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Landscape Pest Notes for July 2023

Cooley Spruce Gall Adelgid (1850-1950 GDD = galls open): Colorado spruce (especially green forms), Sitka and Oriental spruce, and Douglas-fir share this pest’s two host life cycles. Mature adult females lay eggs at the tips of branches. These eggs hatch and the immatures move to new growth and start feeding. The combined feeding and salivary secretions induce the development of a bright green, oval “pineapple” gall on the terminals (as opposed to galls at the base of new growth on Norway spruce from the Eastern spruce gall adelgids). By midsummer, the gall will turn brown and crack open, as the adelgids within mature and emerge as adults. These winged adults migrate to Douglas-fir (or another spruce) and spend the remainder of the summer feeding on the needles, covered with cottony wax.

Coolly Spruce Gall Adelgid = dead, open gall

During late July or early August the adult Cooley spruce gall adelgids will emerge from the opened brown pineapple shaped galls. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Sometimes Douglas-fir is so heavily attacked that needles are spotted, bent, or distorted. Two or more generations can occur on Douglas-fir through the following season (Christmas tree growers will treat Douglas fir when new growth is 3-4 inches). By next fall another winged generation flies back to spruce and lays eggs for the cycle to repeat itself.

Cooley spruce gall adelgid on Douglas-fi

After the Cooley spruce gall adelgid winged adults emerge from the “pineapple” galls on spruce some will relocate & infest Douglas-fir needles. They will remain on this host for the remainder of the summer. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Control by pruning out galls when seen before they open in mid-summer. Place sticky traps out in  summer (Douglas-fir or spruce) (1850-1950 GDD) to determine the timing to spray adults with insecticidal soap (+ sticker). In southern NJ some of the tip “pineapple” galls on spruce will soon open up, and the winged adults will emerged. Except to improve the aesthetic appearance of the trees, there is nothing to be gained by picking off the galls after they have opened. Future control windows will occur during the fall or early spring months, against the overwintering females located at the bases of terminal buds. Some possible treatments include horticultural oil, carbaryl (Sevin), insecticidal soap, or imidacloprid (Merit).

The Landscape Pest Notes for July 2023 contains only insect/mite pests & a couple of predators commonly seen during the month. Contained below are 16 additional pests or predators that appear in the order they are listed as follows: Pine needle scale, Fall webworm, Obscure scale, Pitch mass borer, Two banded Japanese weevil, Aphids, Cicada killer, Juniper webworm, Sapsucker, White pine weevil, Peach tree borer, White waxy lady beetle, Japanese beetle, Oriental beetle, Dogwood sawfly, & Plant leaf galls. [Read more…]

Nursery Pest and Disease Update 6/15/2023

In this edition:

  • Insects:
    • MORE Scale crawlers emerging
    • Borers
    • Beetles
  • Diseases:
    • Oomycete root diseases (Phytophthora, Pythium, Phytopythium)
    • Leaf spots / foliage diseases
    • Boxwood Blight – reminder
    • Virus observations
  • Nutrient Management 
    • Managing Soluble Salts by monitoring EC
    • Plant Tissue analysis
  • Plant Spotlight:
    • American Holly (Ilex opaca)
  • Cumberland Nursery / NJNLA – Twilight: tonight (6/15) for NURSERYMEN ONLY (contact twaller@njaes.rutgers.edu or 856-451-2800 Ext. 1. for details)

Please click “read more” below to get updates on pests, diseases, and other important resources for the week of 6/15/2023.

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Landscape Pest Notes for Early June 2023

Boxwood Spider Mite: (GDD =450-700) (PPI = Kousa Dogwood; Cranberry Bush) This spider mite, which attacks all boxwoods, is neither a true cool nor warm season mite species. It is usually most active with intermediate temperatures during late spring & early summer. The adult is yellow-tan in color with long legs. When the boxwood mites are active, they can be found on both the top & bottom of new growth. Eggs are light yellow & overwinter on leaves & twigs. There are several generations per year.

Boxwood spider mite feeding damage results in foliage with yellow to bronze stippling, which may resemble injury caused by thrips. Both of these insects cause distinctive linear stippling streaks. These symptoms can be diagnostic when observed on foliage. With high mite populations, entire leaves may develop yellowish-white streaks; premature defoliation can occur.

Boxwood Spider Mite symptoms

Boxwood spider mite feeding symptoms. This mite species creates linear streaks on leaves. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Boxwood Spider Mite symptoms - more mild

Boxwood spider mite symptoms that are more mild. The distinctive linear streaks are more clearly observed. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

 

Detected overwintering eggs are treated with dormant oils (2-3%). Although normally unnecessary, summer oils (1-2%) or insecticidal soaps are recommended to control mild mite populations. With high infestations, some reduced-risk materials include spinosad, spiromesifen, acequinocyl, & bifenazate. Examples of other materials include hexythiazoc, abamectin, fluvalinate & acephate. Be aware that fluvalinate is a pyrethroid & can promote spider mite resurgence. Acephate may only provide mite suppression.

The Rutgers Plant & Pest Advisory Blog for Early June 2023 includes some commonly observed insect/mite & disease pests within the landscape during the late weeks of spring & early weeks of summer. In addition to boxwood spider mites, the other insect/mite pests included are juniper scale, bagworm, black vine weevil, bronze birch borer, pear leaf blister mite, & beneficial predacious mite. The disease pathogens included are fire blight, oak leaf blister fungus, black spot of rose, powdery mildew & Verticillium wilt. Some suggested monitoring techniques & variables are listed between the insect/mite & disease pests.     

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Conifer Pest and Disease Update 5/15/2023

In this edition:

  • Insects – Pest Scouting with growing degree-days (250-600 GDD50)
    • Scales
    • Mites
  • Diseases
    • Needle casts (Rhabdocline and Swiss needlecasts – Douglas fir, & Rhizosphaera – spruces)
    • Phytophthora
  • Soil fertility – resources

Please click “read more” below to get updates on pests, diseases, and other important resources for the week of 5/15/2023.

[Read more…]

Nursery Pest and Disease Update 5/15/2023

In this edition:

  • Insects:
    • Scale crawler emergence
    • Borer insects
    • Upcoming problem pests / Redheaded flea beetle / SLF / Pest Scouting Guides
  • Diseases:
    • Leaf spot / foliage disease management
    • Fire blight on Rosaceous hosts
    • Canker fungi
    • Boxwood blight
    • Oomycete root diseases (Phytophthora, Pythium, Phytopythium)
  • Plant Spotlight:
    • NJ native azalea species

Please click “read more” below to get updates on pests, diseases, and other important resources for the week of 5/15/2023.

[Read more…]

Tree Fruit IPM Report for May 10, 2023

Peach:

Bacterial Spot leaf symptoms about 2 weeks old.

Fig. 1 Bacterial Spot leaf symptoms about 2 weeks old.

Bacterial Spot leaf symptoms about a week old.

Fig. 2 Bacterial Spot leaf symptoms about a week old.

Bacterial Spot: Generally we recommend starting at 0.5 ozs metallic copper and gradually lowering the rate as the season progresses. The rate applied will depend on the formulation. Dr. Lalancette published a chart listing common copper formulations and rates for peach and nectarine applications. Avoid combining copper with captan especially if it has been overcast for several days. Also avoid acidic spray solutions when applying copper. Dr. Lalancette has published a handy guide for copper applications in early covers. Antibiotics such as Mycoshield or Fireline may also be used and may offer slightly more residual activity during long wetting periods. Bacterial Spot leaf symptoms have begun appearing in southern county orchards. These infections probably occurred mostly during the heavy rains that occurred on 4/30-5/1. There is a small amount of older symptoms which probably occurred the previous weekend of 4/27-4/28 (Figs. 1&2.).

Oriental Fruit Moth: A biofix point for OFM was set on 4/10 in both northern and southern counties.  The first of two insecticide timings for first generation Oriental Fruit Moth control fall at 170-200 degree days base 45 after biofix. This timing generally coincides with 100% petal fall in peaches. Timings are updated below. Do not apply insecticides until all bloom is off. No Insecticides for OFM are needed where Mating Disruption is implemented.

OFM 1st Generation Timing
Insecticide Type
County/Region Degree Days by  5/8 base 45 Conventional

170-200, 350-375

Diamide

100-150, 300-350

Gloucester – Southern 345 1st –past

2nd –5/8-5/10

1st –past

2nd –past

Middlesex – Northern 327 1st –past

2nd –5/10-5/11

1st –past

2nd –5/7-5/10

Green Peach Aphid: GPA colonies begin forming sometime during bloom. Examine trees for the presence of colonies from pink to shuck split. Count the number of colonies on ten trees and use a treatment threshold of 2 colonies/tree at petal fall for peach, and 1 colony/tree for nectarine. The best way to scout for aphids during bloom is with a beating tray. Blossoms may also be collected, opened, and examined for the presence of aphids using a hand lens. This is particularly important for nectarine blocks. Check 10 trees per block with the beating tray. Collect 50 blossoms per block and examine for the presence of aphids. If more than 1 colony of aphids are found in nectarines, or 2-3 colonies are found in peaches, an insecticide for aphids will be needed when all petals are off. See the NJ Commercial Tree Fruit Production Guide for recommended materials and rates. Aphid colonies are now visible in southern county orchards.

Plum Curculio; Tarnished Plant Bugs; and Other Catfacing Insects: Plum Curculio start to move into orchards at about 88-100 degree days base 50 after January 1. Applications for PC should be initiated once all petals are off, with a second application made with ovicidal materials at 379-402 DD. Currently we have accumulated about 320 DD base 50 in southern counties, and 264 DD base 50 in northern counties. Growers can monitor degree day development at their site by finding the nearest weather station and using the degree day development tool at NEWA. Catfacing insects are starting activity, but will become more of an issue as temperatures warm and mowing and other ground cover activities become more common. Small amounts of catfacing injury are present statewide.

Scale Insects: White peach scale crawlers have not yet emerged but usually begin emergence about the third week of May and continue emergence until about the middle of June. San jose scale crawlers typically begin emergence about late May or Early June and continue emergence for up to 6 weeks. Control options during crawler emergence include the neonicitiniods Actara and Belay (suppression only), and the IGR’s Esteem and Centaur. See the NJ Commercial Tree Fruit Production Guide and the product labels for more information.

Lesser and Greater Peach Tree Borers: Growers using mating disruption for borer control can begin placing dispensers around the end of April and should have them in place by mid-May.

Apples and Pears:

Diseases: Apple Scab, Rust diseases, and Powdery Mildew are the main targets at this stage. The NEWA apple scab model is estimating about 100% ascospore maturity in southern NJ with 100% of cumulative ascospores discharged as of April 15. Northern counties were at Green tip on or about 4/3. The model estimates about 100% ascosppsore maturity for Northern Counties with 100% ascospores released as of April 30. Between tight cluster and first cover include products effective for powdery mildew and cedar apple rust.

Fire Blight: Infections can still occur post bloom so covers with antibiotics when infection events are forecast using the NEWA fire blight model may be beneficial. Remember to rotate streptomycin and oxytetracycline products. Fire Blight symptoms began appearing in southern county apple and pear orchards this week. Typically it is recommended to cut out infected limbs however this is a practical decision that must be made. This blog post from Michigan State may be helpful to decide whether it is worth cutting out infected tissue.

Rust Diseases: The two most common rust diseases that affect pome fruit are Quince Rust and Cedar Apple Rust. In some years these diseases can be troublesome in commercial orchards. Most disease control programs for scab will also control rust. In organically managed blocks in the east options are limited for approved materials that are effective for rust. Potassium Bicarbonate products have shown good efficacy for rust diseases in trials performed in Virginia. Organic growers should seek out and plant rust resistant cultivars. Cultural controls are not practicable due to the widespread presence of alternate host Junipers both wild and cultivated. Rust disease development on junipers should now be producing large spore releases during wetting periods. See this link for pictures of rust on pome fruit and juniper.

Dogwood Borer: Growers who plan to use mating disruption for Dogwood Borer should have ties in place by the end of May. See the Product label and the NJ Commercial Tree Fruit Production Guide for more Information.

Codling Moth (CM): The first codling moth flight has started. A biofix was set for CM on April 17th in both northern and southern counties.

Codling Moth Degree Day Timing
Application and Insecticide Type
County Area Biofix Rimon:

75-100DD + 14-17 days later

 

Intrepid

150 + 450 DD

Diamides – Altacor, Voliam mixes: (150-200 DD)

Cyd-X, Carpovirusine

250 DD + every 7-9 days during brood hatch (later if first spray is an IGR)

Standard Insecticides –  Delegate, Avaunt, OP’s, carbamates, pyrethroids

250 DD + 550 DD

 

DD 75 100 150 450 250 250 550
Southern April 17 past 5/7 5/11 Too far off 5/17 5/17 Too far off
Northern  5/7  5/10  5/12 Too far off 5/21 5/21 Too far off

Pear Diseases:  Continue managing for Rust, Fire Blight and Fabrea Leaf Spot through May.

Grapes: The most important diseases to manage at this time are Phomopsis, Black Rot, and Powdery Mildew. More information about early season disease control can be found in this blogpost from Virginia Tech. SLF hatch began in southern counties sometime during the last week of April. There is no need to control SLF at this time.

Tree Fruit Trap Captures – Southern Counties

STLM TABM-A CM BMSB OFM-A DWB OFM-P TABM-P LPTB PTB
4/15/2023 433 20 1
4/23/2023 423 1 13 8 0
4/30/2023 417 7 15 4 1 0
5/06/2023 9 2 3 1 0 0

Tree Fruit Trap Captures – Northern Counties

STLM TABM-A CM BMSB OFM-A DWB OFM-P TABM-P LPTB PTB
4/8/2023 10
4/15/2023 20 3
4/30/2023 28 11 6
5/06/2023 22 2 19 9

Phenology Table: Based on annual observations made in Gloucester County.

Pest Event or Growth Stage Approximate Date 2023 Observed Date
 Bud Swell (Redhaven)  March 23 +/- 15 Days March 7
1/4″ Green Tip Red Delicious March 31 +/- 13 Days March 27
Pink Peach (Redhaven) April 4 +/- 15 Days March 24
Tight Cluster Red Delicious April 9 +/- 13 Days April 7
Full Bloom Peach (Redhaven) April 9 +/- 14 Days April 4
Pink Apple (Red Delicious) April 14 +/- 12 Days April 11
Full Bloom Apple (Red Delicious) April 22 +/- 11 Days April 16
Petal Fall (Redhaven) April 22 +/- 10 Days April 15
Petal Fall (Red Delicious) April 27 +/- 13 Days  May 3
Shuck Split (Redhaven) April 30 +/- 11 Days April 21
Pit Hardening June 15 +/- 9 Days