 |
 |
|
|
 |
Impact of cool weather
on codling moth monitoring and management
John Wise and Larry Gut
Entomology
|
The cool temperatures over the last three weeks
have prolonged the calendar time normally necessary for codling
moth to go from first sustained flight (biofix) to egg hatch. Most
counties in the central and southern regions of the state biofixed
for codling moth on the May 17-18 weekend, but have only accumulated
150 GDD base 50 since that time. The research that the codling moth
degree-day model is built on shows early egg hatch to be at 250
GDD after biofix. Therefore the eggs that were laid by those initial
codling moth adults three weeks ago still require an additional
100 GDD base 50 to hatch. This illustrates the benefits of monitoring
GDDs, which correlate to insect development, instead of making management
decisions solely on a calendar date basis.
It should be noted that not all insecticides should
be timed for the 250 GDD egg hatch timing. For example, if you plan
to use the insect growth regulator, Intrepid, then biofix + 150
GDD spray timing is optimal. The following chart, modified from
the Michigan Fruit Management Guide (E-154) should
help distinguish optimal timing and use of some insecticide options.
|
Common name
(Trade name)
|
GDD
timing post-biofix
|
Rate/acre
|
PHI
|
REI
|
|
Azinphosmethyl
(Guthion
50WP)
*
14 day REI for activities like hand thinning (see label)
|
250
|
2
lb
|
14
d
|
48
hr*
|
|
Phosmet
(Imidan
50WP)
|
250
|
2.25-3.0
lb
|
7
d
|
24
hr
|
|
Esfenvalerate
(Asana
XL 0.66EC)
|
250
|
9.6-14.5
oz
|
21-28
d
|
12
hr
|
|
Fenpropathrin
(Danitol
2.4EC)
|
250
|
10.6-21.3
oz
|
14
d
|
24
hr
|
|
Spinosad
(SpinTor
2SC)
|
250
|
7.5-10.0
oz
|
7
d
|
4
hr
|
|
Acetamiprid
(Assail
70WP)
|
200-250
|
3.4
oz
|
7
d
|
12
hr
|
|
Methoxyfenozide
(Intrepid
2F)
|
150
|
16
oz
|
14
d
|
4
hr
|
|
Pyriproxyfen
(Esteem
35WP)
|
100
|
5
oz
|
45
d
|
12
hr
|
|
|
 |
Apple scouting through the summer
months
David Epstein, Larry Gut, John Wise, Jim
Laubach, John Bakker and Doug Murray
|
The summer period covers over three months of the
growing season and in some cases several generations of a single
pest. In this article, we will introduce pests and the appropriate
scouting techniques in the chronological order that they will most
likely appear in the orchard. The pests are: European and twospotted
spider mites, green apple aphids, spotted tentiform leafminer, tarnished
plant bug, apple scab, plum curculio, and white apple and potato
leafhoppers.
European red mite and twospotted spider
mite scouting continues through the season, although thresholds
may change. We monitor mites using a 100-leaf sample, 50% spur leaves
and 50% shoot leaves, throughout the summer period. Control measures
may be warranted for mature, healthy trees based on the following
thresholds:
§ 2-3
mites per leaf from petal fall to mid-June
§ 5-7
mites per leaf from mid-June through July
§ 10-15
mites per leaf in August
The presence of predaceous mites (more than 1 per
leaf) may justify delaying a treatment and repeating the cycle the
following week.
Monitoring for green apple aphids (GAA)
will continue as long as new terminal growth is present. GAA prefer
to feed on the underside of leaves on growing shoot tips and stems.
Estimate the average number of aphid infested leaves on terminals.
Generally, an average of three to four infested leaves is needed
before fruit damage from honeydew occurs. In young orchards, lower
levels of aphid infestation (1 to 2 leaf colonies) will inhibit
growth of trees.
Continue to monitor egg and larval stages of spotted
tentiform leafminer, but now include the tissue-feeding stage.
Use the accompanying table for monitoring and treatment decisions.
Spotted tentiform leafminer (STLM)
|
STLM
|
End
of 1st generation
|
Early
2nd generation
|
Late
2nd generation
|
Early
3rd generation
|
|
Monitoring
|
Check
50 tented mines from 25 trees to determine % parasitism.
|
Sample
50 or 100 leaves per block, count # mines per leaf.
|
Sample
50 or 100 mines and determine % parasitism.
|
Sample
50 or 100 leaves per block, count # mines per leaf
|
|
Threshold
(vary based on tree structure and variety)
|
|
2-3
per leaf, higher if 30-35% parasitism was found in first sample.
|
|
5-8
mines per leaf, higher if 35% parasitism
|
Continue to monitor for tarnished plant bug,
mindful that orchard mowing or drought conditions may drive adults
from the ground cover into the trees. Also continue to monitor for
new apple scab lesions on fruit and leaves, new symptoms
of powdery mildew, and fire blight infections.
Monitoring for plum curculio adults and
egg-laying should continue for at least 6 weeks after petal fall.
Any new fruit damage should be noted as to location and severity.
Oriental fruit moth monitoring will continue with traps,
but the focus for damage assessments should now be on fruit. Fruit
injury from Oriental fruit moth is often indistinguishable from
codling moth injury. Control treatments for first generation Oriental
fruit moth egg hatch occurs at 150-170 degree days post biofix base
45ºF, second generation egg hatch at 1125-1150 degree days base
45ºF, and third generation at 2250-2280 degree days base 45ºF.
Within two weeks of petal fall, you may begin to
see white apple leafhopper nymphs and potato leafhoppers.
White apple leafhoppers are the most significant of the two and
will appear as pale white nymphs on the lower surfaces of older
leaves. These nymphs will develop into adults over a 30-day period,
the second generation emerging 30 days later. Note the difference
between the white apple leafhopper and the potato leafhopper,
which is green and stays mostly near the actively growing terminal
leaves. We will monitor for first generation white apple leafhopper
by counting the number of nymphs found on 100 leaves selected from
leaf clusters and reporting this as the average number of nymphs
per leaf. For the second generation we will select our 100 leaves
from the mid-shoot area. Thresholds for trees with sparse canopy
and a heavy crop load is less than for trees with luxurious canopies.
Generally, 1 to 3 leafhoppers per leaf will bleach around the midrib
only, 8 per leaf will stipple the entire leaf and create problems
for workers at harvest.
Obliquebanded leafroller pheromone-baited
traps should be placed in the orchard three weeks after petal fall,
and monitored for the first sustained catch for biofix purposes.
The obliquebanded leafroller model will predict egg hatch and help
determine when to start monitoring for larvae. Larvea from the first,
or summer generation, may be found in a couple of different locations
in the tree. Newly hatched larvae frequently head for the tip of
the new terminal growth where they will feed on unfolding leaves.
Larvae may also feed on fruit, especially where it is clustered,
by attaching a leaf to the fruit and feeding underneath it. These
larvae are more difficult to detect but are important due to their
potential of causing significant economic loss. Monitor by counting
the number of larvae found on100 terminals and fruit clusters.
Obliquebanded leafroller
|
DD° Base
42 (Post Biofix)
|
Event
|
Action
|
|
Tight
cluster
|
Majority
of larvae have emerged from shelters
|
Examine
fruit buds for larval activity
|
|
0
DD° =biofix (~900 DD° after Jan 1)
|
1st
sustained moth captures
|
Set
DD° = 0
|
|
220-250
DD°
|
Peak
moth flight - overwintering generation
|
|
|
400-450
DD°
|
Start
of egg hatch
|
Timing
for treatment
|
|
1000
DD°
|
End
of egg hatch
|
|
|
2300
DD°
|
Peak
moth flight - 2nd generation
|
|
|
2750
DD°
|
Start
of 2nd generation egg hatch
|
Timing
for treatment
|
San Jose scale should be monitored with
pheromone-baited traps if there is a history of pest problems. Yellowish
crawlers generally are present 300-350 degree days base 50ºF after
the first catch of either generation. Note the presence or absence
of crawlers and their subsequent damage to fruit.
Dogwood borer overwinters as larvae in the
burr knots or trunk of the tree. You should be scouting for reddish-brown
frass and pupal skins in and around burr knots as an indication
of an infestation. Codling moth monitoring will continue
with traps, but with the addition of damage assessments on fruit.
Note the location and severity of any fruit injury.
Codling moth
|
DD° Base
50 (Post Biofix)
|
Event
|
Action
|
|
Pink
bud
|
Development
of overwintering larvae
|
Set
traps
|
|
0
DD° =Biofix (~200 DD° after Jan 1)
|
1st
sustained moth captures
|
Set
DD° = 0
|
|
250
DD°
|
Start
of 1st generation egg hatch
|
Timing
for 1st treatment if over threshold
|
|
1000
DD°
|
Expected
end of 1st generation activity
|
|
|
1200-1250
DD°
|
Start
of 2nd generation egg hatch
|
Timing
for 1st treatment if over threshold
|
|
2100
DD°
|
Expected
end of 2nd generation activity
|
|
Approximately 6 weeks after petal fall or before
900 days base 50 (late June in southern Michigan to second week
of July in northwest Michigan), apple maggot sticky traps
should be placed in the orchard. Adult fly emergence often follows
rainfall events, with emergence typically delayed if the soils remain
dry. Peak emergence generally occurs between 1400 and 1700 growing
degree days base 50, but is highly dependent on site specific weather
conditions.
|
|
 |
Section 18 labels approved for Admire
and Provado in Michigan blueberry
Rufus Isaacs
Entomology
|
Emergency Section 18 labels have been granted by
the Environmental Protection Agency for use of two formulations
of imidacloprid against Japanese beetle in Michigan blueberries.
The labels for Provado 1.6F and Admire 2F cover all Michigan counties,
and allow application of these two products until September 30,
2003. This article provides some recommendations for blueberry growers
to achieve maximum effect from applications of these products.
Preventative grub control
Admire is the soil-applied formulation of imidacloprid,
which targets the young larvae hatching from eggs that will be laid
in the soil this summer. Application of Admire is therefore a preventative
treatment to reduce beetle infestation in 2003. It is important
to realize that this treatment will have minimal effect on beetle
emergence this year because most grubs are fully grown by late June
and are not at a susceptible stage.
Admire should be applied to grassy regions of blueberry
fields where egg laying is expected to be highest (this is likely
to be grassy row middles, drive lanes, and headlands). Application
must be made by the start of Japanese beetle egg laying (typically
by July 4) for it to be present in the soil when larvae hatch. Applications
must be watered in with 0.5 to 1 inch of applied water or rain for
it to move through the thatch layer and be present in the root zone
where larvae start feeding. There is a seven-day pre-harvest interval
(PHI) with this product.
Our research trials on Japanese beetle grubs in
Michigan blueberry soils conducted in 2002 showed similar activity
of the 16 oz and the 25 oz rates when applied in mid-July, providing
over 85 percent reduced grub density in the fall compared to untreated
areas. Even greater control is expected from an application timed
before egg laying begins. Imidacloprid is quite stable in the soil,
and so only one application is required per year, providing control
of larvae throughout the two to three month egg-hatching period.
This longevity makes this insecticide one of the few where effectiveness
is not greatly affected by application a week before egg laying
begins.
The greatest densities of Japanese beetle grubs
have generally been found in permanent sod around blueberry fields.
An economical use of Admire might be to apply it only to headlands
and drive lanes where beetle egg laying and grub densities are highest.
Using this approach on a 20-acre field this year would be expected
to significantly reduce the amount of beetle immigration in 2004,
spraying to less than one acre of total land (the headlands and
drive lanes).
Foliar treatment against adults
The foliar formulation of imidacloprid, called
Provado, can be used to help protect foliage and fruit from feeding
by Japanese beetle. Application of this product at 8 oz per acre
provides initial lethal activity against adult Japanese beetle.
As the compound is absorbed into the leaves, lethal activity declines
and sub-lethal effects, such as reduced feeding and paralysis continue
for seven to ten days. This product has a three-day pre-harvest
interval. This product requires thorough coverage for optimal control,
because beetles can move to untreated regions of bushes if residues
are not throughout the bush.
Regardless of the formulation used, a maximum of
0.5 lb active ingredient is allowed. This means that if Admire was
applied to a field at the 16 oz rate (0.25 lb active ingredient),
then two applications of Provado at 8 oz could still be made. However,
if the 25 oz rate of Admire was used, then only one Provado application
could be made.
Environmental safety considerations outlined on
the labels should be closely followed, particularly near bodies
of water. As always, label directions should be carefully followed
when using these products, and the label must be in the possession
of growers applying these products. Copies can be acquired from
suppliers, or the Emergency labels can be downloaded by visiting
these links. Admire in blueberries:
http://www.ipm.msu.edu/CAT03_frt/pdf/6-10-03Admire.pdf
Provado in blueberries:
http://www.ipm.msu.edu/CAT03_frt/pdf/6-10-03Provado.pdf
Editor's note: Another resource for labels is
the MSU Fruit Area of Expertise Team web site. The team posts all
pesticide Section 18 and 24c labels throughout the season at:
http://web1.msue.msu.edu/fruit/MIfrt_s18.htm
|
|
 |
Japanese beetle survey: Help us
help you
Matt O'Neal and Rufus Isaacs
Entomology
|
As many growers, gardeners and homeowners in the
Lower Peninsula know, Michigan faces a prolific pest in the Japanese
beetle. This iridescent beetle has moved from the eastern coast
of the United States, where it was introduced, and is now a significant
pest of turfgrass, small fruit and some field crops. In 2002, the
National Agricultural Pest Information System (NAPIS) reported Japanese
beetles within the southern most counties of the Lower Peninsula
(Figure 1). However,
we anticipate its spread to continue to the north and west across
Michigan.
Effective management of this pest requires a proactive
approach. To better inform the public and assist researchers and
state extension agents, our colleagues at the University of Illinois
have designed a website to help us track this pests' spread across
Michigan: http://www.pmcenters.org/northcentral/jbeetle/
At this website, you can click on the reporting
beetles link, and follow the subsequent instructions to report the
location and level of Japanese beetle infestation. We invite all
who have encountered this beetle in their home or commercial fields
to report them to this website. This information will be reported
back on the website as regional maps, illustrating the current range
of Japanese beetle.
Reporting Japanese beetle infestations will help
us better understand the landscape and climate factors that may
impact this invasive species' ability to spread across the US. In
return, there are several pages describing the biology of the beetle
and management options for the adults and grubs. By helping us to
identify the current range and population level, we can better help
you to manage this destructive pest.
Figure 1. 2002 reported range of Japanese
Beetle (JB) in US. Data from National Agricultural Pest Information
System. Figure from National Agricultural Pest Information System
web site:
http://www.ceris.purdue.edu/napis/pests/jb/imap/jb2002.html
|
|
 |
Rainy weather conducive to phomopsis
development in grapes
Annemiek Schilder
Plant Pathology
|
Spore release and dispersal
The rainy, cool spring so far has been conducive
to spore release and infection by Phomopsis
viticola, the fungus that causes Phomopsis cane and leaf spot
in grapes. Early in the season, spore release tends to be patchy
in vineyards, but later on, spores are detectable at most sites.
Rainwater caught in traps (5-inch-diameter funnels attached to 2-liter
soda bottles) that were placed in vines in a Niagara vineyard in
Van Buren County has contained infectious spores every week since
mid-April of this year. Over a million spores per trap have been
collected on occasion. Phomopsis spores are rain-splash dispersed
and their dispersal range is generally limited to the distance that
rain drops splash. However, rain accompanied by high winds can lead
to dispersal over longer distances. More typically, Phomopsis spreads
within vines and between neighboring vines. Spread across rows is
less common.
Symptoms
Conditions also have been good for infection. The
optimum temperature for infection of shoots is 60ºF, and of leaves
is 60-68ºF. However, infection of both tissues is possible between
50º and 86ºF. At least 6 hours of leaf wetness is required at the
optimum temperature and up to 20 hours of wetness are needed at
the extremes. Evidence of Phomopsis infection, such as numerous
small yellow spots with dark brown specks in the center, can now
be seen on leaves in unsprayed or lesser sprayed areas in vinyards.
Large numbers of lesions can lead to puckering of the leaves. Some
shoots are also starting to show small brown to black scabby areas.
If you are seeing a lot of leaf lesions, this indicates a high risk
of rachis infections. While some rachis infections on flower clusters
may have occurred already, the probability of spores hitting the
rachis may be greater now that flower clusters have expanded. All
indications are that spore release will continue through bloom and
early fruit development, so be sure to protect the clusters during
this period.
Control
Control of Phomopsis is recommended at least through
berry touch. In areas where bloom has not yet occurred, EBDC sprays
are the most economical option for disease control. Where bloom
has started, strobilurins (e.g., Sovran or Abound) or Ziram are
good options. After bloom, strobilurins have consistently provided
better control of Phomopsis than strictly protectant fungicides
in small plot trials in Michigan. However, this could be related
to canopy density and coverage. Since rachis infections are mostly
to blame for yield losses, thorough coverage of clusters is crucial
in protecting the rachis and berries from infection. Increased spray
volume, spraying every other row or even every row, and reduced
speed can help achieve this.
|
|
 |
Pre-harvest blueberry IPM meeting
Al Gaus
Berrien County
|
Berrien County MSU Extension will host a twilight
pre-harvest blueberry IPM meeting on Thursday, June 19. It will
start at 6:30 PM and end at 8:00 PM. It will be held at Klug's Blueberry
Farm, Edward Klug, owner, 11984 Landon Rd, Baroda, Michigan. The
farm is located just north of Browntown between Cleveland and Holden
Roads (southwest of Baroda, southeast of Bridgman). It will include
updates on disease, insect and weed management by Drs. Annemiek
Schilder, Eric Hanson, and Rufus Isaacs, as well as other helpful
information for the pre-harvest time frame.
This meeting
has been approved for be one RUP recertification credit. There is
no cost to attend the meeting.
|
|
 |
| Field
Day at Trevor Nichols Research Complex |
We will be having a research field day at the Trevor
Nichols Research Complex (TNRC) on Thursday, September 25 from 1:00
PM to 5:00 PM. The field day will focus on insect and disease research
and efficacy trials that were carried out this season at the TNRC
by Larry Gut, Rufus Isaacs, Mark Whalon, Annemiek Schilder and John
Wise. A social time will precede the tour with food and refreshments
starting at noon in the new "Angus J. Howitt IPM Training Room."
The TNRC is located at 6237 124th Ave. in Fennville, MI.
See the TNRC web page for directions: http://www.maes.msu.edu/tnrc/
|
|
 |
|
|
 |
1
- Southwest
Mark Longstroth
Bill Shane
Al Gaus
|
Weather
Warmer more normal weather returned after a cold
and cloudy beginning of the week. A cold front with high winds and
thunderstorms passed through on Sunday (June 8). Hail was reported
in some areas. This storm did not affect Lake Shore area growers
but the storm gathered strength as it moved inland. A third of an
inch of rain or more fell from scattered thunderstorms. This week's
forecast is for warmer weather and the chance of showers. Highs
by the weekend are predicted to be in the 80s.
Southwest Michigan Growing
Degree Day Totals through June 8
|
|
Location
|
GDD 42
|
GDD 45
|
GDD 50
|
|
SWMREC:
|
923
|
730
|
454
|
|
Lawton:
|
981
|
786
|
508
|
|
Grand Junction:
|
952
|
767
|
502
|
|
Trevor Nichols:
|
763
|
591
|
358
|
Insects
Insect activity remained low. Rose chafers are
emerging. Tarnished plant bug feeding
scars were found in apples and peaches. Some plum curculio egg-laying
scars were found (apples, cherries, plums and nectarines). Warmer
days and nights should bring plum curculio out. We are still catching good numbers of
Oriental fruit moth and codling moth. Potato
leafhoppers were found in grapes and apples.
Tree fruit
The peach crop looks good. Tree color looks better but leaves are still
pale. The trees should green up when the weather warms up later
this week. We are now at 730 GDD base 45, 480 GDD since Biofix
for Oriental
fruit moth on April 24. One grower reported shoot strikes but
we have not seen any shoot flagging from Oriental fruit moth in
the shoot tips. The first rose chafer were found in peaches in northern
Berrien County. Tarnished plant bug feeding injury can be found
on peach fruit. This is especially a problem after cover crops are
mowed and the adults move into the trees and attack the young fruit.
Bacterial spot symptoms can be found in some peaches.
In tart
cherries, Sunday's high winds caused trees to blow down and
blew fruit out of the trees. In some orchards the fruit is marked
by frost and wind whip. Bacterial canker leaf and fruit symptoms
can be found in tart cherries and are easy to find in sweet cherries.
Cherry leaf spot symptoms are beginning to appear. Some plum curculio egg laying
scars were found, but so far pressure has been light. We expect
that there will be more egg laying later this week with warm humid
conditions. Growers need to protect against cherry leaf spot. In
sweet cherries early varieties are starting to yellow to straw color.
Ripening cherries need to be protected from brown rot.
In plums,
the June drop is ending. The European
plum crop has thinned out well and looks good. Bacterial spot
symptoms can be found on plum leaves. Pits are hardening in Japanese
plums. The Japanese plum crop is very spotty.
Apple
king fruit are an inch in diameter. We seen very little drop even
though the size difference between the king fruit and side fruit
is pronounced. I hope that most of the small side fruit will drop.
Some growers are considering thinning with Ethephon. I recommend
that they wait for warmer weather later this week.
No new apple scab infections. Scab lesions are
easy to find in some orchards on the fruit and leaves. If growers
have no scab lesion in their orchards they can relax their protection.
If they have scab lesions they need to continue an active scab protection
program.
Fire
blight symptoms are increasing. Cankers and collapsing shoots
are oozing and we are seeing secondary spread to other shoots. Strong
winds, rain and hail Sunday will cause trauma blight in infected
orchards.
We have accumulated 150 GDD, since we biofixed
codling moth on May 18
at 300 GDD base 50. Controls are usually timed for 250 to 350 GDD
after biofix, in about a week. New materials such as Intrepid are
timed earlier. See the article on codling moth control in this issue
of the Fruit CAT Alert . European red mites are
scarce and are laying eggs. No spotted tentiform leafminer
mines have been found yet. Leafroller
larvae can still be found in terminals. White apple leafhopper
nymphs and potato leafhopper adults are increasing.
Small fruit
Blueberry
fruit are pea-sized. The fields still seem yellow and pale. The
cool weather has made virus symptoms apparent in many older fields.
Growers need to protect the fruit from anthracnose and alternaria.
Mummy berry shoot strikes are dry and easy to find. The
normal shoestring virus symptoms are small strap-like leaves and
reddish streaks on young shoots. However, this year we are seeing
a red stain, associated
with the leaf veins in the center of the leaves, that resembles
a red oak leaf. Cherry fruitworm
and cranberry
fruitworm trap catch numbers are up and egg hatch has begun.
Leafroller larvae are feeding in the shoot tips.
Concord
and Niagara flower buds are separating in
the cluster. Wild grapes are blooming and we expect bloom later
this week. Both phomopsis and black rot leaf lesions are visible
in unsprayed vineyards. Grape berry moths are flying.
They will probably start to lay eggs during bloom. Growers need
to time their pesticide applications for egg hatch, a week away.
Southwest Michigan Grape Growing
Degree Days Totals from April 1 to June 8
|
|
Location
|
GDDbase 50
|
|
SWMREC from April 1:
|
405
|
|
Lawton From April
1:
|
465
|
Strawberry
fruit are coloring and harvest has begun.
Raspberries
are still blooming.
Cranberries
are at the jewel stage. Bloom has started on the most advanced shoots.
Meetings
The next Monday Fruit Management
meeting will be at Bjorge's Fruit Acres Farm, at the
corner of Friday and Carmody roads, approximately 2 miles south
of the Coloma exit I-94, on June 16 at 5:00 PM.
There will be a pre-harvest blueberry meeting June
19 at 6:30 PM. The focus of this meeting will be in blueberries.
For more information check the Fruit Hotlines at Van Buren (269)
657-6380 and Berrien (269) 944-4126 ext. 1.
|
|
 |
2 - Southeast
Bob Tritten
|
Weather
Rain and cold temperatures were the main story
of last week. Damp weather mid- to late in the week brought more
disease control pressure in tree fruits. More heavy rainfall and
severe weather swept across Southeast Michigan on Sunday evening
(June 8). Many people reported hail and a few tornados (one at the
Tritten home). Warmer weather does not seem to have advanced many
of the insects as quickly as what I had expected. Most farms are
reporting adequate amounts of soil moisture. Strawberry harvest
is expected to begin very late this year.
|
Southeast
Michigan growing degree day totals for March 1 to June 10,
|
|
Location
|
GDD42
|
GDD45
|
GDD50
|
|
Flint
|
992
|
767
|
525
|
|
Romeo
|
878
|
679
|
435
|
|
Petersburg
|
958
|
739
|
503
|
Tree fruits
Apples
are mostly in the 14 mm to 16 mm range. Apples are finally at petal
fall to 6 mm for fruit growers close to Lake Huron. Codling moth
flight has been heavy at many farms this year. Even pheromone disruption
blocks seem to have heavy codling moth numbers. Plum curculio has
been notably absent in most apple blocks this year. I have seen
a few stings on fruit, but very few. Rosy apple aphid colonies are
more frequent on the insides of trees. Some leaf curling is beginning
to develop from rosies. White apple leafhopper populations are still
present, however adult numbers are fairly low. Spotted tentiform
leafminer adults are still flying, however at fairly low levels.
We are seeing nymphs at a few farms and sap feeders at others. Overall
leafminer populations seem to be low this year. Oriental fruit moth
trap catches have dropped considerably in the last week. I am seeing
a few shoot strikes from Oriental fruit moth. A few obliquebanded
leafroller and redbanded leafroller larvae are still present, however
numbers are very low. These larvae are now fairly large in size.
European red mite eggs are now present and numbers are fairly high
on a few trees, however most surrounding trees have low levels of
mites. At this time very few blocks have reached a point where miticides
need to be applied. There is a distinct lack of predators in most
tree fruits this year. Apple scab spore discharge is still taking
place in the Romeo area (equipment in the Flint area was damaged
from tornados and will not be available for the rest of the season).
So, I am not calling an end to primary apple scab season as of yet.
No confirmed fire blight strikes have been seen yet.
Peach
fruits are growing well, however many blocks of peaches have poor
color this season. A few Oriental fruit moth shoot strikes have
been seen.
Small fruits
Strawberries
are at thimble size to early pink at a few farms. Most farms are
considering beginning harvest around June 18 to 22. However, first
harvest is a bit hard to predict at this time. This will be one
of the latest strawberry harvest seasons that we have. I am continuing
to see a low level of strawberry clipper at several farms. Some
leaf spot diseases have been reported at a few farms.
Raspberry
growth on fall red raspberries is continuing quite well with most
being about 12" to 15" tall. Summer red raspberries are now in bloom.
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3 - Grand
Rapids Area
Phil Schwallier
Amy Irish Brown
Carlos Garcia-Salazar
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West Central Michigan
degree days accumulated
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Weather Station
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Base 42 ºF
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Base 50 ºF
|
|
West Olive
|
892
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459
|
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Holland
|
906
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458
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Tree fruit
Most apple varieties are in the 10 to 18
mm stage now. Growers have been applying thinners where needed,
but some varieties are thinning down on their own. Apple leaves
still look pale from the cold weather. We are also seeing tree decline
- possibly due to winter injury - in both apple and sweet cherry.
We did not catch any apple scab spores with the
last rain and have called an end to primary apple scab for the 2003
season. Scab is showing up in some blocks. Some fire blight is showing
up in commercial apple blocks in light amounts. This is most likely
from the Mother's Day (May 11) weekend and appears to be blossom
blight, but we had high winds that weekend and some of the symptoms
could be from that trauma event. Symptoms seem to be isolated to
hot spots in orchards where blight has been found before.
Codling moth trap numbers are still very high in
some blocks even with the cooler than normal weather. Proper timing
of cover sprays for codling moth will be very important this year,
but we are probably still 7 days away from the 250 GDD50 threshold
for early egg hatch spray timings. We have only accumulated 155
GDD50 since the regional May 19 biofix. Degree day accumulations
are normally about 15 per day for base 50, but the cooler than normal
temperatures have been giving us daily accumulations of less than
10 per day, therefore slowing the development of this model.
Obliquebanded leafroller are getting large and
moving out of the window for good control at this time - most are
pupating. White apple leafhopper continue to emerge and develop.
Spotted tentiform leafminer are mostly in the sap feeder stage and
mines should be seen at any time. Plum curculio egg-laying damage
continues in apples in normal amounts. Cover sprays for plum curculio
should be maintained for another 10 days.
Small fruit
Blueberries in west central Michigan are
still in bloom. The varieties Bluecrop and Blueray are in early
green fruit while Jersey is in petal fall stage. In general, the
bloom period has been delayed for most of the varieties. In some
instances, the difference between bloom stages among varieties is
at least one week apart. For instance, in some fields the variety
Bluecrop is in green fruit stage but in the same sites Jersey just
started the petal fall stage. Since most growers have a mix of early
and late season varieties, this long bloom period is causing logistic
problems for pest and disease control. In early season varieties
that are in green fruit stage sprays against fruit worms and early
season blueberry diseases have been delayed because pollinator insects
are still working in late season varieties adjacent to them.
Small fruit insects
Regarding
insect pests, the emergence of the redbanded leafroller has concluded
and the obliquebanded leafroller has not emerged, yet. Still we
are seeing leafroller feeding ranging from 1.5 to 4 percent but
leafroller predation by birds and other predators ranged from 80
to 90 percent. Larvae responsible for this feeding are a complex
of leafrollers: OBLR, RBLR and Pandemis.
The
flight of cherry fruitworm moths has continued in both Allegan and
Ottawa counties with moth captures in the pheromone traps ranging
from 2 to 10 moth per trap per week. Cherry fruitworm eggs and fruit
damage by the larvae have been found in both counties. Regarding
the Cranberry fruitworm, adult moths continued emerging in both
Ottawa and Allegan counties. We observed a large emergence of cranberry
fruitworm adult moths over the weekend and we expect a large oviposition
in the next three to five days. So at this time scouting for eggs
is recommended to time pest control actions against this pest.
Meetings
There will be a blueberry growers meeting
on July 8, from 1:00 - 5:00 PM at the Trevor Nichols Research Station
in Fennville.
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4 - West
Central
Mira Danilovich
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Weather and crop development
With the high temperatures only in the 60's the
weather is still rather cool. We are more than 100 GDD50 behind
normal. We did get some much-needed rain over the weekend. All three
automated stations in the district registered comparable amounts
of only about 0.3-inch. This is not nearly enough to erase nearly
1.5 inches of deficit that we have incur since the beginning of
April.
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West
Central Michigan growing degree day totals
As of Sunday, June 8.
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Location
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GDD42
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GDD45
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GDD50
|
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Hart
|
698
|
579
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