Archives for June 2023

June 14, 2023 , and

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.

[Read more…]

Filed Under: Landscape, Nursery, & Turf, Nursery, Turf Tagged With: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,
June 13, 2023

Got leaves?

Have you taken a look at your sycamore lately? Seeing any leaves this spring? Looks like a little problem!

brown, angular leaf spots on plane tree leaves

Classic angular leaf spot and twig blight of sycamore anthracnose. Photo: Richard Buckley, Rutgers PDL

Samples of deciduous shade trees diagnosed with anthracnose have steadily found their way into Rutgers Plant Diagnostic Laboratory this spring. Anthracnose is a common fungal disease of shade trees that results in angular leaf spots, cupping or curling of leaves, and premature defoliation. Green stems and twigs can become infected, causing twigs to dieback and overwintering cankers to form. We’ve had samples of sycamore and London plane tree, but have also had ash, beech, maple and a bunch of oaks.

water-soaked, necrotic spots on distorted ash leaves

Ash anthracnose causes necrotic spots and distorted leaves. Photo: Richard Buckley, Rutgers PDL

The fungi responsible for anthracnose in shade trees are all unique. The fungus that attacks sycamore is not the same as the fungi that cause ash, beech, dogwood, maple, or oak anthracnose. Each tree species has a specific fungus causing its own anthracnose disease, so for example, the beech anthracnose fungus does not infect oaks and the oak anthracnose fungus does not infect maples and so on.

brown, angular spots on silver maple leaves

Marginal necrosis and irregularly-shaped, angular leaf spots on silver maple (Acer saccharinum). Photo: Sabrina Tirpak, Rutgers PDL

Infections by anthracnose causing fungi are favored by cool, wet conditions during the budbreak period in the spring. When the weather favors one of these fungi, it generally favors all of them, so we see the disease to some degree on many different hosts. Anthracnose fungi survive winter in buds, small twig cankers, or fallen leaves depending on which types of trees and fungi are involved. In the spring, the spores are moved by wind and water to newly forming leaves. The longer the weather conditions remain cool and wet, the more damage one can expect. Once the weather becomes dry and the leaves mature, the disease cycle ends and the tree will replace lost leaves with new ones.

brown spots along beech leaf veins

Beech anthracnose. Photo: Sabrina Tirpak, Rutgers PDL

Anthracnose can cause a very visible leaf lesion, and depending on the fungus/tree species dynamic, may defoliate the tree. Sycamore anthracnose causes a very significant defoliation, while beech anthracnose rarely does. Furthermore, it is not uncommon for the causal fungus to kill the buds before they open in the spring. It’s also not uncommon for the fungus to kill new green stems and twigs. Although these diseases often seem severe, they have little long-term impact on overall tree health. Leaves and buds damaged early in the season are often replaced by mid-summer.

distorted oak leaves with small spots

Small spots with yellow borders and distorted leaves, caused by oak anthracnose. Photo: Sabrina Tirpak, Rutgers PDL

So, what do we do about anthracnose? Not much, really! Rake and remove fallen leaves. Improve plant vigor with fertilization and irrigation in times of drought, and prune all of the dead and dying limbs. Fungicides can be used to prevent the problem in high-value trees. Begin treatments at budbreak to protect the new growth and repeat the treatments 2-3 times at the label specified intervals. Proper timing and good coverage are essential, which will necessitate a licensed professional applicator to make the applications.

By the way, it is too late for fungicide protection this season!

Fungal diseases in most ornamental plants can be prevented with applications of one or a combination of the following active ingredients: FRAC M3 mancozeb; FRAC M5 chlorothalonil; FRAC 1 thiophanate-methyl; FRAC 3 metconazole, myclobutanil, propiconazole, tebuconazole, triademefon, triflumizole; FRAC 7 boscalid, flutolanil, oxycarboxin; FRAC 11 azoxystrobin, fluoxastrobin, kresoxim-methyl, pyraclostrobin, trifloxystrobin; FRAC 12 fludioxonil; and/or FRAC 19 polyoxin-D. Be sure to follow all label specifications for the host plant, the specific diseases controlled, as well as rates, dilution, and timing.

Filed Under: Landscape, Nursery, & Turf, Plant Diagnostic Lab, Uncategorized Tagged With: , ,
June 13, 2023

Cucurbit Downy Mildew Alert – Cucumber – 6/13/23

Cucurbit downy mildew has been confirmed on cucumber in Atlantic County in southern New Jersey. This is the first report of CDM in the state and region this growing season. All cucumber and cantaloupe growers should scout on a daily basis and initiate a preventative fungicide program immediately. All other cucurbit plantings need to be scouted on a regular basis. CDM was last confirmed on cucumber and butternut squash in coastal South Carolina. Remember, some CDM isolates fall into Clade I which predominately infect watermelon, pumpkin, and squash, where CDM isolates in Clade II predominately infect cucumber and cantaloupe.

For more information on CDM, the clades, and CDM control please click here.

Cucurbit downy mildew

Cucurbit downy mildew sporulating on the underside of an infected cucumber leaf.

Filed Under: Vegetable Crops Tagged With:
June 9, 2023

Time to Control Yellow Nutsedge

Now is the ideal time to control yellow nutsedge (Cyperus esculentus). This plant is a perennial that grows best during the heat of summer and survives the winter through underground tubers. While the drought may have limited nutsedge emergence in unirrigated areas, it is visible and rapidly growing in irrigated beds and lawns. Yellow nutsedge […]

Filed Under: Landscape, Nursery, & Turf, Turf
June 9, 2023 and

Tree Fruit IPM Report for 06/09/23

Peach:

Bacterial Spot: Fruit symptoms from this set of infections have begun to appear in southern counties. So far fruit symptoms are very low and only in highly susceptible varieties. One of the few benefits of a dry spring dry spell is lower disease incidence. Peaches are close to pit hardening and at that point fruit will develop some resistance to bacterial spot. Infection s can still occur but will be less unsightly and may still make grade. Growers should continue to manage using Oxytetracyclene and lower rates of copper, especially around rainy periods and severe weather.

Oriental Fruit Moth: A biofix point for OFM was set on 4/10 in both northern and southern counties.  All timings for first generation OFM have past.

OFM 2nd Generation Timing
Insecticide Type
County/Region Degree Days by  6/9 base 45 Conventional

1150-1200

 Diamide

1075-1150
Gloucester – Southern 888 1st –6/21-6/23

2nd – too far off

 1st –6/17-6/19

2nd – too far off
Middlesex – Northern 862 1st –6/22-24

2nd – too far off

 1st –6/18-6/20

2nd – too far off

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. Additional applications with effective materials may be made between 520 and 730 DD base 50. Currently we have accumulated about 702 DD base 50 in southern counties, and 630 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 active, and activity is increasing with fry weather and summer temperatures. Very little recent fruit feeding has been observed.

Scale Insects: White peach scale crawlers should be at peak crawler emergence in southern counties. San jose scale crawlers began emergence about 5/31. SJS crawlers typically peak in mid-June and continue emergence for up to 6 weeks. Control options during crawler emergence include Neonicitiniods (suppression only), and the IGR’s Esteem and Centaur. See the NJ Commercial Tree Fruit Production Guide and the product labels for more information.

Thrips: If the current dry spell continues Flower Thrips may become an issue in highly colored ripening fruit, especially in poorly managed ground covers that contain clover or other flowering weeds. Thrips damage appears as “silvering” and usually appears on fruit close to harvest.

Early Season Thrip Injury on Nectarine

Fig. 1. Early Season Thrips “silvering” on Nectarine.

If populations are high damage can be extensive. Presence of thrips may be scouted for using a beating tray to detect the presence of adults and nymphs in the tree. Flowering weeeds and shrubs on orchard edges may also be scouted by shaking flowers onto a beating tray or a sheet of paper. Delegate or Entrust at the highest labeled rate are the usual recommended materials for thrips in stone fruit. Lannate may be effective in some orchards but has not worked well in recent years. These materials all have short PHI’s and may be applied close to harvest when damage typically appears. Thrips have also been observed to mark cherries. Damage is different than peach and appears as a dark streak in a similar pattern as silvering. See the NJ Commercial Tree Fruit Production Guide for more information.

Apples and Pears:

Diseases: Now that primary scab has ended, the focus turns toward summer diseases such as fruit rots (esp. Bitter rot), and sooty blotch and fly speck. Bitter rot control has been difficult at best in recent years even where management programs have been rigorous. Research has suggested products such as Merivon, Luna Sensation and Inspire Super may be effective, and longtime reliable broad spectrum fungicides such as captan and ziram should provide control. Experience has suggested that the addition of phosphorous acid products such as Prophyt or Rampart to captan sprays may improve control. Observations are that these products improve control of other summer diseases such as sooty blotch and flyspeck, and may help suppress scab infections where present.

Fire Blight: Fire Blight symptoms began appearing in southern county apple and pear orchards the week of 5/1. 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. Once the terminal buds set, typically in July, infected wood should be removed to prevent colonization by the bitter rot pathogen.

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. Trap captures began increasing again in southern counties this week. Timings are updated below.

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 past past 6/7 past past 6/11
Northern  April 17  past  past  past 6/8 past past 6/13

Tufted Apple Budmoth (TABM): A biofix for TABM was set in southern county orchards on 5/8. Nothing needs to be done for TABM at this point. The first alternate middle applications for TABM will be on or about 6/12 in southern counties. This has been considered a minor pest in recent years. Many materials used for Codling Moth will also control TABM.

Pear:  Second generation pear psylla began hatching about 5/15. Options for control include spynosyn products such as Delegate and Entrust, and the neocitinoids (IRAC group 4A). The addition of 0.25-1 gal of summer oil may improve control. Other options include Movento, the IGR’s Esteem and Centaur, and products containing abamectin. Be sure to read and follow the label instructions regarding the addition of penetrants for abamectin products. Pear Psylla are still actively laying eggs and nymphs continue to hatch.

Grape: Early blooming native grapes were at 50% bloom on 5/24, therefore we have set the the Grape Berry Moth biofix at 5/24 for southern counties. Typically we would use the bloom date for V. riparia to set the biofix date, however the usual locations we have used in the past did not have viable vines to look at, and it is difficult to scout new locations for V. riparia this year. Since V. riparia typically blooms with early natives we used Concord and Ives to set the biofix. The model works best when growers record their own bloom dates and use the Grape Berry Moth model at NEWA. Applications for GBM using Intrepid or Diamides should be made at 810 DD base 47. Other effective materials can be applied a few days later. Currently we are at 167 DD in southern counties. Applications have been historically made around the end of June in southern counties.

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 4
4/30/2023 417 7 15 4 1 0
5/06/2023 9 2 3 1 0 0
5/13/2023 18 2 7 2 3 0 6 6
5/20/2023 5 18 6 0 51 0 13 67
5/27/2023 1 11 4 0 17 0 11 49
6/03/23 3 8 2 1 24 0 13 65

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
5/13/2023 34 1 3 2 5 0
5/20/2023 31 6 7 1 6 0
5/27/23 16 18 4 1 17 3 11
6/03/23 12 26 2 0 17 2 12

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

 

 

Filed Under: Tree Fruit, Uncategorized, Wine Grape
June 8, 2023

Magnesium Deficiency in Tomato and the Relationship with other Important Nutrients

How can growers prevent nutrient deficiencies in crops? Soil testing and tissue testing for fertility management of vegetable crops is key to having the correct levels of nutrients to have a high yielding, high quality crop to harvest and market. Soil testing is best done in fall so that pH levels can be adjusted with soil amendments like lime that correct pH levels for maximum return on fertilizer uptake. Why adjust pH to proper levels? Plant nutrients are hindered in availability when soil pH is too high or too low. Besides pH, fertility levels are important to monitor and adjust pre-plant for the best start to new seedlings and transplants.

With tomato production it is widely known that calcium (Ca) levels in soil are important for prevention of blossom end rot. Therefore, tomato growers have focused on application of adequate and even high levels of calcium to prevent this fruit disorder. Another primary nutrient, potassium (K) is also important for plant and fruit quality for regulating water movement/water loss in the plant and other functions. In addition, it is important to also pay attention to magnesium (Mg) levels. Ca, K, and Mg are all important in successful tomato production. It is important to know these nutrients compete with each other for plant uptake and their proper levels based on soil and tissue testing.

Even though blossom end rot resulting from Ca deficiency can cause tomato fruit to be unmarketable, Mg deficiency can reduce overall plant health and ultimately quality and yield. Low K in the plant can make the plant less tolerant of heat and drought stress. Magnesium in tomato plants plays an essential role in photosynthesis (the process of the plant to make energy to fuel growth), protein synthesis (necessary in cell formation), activation of plant enzymes (necessary for many cellular and growth functions), and chlorophyll synthesis (the green pigment in plants that is essential for optimum plant growth).

Magnesium deficiency can occur, especially in sandy soils, when soil is overwatered or after heavy rainfall events. However, when Ca and Mg levels are out of balance, deficiencies can still occur even when both are showing adequate levels in the soil. It is more important to look at the actual levels. If one is significantly higher than the other deficiency symptoms may occur. Since both Ca and Mg are +2 ions in soil when taken up by plant roots, the plant indiscriminately takes up these two nutrients. Therefore, if there is abundant Ca and lower Mg, Mg deficiencies may be seen. Conversely, when Mg levels are higher than Ca levels blossom end rot may be seen. It is best to have these two nutrients in soil at the same levels to keep a balance in uptake and ultimately promote both healthy fruit formation and foliage growth. Allowing Mg levels to remain deficient in the plant will result in lower yields and less energy for fruit production later in the plants lifecycle.

Magnesium deficiency is first seen on tomato plants as interveinal chlorosis – yellowing of leaf tissue between the veins of older leaves. Eventually the leaves become mostly yellow and purplish-red spots that become necrotic on the interveinal tissue may occur. See photos taken in the field on June 7, 2023.

Deficiency symptoms can be seen at any stage of growth, but are generally first seen when plants begin to flower, start fruit set, and fruit enlargement. When plants change from vegetative growth (production of leaves and stems) to reproductive growth (flowering and fruiting) leaves are stressed and energy and resources are reallocated into growth and development of new progeny (seed and fruit).

Fortunately, Mg deficiency is easily corrected when caught early in the tomato plant’s growth by the application of Epsom salts. Rates differ depending on soil type, soil levels, and plant tissue levels. Mg rates can vary from 5-25 pounds per acre. Application can be done through drip irrigation systems or applied on the soil surface by spraying near the rootzone. When applying through the drip tape, be sure to run the lines with clean water for at least 20 minutes after the salts have gone thorough to prevent salt build up in the emitters. Foliar applications of Mg can be sprayed on plants, but are not as efficient as soil application and root absorption. There are other products available to correct low levels of Mg, but most data available for the use of Epsom salts to raise Mg levels. Pre-plant, the use of high Mg liming products can balance Ca and Mg levels in soil if Mg levels are lower than Ca levels. Therefore, when lime is needed to raise pH it is very important to look at Ca and Mg levels on the soil test results before selecting which type of lime will work best for adjusting the levels of these two very important plant nutrients.

When managing fertility levels for successful crop production, it is important to know the levels of plant nutrients in soil and tissue tests. It is as important to understand the interactions between plant nutrients and how they affect plant growth. Seeing an “optimum” or “sufficient” level on a soil or tissue test report is not enough to fully determine what is needed for high yielding, high quality crops.

Filed Under: Organic Production, Vegetable Crops Tagged With: ,