apple aphid numbers have been very low this season. In all situations
I've seen, predators have been controlling the aphids and no insecticide
- Leafminer adults from the first generation have mostly emerged from
the mines by now. If you need to treat for leafminer, now is a good time
to apply the first spray of Provado. Since the second generation is much
more spread out than the first generation, you will probably need a second
application of Provado 10-14 days after the first application.
7/1/03 - Plum curculio is definitely over. I know that UMASS
said they were still getting plum curculio migration, but I have not seen
any new plum curculio stings after looking in many orchards. I do see
fresh plum curculio stings in an unsprayed orchard I'm checking. This
is much different because plum curculio will keep laying eggs until the
end of July if they are not killed. So as long as you sprayed an insecticide
on June 12 or later, you should be all set with respect to plum curculio.
It wouldn't hurt to continue checking fruit for new damage. That way you
will be confident that your fruit is safe.
-Hopefully everyone has apple scab under control by now. It seems
as though most growers have been able to keep it off the fruit. You should
be on your summer schedule now of Captan every 2 weeks or Captan plus
Topsin M every 3 weeks. If you are still experiencing too much scab, you
could still apply Sovran or Flint to help protect the fruit. You are allowed
4 applications a year.
- All the leafminers mines from the first generation are visible
now from the upper leaf surface. It is a good time to check your orchard
and see if a treatment is needed against the second generation. The threshold
is 13 mines per 100 fruit cluster leaves. You need to count only fruit
cluster leaves because these were the leaves available when the leafminer
moths were laying eggs way back in April and May. If you reach this threshold,
perhaps you should treat with Provado in about a week and again about
10 days later. The second generation is more spread out than the first
generation, so two applications of Provado are probably necessary to provide
- Green apple aphids are present and so are plenty of aphid predators.
I don't think anyone should need to spray for aphids.
- San Jose scale crawlers may have started to crawl by now. I will
check a site this afternoon and let you know what I find. The chemical
Esteem should work well against San Jose crawlers. This should be used
only if you have a known problem. The red spots from San Jose scale should
be showing up on apples in a couple of weeks. Check the picture in your
pest management guide if you aren't sure what they look like.
6/24/03 - If you listened to yesterday's phone message, then you
heard me say that plum curculio season may not be over. I'm happy to report
that I mis-read a chart and that we should be beyond plum curculio season.
I still advise checking border row trees for fresh injury. Fresh injury
doesn't have any tan, corky, callus tissue associated with it. The wounds
are small mushroom shaped slits and tend to be a bit orangey around the
edges of the cut. If you find fresh injury you may want to make another
- White apple leafhoppers are starting to fly now. There is probably still
time to spray against this pest. Use Thiodan, Provado, or Sevin. The damage
is on the older leaves and shows up as white stippling damage on the top
side of leaves. If you turn a damaged leaf over, you will probably still
see some white apple leafhopper nymphs. The adult white apple leafhopper
will lay eggs soon, but these eggs won't hatch until mid-late August.
It is better to control them now rather than waiting to so close to harvest.
- If you are finding adult leafhoppers, but don't see nymphs or damage,
you probably have rose leafhoppers migrating into your orchard. This pest
starts out the year on rose and then migrates to apples about this time
of year. I don't think I have seen any this year yet. The rose leafhopper
remains on apples for the rest of the summer, having 2 generations before
returning to rose to lay eggs to over winter. If you have rose leafhopper
adults now, you should wait a couple of weeks and treat the next generation
nymphs after they hatch. Again, Thiodan, Provado, or Sevin will control
- If you trees are free of apple scab you can switch to a summer schedule
of Captan every 2 weeks or Captan plus Topsin M every 3 weeks. If you
can find much scab and it turns rainy again, be sure to be protected with
6/17/03 - If you apply an insecticide this week (sometime after
6/13) you should be protected against plum curculio for the rest of the
season. If your last spray was before 6/13, you should probably re-apply
an insecticide to make sure you control PC through the entire time when
they migrate into the orchard.
-In addition to the insecticide, you should apply a full rate of a fungicide,
whether or not you have any scab in the orchard.
6/13/03 - Not much new to report. Once it stops raining I expect
everyone to re-apply insecticide and fungicide. Scab as well as other
diseases are active in most orchards. Plum curculio are expected to continue
migrating into orchards and your trees need to be protected. Hopefully
it will dry out soon!
6/10/03 - The predicted end of plum curculio migration is 6/21
in the Greenville area, and 6/24 along the coast. You need to have insecticide
coverage until the end of plum curculio migration. That means if your
insecticide application lasts 2 weeks (if it is not all washed off by
rain) then your last plum curculio insecticide needs to be applied on
6/7 or later (or 6/10 or later for the coast). The end of plum curculio
season is predicted by predicting the number of expected degree days and
this comes from predicting the weather. So, if the weather returns to
unseasonably cool conditions, this will delay the end of plum curculio
season. This means if it gets too cool, plum curculio will continue to
migrate into orchards for a longer period of time. I will continue to
update when we think the end of plum curculio season will be.
- Be sure to attend the twilight meeting at
in Westport, MA on Thursday,
June 12 at 4:30.
6/4/03 - Scab -We are past primary
scab season, but I don't think anyone should switch to a summer spray
schedule yet. I have been seeing some apple scab at several orchards and
all this wet weather is making it very easy for secondary lesions to form.
Continue to keep protected with a fungicide for at least another week.
Hopefully by then everyone can switch to summer schedule of using reduced
rates of Captan every 2 weeks or Captan plus Topsin M every 3 weeks. I
really like the plan of: use Captan, wait 2 weeks, then use Captan plus
Topsin M, wait 3 weeks and then spray just Captan again - alternating
- Plum curculio- I was surprised how many plum curculio scars I
saw on unsprayed trees yesterday. The scars did not seem very fresh. They
were probably made at least 5 days ago. I did find some scars in sprayed
trees as well. I think the scars were made after the 2 inches of rain
on 5/26 and before the grower sprayed again with insecticide. This cool
weather will probably extend the plum curculio season, meaning you'll
probably need to make more applications of insecticides than usual to
get adequate control. Use full rates of Imidan, Guthion or Avaunt. If
your orchard is large enough to warrant a border row spray, you could
now switch to that approach. Spray the outside two rows all around the
- Leafminers - As I said 6/2 - we are nearing the end of the time
to be able to treat for first generation leafminers. I think only AgriMek
will be effective now.
6/2/03 - At URI's East Farm orchard today
I found a leafminer mine which had advanced to the tissue feeding stage.
This is when the mine is visible from the upper leaf surface as a pucker
in the leaf covered with small, white spots. If you are planning to treat
for first generation mines, now is the time to apply AgriMek. It is actually
bit late to use Provado now. If mines are present, they are mostly visible
from the undersides of fruit cluster leaves as small, silvery patches.
We use a spray threshold of 13 mines per 100 fruit cluster leaves.
- Also at East Farm today I found summer eggs of European red mites on
the underside of Red Delicious leaves. These are the first summer eggs
I've seen. Miticide choices at this time include AgriMek, Apollo, or Savey.
5/30/03 - Yes, I find scab, but so far it
doesn't look too bad. Another week from now should give us a much better
picture of how bad the scab will be. It sounds like we are in for more
wet weather this weekend. Ugh.
- I think most growers applied an insecticide against plum curculio this
past week. I actually found a scar on an apple yesterday. You know they
are ready to attack. If the cool weather persists, it will drag out how
long we need to worry about plum curculio. If you applied a full orchard
insecticide this week, you can probably switch to spraying just the 2
outside border rows for the rest of plum curculio season. Many orchards
in Rhode Island are small and so spraying the 2 outside rows all around
the orchard means you cover nearly the whole orchard.
- I saw many leafminer mines in one orchard today. Look now on the underside
of leaves for the small, silvery mines. If you find 13 mines per 100 fruit
cluster leaves, consider applying Provado or AgriMek.
- European red mites are nymphs and adults now. Soon they will be laying
the first generation summer eggs. Apollo, Savey, or AgriMek will still
control red mites if applied soon.
5/28/03 - These
off and on showers are dreadful for spreading apple scab! I've copied
some of NY's Scaffold newsletter about using Captan during periods of
extended cloudy weather:
CAUTION WITH CAPTAN (Dave Rosenberger, Plant Pathology,
Highland) Fruit growers should be very cautious about using captan during
the next 7-10 days because weather conditions over much of the state have
left apples, peaches, plums, and cherries unusually susceptible to captan
injury. Captan is an effective, broad-spectrum fungicide that is labeled
for many fruit crops. However, when absorbed into plant tissue, captan
causes phytotoxicity that appears as leaf spotting, shot-holing, and leaf
yellowing. When combined with other products that enhance uptake into
leaves, captan applied at this time of year can cause complete defoliation
of peach and nectarine trees. To be safe, growers should avoid applying
captan until trees have had several days of sunny, dry weather.
The risk of captan injury is greatest when the annual spring growth flush
of fruit trees coincides with an extended period of cloudy, cool, damp
weather. The growth flush on fruit trees begins when terminal shoots start
growing during or shortly after bloom. The cuticle (the waxy layer on
the leaf and fruit surfaces) develops in response to heat and water stress.
During cloudy and damp weather, there is little danger from heat or water
loss and trees therefore produce only a thin cuticle to protect the newly
formed leaves and enlarging fruitlets.
The same waxy cuticle that serves to prevent water loss also prevents
captan from entering and injuring living cells beneath the plant cuticle.
Some varieties of plums and cherries almost always develop a leaf spot
or shot-hole after captan is applied because, even under the best conditions,
some captan enters and kills leaf cells of these varieties. For most other
fruit crops, captan causes little or no injury except during unusual seasons
when weather conditions inhibit cuticle development.
Even when plant tissue has only a thin cuticle, captan by itself will
rarely cause phytotoxicity (except to those plum and cherry varieties
that are especially susceptible to captan injury). Problems often arise,
however, when captan is mixed with other agrichemical products. Spray
adjuvants that enhance the transport of captan through the plant cuticle
can greatly increase the phytotoxicity of captan, especially when the
plant cuticle is thin at the time spray is applied. Adjuvants that enhance
uptake of captan include spray oils, some spreader-stickers, and other
petroleum-based carriers commonly found in products that are formulated
as liquids or emulsifiable concentrates.
scab symptoms are appearing in orchards, the best option for stopping
further spread of apple scab is to apply a combination of an SI fungicide
along with the maximum label rate of captan. To avoid phytotoxicity problems,
however, growers may need to use an SI-plus-mancozeb combination for the
next week to avoid the potential phytotoxicity that could result if captan
is applied at this time. This is especially true if Sevin XLR Plus will
be applied for thinning or if spray oil will be applied with a miticide
during the next week. Those who opt to apply captan despite the risks
are advised not to use spray adjuvants that might enhance trans-cuticular
movement of captan.
Scaffolds always says something
interesting. The newsletter is published Mondays and you can have them
email it to you or simply go onto the Scaffolds
This wet weather is giving cedar apple rust a good opportunity to cause
problems. The orange galls on eastern red cedars release spores during
rainy periods from April up until about mid-June. These spores land on
apples and cause the characteristic orange lesions. Golden Delicious,
Mutsu and Cortlands are particularly susceptible to cedar apple rust.
Effective fungicides include Rubigan, Nova, Procure, Manzate, Polyram,
and Dithane. Rusts can not be managed with post-infection sprays.
5/27/03 - I'll write more tomorrow. The short
message is spray a fungicide soon. I'm finding at least a little scab
in most orchards. Even though we may be at the end of primary scab season,
you'll need to keep your trees protected for at least the next two weeks.
It takes about 2 weeks for lesions to start appearing once an infection
period has occurred. With all the rain we received on Monday, 5/26, there
is probably very little fungicide still on the foliage and fruit.
- If you have applied a post bloom insecticide, you can probably put off
spraying another insecticide until warmer temperatures are forcasted (70's).
If you have not applied a post bloom insecticide it is probably best to
apply one soon.
5/23/03 - Ugh! This horrible weather continues.
Spray a fungicide as soon as you can! If you see much scab in your orchard,
spray Sovran or Flint.
5/22/03 - What a big ugly infection period
we are experiencing. It started yesterday mid-day and is continuing right
through tonight and ending???????
- It makes a lot of sense to spray fungicides now, but leave out the insecticide
until the weather warms up. Plum curculio and other insects are not active
in this weather. Remember, plum curculio won't attack the fruit until
the fruit measure 9mm in diameter.
5/18/03 - I think we had one large
infection period last week from 5/12-5/14.
- The next wetting period (rain event) could release the last of the primary
scab spores for the season. This is not the case if your orchard is near
the coast and have not reached petal fall. Orchards in cooler regions
will reach the end of primary scab season about one week after petal fall.
- I started seeing a lot of apple scab lesions on 5/15. Check your trees
now. If you find more than a little bit of scab, spray Sovran or Flint
- Ron Prokopy from UMASS says that plum curculio won't attack apples until
they are 9mm. That information in combination with the cool forcast probably
means you can delay your petal fall insecticide for several days.
5/12/03 - Today's weather is probably causing another
apple scab infection period. Even though we
did not get much rain, there are puddles on some leaves that have been
wet all day. Spores would have been released this morning after last night's
- Every few days we have had an infection period. Many growers may be
in trouble with scab! I did see two tiny lesions on an unsprayed tree
today. They were on the oldest cluster leaves. The lesions are probably
from our first infection period on April 22. It has taken this long for
the lesions to appear. If you do find lesions between now
and petal fall, you may want to apply Sovran or Flint to try to burn out
- This cold weather has perhaps discouraged leafminers from laying many
eggs. I only see large number of eggs in one orchard. Laefminers can be
controlled at petal fall with Provado or AgriMek at first cover. AgriMek
has the estra bonus of controlling mites. Remember AgriMek must be mixed
with oil or an adjuvant.
- I did see a few newly hatched white apple leafhopper nymphs today. If
you have had trouble with white apple leafhopper in the past you can spray
at petal fall withThiodan or Provado. Provado will probably be effective
at very low rates (like 1 oz. per 100 gal).
- I started catching European apple sawflies on white
sticky traps. Sawflies can easily be controlled at petal fall with Imidan
5/8/03 - We are sure in a wet weather pattern. We've had two
infection periods, one on May 6th and another
one today, May 8. Apple scab is at its peak now - so be well prepared.
- I spent the day on Aquidneck Island and in Little Compton. Apple trees
there are about 7 days behind the Greenville area. Most trees are between
tight cluster and early pink. I did find hatched European red mite eggs
as well as Z. mali predators. This makes me think that European red mites
started hatching in the Greenville area around May 1st.
- I found many leafminer eggs at one orchard (about 5 eggs per cluster).
As I stated 5/5, leafminer eggs are laid on the underside of leaves and
look like small clearish blobs. You have to use a magnifier to see them.
Finding 13 eggs on 100 cluster leaves could be used as a threshold. (That's
100 cluster leaves, not 100 clusters). I did see one hatched leafminer
egg today. Chemical control options include Provado at petal fall, AgriMek
at first cover, or Assail (though I don't know the timing - but I will
5/5/03 - Tarnished
plant bugs. I caught many tarnished plant bugs on traps today. I found
18 on one trap in an orchard of dwarf trees, though many other traps have
none. In orchards with many plant bugs, Imidan applied at pink will control
- Leafminers. Leafminer trap captures have
exceeded the pink threshold in some orchards. I started seeing leafminer
eggs today. They can be found on the underside of leaves and look like
small, pale blobs. Leafminer mines can be controlled after petal fall.
- European red mite egg hatch is well under way. I also found many Z.
mali mite predators in some orchards. In one orchard I also found many
pest yellow mites, which I'll watch closely.
5/4/03 - For those of you that had a shower
on Tuesday afternoon, April 29, and it stayed wet through the night -
it was the third infection period. We had a fourth infection period on
Thursday, May 1st. I'll have more to report on Monday, May 5th.
4/28/03 - We had our second apple
scab infection period on April 26.
- A lot of growers were out spraying this morning so I didn't check many
insect traps today. We are above the threshold of 8
leafminers per trap at URI's East Farm orchard.
- It will still be at least another week before apple scab lesions start
to appear on leaves from the 4/22 infection period.
- Now is the best time to apply dormant oil for European red mites. Reduce
oil to 1.5 gal/100 gal water.
- If you were not well protected from either apple scab infection period,
consider applying Rubigan or Nova at the full label rate.
4/22/03 - First apple
scab infection period of the season. Caught a few more leafminer
adults on red traps at URI's East Farm (10 on 3 traps).
4/21/03 - We haven't had an apple scab infection period
yet, but that could quickly change tomorrow (Tuesday). Rain is expected
with temperatures in the high 40's. At 48 degrees only 12 hours of wet
leaves are needed to cause an infection. Most growers have applied a protectant
fungicide. For those of you that have not, a fungicide with kick-back
action will be required as soon as it is possible. In Massachusetts and
New York, apple scab spores are ahead of schedule. More apple scab spores
are probably ready to be released now, than would normally be ready at
half inch green.
- Caught our first leafminer adult on a red sticky trap. Only caught one
adult on 30 traps checked. If you have traps,
set them out now or it will be too late to use them accurately.
- Caught several tarnished plant bugs today in white sticky traps. One
orchard had an average of 3 per trap. The threshold by tight cluster is
5 per trap.
4/16/03 - trees have advanced rapidly during these
two days in the 70's. Since green tissue is available, the threat of apple
scab is real! Apply protectant fungicides soon.
- Caught 2 tarnished plant bugs on one white sticky trap in one orchard.
I've only checked traps in 3 orchards so far. Tarnished plant bugs are
not a problem at this time. For many years, we have not had a problem
with tarnished plant bugs.
- No leafminer caught on red sticky traps yet.
-I plan to start the recorded pest message on April 21st (949-1456)
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