Rhode Island Apple IPM
2001 - Current Pest Report - Visual
Tree Stage for McIntosh trees:
4/2/01 - Silver tip
4/9/01 - buds breaking
4/18/01 - 1/4 inch green
4/20/01 - 1/2 inch green
4/23/01 - tight cluster
5/1/01 - pink
5/3/01 - bloom
5/12/01 - petal fall
8/9/01 - I haven't done much scouting this week because
I am spending the week collecting leaves and soil for leaf tissue analysis.
I did check the one Early Williams tree where I set up 9 apple maggot
fly traps. Over seven days I caught a total of 58 apple maggot flies.
That averages to more than 6 AMF per trap. If it has been more than 14
days since you applied an insecticide, you may want to reapply now.
- I found quite a few two spotted spider mites in one orchard. Two spotted
mites are usually controlled well with an application of Vendex plus a
chemical such as Tactic or Silwet. Vendex and oil work well together too,
but usually growers resist using oil because they want to use Captan.
8/3/01 - Even more apple maggot
flies caught! Many orchards are above the threshold of 1-2 AMF per
trap. Remember I set up 9 traps in one Early Williams tree to try and
trap out apple maggot flies in that tree? On July 16 I caught 76 AMF in
5 days. I checked the traps again on 8/2 (after 16 days) and caught 130
AMF. The tree had even been sprayed with Imidan on July 19. Now is
not the time to stretch too far
between insecticide applications. Keep the interval to about 14 days.
- Rose leafhopper are still numerous in some orchards. Orchards sprayed
with Provado for leafhoppers are still well controlled. Orchards sprayed
with Sevin or Thiodan for leafhoppers may need to be re-treated. Check
now on the underside of leaves for the small, white nymphs.
- I found a few adult leafminers on 8/2. These are probably new adults
from the second generation. Soon they will begin to lay eggs for the third
generation. We do not recommend spraying for the third generation leafminers
because the generation is too spread out and can't be adequately controlled.
- The yellow spider mites I've been refering to this summer seem to be
well controlled now by mite predators. There may still be some instances
where the yellow spider mites are causing problems. The mites are on the
underside of leaves and tend to be located near the mid-vein. The mites
cause a general yellowing of the foliage and may cause some brown patches
to appear, primarily on the lower leaf surface. Yellow spider mites appear
to be easy to control with miticides.
- European red mites are causing bronzing in some orchards. In many cases,
mite predators are also building up and will hopefully control the red
mites. If there aren't enough predator mites (at least one predator per
leaf) the pest mites will probably need an application of miticide.
7/31/01 - I caught more apple
maggot flies today. I think the rain from last week did bring out
more flies. I realize that northern RI received much less rain than southern
RI, but there were more AMF caught in some orchards.
- I saw one apple with fly speck today. Spray with a fungicide if it has
been 2 weeks since spraying Captan or 3 weeks since spraying Captan plus
- Still scout for European red mites, two spotted mites, and yellow mites.
The spray threshold for mites is 5 mites per leaf or 75% of leaves with
mites. I am still finding many mite predators. I especially find the bright
yellow Z. mali mites.
7/23/01 - Apple maggot fly traps captures seem to be
dropping off. I expect we'll see another flush of apple maggot fly activity
after we get a soaking rain. Also, many growers have applied an insecticide.
Applying insecticides reduces apple maggot fly activity! When you look
at the apple maggot fly capture chart, but sure
to notice when traps were checked at a particular orchard. For instance,
at East Farm I caught 17 flies on 3 traps today, but I hadn't checked
these traps for 3 weeks.
- Rose leafhoppers are still present and you can still spray for them
- It is definitely too late to spray for second generation leafminer.
I expect to see second generation adults emerging in a week or so.
- Yellow mites continue to be found in many orchards. Luckily there are
plenty of predators (Z. mali) in many locations. In most situations
the predators are taking care of the yellow mites.
- Give me a call (874-2750) or email (firstname.lastname@example.org) about leaf tissue analysis
samples (see 7/20/01 entry).
7/20/01 - I visited the orchard where the grower was
planning on applying AgriMek against yellow spider mites, Eotetranychus
carpini borealis. Well, he had not applied the AgriMek yet, he was
going to apply it tonight. I thought I'd check out the trees and when
I did I found most of the yellow spider mites had been killed by the predator
mite, Zetzellia mali. I had seen some predator mites there last
week, but not many. I think the predators were primarily eggs or small
nymphs last week, and difficult to see. I was pleased to tell the grower
not to bother with the AgriMek. Rhode Island apple growers, if you want
me to check on predator numbers in your orchard next week email me at
- In June, Lisa Tewksbury and I took a Plum Pox sample from many RI peach
orchards. All samples from Rhode Island were negative for the Plum Pox
- I'm trying to figure out how many leaf tissue analysis samples I'm going
to take this summer. If you'd like me to come to your orchard and take
a sample to send to University of Maine, send me an email. I'm planning
on taking samples in early August. I believe the cost is $25 per sample.
This is an excellent way to see what nutrients your trees need.
7/19/01 - Today I was mostly in orchards without apple
maggot traps. I did see one live female apple maggot fly on a Lodi or
Yellow Transparent apple (I forget which one). If you haven't sprayed
yet for apple maggots, now is probably a good time to do so. Half rates
of Guthion or Imidan work well. Sevin will also control apple maggot fly
but the control doesn't last very long and Sevin is more harmful to mite
predators (than Imidan and Guthion).
- Many orchards need to spray trees for rose leafhoppers. Look now on
the underside of leaves for the small, white nymphs. Provado, Thiodan,
or Sevin controls leafhoppers very well. Imidan and Guthion do not control
- European red mites and yellow mites have been building in some orchards.
You may remember I mentioned before that one grower with a high number
of yellow mites used Apollo. The Apollo controlled the yellow mites very
well. Another grower used Agrimek against the yellow mites. I have not
been back to this orchard to check on the results (maybe I'll get there
tomorrow). Vendex also controls the yellow mites well.
7/16/01 - On 7/11, I set up 9 apple maggot fly traps
in one very large Early William tree to try and trap out the apple maggot
flies that were attracted to this early maturing tree. Today I checked
the traps and found 76 apple maggot flies on these 9 traps! I also had
4 other traps set up throughout the orchard. On these 4 traps I caught
a total of 8 amf. Apple variety really makes a difference! Each orchard
is different too. In some orchards we rarely catch any apple
- Rose leafhoppers can be found now as adults, young nymphs and old nymphs.
This makes leafhopper control challenging. I still think now is a good
time to control leafhoppers.
7/13/01 - More apple maggot flies
were caught this week. I'm catching them primarily on traps set up in
early maturing varieties, but also on traps set up in Cortlands and Red
Delicious. Early maturing varieties should probably sprayed now with an
insecticide, but varieties that mature in Septmeber or later can probably
wait a week before an insecticide is needed against apple maggot fly.
- Rose leafhoppers are ready to be controlled now. Check the underside
of leaves, and if you find 25 nymphs per 100 leaves consider applying
Provado, Thiodan or Sevin. I've heard Cornell Cooperative Extension is
reporting that leafhoppers can be controlled with 1/2 ounce of Provado
per 100 gallons of water.
- Second generation leafminer larvae are beginning to advance to the tissue
feeding stage now. It is now or never if you wish to control second generation
leafminer. Look on the underside of youngest leaves for the small mines.
A method to decide about treating for leafminers is to examine the oldest
leaves. If you find 13 old mines out of 100 old leaves, consider treating
with Provado for this second generation. I repeat, it is nearly too late
to adequately control the second generation.
- European red mites are bronzing some foliage. If you see bronzing, look
for motile mites and treat with Pyramite if needed. I am also finding
many yellow spider mites in some orchards. These mites look very similar
to two spotted spider mites, but don't have the spots. The yellow spider
mites are typically found on the underside of leaves near the mid-vein.
Yellow mites cause a yellowing or light brown patches to form on the underside
of leaves. I've seen them do considerable damage in some orchards. I know
they can be controlled with Vendex at 1 lb/100 gal plus Silwet or Tactic
at 6 ounces per 100 gal finished spray mix. I do not know how well other
miticide treatments work. One grower is trying Apollo and another is trying
AgriMek. I'll let you know how well these treatments work.
- Now is a good time to spray tree trunks with Lorsban to control dogwood
borers. Three to four year old trees are extremely susceptible to borers.
Lorsban, during this time of year, can only be applied to the tree trunks.
Also, be sure to keep weeds down around tree trunks.
7/6/01 - Many apple maggot flies
captured at URI's ochard, but we have a built in population from last
year because we didn't spray a large section of the orchard. These flies
did not need to migrate into the orchard - they were already there! We
will spray Imidan early next week to control apple maggot flies. In commercial
orchards, apple maggot flies need to migrate into an orchard since the
flies were killed the year before by insecticides.
- I saw many more rose leafhopper nymphs today. I think next week will
be a good time to control them with Thiodan or half rates of Provado.
-I found more potato leafhoppers on young as well as mature trees today.
Remember, you only need to control potato leafhoppers on young trees,
where you want maximum tree growth.
- Green apple aphids have been totally controlled by aphid predators (almost).
Ladybug larvae are present in huge numbers. Ladybug larvae (Harmonia
axyridis) look like black and red alligators (sort of).
7/2/01 - Rose leafhopper nymphs are beginning to hatch.
They are tiny white insects on the underside of leaves. It's too early
to spray for them now because not many have hatched yet. Proper timing
to spray against rose leafhoppers will probably be in about a week. Insecticide
choices include Thiodan, Provado (one ounce per 100), or Sevin. Out of
these three insecticides, Sevin will be the most harmful to mite predators.
- Leafminer second generation mines are becoming visible now. If you find
many mines from the first generation (more than 13 mines per 100 fruit
cluster leaves) consider applying Provado against the second generation.
Proper timing for this application is probably in about a week. To control
leafminers, Provado must be applied at the 2 ounce per 100 gallon rate
and may need to be applied a second time, about 10 days after the first.
-I found many potato leafhoppers on young trees at one orchard. Potato
leafhoppers are harmful to young trees because they stunt tree growth.
Potato leafhoppers are not a problem on mature trees. Check on the under
side of the terminal leaves for the small, pale-green leafhoppers. If
your young trees have many potato leafhoppers, apply an insecticide.
6/28/01 - San Jose scale are visible on fruit now as
red spots with a scale insect in the middle of each spot. I also found
many crawlers still crawling around. The best time to treat for San Jose
scale is when the crawlers first emerge in mid June and then again about
10 days later. If you are finding damage on the fruit now it is probably
somewhat beneficial to spray now since the crawlers are still around;
though it should be applied very soon. San Jose scale should be treated
only if you know you have a problem. Guthion, Imidan, and Provado are
effective against crawlers.
- Plenty of green apple aphids in all orchards, but plenty of predators
too. Only spray for aphids if you find sticky aphid honeydew building
up on the fruit. Thiodan or Provado at low rates (half rates or lower)
control aphids well.
- Leafminers are still emerging as adult moths. I have yet to see any
mines from the second generation, though I expect to find them soon. Now
is not the time to spray for leafminers. Probably late next week will
be a good time to spray for leafminers (using Provado).
-Leafhoppers (white apple and rose) are primarily adults now. I haven't
seen any nymphs of the rose leafhopper yet; I expect to start seeing them
- I have caught 3 apple maggot flies on a total
of 9 traps checked. The threshold for apple maggot fly is 1-2 AMF per
trap. Insecticide should not be applied at this time to control apple
maggot fly. Apple varieties that ripen in September or later probably
do not need to be sprayed with an insecticide until late July.
- To control summer diseases on fruit apply Captan every two weeks or
Captan plus Topsin M every three weeks. Flint and Sovran also control
summer diseases well. These materials can be used only four times a season.
Flint has a 14 day preharvest interval and Sovran has a 30 day preharvest
6/25/01 - Not much going on in the orchards these days.
The only problem I see is more leafhoppers than usual. In most instances
the leafhoppers are adults and shouldn't be sprayed now. I did see one
orchard where many of the leafhoppers are still nymphs so a spray of Thiodan
or Provado will probably be beneficial at this time.
- I do continue to see plenty of green apple aphids - but I see lots of
6/22/01 - I found a little bit of scab in a few orchards
today. Scout now for the velvety, olive green lesions. If you can't see
lesions by now, your trees are probably scab-free and should remain so
for the rest of the season. If you find more than a small amount of scab,
consider applying Sovran or Flint to reduce apple scab spore production.
- Leafminer second generation adults have been emerging over the past
week. The second generation mines will be developing soon. If you find
more than 13 mines per 100 fruit cluster leaves from the first generation,
consider applying Provado in about 1 week or so. The Provado should be
applied when just a few of the second generation mines have advanced to
the tissue feeding stage (when mines are visible from the upper leaf surface.)
More than 90% of the mines should still be in the sap feeding stage. For
adequate control, you may need to apply Provado a second time, about 10
days after the first application.
- I see leafhoppers flying around in most orchards. These could be white
apple leafhoppers or rose leafhoppers. If they are rose leafhoppers, next
generation nymphs should be appearing on the underside of leaves in about
a week or so. If they are white apple leafhoppers, next generation nymphs
won't appear until August. Whichever species they are, you should not
spray for leafhoppers at this time.
- I have not seen many potato leafhoppers yet this year. Be sure to check
young trees for potato leafhoppers on the underside of leaves at the tips
of branches. Potato leafhoppers can stop shoots growing. This is all right
on mature trees, but not on young trees where you want as much growth
as possible. If you find many potato leafhoppers on young trees, spray
them with Imidan or Guthion. If that doesn't control them use Provado,
Thiodan or Sevin.
- Green aphids can be found in all orchards now. I am also finding aphid
predators in all orchards. Don't spray an insecticide for aphids, the
predators will control them if you let them.
- European red mite threshold for June is 60% of leaves with motile mites.
- This year's June drop seems larger than usual. I'm chalking this up
to the freeze on May 7 stressing the trees.
6/18/01 - Wow, another big rain storm. I heard some
areas received 6 inches of rain yesterday!
- I have not found any fresh plum curculio scars. Continue to check borders,
but I really believe plum curculio are finished for the year.
- Until apple maggot fly, the only insects to be concerned with are rose
leafhoppers, potato leafhoppers, and leafminers. For rose leafhoppers,
don't spray anything now. Wait for the next generation nymphs to appear
in a couple of weeks.
- For potato leafhoppers, watch your young trees for leafhoppers on the
growing tips. I did see a couple of potato leafhoppers today, but not
many. Potato leafhoppers are generally not a problem on mature trees.
-Leafminers have begun to emerge as the next generation adult moths. Soon
these moths will mate and lay eggs to begin the next generation mines.
If you find more than 13 mines per 100 fruit cluster leaves, you may want
to spray the next generation mines with Provado. The timing for this is
probably in about 10-14 days. A second application of Provado (about 14
days after the first spray) is probably necessary to provide good leafminer
- I had hoped to find more leafminers killed by parasites. In the two
orchards I checked, about 30% of mines were parasitized. This is the percent
parasitized we usually find in the first generation mines.
- Continue checking for scab lesions until the end of the week. If you
don't find lesions by Friday you can certify yourself scab-free! If you
do find more than just a few lesions, consider applying Sovran or Flint
to reduce the number of scab spores produced.
- It should be a quiet time in the orchard now. Most orchards should not
require an insecticide spray until apple maggot fly time in July.
6/11-6/14 - Sorry for the late update - computer problems!
-No fresh plum curculio scars found on trees sprayed since 6/2 - even
though we received 1 - 2 1/2 inches of rain on 6/11 (washing off insecticide)
and even though we've had great plum curculio weather for most of the
week. Still, the wisest thing to do is check trees near woods and look
for fresh scars. If you find fresh scars, apply Imidan or Guthion to border
-Rose leafhoppers have been migrating from roses to apples over the past
week. If flying leafhoppers suddenly appeared in your orchard, they are
probably rose leafhopper. If you find white stippling damage on older
leaves along with flying leafhoppers, you probably have white apple leafhopper
(or a combination of both species). Don't bother spraying for them now.
Wait until the next generation of leafhopper nymphs appear. If you have
rose leafhopper, nymphs will appear within the next couple of weeks. Next
generation white apple leafhopper won't be around until August. There
still may be some white apple leafhopper nymphs in your trees. If you
have large numbers of nymphs now, these can be controlled with Provado,
Thiodan or Sevin.
- Potato leafhoppers should be arriving soon. These feed on the end of
branches causing the leaves to cup and turn pale. This is not a problem
on mature trees, but should be controlled on young trees since potato
leafhopper feeding reduces terminal growth. Imidan or Guthion will hopefully
control potato leafhopper, but you may need to use Provado, Thiodan or
- I'm finding lots of leafminer parasites at our URI orchard. I think
about 60% of the mines are parasitized. I'll let you know more next week.
- Mite threshold for June is 60% of leaves with motile mites.
- I've been looking for San Jose scale crawler emergence. They usually
emerge around June 10th. As of June 14 I have not seen any crawlers. If
you know you have a San Jose scale problem, use a magnifying glass to
look at infested limbs for the tiny, yellow crawlers. Imidan or Guthion
should be applied when crawlers first emerge and then again about 10 days
- Scab lesions have started to become visible. I've seen just a tiny bit
of scab in commercial orchards. Check your orchard for lesions now.
6/8/01 - I found a lot of fresh plum curculio egg laying
scars on trees not sprayed with an insecticide since the June 2 rain.
If you have not sprayed since then, you should tonight or tomorrow morning.
I think most of the damage I found occurred within the last 24 hours.
I expect plum curculio to be very active over the next few days.
- White apple leafhoppers are primarily adults now. In nearly every orchard
I see a few leafhoppers flying around. This is not the time to spray for
them! If you need to control white apple leafhoppers you'll have +to wait
until the second generation nymphs are present in August.
- It is also too late to spray for first generation leafminer. If you
find more than 13 mines per 100 fruit cluster leaves, consider spraying
for the second generation sap feeding mines. The time for this is usually
early July. Remember, if your crop is light, your trees can tolerate more
- Green apple aphids are starting to build up. So are aphid predators.
Give the predators a chance and don't spray for aphids.
- European red mite summer eggs are beginning to hatch. The threshold
for June is 60% of leaves with red mites. Mites are not such a problem
as in years past since we have effective miticides: Apollo, Savey, and
- I finally found apple scab lesions on unsprayed apple leaves. Also,
someone told me they saw scab on fruit. Check now for lesions! Probably
the best materials to spray on scab lesions is Sovran or Flint.
- I consider primary scab season over.
- Don't forget the twilight meeting June 14 at Don Smith's on route 102
6/4/01 - Primary apple scab season is definitely over.
I'm still waiting to find my first apple scab lesion of the season. Check
carefully over the next two weeks to see if any scab lesions appear.
- I did see some fresh plum curculio feeding today. Even though it's been
chilly, some plum curculio were active over the weekend. I expect more
plum curculio damage - maybe tomorrow if temperatures reach toward 80
degrees. I recommend either a border row spray or a full orchard spray
with Imidan or Guthion. I expect that will be the last insecticide needed
to control plum curculio this year.
- It is too late to control first generation leafminer with AgriMek or
Provado. More than 50% of the mines have advanced to the tissue feeding
stage and once advanced, they can't be controlled with insecticide. If
you are finding mines now, the best thing to do is to wait and control
the next generation sap feeding mines with Provado.
6/1/01 - At the URI orchard I found several leafminers
that have advanced to the tissue feeding stage (when the mines are visible
from the upper leaf surface). Check now on the underside of oldest leaves
for mines. If you find 13 mines out of 100 fruit cluster leaves consider
spraying Agri-Mek as soon as possible. Once leafminers are in the tissue
feeding stage they will not be controlled with insecticides, so Agri-Mek
must be applied before many have advanced. Agri-Mek must be mixed with
something to help it penetrate leaves. Mixing Agri-Mek and oil appears
to give the best results. Agri-Mek will also control European red mites.
- Still no fresh plum curculio scars.
- Apple scab lesions appear 9-17 days following an infection period. I
expect to find lesions in unsprayed trees any day now.
5/31/01 - There are reports of primary scab spores
still waiting to be discharged in New York. If there are still spores
in New York (Hudson Valley) there are probably still spores in Rhode Island.
Growers should have fungicide coverage going into this weekend. And then
primary scab season should really be over.
- Plum curculio have not been very active since 5/19, 5/20. I've seen
a few fresh scars, but not many. I do expect plum curculio to become active
again once it warms up above 70 degrees. Spray Imidan or Guthion before
warm weather is anticipated.
- European red mites not controlled prebloom have caused some bronzing
in two orchards. Apollo or Savey can be applied
now if you find more than 30% of leaves with red mites.
5/25/01 - We received more than 2 inches of rain over
the past 4 days, washing off any pesticide that had been applied earlier.
Many growers were out spraying today - to recover with fungicide and insecticide.
Even though we should be past primary scab infection season, I think it
is a good idea to reapply fungicides, especially a fungicide with kick
back such as Rubigan, Nova, Procure, Flint or Sovran. These fungicides
will also control cedar apple rust. You may have noticed all the orange
globby spore structures on cedar trees. During periods of wet weather
at this time of the year, spores are released from fungal structures on
cedar trees and make their way to apple trees.
- I didn't find any fresh plum curculio scars today. I don't think they
have been active since last weekend. I do expect them to resume their
activity as soon as temperatures return to the 70's or 80's. Before the
weather gets warm, all growers should have sprayed with Imidan or Guthion.
At the URI orchard, we applied the insecticide Avaunt for the petal fall
spray. So far this treatment has been working well. I'll let you know
how happy we are with Avaunt at the end of plum curculio season.
- I did see some leaves bronzed by European red mite feeding. Check your
leaves now and treat with Apollo, Savey or Pyramite if you find 30% of
leaves with red mites. If Apollo or Savey was applied to the trees last
year, you should not spray it again this year. Apollo and Savey are very
similar pesticides and should be considered the same when thinking about
miticide resistance management. To prolong the lives of Apollo and Savey,
these chemicals should not be applied to the same blocks two years in
- If you are planning to control leafminers with AgriMek this year, now
should be a good time for treatment. AgriMek must be applied with a material
to help it penetrate apple leaves. Adding oil to the AgriMek gives the
best results. Some growers have not been satisfied with AgriMek when it
was mixed with a surfactant. If you are going to apply AgriMek, might
as well mix it with oil and not use Captan for at least 10 days.
5/23/01 - We did need the rain , but I'm ready for
the sun to shine. This wet weather is probably releasing the last of the
primary apple scab spores. If you applied a fungicide recently, you should
be all set through this wet period. Those growers that had significant
scab last year should apply a fungicide after this rain - to give extra
protection against scab.
- Plum curculio were active this past weekend. I found many plum curculio
scars on unsprayed trees. Once the temperatures warm up, plum curculio
will most likely be active again. Apply Imidan or Guthion before the temperature
- European red mites are numerous in some orchards that did not apply
dormant oil. Mites are much easier to control nopw than they used to be.
If 30% of leaves have red mites, consider applying Apollo or Savey. This
is assuming you have a crop of apples. If you have a very small crop,
it is probably not necessary to spray for red mites.
5/18/01 - I am happy to report that it looks like more
fruit out there than I thought there would be. Some orchards still look
totally wiped out, but other orchards look better. I'd guess, at this
point, that it looks like a 25% crop from a 'normal' year. That does not
mean that 25% of the fruit are alive. What I see is about 1 fruit/ 2-3
clusters, which I estimate at a 25% crop. It varies incredibly from orchard
to orchard and tree to tree. Some later blooming varieties were not hit
as hard as others.
- I have not seen any plum curculio damage, but I have heard that one
grower saw some injury. I think everyone should have sprayed a petal fall
insecticide by now, or should do so very soon. Plum curculio could be
active this weekend if temperatures really reach 76 degrees (as forcasted).
- European red mites have started laying eggs. If you don't have much
of a crop then don't worry about red mites at this time. If you do have
a crop you should apply a miticide if 30% of leaves have red mites. Use
a miticide that kills eggs such as Savey or Apollo.
- Read the May 11th entre if you have white apple leafhoppers in your
orchard. I have found only one orchard with high numbers of white apple
5/16/01 - Looks like we had our first apple scab infection
period starting yesterday afternoon and continuing through today. I'm
not sure there was enough wetting to cause spores to be released, but
we must consider it an infection period.
- I only looked at one orchard in Northern RI today, but I saw much more
fruit than I expected to see!!!!! Some fruit with brown interiors are
still continuing to grow but many more had green interiors. I'll check
more orchards on Friday, May 18th.
- Saw my first hatched leafminer today.
5/13/01 - I visited many orchards on May 10 & 11
and mostly what I found was not good. Many orchards are close to 100%
bud kill from the May 7th freeze. A big question is, what will the fruit
be like from those buds that lived? I think we can expect many misshapened
fruit due to improper seed development. Only time will tell.
- So what to do? I think everyone should apply a petal fall insecticide
spray, even if you think you have nothing left to spray. You may be surprised
what survives. After the petal fall spray you can reassess - and decide
at that time if you should continue spraying throughout the season. As
far as fungicides go, continue spraying fungicides until the end of primary
scab season - for about another 10-14 days. After this time, as long as
your trees are free from scab you can stop spraying all together if you
don't have a crop to protect.
- If your trees were hit with the freeze, don't be concerned with mites
or leafminers. Light crops can tolerate many more leafminers and mites
than trees with a full crop.
- One insect you may be concerned with even if you don't have a crop is
white apple leafhopper. Usually white apple leafhoppers are controlled
when Sevin is applied for thinning. Since not much Sevin will be applied,
leafhoppers could developed unchecked in many orchards. If leafhopper
numbers are high early in the season, extensive leaf damage may affect
bud formation. Look now for the small white nymphs on the underside of
leaves. I was in an orchard on 5/11 where there were several leafhoppers
per leaf. We don't have a good threshold but 25 nymphs per 100 leaves
has been suggested as a threshold. Thiodan or Provado ( 1 oz/ 100 rate)
should control leafhoppers well.
- I do not have many European apple sawfly traps set
up, but on the ones set up, I have not caught many sawflies. It looks
like this is a light sawfly year. This means that it is probably not necessary
to rush out and spray an insecticide at petal fall, instead you can wait
until the weather is right for plum curculio.
- Plum curculio should have moved into the orchard during all the warm
weather we have been experiencing. They will begin to feed and lay eggs
when the weather gets damp. Plum curculio like to feed and lay eggs especially
during evening showers when the temperature is above 60 degrees. We may
have exactly those conditions shortly. It is best to apply an insecticide
before plum curculio begin damaging fruit.
5/9/01 - I have not been out to many orchards since
the May 7th freeze. I have talked to a few growers and it sounds very
bad. I did check buds at Phantom Farms in Cumberland. Here 50-60% of the
buds were dead. This surprised me greatly because I have never known them
to have any frost damage. I talked to another grower who thinks he is
close to 100% kill. I will get to as many growers as possible on Thursday
May 10, and report what I find at the Twilight
- The freeze/frost changes things. You need to assess your orchard before
making thinning decisions. To check buds for alive or dead - cut them
in half with your finger nail or knife. Dead buds are brown in the middle;
live buds are green all the way through.
- I have not found any hatched leafminer eggs yet, but I expect to see
them any day. Last year I first found hatched eggs on May 11. If you are
spraying for leafminers, Provado should be applied at petal fall or soon
after. AgriMek can be applied closer to first cover. If you are using
AgriMek, you need to add something to the tank mix to help it penetrate
the leaves. Oil works the best.
-Now is a good time to check the orchard for European red mites. Look
on the under side of the oldest leaves for the small red mite nymphs.
A very good place to check for mites is the leaf clusters that grow directly
out of Red Delicious limbs. If you find more than 30% of the leaves with
mites, consider applying Apollo or Savey at petal fall or soon after.
- I do not have many European apple sawfly traps
set up this year, but the ones I have set up do not have many sawflies
on them. Perhaps this is a light year for European apple sawfly.
- Still no apple scab infection period (unless you count the slight one
April 12). This weekend could be a major infection period. Unless the
forcast changes, all growers should apply a fungicide before the forcasted
5/3/01 - McIntosh trees are blooming in most areas.
Many bees were seen visiting flowers today. Looks like a big bloom, and
could be a big set with all the bee activity. Be ready to thin at petal
- Saw more hatched European red mites today. It is probably too early
to see if you'll need to treat for mites at petal fall, since all the
eggs have not hatched yet. Within the week all the red mite eggs should
hatch that are going to hatch, and you can look for red mites at that
- I see mite predators in nearly every orchard.
- If we actually get rain 5/4 or 5/5, many mature spores will be discharged
and potentially cause an apple scab infection period. I recommend all
orchards be protected with a fungicide for the forcasted rain. A fungicide
with kick back (Nova, Rubigan, Procure, Sovran, or Flint) can be applied
after the rain, but you need to be sure you'll be able to get in and spray
within 96 hours of when the rain starts.
5/1/01 - This warm weather is really pushing everything.
McIntosh trees in northern RI are in pink bud stage.
- Found hatched European red mite eggs in one orchard today in
northern RI. This means oils applied today or later will not be as effective
controlling red mites. Trees located in cooler areas (such as near the
coast) probably have a couple of more days before red mite eggs start
- I've still seen only one cluster with rosy apple aphids this year.
- Found 2 European apple sawfly adults on tarnished
plant bug traps today. Set up white sticky traps now for EAS. Set traps
at head height on the south side of trees, choose border trees or one
4/27/01 - Leafminer adults have been laying eggs. I
can easily find eggs in 4 orchards. I plan to check more orchards next
week. See the leafminer page for specifics.
-I am convinced that the mites I saw on 4/23/01 are the
yellow spider mites. I have seen them in several orchards so far this
year, but hopefully they will not become troublesome. Right now they can
serve as food for mite predators. I do see Z. mali and A. fallacis
in orchards now.
- I've only seen one fruit bud cluster with rosy apple aphids this year
- and I have looked at many clusters! Check now, especially in Cortlands
for this pest. Rosy apple aphids are usually in curling leaves. They are
generally brownish-purple with a white cast to them.
- We've gone a long time without the chance for an apple
scab infection period. When we do get an infection it could be quite severe
since so many spores will be discharged.
- No European red mite eggs found hatched yet.
4/24/01 - At URI's orchard we've caught a cummulative
average of 93 leafminer adults per trap. I can easily find eggs on the
underside of leaves, about 2 eggs per cluster. With the aid of a magnifying
glass, the eggs look like small, pale gelatinous blobs.
4/23/01 - What a difference a bit of heat makes! McIntosh
trees will be at tight cluster by the end of the day.
- Finding leafminer eggs on the underside of leaves. Found at least 1
egg per cluster in one orchard. I don't have a good threshold for eggs
but I believe that 1 per cluster is far above the threshold. So, maybe
4 eggs per 25 clusters is a reasonable threshold.
- I found a few buds damaged by tarnished plant bug - see a drop of clear
liquid on bud. This droplet is oozing plant juice from a tarnished plant
bug sting. Check now for damaged buds. I don't have a threshold for damaged
buds - use your own judgement.
- Finding yellow mites in some orchards. I think this looks like the same
mite I found in a few orchards last year, but I'm not sure. If it is the
same one (identified as the yellow spider mite, Eotetranychus carpina
borealis) then I shouldn't have been able to find it until petal fall.
I need to check into this!
4/20/01 - I am so glad to be wrong! There was no infection
period 4/18 because it dried out so quickly in the afternoon. It did not
stay wet all night like I thought it would.
- Still time to set up red leafminer traps - but don't wait. We've already
caught more than 10 per trap at URI's orchard. We've only caught a few
in commercial orchards.
- I saw many pear psylla eggs today (more than 10 per
bud). If you haven't applied oil on pears by
now it is probably to late deter pear pyslla egg laying. I did see European
red mite eggs on the pear twigs so oil will still be good for controlling
red mites on pears.
- Some growers have applied oil and fungicide - you should too!
4/18/01 - I believe this wet weather will cause an
apple scab infection period. When the rain started around 3:30pm yesterday,
it was about 44 degrees. After a couple of hours it had dropped to 40
degrees and remained there for about 10 hours. The temperature then dropped
to around 34 degrees and has been there for about 6 hours. The wet weather
will probably continue through the night of 4/18/01. At 34 degrees it
takes 48 hours of leaf wetness to cause an infection. But the spores already
got a head start at 40 degrees for 10 hours. At 40 degrees only 29 hours
are needed to cause an infection. We really need to figure out what the
average temperature is during a wet period. Right now the average temperature
for this wet period is about 38 degrees. At 38 degrees, 37 hours of leaf
wetness are needed to cause an apple scab infection period.
- Caught 42 leafminers on 4 red traps at URI's orchard (10.5 per trap).
The old threshold numbers for apple blotch leafminer are not very useful
- but - they are a rough gauge. The old threshold is 8 per trap by tight
cluster - which we have exceeded at URI.
4/13/01 - Hudson Valley, NY is reporting 23% mature
apple scab ascospores. Scab spore maturity is advanced this year compared
with fruit bud development. Economically important scab infections are
believed t be possiboe once spore counts reach 15%. Dave Rosenberger from
NY has issued a caution to growers that they should be prepared to spray
as soon as freen tissue is evident. This is not a year to wait for tight
cluster to begin your scab control program! If you had scab last year
(as most growers did), you should apply a fungicide now.
4/10/01 - Found 6 leafminers on one trap red and found
one tarnished plant bug on one white trap. I'll bring traps with insects
to twilight meeting at Dame's Farm, 5:30 on April 12.
4/9/01 - Not too much activity
in the orchards though buds are breaking. Do not see any leafminers or
other important insects.
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