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May 9, 2005 Volume 14 No. 8 Update on Pest Management and Crop Development

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Upcoming Events

Upcoming Pest Events | Phenologies | Trap Catches | Pest Focus | Insects | diseases

Current DD accumulations
43°F
50°F

(Geneva 1/1-5/9):

277.1

125.2

(Geneva 1/1-5/9/2004):

348.6

176.8

(Geneva "Normal"):

369

182

(Geneva 5/16 Predicted):

399.1

200.2

(Highland 1/1-5/9):

379.6

182.1

 

Coming Events:

Ranges:

 

American plum borer 1st catch

325-527

139-281

Codling moth 1st catch

389-587

188-324

Comstock mealybug 1st gen crawlers present

215-441

80-254

European red mite egg hatch

231-337

100-168

Lesser appleworm 1st catch

239-537

104-286

Mirid bugs 1st hatch

342-474

170-242

Oriental fruit moth 1st catch

202-382

78-204

Pear psylla 1st egg hatch

174-328

60-166

Rose leafhopper nymphs on multiflora rose

239-397

96-198

Rosy apple aphid nymphs present

134-244

56-116

Spotted tentiform leafminer 1st flight peak

250-408

112-210

McIntosh at bloom

348-422

171-221

Red Delicious bloom

380-496

196-244

Peach at bloom

253-321

114-156

Pear at bloom

301-397

145-203

Plum at petal fall

334-440

155-237

Sweet cherry at petal fall

338-426

168-226

Tart cherry at petal fall

406-500

208-270

 

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Phenologies

Upcoming Pest Events | Phenologies | Trap Catches | Pest Focus | Insects | diseases

Geneva:  

Apple (McIntosh):

Pink

Apple (R. Del.):

Pink

Apple (Empire):

Pink

Pear:

Early bloom

Sweet Cherry:

25% Petal fall

Tart Cherry (Mont.):

Bloom

Plum:

Bloom

Highland:

Apple (McIntosh):

10% Petal fall

Apple (Red Delicious):

Bloom

Pear (Bartlett):

10-30% Petal fall

Plum:

Bloom

Apricot:

Petal fall

Sweet Cherry:

Petal fall

Peach (early):

Petal fall

Peach (late):

Late bloom

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Trap Catches

Upcoming Pest Events | Phenologies | Trap Catches | Pest Focus | Insects | diseases

TRAP CATCHES (Number/trap/day)        
Geneva

4/28

5/2

5/5

5/9

Redbanded Leafroller

1.7

15.8

0.0

3.6

Spotted Tentiform Leafminer

0.0

0.8

0.5

12.5

Oriental Fruit Moth

0.0

0.0

0.0

0.0

Lesser Appleworm

0.0

0.0

0.0

0.0

 

Highland
(Dick Straub, Peter Jentsch)
4/26
5/2
5/9
 

Green Fruitworm

0.1

0.2

0.0

Redbanded Leafroller

3.5

11.0

4.4

Spotted Tentiform Leafminer

11.1

46.2

28.2

Oriental Fruit Moth

0.3

0.2

0.4

Lesser Appleworm

0.0

0.2*

0.0

San Jose Scale

-

0.0

0.0

* = 1st catch

 

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Pest Focus

Upcoming Pest Events | Phenologies | Trap Catches | Pest Focus | Insects | diseases

(Highland): San Jose Scale model degree days (base 50 F) since March      
1 = 181.8

(Phelps, Ontario Co.): 1st Oriental Fruit Moth catch today, 5/9.

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Insects

Upcoming Pest Events | Phenologies | Trap Catches | Pest Focus | Insects | diseases

INCOMING

ORCHARD RADAR DIGEST

Geneva Predictions:
Roundheaded Appletree Borer
RAB adult emergence begins: June 1; Peak emergence: June 16.
RAB egglaying begins: June 11. Peak egglaying period roughly: July 1 to July 15.

Lesser Appleworm
1st LAW flight, first trap catch expected: May 13; Peak trap catch: May 24.

Mullein Plant Bug
Expected 50% egg hatch date: May 20, which is 6 days before rough estimate of Red Delicious petal fall date.
The most accurate time for limb tapping counts, but possibly after MPB damage has occurred, is when 90% of eggs have hatched.
90% egg hatch date: May 24.

Obliquebanded Leafroller
1st generation OBLR flight, first trap catch expected: June 13.

Oriental Fruit Moth
1st generation OFM flight, first trap catch expected: May 7.
Optimum 1st generation first treatment date, if needed: May 23.

Redbanded Leafrolloer
Peak trap catch and approximate start of egg hatch: May 8.

San Jose Scale
First adult SJS caught on trap: May 20.

Spotted Tentiform Leafminer
1st STLM flight, peak trap catch: May 15
1st generation sapfeeding mines start showing: May 24.
Optimum sample date is around May 25, when a larger portion of the mines have become detectable.

White Apple Leafhopper
1st generation WALH found on apple foliage: May 16.

Highland Predictions:

Roundheaded Appletree Borer
RAB adult emergence begins: May 27; Peak emergence: June 11.
RAB egglaying begins: June 6. Peak egglaying period roughly: June 25 to July 9.

Lesser Appleworm
1st LAW flight, first trap catch expected: May 7; Peak trap catch: May 17.

Mullein Plant Bug
Expected 50% egg hatch date: May 18, which is 1 day before rough estimate of Red Delicious petal fall date.
The most accurate time for limb tapping counts, but possibly after MPB damage has occurred, is when 90% of eggs have hatched.
90% egg hatch date: May 22.

Obliquebanded Leafroller
1st generation OBLR flight, first trap catch expected: June 7.

Oriental Fruit Moth
Optimum 1st generation first treatment date, if needed: May 17.

San Jose Scale
First adult SJS caught on trap: May 13.

Spotted Tentiform Leafminer
1st generation sapfeeding mines start showing: May 17.
Optimum sample date is around May 18, when a larger portion of the mines have become detectable.

White Apple Leafhopper
1st generation WALH found on apple foliage: May 10.

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OFF 'EM

HANDGUNS BLAZING
(Harvey Reissig & Dave Combs, Entomology, Geneva)

   Before the internal worm management decision process gets started in earnest this season, here is a synopsis of a small-plot efficacy trial conducted against oriental fruit moth in Wayne Co. last year.

   The effectiveness of different schedules of Imidan were compared against oriental fruit moth in commercial WNY apple orchards in 2004.  Tests were set up in two small plots (approx. 1/3 A), in two commercial orchards in Wayne County.  Both of these small plots had been used in the past for OFM studies and were heavily infested during the 2003 growing season.  Many of the unsprayed trees in 2003 had a 40-60% infestation level of OFM at harvest.  In order to time sprays, a network of 24 OFM traps was maintained throughout western NY, and checked weekly throughout the season.  The first egg hatch for each generation was estimated to occur at 175-200 DD (Base 45 F) after the biofix (first sustained catch of moths).  Four treatments were compared in each orchard:

   (1) Protective Schedule: Imidan was applied at pink (6 May), petal fall (21 May) and as cover sprays on 3, 16, and 30 Jun; 20 Jul; and 2, 17, and 31 Aug.

   (2) Optimum Timing: Imidan was applied at the estimated first hatch of eggs against each generation.  The first generation spray was applied at pink (6 May) based on pre-season estimates of OFM phenology.  The second generation spray was applied based on a pheromone trap biofix and DD calculations on 20 Jul.  The third generation of OFM was delayed until after the third flight had started during the last week in Aug, and applied on 31 Aug.  A fourth spray in this treatment was never applied because the flight continued throughout September and growers were reluctant to spray after Labor Day. 

   (3) Late Season Control: The first spray was applied on 20 Jul at the estimated first hatch of eggs of the second generation using methods described for the Optimum Timing schedule, followed by another cover spray on 2 Aug.  A final spray was applied on 31 Aug, and a fourth spray was not applied after September because of concerns outlined above. 

   (4) Untreated Check: No insecticide sprays were applied to a small block of 12-16 trees along the outside edge of the research plot. 

   The same rate of Imidan 70W (3 lbs/A) was applied in all applications in all treatments with a high-pressure handgun sprayer to ensure adequate coverage.  Damage from the first generation was estimated on 23 Jul by inspecting 100 fruits on each of 5 trees in each treatment.  Apples were sampled again on 10 Sept (100 fruits on 3 trees/trt) to estimate cumulative damage from the first and second generations of OFM.  Fruit was picked on 8 Oct, which is a normal harvest date for late maturing apple cultivars in NY, and 100 fruits on 4 trees/trt was examined to estimate seasonal damage from all three generations of OFM.  Data from the two combined orchards was subjected to an AOV with SuperAnova.  Means were separated with Fisher’s Protected LSD Test (P<0.05).  Data was transformed Arcsin (Sqrt X) prior to analysis.

   OFM damage was considerably lower in the Untreated Check plots throughout the season than in 2003, probably because of the unseasonably cool and rainy weather throughout the summer (Table 1).  After the first generation, 13.4% and 5.0% of the fruit was infested in the checks in the two orchards, and damage in the combined orchards averaged 9.2%.  When data from the combined orchards was analyzed, only the Protective schedule significantly reduced damage from the first generation below that in the Untreated Checks.  Since no OFM sprays had yet been applied in the Late Season treatment, damage in this plot should have been similar to that in the check.  However, the lack of control in the Optimum Treatment suggests that the single spray at pink was ineffective against the first generation, probably because flight of the first generation of OFM was later than normal and did not even begin until bloom in 2004. 

   Average fruit injury in the combined Check plots increased to 15.7% after the second generation, and only the Protective treatment significantly reduced fruit damage, although damage was lower than that in the Check plot in the Late Season combined treatments.  At harvest (8 Oct), damage in the combined orchards Checks (17.4%) was only slightly higher than the average damage resulting from the first and second generations, which suggests that damage from the third generation of OFM was relatively insignificant during 2004.  The results from this study show that Imidan can still adequately control OFM in problem apple orchards in NY if it is applied frequently at high rates with thorough coverage.  In these heavily infested orchards, neither of the 3-spray programs, the Optimum Timing or Late Season Schedule, were as effective as the Protective Schedule, although damage in both of these treatments at harvest was lower than that in the Check.  Even though the effectiveness of both of these reduced-spray schedules was similar during 2004, it is possible that results from these strategies could vary from year to year, depending upon seasonal weather patterns that may affect OFM phenology. 

Table 1


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Diseases

Upcoming Pest Events | Phenologies | Trap Catches | Pest Focus | Insects | diseases

LET'S HAVE SMOR

TESTING SCAB RESISTANCE TO FUNGICIDES:
SMOR AS A SERVICE
(Wolfram Koeller & Diana Parker, Plant Pathology, Geneva)


    Nine fungicides (Syllit; Topsin M or Methyl-T; Nova, Procure and Rubigan; Flint and Sovran; Vangard and Scala) belonging to four classes of chemistries are labeled for the post-infection control of apple scab.  Unfortunately, many of these materials have lost their activity because the scab fungus developed resistance.  In response, we have worked on the site-specific management of resistance (SMOR).  The SMOR concept is simple: Test the sensitivities of individual orchards and only use the post-infection materials that are still active.  Who would do the sensitivity tests to find out where individual orchards stand?  We are prepared to provide this test service for the 2005 season for a cost-covering fee of $800.

We must have 50 apple leaves with scab lesions to do these sensitivity tests.  There are two modes of testing, a 'forward mode' and a 'rescue mode'. 

   In the 'forward mode', a scab control failure has not been a problem in previous seasons, but a grower wants to know for how much longer the post-infection fungicides used will last until resistance sets in.  Naturally, leaves with at least one visible scab lesion will not be found easily.  In this case, six trees at the opposite corners of a typical orchard block must be left unsprayed until scab lesions develop on cluster leaves.  The 50 leaves with scab lesions are then collected and submitted to our test facility.  After that, the corner trees are included in all subsequent treatments.  Alternatives to such corner trees are unsprayed trees close (no more than 1,000 feet) to the orchard block, or a recently abandoned (no more than two seasons) orchard where scab had been managed with the same fungicide program. 

   In the 'rescue mode', leaf scab develops unexpectedly after post-infection fungicides have been applied.  In this case, finding leaves with scab lesions will not be a problem.  However, the leaves submitted for testing must be collected before a 'rescue' spray is applied.  Otherwise, the scab spores already sprayed will not germinate and, therefore, cannot be tested.

The collection and shipment of leaves to our test facility are crucial steps in the procedure:

  • The 50 leaves with visible scab lesions must be collected from as many trees as possible to reflect the sensitivity of the entire orchard.
  • The leaves must be stored in paper bags (e.g., an open mail envelop).  Plastic bags must be avoided, because the moisture building up in plastic bags will cause prohibitive problems.
  • Once the leaves are collected and stored in an open paper bag, they must be kept at a relatively cool place (lower than 75 F).  Spores of the scab fungus are very sensitive to heat and will be 'dead on arrival', if they are heated up; for example, inside a car or a truck cab on a sunny day. 
  • The open paper bag with leaves must be shipped to our test facility by overnight mail.  Surface mail takes too long to keep the spores of the scab fungus viable.  Prior to overnight shipment, the leaves can be kept in a regular refrigerator, but never longer than for two days.

Leaves are sent to (no weekend delivery):

   Diana Parker, Cornell University, Department of Plant Pathology, 630 West North Street, Barton Laboratory, New York State Agricultural Experiment Station, Geneva, NY 14456.  (Telephone 315-787-2400). 

   The minimum requirement included with the shipment of leaves will be the name, the address and the telephone/e-mail number of the submitter.  Much appreciated would be a 'warning' to Diana Parker, either by phone (315-787-2400) or by e-mail (dmp2@nysaes.cornell.edu) prior to the shipment.  

What happens next ?

The submitter will be contacted before sensitivity tests are initiated.  A brief form with simple questions will be sent (mail, fax, e-mail).  This form will include the assurance that a fee of $800 will be charged after a sensitivity diagnosis has been provided for the orchard sampled.  The test submission form and instructions can also be obtained from Cornell's regional extension tree-fruit specialists.

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THE MASK

BLOSSOM-END ROT OF APPLE: PHANTOM OF THE ORCHARD?
(Dave Rosenberger, Plant Pathology, Highland)

    In northeastern United States, blossom-end rots of apple are caused by at least three different fungi: Sclerotinia sclerotiorum, (the cause of white mold on beans), Botrytis cinerea (the gray-mold fungus), and Botryosphaeria obtusa (the black rot fungus).  When blossom end rot is caused by B. obtusa, symptoms usually develop only as fruit begin to ripen in autumn, even though the sepal infections may have occurred earlier in the season.  Symptoms of blossom-end rots caused by the other pathogen appear during summer.

   Blossom-end rot, caused by B. cinerea, is sometimes called "dry eye rot."  I have seen only a few apples with dry eye rot during 25 years of fieldwork in southeastern NY.  The disease develops when B. cinerea colonizes dying petals and then moves into sepals and eventually into the fruit.  Botrytis infections in sepals may remain quiescent until after harvest and then develop into fruit decays during storage, but the relationship between sepal infections at petal fall and subsequent incidence of gray mold decay during storage has not been proven. 

   Most of the blossom-end rot seen in NY and New England should be called calyx-end rot because it is caused by S. sclerotiorum.  The key difference between dry eye rot caused by B. cinerea and calyx-end rot cause by S. sclerotiorum is that the former usually appears as a circular rot centered on and completely encompassing the calyx, whereas the latter is almost always offset to one side of the calyx.  Calyx-end rot infections often stop expanding and die out when lesions reach a quarter to a half-inch diameter.  Fruit with these dried out lesions will appear normal at harvest except for the small dry lesion visible at the calyx.  In some years and on some varieties, however, calyx-end rots attract attention in midsummer because affected fruit color prematurely.  Fortunately, fruit that ripen prematurely usually drop from the tree before harvest.

   No one has studied the epidemiology and control of S. sclerotiorum on apples.  Most of what we know about the life cycle and effective controls for this fungus comes from other crop systems.  The fungus can colonize a wide range of broad-leaved plants and forms sclerotia (black pebble-like resting structures) that allow it to survive over winter.  These sclerotia germinate and produce wind-dispersed ascospores in spring.  The ascospores germinate and grow on senescing flower petals and then invade the subtending plant tissues.

   Calyx-end rot in apples has been observed primarily where growers relied exclusively on mancozeb or mancozeb-SI combinations for scab control, but it never showed up in ALL orchards using those fungicide programs.  Presence/absence of this disease may be related to the prevalence of certain broad-leaved plants in the ground cover.  However, we have no data to indicate which ground cover plants in apple orchards are most likely to harbor the disease or why it occurs in some orchards and not others.

   Because of the sporadic and unpredictable nature of this disease, and because losses are usually minimal even when the disease shows up, it is rarely cost-effective to target sprays specifically for calyx-end rot except for blocks where the disease was observed in previous years.  Where there is historical precedent for concerns about calyx-end rot, captan or Topsin M applied during bloom and/or at petal fall will probably provide adequate control.  Topsin M was very effective against S. sclerotiorum in bean fields, but resistance to this fungicide developed in some fields after it was used for many years.  No one knows whether S. sclerotiorum has developed resistance to Topsin M in apple orchards.

   Vangard and Scala are very effective against Botrytis diseases, but they have proven less effective against S. sclerotiorum in vegetable disease trials conducted at Geneva.  No one has data to show whether Vangard and Scala are more effective than captan for controlling calyx-end rot on apples.  Given that uncertainty, the decision to use Vangard or Scala in bloom and petal fall sprays should be based on their cost-effectiveness for scab control rather than on the possibility that they will control calyx-end rot.


This material is based upon work supported by Smith Lever funds from the Cooperative State Research, Education, and Extension Service, U.S. Department of Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture. Return to top