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May 6, 2002 Volume 11 No. 8 Update on Pest Management and Crop Development

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Table of Contents:
UPCOMING PEST EVENTS
PHENOLOGIES
PHEROMONE TRAP CATCHES
PEST FOCUS

INSECTS
     Petal fall pest control

 

Scaffolds is published weekly from March to September by Cornell University -- NYS Agricultural Experiment Station (Geneva), and Ithaca -- with the assistance of Cornell Cooperative Extension.

New York field reports welcomed. Send submissions by 3 p.m. Monday to:

Scaffolds Fruit Journal

Editors: A. Agnello, D. Kain

Dept. of Entomology, NYSAES

Geneva, NY 14456-0462

Phone: 315-787-2341 FAX: 315-787-2326

 

Scaffolds 2002 index

Upcoming Pest Events

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

 

 Current DD accumulations
43°F
50°F
(Geneva 1/1-5/6):

375

195

(Geneva 1/1-5/6/2001):

333

194

(Geneva "Normal"):

307

144

(Highland 1/1-5/6):

549

291

 
Coming Events: Ranges:  

American plum borer 1st catch

194-567

55-294

Codling moth 1st catch

273-805

141-491

Comstock mealybug 1st gen crawlers in pear

220-425

82-242

European red mite egg hatch

157-358

74-208

Mirid bugs 1st hatch

322-481

156-246

Obliquebanded leafroller larvae active

149-388

54-201

Pear psylla egg hatch

111-402

55-235

Rose leafhopper nymphs on multiflora rose

188-402

68-208

San Jose scale first catch

189-704

69-385

Spotted tentiform leafminer 1st flight peak

180-544

65-208

Tarnished plant bug adults active

71-536

34-299

McIntosh at petal fall

418-563

210-298

Pear at petal fall

343-544

144-275

Peach at shuck split

362-518

174-287

Plum at fruit set

411-527

206-287

Sweet cherry at fruit set

381-518

171-287

Tart cherry at petal fall

385-563

185-289


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Phenologies

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

 

Phenologies

(Geneva):

Apple (McIntosh):

Bloom

(Red Delicious):

King Bloom

Pear:

50% Petal Fall

Peach:

Petal Fall

Tart Cherry:

Bloom

Sweet Cherry:

Petal Fall

Plum:

Petal Fall

(Highland):

Apple (McIntosh):

90% Petal Fall

(Golden Delicious):

50% Petal Fall

Pear (Bartlett):

8mm Fruit

Peach:

Shuck Split

Plum (Stanley):

Shuck Split

Quince:

Full Bloom

Cold weather over the past two weeks slowed tree development, resulting in an extremely extended bloom period for apples. On early apple varieties such as Jerseymac, the oldest king fruit are at 8 mm diameter while 20% of the clusters are still in full bloom. 

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Trap Catches

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

 

TRAP CATCHES (Number/trap/day)

Geneva        
 

4/25

4/29

5/3

5/6

Green Fruitworm

0.3

0.3

0.0

0.0

Redbanded Leafroller

2.3

0.0

0.3

1.0

Spotted Tentiform Leafminer

15.5

4.5

23.6

103

Oriental Fruit Moth

1.0

0.0

0.3

32.0

Lesser Appleworm

0.5

0.0

0.3

79.2

Codling Moth

0.0

0.0

0.0

0.0

San Jose Scale

-

-

0.0

0.0

Highland (Dick Straub, Peter Jentsch):

       
 

4/15

4/22

4/29

5/6

Green Fruitworm

0.2

0.1

0.0

0.0

Redbanded Leafroller

1.9

2.6

11.0

4.1

Spotted Tentiform Leafminer

4.8

111

9.9

10.0

Oriental Fruit Moth

0.9

29.5

0.3

4.0

Codling Moth

-

-

0.1*

0.0

Lesser Appleworm

-

-

0.0

0.0

Tufted Apple Budmoth

-

-

0.0

0.0

Variegated Leafroller

-

-

0.0

0.0

* = 1st catch

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Pest Focus

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

 

Orleans Co.: Pear Psylla nymphs and White Apple Leafhopper nymphs noted.

Highland: Obliquebanded Leafroller, Redbanded Leafroller, and Green Fruitworm larvae and feeding damage noted. Pear Psylla hardshells observed.


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Insects

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

 

A PILE OF PETALS AT YOUR FEET

(Art Agnello, Entomology, Geneva)

 

Before we completely lose the opportunity to address spring pest decisions, as the trees seem destined to get the whole season over with by July, we should probably discuss a few petal fall considerations and how this year's highly irregular weather may be affecting what the insects are and aren't doing out there.

First of all, this is one of those years where the long-observed relationships between tree development and pest activity may not exactly hold true to our expectations. The concept of what's "normal" is a tenuous one, and easily subject to modification after something generally thought to be rare occurs more than once or twice. We have now seen a few years where the tight cluster-to-pink-to-bloom sequence has been contracted into just a few days, and the result can easily have the trees outrunning the insects. This differential response to heat units appears to push certain pest events "back" one or two phenological stages, compared with what we normally expect. Mite eggs, which normally start hatching at tight cluster, hold on until pink or later; leafminer eggs aren't seen until bloom rather than pink; oriental fruit moths, normally in full flight by peach petal fall, are only just starting to appear in traps. Other species, such as pear psylla and tarnished plant bug, may be quick responders, needing only a day or two of warm temperatures to explode into full activity. This might have been why we heard so many reports of TPB activity at the start of the warm-up period, not because they were necessarily more numerous this year.

Growers may be better advised to base their petal fall spray needs on what is actually going on in the field at this moment rather than what "normally" occurs at petal fall. Some specifics:

Mites

If you managed to get a prebloom oil or miticide applied, fine. If you didn't, and are concerned about early buildup in certain problem blocks, Apollo and Savey are just as appropriate to consider at petal fall as is Agri-Mek, which we normally recommend at this time. Nymphal populations are still likely to be small enough to be effectively handled by any one of these materials, if they fit into your product rotation (i.e., weren't used last year).

Obliquebanded Leafroller

Because these insects overwintered as 1st or 2nd stage larvae, they probably haven't had enough time to feed and grow as much as in a normal year, and may be somewhat smaller than they usually are by petal fall.This translates into potentially higher control efficacy with whatever product is used against them, as smaller larvae are generally easier to kill. Among the selective insecticides available, Confirm and B.t. products such as Dipel are options, and the latter can be used while blossoms are still present. Pyrethroids such as Asana or Danitol can also be effective, depending on past use history, but be aware of their broad-spectrum effects, which can work both for and against you, according to how many beneficial mites and insects you can afford to lose.

Oriental Fruit Moth

OFM has been receiving more attention recently, as we have been made increasingly aware of its ability to overcome some of the older OP-based control programs, particularly in peaches. However, now that we've made such a big stink about starting to consider control at petal fall instead of shuck split, this year has us seeing a flight that's just barely getting off the ground even though many peach orchards are certainly at (or past) petal fall. To maximize the efficacy of your 1st brood control, growers in western N.Y. at least could probably wait until the end of this week before starting a program such as Asana, backed up 10-14 days later.

On the Other Hand: Plum Curculio and European Apple Sawfly

The activities of these two pests may not be so easily waylaid by advanced tree development, because they tend to be active and in the trees during bloom in a normal year anyway, and the only reason we don't worry about them until petal fall is that there's no fruit around to be bothered until then.

Plum curculio adults move into orchards from overwintering sites in hedgerows or the edges of woods and adults are active when temperatures exceed 60°F. Adult females oviposit in fruit during both day and night but feed mostly at night. Depending on temperature, overwintering adults remain active for two to six weeks after petal fall. Because adults are not highly mobile, orchards near overwintering sites, woodlands, and hedgerows are most susceptible to attack. Fruit damage is usually most common in border rows next to sites where adults overwinter. Although initial post-bloom sprays for plum curculio control should begin at petal fall, growers are often unsure how many additional sprays will be necessary to maintain protective chemical residues to prevent subsequent damage throughout the PC oviposition cycle, which varies according to temperatures and weather patterns after petal fall.

Following from the fact that PC activity and oviposition are greatly affected by temperature, an oviposition model has been developed to determine when control sprays after petal fall are no longer necessary to protect fruit from PC damage. This model is based on the assumption that residues from control sprays after petal fall only need to be maintained on fruit and foliage until about 40% of the oviposition cycle is complete, which is predicted by the model to occur at 340 DD (base 50°F) after petal fall. Probably, this strategy works because, after 40% of PC oviposition is complete, adults usually are not moving into the orchard from outside sources, or moving around within orchards from tree to tree. Therefore, by this time, adults residing in treated trees have already been killed by insecticide residues and are unable to complete the remainder of their normal oviposition cycle.

In order to use this strategy: (1) Treat the entire orchard at petal fall with a broad spectrum insecticide. (2) Start calculating the accumulation of DD after petal fall (base 50°F). (3) No additional sprays are necessary whenever the date of accumulation of 340 DD falls within 10-14 days after a previous spray.

European apple sawfly, a primitive bee and wasp relative, shows a preference for early or long-blooming varieties with a heavy set of fruit. This insect is generally a pest mainly in eastern N.Y. The adult sawfly emerges about the time apple trees come into bloom and lays eggs in the apple blossoms. Young larvae begin feeding just below the skin of the fruits, creating a spiral path usually around the calyx end. This early larval feeding will persist as a scar that is very visible at harvest. Following this feeding, the larva usually begins tunneling toward the seed cavity of the fruit or an adjacent fruit, which usually causes it to abort. As the larva feeds internally, it enlarges its exit hole, which is made highly conspicuous by a mass of wet, reddish-brown frass. The frass may drip onto adjacent fruits and leaves, giving them an unsightly appearance. The secondary feeding activity of a single sawfly larva can injure all the fruit in a cluster, causing stress on that fruit to abort during the traditional "June drop" period.

Certain insecticides that control these pests also adversely affect bees, which can pose a problem at petal fall because certain apple varieties lose their petals before others. In blocks of trees where petal fall has occurred on one variety but not the others, the variety that has lost its petals is likely to sustain some curculio or sawfly injury until the insecticide is applied. One newly registered insecticide with activity against both pests, Avaunt, may have a slight advantage in this case. Although highly toxic to bees exposed to direct treatment, it is relatively non-toxic when dried. To minimize the hazard to honey bees, apply any pesticide only after ALL petals have fallen in the block and when no bees are actively foraging on blooming weeds (evening is better than early morning).

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________________________________________________________________________

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.

Scaffolds is published weekly from March to September by Cornell University -- NYS Agricultural Experiment Station (Geneva), and Ithaca -- with the assistance of Cornell Cooperative Extension. New York field reports welcomed. Send submissions by 3 p.m. Monday to:

Scaffolds Fruit Journal
Editors: A. Agnello, D. Kain
Dept. of Entomology, NYSAES
P.O. Box 462
Geneva, NY 14456-0462

Phone: 315-787-2341 FAX: 315-787-2326

E-mail: ama4@cornell.edu

Online at <http://www.nysaes.cornell.edu/ent/scaffolds/>

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