Tree Fruit IPM Advisory


USU Tree Fruit IPM Pest Advisories provide nearly weekly updates on current insect and disease occurrences, biology, and treatment recommendations for Utah. Updates run from mid-March through September.

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Greater Peachtree Borer, Controlling Birds, Rainfastness of Pesticides


pdf version

July 8, 2011

In this Issue:

What to Look for/Do Now:

  • Second generation start dates for codling moth added to spray timing table.
  • Watch for spider mites.
  • Continue monitoring for cherry powdery mildew and treat if necessary
  • Greater peachtree borers have been caught in the Wasatch Front area.
  • Commercial growers mark your calendar:  USU Extension Tree Fruit Field Day, Utah County, August 18


Current Insect and Disease Activity

APPLES/PEARS

Codling Moth

 

Determine the success of your first generation spray program in the next few weeks.  Check fruit for stings (where the larvae was unsuccessful in entry) and entries.  Look where fruit touch each other, or where fruits and leaves touch.  Often, this is where larvae will enter the fruit, either due to the fact that the fruit is not protected by insecticide in these areas, or it offers the larva better protection from predators.


The "when do I spray" table below has been updated with the start date for 2nd generation codling moth egg hatch.  The first generation egg hatch will end late next week for most locations along the Wasatch Front (near the end of July for cooler locations).  The "break" between end of 1st generation egg hatch and beginning of 2nd generation ranges from about 4-6 days.  So keep this in mind if you still need to apply one last spray for 1st generation.  If it lasts until the end, then you won't need to spray again until the beginning of the second generation.


Leafhoppers

 

 

Leafhoppers have been active since egg hatch around petal fall, and are very noticeable now that they have matured to adults. If you look on the underside of a leaf showing symptoms, you will notice white “skins” where leafhopper nymphs have molted from one stage to the next. There are two generations of leafhopper per year, and the second generation which will show up in late summer, can be large if the first generation is not controlled. Apple trees can tolerate a large population (more than 6 nymphs/leaf) before any damage occurs to fruit, but hopping and flying insects can be a nuisance during harvest.

Growers who are using acetamiprid (Assail, Ortho Max) for codling moth should see leafhopper control, too. Otherwise, consider Belay or Actara. (Leafhoppers are usually not pests on backyard trees.)

 


Spider Mites

 

Spider mite activity is slowly increasing, on apples, peaches, and cherries. Check for mites on your own trees by examining the leaves on the lowest branches first. (Mites overwinter in groundcover and migrate up the tree in hot, dry weather.) Look for stippling (whitish spots) on the leaves, and turn them over. Using a hand lens, look for the slow-moving mites.

Before making a decision on whether to treat, look for predatory mites within the pest mite population. These are fast moving mites, about the same size, that can prevent spider mite densities from exceeding economic thresholds. If predators are present, then a treatment may not be necessary.

A 0.5-1% application of horticultural oil is very effective on mites, especially when populations are low. When treating, good coverage is essential.

 


Appleleaf and Pearleaf blister mites

 

 

Damage from blister mites is becoming obvious at this time of year. These minute, 4-legged mites feed inside the blisters that form on the leaves, and in late summer, they migrate to leaf buds to continue feeding and to spend the winter.

The blisters have started turning brown (apple) to black (pear), and will continue to darken as the summer progresses. Note that there is nothing to do for treatment at this time of year, but an application of 1% oil just before leaf drop, and 2% oil at the delayed dormant timing, can effectively control this pest.


STONE FRUITS

California Prionus Root Borer

 

 

Prionus larvae of this insect bore within the roots of stone fruits, in particular sweet cherry. The only way to tell if an infestation is present is to dig up roots to look for larvae or damage. A minor infestation will cause tree wilting and possibly yellowing of leaves due to lack of water and nutrient uptake. A heavy infestation will kill trees. The problem tends to be more severe in sandy soils. Prionus also feeds on other ornamentals, including gambel oak and maple.

The adult is a very large (1-2-inch), brown beetle that emerges from pupation in July. They were trapped in the Perry area July 5, and will continue emerging for the next month. Adults fly only at night during their short 10-20 day life span. They do not feed; their only objective is to mate.

After mating, the female lays 150-200 eggs just below the soil surface and near the trunk of trees. Larvae seek out roots for feeding. They begin at the smallest diameter roots and eventually move to larger diameter roots toward the crown of the tree. This process can take 3-5 years. Mature larvae are up to 3 inches long.

There are very little control options except to keep trees healthy, completely remove infested trees, and avoid planting in infested sites.

Recently, the female sex pheromone was identified, and a lure is now available, made by ConTech. One option for small farms or backyard trees would be mass trapping over a period of several years. There is some evidence that this can reduce the population over time.

Entomologist Diane Alston and Box Elder County Ag Agent, Mike Pace, are testing the use of high loads of pheromone to disrupt the mating process (mating disruption). So far, results look good with traps at test sites catching very few beetles. A mating disruption product may be available within the next 1 to 2 years.


Greater Peachtree Borer

 

 

The first borer moths of the season were caught this week, so all growers in the Wasatch Front region should begin treatment now on peach, nectarine, and apricot. We don’t expect to see moths in Cache or Carbon counties for at least 2-3 more weeks.

Greater peachtree borer (sometimes called trunk, root, or crown borer) is a day-flying moth that resembles wasps. You may see them (thin, metallic blue-black body with clear wings) resting on leaves. Adults lay eggs on the lower 12” of the tree trunk or on nearby soil, and larvae bore their way into the wood and remain there for the next 9-11 months.

Sprays only need to be applied to the lower 12-18” of the trunk and any exposed roots. The residual material on the bark will kill the eggs laid by the adults as well as newly hatching larvae. Materials that contain permethrin (that are labeled for fruit trees) will provide the best control. Sprays should be applied 14-21 days apart, through the end of September.

 

Production Information

Preventing Injury from Birds

Robins, starlings, blackbirds, grackles, and even our beautiful orchard oriole can sometimes be a nuisance by stealing precious fruit crops such as sweet cherries and grapes. Crops growing near roosting or nesting areas, trees, or ponds, are the most vulnerable.

Because birds acclimate quickly to some bird control options such as uniform movements or noise patterns, it is important to use a variety of methods rather than relying on one option. The options available include using visual repellents, barriers, or chemical sprays. Larger farms may also incorporate noise or roosting sites to attract larger birds of prey.

Visual Repellents

 

Scaring tactics using visual objects are probably the least effective option, but when combined with other tactics, can be helpful. Options include “scare eye balloons” that depict eyes (or the gaping mouth) of a hawk. Research in Ontario has shown that the yellow colored balls are most effective on blackbirds, sparrows and finches, but that no color affects robins and waxwings. To be effective, they should be suspended above the crop and allowed to blow in the wind. Shiny streamers and mirrors reflect the sun, and when distributed over a wide area, confuse birds. Fake hawks, snakes, or other objects have no effect.

Physical Barriers

Using netting provides the best control on smaller crops, but is expensive or impractical on large cherry trees. The netting may be draped over the crop or fastened to an overhead structure which completely encloses the crop.

Chemical Control
Many chemicals have been tested over the last several decades, but few have provided acceptable control without any health risks. Research that began out of Cornell in the late 1990s found that methyl anthranilate, a flavor component of Concord grapes, is repellent to most birds. This food-grade chemical is used in certain gum, candy, juice, and soft drink products. In research trials, however, it was found to lose effectiveness after about 3 days, is not rainfast, and must be consumed in high quantities to be effective. It is registered as FruitShield.

Noise
Loud blasts of noise at irregular intervals can scare birds away (as well as neighbors). Bird-bangers (cannons) can fire shots at a random times and locations. Ideally, sounds should be spaced no more than 3 minutes apart. Birds get used to sounds that never change and are regularly spaced. Cannons are not practical on smaller farms where the loud noise will disturb neighbors. Other options are a warbling alarm-type signal or distress calls. The alarm calls prevent birds from communicating with each other so that they eventually leave the area, and the distress calls prevent nesting and also attract birds of prey. An effective noise device for larger farms is a pistol-fired whistling or banging cartridge that is shot into the air to prevent flocks from entering the area.

For effective bird control, it is important to use a variety of options and start early before birds become habituated to the site.


Rainfastness of Pesticides

Dr. John Wise at the Michigan State University Trevor Nichols Research Center, began testing many pesticides for rainfastness starting in 2006. They have been using a rainfall simulation chamber to conduct trials on fruit crops.
What he found was:

  • The organophosphate insecticides (Imidan, Guthion) are the least rainfast. On the other hand, they are highly toxic, which may overcome the need for an immediate re-application after a rain event.
  • Neonicotinoid insecticides (Provado and generics, Assail) are slightly more rainfast, but can be washed off. Keep in mind that these products are systemic, and can move into the plant tissue. Material that has had time to enter tissue is completely rainfast (about 4 hours).
  • Pyrethroid, carbamate and IGR insecticides (Warrior, Pounce, Sevin, Esteem, etc.) are moderately susceptible to wash-off, and vary in their toxicity to the range of relevant fruit pests.
  • Diamide and spinosyn insecticides (Delegate, Altacor, Success) are highly rainfast.

He has developed the following rainfastness charts:

General Rainfastness for Various Chemical Classes Under Different Rain Amounts

  Rainfall <0.5 inch Rainfall <1 inch Rainfall <2 inch
Insecticide Class Fruit Leaves Fruit Leaves Fruit Leaves
Organophosphates L M L M L L
Pyrethroids M M L M L L
Carbamates M M L M L L
IGRs M H        
*Neonicotinoids M H L L L L
Spinosyns H H H M M L
Diamides H H H M M L
*Avermectins M H L M L L

*Systemic residues remain within plant tissues
H=highly rainfast (less than 30% removed), M=moderately rainfast, L=low rainfast (more than 70% wash-off)

 

Apple Insecticide Precipitation Wash-off Re-application Decision Chart:  Expected codling moth control in apples, based on each compound’s inherent toxicity to CM larvae, maximum residual, and wash-off potential from rainfall.

   Rainfall=0.5 inch  Rainfall=1.0 inch  Rainfall=2.0 inch
Insecticide  *1 day *7 days  1 day 7 days 1 day 7 days
Guthion        X   X
Imidan        X   X
Asana    X  X  X  X X
Calypso        X  X X
Assail    X  X  X  X X
Proclaim    X    X  X X
Delegate           X
Altacor           X
Belt           X

* Number of days after insecticide application that the precipitation event occurred.
X – Insufficient insecticide residue remains to provide significant activity on the target pest, and thus re-application is recommended.
- An un-marked cell suggests that there is sufficient insecticide residue remaining to provide significant activity on the target pest, although residual activity may be reduced. 

 

 

Upcoming Monitoring/Insect Activity

Pest

Host

Appearance/Management

Codling moth

apple fruit

Second generation begins late July

San Jose scale

apple mostly

Treat crawlers in early July

Pear psylla

pear

Second generation egg hatch begins early July

Peach twig borer

peach, nectarine, apricot

Egg hatch begins late June

Peach powdery mildew

peach

Look for powdery lesions (peach powdery mildew) or rust-colored lesions (apple powdery mildew) in June and July

Cherry powdery mildew

cherry

Look for small white lesions on new foliage near the base and interior of the tree

 

Degree Day Accumulations and Insect Development

Click here for information on degree days.

March 1 - July 6

County

Location

Codling Moth, 1st Generation

 Peach Twig Borer, 1st Generation

DD
(post biofix)

% Moth Flight

% Egg Hatch

 DD
(post biofix)

% Moth Flight

% Egg Hatch

Box Elder

Perry

460

85

45

228

51

1

Tremonton

449

84

42

---

---

---

Cache

River Heights

532

92

64

196

38

0

Smithfield

502

90

54

174

30

0

Carbon

Price

644

98

80

338

85

11

Davis

Kaysville

664

98

83

443

97

43

Grand

Castle Valley

1348

51

15

948

3

0

Iron

Cedar City

644

98

80

495

99

62

Salt Lake

Holladay

729

99

90

540

100

75

West Valley City

748

100

91

558

100

79

West Jordan

689

99

85

---

---

---

Tooele

Erda

581

95

70

485

98

50

Tooele

643

98

80

573

100

82

Uintah

Vernal

689

99

86

445

97

43

Utah

Alpine

525

92

59

150

23

0

American Fork

615

96

73

453

97

45

Genola

749

100

91

392

93

24

Goshen

462

85

45

215

45

0

Lincoln Point

647

98

80

315

78

7

Lindon

518

91

58

262

64

2

Provo

---

---

 ---

517

99

68

Payson

637

98

80

 ---

---

---

Santaquin-West

636

98

80

203

38

0

West Mountain

634

97

89

---

---

---

Weber

Pleasant View

671

98

83

464

98

51

Wasatch

Heber City

421

80

32

---

---

---

Wayne

Capitol Reef

687

99

86

---

---

---

 

Codling Moth - When to Spray

Continue to apply your chosen material(s) at the interval provided on the label.  Make sure fruit is well protected during the period of greatest egg hatch.  You do not need to spray between generations.
  

County

Location

Period of Greatest Egg Hatch (340-640 DD)

Keep Fruit Protected up To: (1020 DD)

Second Generation
(1120 DD)

Period of Greatest Egg Hatch: 2nd Generation (1320-1720)

Box Elder

Perry

past

July 23

July 27

Aug 3 - Aug 21

Tremonton

July 1 - July 14

July 28

July 30

Aug 10 - Aug 29

Cache

River Heights

June 26 - July 12

July 27

Aug 2

Aug 10 - Aug 31

Smithfield

June 29 - July 12

July 27

Aug 1

Aug 9 - Aug 28

Carbon

Price

June 25 - July 12

July 31

Aug 2

Aug 9 - Sept 3

Davis

Kaysville

past

July 18

July 25

Aug 1 - Aug 18

Grand

Castle Valley

past

past

past

July 5 - July 19

Iron

Cedar City

past

July 22

July 26

Aug 3 - Aug 21

Salt Lake

Holladay

past

July 13

July 19

July 27 - Aug 9

West Valley City

past

July 15

July 20

July 27 - Aug 11

West Jordan

past

July 21

July 22

July 29 - Aug 13

Tooele

Erda

past

July 21

July 27

Aug 2 - Aug 18

Tooele

past

July 20

July 25

July 31 - Aug 16

Uintah

Vernal

past

July 23

July 27

Aug 4 - Aug 24

Utah

Alpine

June 20 - July 10

July 26

July 31

Aug 9 - Aug 27

American Fork

past

 July 23

July 27

Aug 3 - Aug 20

Genola

past

July 19

July 21

July 29 - Aug 14

Goshen

past

July 22

July 30

Aug 10 - Aug 27

Lincoln Point

past

July 21

July 25

Aug 2 - Aug 18

Lindon

past

July 17

July 21

July 29 - Aug 13

Payson

past

July 19

July 25

Aug 2 - Aug 18

Santaquin-West

past

July 21

July 25

Aug 2 - Aug 19

West Mountain

past

July 19

July 24

Aug 2 - Aug 18

Weber

Pleasant View

past

July 18

July 23

July 30 - Aug 14

Wasatch

Heber City

July 1 - July 18

Aug 8

Aug 15

Aug 25 - Sept 29

Wayne

Capitol Reef

past

July 13

July 20

July 29 - Aug 13

  

Peach Twig Borer - When to Spray


If you had moderate to severe PTB damage last year, use the earlier spray date; if you had very little PTB damage last year, use the later date to start sprays.  These two dates correspond to 300 and 360 degree days after biofix, or 5% and 16% egg hatch.  End of egg hatch, where you should “keep fruit protected up to” is at 800 degree days.  The second generation egg hatch (5%) starts at 1200 DD.
 

County

Location

Start Sprays
(large population/ heavy damage)

Start Sprays
(small population/ little to no damage)

Keep Fruit Protected Up To:

Start sprays, 2nd Generation

Box Elder

Perry

past

past

July 25

Aug 8

Cache

River Heights

July 12

July 15

Aug 3

Aug 21

Smithfield

July 12

July 14

Aug 1

Aug 18

Davis

Kaysville

past

past

July 20

Aug 4

Grand

Castle Valley

past

past

past

July 15

Iron

Cedar City

past

past

July 20

Aug 4

Salt Lake

Holladay

past

past

July 15

July 29

West Valley City

past

past

July 16

July 29

Tooele

Erda

past

past

July 18

Aug 1

Tooele

past

past

July 16

July 29

Uintah

Vernal

past

past

July 24

 Aug 10

Utah

Alpine

July 12

July 15

Aug 3

Aug 20

American Fork

past

past

July 21

Aug 5

Genola

past

past

July 22

Aug 7

Goshen

July 7

July 10

July 27

Aug 15

Lincoln Point

past

past

July 18

Aug 2

Lindon

past

past

July 18

Aug 3

Provo

past

past

July 17

Aug 1

Santaquin

July 9

July 13

July 29

 Aug 14

Weber

Pleasant View

past

past

July 19

Aug 2

 

Spray Materials - Commercial Applicators

The options provided below are not all-inclusive and are not endorsements of USU.  Please check the label before mixing.

Target Pest

Host

Brand

Chemical

Amount
per acre

REI

Comments

Codling Moth

apple

Altacor 35WDG

chlorantraniliprole

3.0-4.5 oz

4 h

re-apply based on product interval through each generation until harvest or Sept. 15

Assail

acetamiprid

1.7-3.4 oz

12 h

Belt SC

flubendiamide

5 oz

12 h

Delegate 25WG

spinetoram

6-7 oz

4 h

Imidan 70W

phosmet

3.5-5.3 lbs

3 d

Voliam Flexi

thiamethoxam +chlorantraniliprole

4-7 oz

12 h

San Jose scale

apple

acetamiprid

Assail

3.4 oz

12 h

Talus:  one application/season
Esteem:  45-day PHI; but provides excellent control

buprofezin

Talus

see label

 

pyriproxifen

Esteem

4-5 oz

12 h

Woolly apple aphid

apple

Assail

acetamiprid

1.7 oz

12 h

apply post bloom only if scouting shows that this pest is present

Beleaf

flonicamid

2-2.8 oz

12 h

Calypso

thiacloprid

2-4 oz

12 h

Clutch

clothianidin

2-3 oz

12 h

Admire Pro; generics

imidacloprid

see label

12 h

Peach twig borer

peach, nectarine

Belt

flubendiamide

3-4 oz

12 h

reapply based on protection interval until harvest

Altacor

chlorantraniliprole

3.0-4.5 oz

12 h

Delegate

imidacloprid

4.5-7.0 oz

12 h

Imidan

phosmet

4.25 lbs

12 h

Voliam Flexi

thiamethoxam+ chlorantraniliprole

4-7 oz

12 h

Greater peachtree borer

peach, nectarine, apricot

chlorpyrifos

Lorsban

see label

4 d

Lorsban:  max once/season; do not allow spray to touch foliage/fruit
Thionex:  max twice/season

endosulfan

Thionex

see label

4 d

esfenvalerate

Asana

see label

12 h

pemethrin

Pounce

4-8 oz

12 h

Powdery mildew

peach

Adament

tebuconazole+ trifloxystrobin

4-8 oz

4 h

monitor fruit and leaves for powdery mildew and only apply if necessary; chance of fruit infection decreases after pit hardening

Abound

azoxystrobin

11-15 oz

12 h

Orbit, Tilt

propiconazole

4 oz

4 h

Pristine

boscalid+ pyraclostrobin

2-2.4 oz

12 h

Western Cherry Fruit Fly

cherry

Altacor

chlorantraniliprole

3.0-4.5 oz

4 h

start applications when fruit develops salmon blush color on top of yellow and continue until harvest

Assail

acetamiprid

5.3-8 oz

12 h

Delegate

spinetoram

4.5-7 oz

4 h

GF-120

spinosad+bait

10-20 oz

4 h

Admire Pro; generics

imidacloprid

see label

12 h

Powdery mildew

cherry

Abound

azoxystrobin

11-13 oz

4 h

 

Pristine

boscalid+ pyraclostrobin

10.5-14.5 oz

12 h

Quintec

quinoxyfen

7 oz

12 h

Rally

myclobutanil

2.5-6 oz

24 h

Rubigan

fenarimol

6-12 oz

12 h

 

Spray Materials - Residential Applicators

Note that these treatments are only recommended if you know you have the particular pest in your trees.

 

Target Pest

Host

Chemical

Example Brands

Comments

Codling moth

apple, pear

Conventional

 

acetamiprid:  every 14 days
carbaryl:  every 14 - 21 days
malathion:  every 7 days
gamma-cyhalothrin:  every 14 days
bifenthrin:  every 14 days; pears only


hort. oil:  lasts 5-7 days for killing eggs; use at beginning of each generation; apply at 1% rate only when temperatures are below 80; follow up with a different product


spinosad:  every 7 days
codling moth virus can only be purchased online

acetamiprid

Ortho Max Flower, Fruit, and Veg.

carbaryl

Sevin, Bonide Fruit Tree Spray, etc.

malathion

Malathion

gamma-cyhalothrin

Spectracide Triazicide

bifenthrin

Ortho Max Lawn and Garden Insect Killer

 

 

Soft/organic

 

hort. oil (1%)

Many products

spinosad

Green Light Lawn and Garden Spinosad; Gardens Alive Bull’s Eye; Ferti-Lome Borer, Bagworm, Leafminer & Tent Caterpillar; Monterey Garden Insect Spray; Natural Guard

codling moth virus

Virosoft, Cyd-X

San Jose scale

apple

Conventional

 

two applications spaced 7-14 days apart should be enough

carbaryl

Sevin

 

 

Soft/organic

 

hort. oil

many options

neem oil

Concern, Garden Safe, others

Peach twig borer

peach, nectarine

Conventional

 

see comments under Codling Moth

permethrin:  every 14 days; this ingredient is becoming less available in stores

Surround:  every 3-5 days; works to repel, not kill insects; only moderate control; must purchase online

acetamiprid

Ortho Max Flower, Fruit & Veg

carbaryl

Sevin, Bonide Fruit Tree Spray, etc.

malathion

Malathion

permethrin

Basic Solutions Yard & Garden, Bonide Eight

 

 

Soft/organic

 

spinosad

see ‘codling moth’ above

kaolin clay

Surround

Greater peachtree borer

peach, nectarine, apricot

permethrin

Bonide Eight, Green Light Borer Killer, Bonide Borer-Miner Killer, Enforcer Outdoor Insect Killer, Hi-Yield Broad Use Including Gardens; Lilly Miller Multi-Purpose Insect Spray

permethrin:  apply every 14-21 days until mid-September in highly infested areas; apply twice (now and one month later) in low infestations

carbaryl:  must be applied every 7 days

carbaryl

Sevin, Bonide Fruit Tree Spray

Aphids

all fruit trees

carbaryl

Bayer Advanced

start with a single application

bifenthrin:  pears only

bifenthrin

Ortho Bug-B-Gone

malathion

Bonide, Malathion

neem oil

Green Light

permethrin

Lilly Miller

Powdery mildew

all fruit trees

bayleton

Bonide

do not apply lime sulfur when temperature is over 75 degrees F

Neem oil and Kaligreen are organic options

lime sulfur

Lilly Miller

propiconazole

Ferti-Lome

neem oil

Garden Safe

potassium bicarbonate

Kaligreen

Western cherry fruit fly

cherry

carbaryl

Sevin

start applications when fruit in sunniest locations develop a salmon blush

malation:  make sure cherry is on label

spinosad:  every 7 days

malathion

Malathion

pyrethrin

Concern Multi-Purpose

(Soft/Organic)
spinosad 


see above

 


Precautionary Statement:  Utah State University Extension and its employees are not responsible for the use, misuse, or damage caused by application or misapplication of products or information mentioned in this document.  All pesticides are labeled with ingredients, instructions, and risks.  The pesticide applicator is legally responsible for proper use.  USU makes no endorsement of the products listed herein.