Archives for June 2024

June 23, 2024 Kate Brown

Beat the Heat: NWS Forecast Tools

The National Weather Service has graphical forecasts for many weather variables including heat index and wet bulb globe temperature which can be used to evaluate risk of heat stress. These predictive tools may be utilized to evaluate the risk of heat stress up to one week in advance and may aid in planning of field activities.

Heat index: describes the apparent temperature based on air temperature and relative humidity in shady locations.
Wet bulb globe temperature: incorporates air temperature, relative humidity, solar radiation, and wind speed. May be more representative of field-based working conditions.

To access these graphical forecasts, visit https://digital.weather.gov/ and select either Wet Bulb Globe Temperature or HeatRisk experimental (i.e., heat index) from the drop-down menu. Zoom in to your location by holding your cursor over the area and scrolling with your mouse, or use the provided Zoom and movement tools in the upper left of the graph.

Article By: The Rutgers Farm Health and Safety Working Group: Kate Brown, Michelle Infante-Casella, Stephen Komar and William Bamka

Filed Under: Commercial Ag Updates Tagged With: Farm Safety, heat stress

June 21, 2024 Andy Wyenandt

The Curious Case of the Virus Infected Tomato Fruit

Original Article published on 6 June 2024 by Dr. Jerry Brust, University of Maryland Extension

Ben Beale, educator from St. Mary’s County found an odd thing last week. He found in a grower’s high tunnel, tomato fruit that had the symptoms of a virus infection, but there were no foliar symptoms on any of the plants. Some fruit on a cluster had symptoms while other fruit on the same cluster looked perfectly fine. Ben had the fruit tested and got a fast response from Jill Pollok at the University of Delaware Diagnostic Clinic and it was Tomato Spotted Wilt Virus. The cultivar in question Big Beef Plus has TSWV resistance. There could be one or two possibilities for TSWV symptoms showing up in a resistant cultivar and for fruit symptoms but not any foliar symptoms of the virus.

We will look at how tomatoes can get infected by the TSWV (if you already know how this works skip down to the next paragraph). Tomato spotted wilt virus (TSWV) is an obligate parasite, i.e., it must have a living host and must be moved from one plant to another by thrips or through cuttings or possibly seed. This disease can affect tomato and other Solanaceae crops as well as lettuce, beans and cucumber. TSWV may occur in the field but tends to affect greenhouse and high tunnel crops more severely. The virus is transmitted most efficiently by Western flower thrips (WFT) (Frankliniella occidentalis), and less so by Onion thrips (Thrips tabaci), Tobacco thrips (Frankliniella fusca) and several other thrips species. It is not transmitted by Eastern flower thrips (Frankliniella tritici). Only immature thrips can acquire the virus, which they can acquire within 15 minutes of feeding, but adults are just about the only stage able to transmit the virus. Adults can transmit the virus for weeks. It may take 2 – 4 weeks from when the adult thrips first feeds on a plant until initial symptoms are observed. Because of this TSWV appears to worsen in plantings over time.

Why are we seeing fruit symptoms but little if any foliar symptoms? The most likely explanation is that TSW viruliferous thrips fed on the flowers or very young fruit. The resistance to the TSWV is expressed (active if you will) in the non-reproductive parts of the plant but not expressed to any extent in the reproductive parts (flowers and fruit) of the plant. Even though the flower and fruit can act as an entry point into the plant the resistant tomato does a good job of limiting the virus into any other areas of the plant. Thus, under low to moderate feeding pressure (1-4 thrips/flower) only the fed upon fruit or possibly a few other fruits on the same cluster become infected. The other possibility is that the TSWV resistance in Big Beef Plus is intermediate and under environmental stress it may not be ‘complete enough’ to protect all of the plant.

The first question above as to why is the virus showing up at all in a resistant cultivar can be explained by the above paragraph. But there may be another possibility although not in this particular case, that we will have to watch out for in the coming years. And that is resistance- breaking virus variants. The Sw-5b gene (Sw-5) is the most widely used resistance gene for TSWV in tomato. It not only provides resistance to TSWV but also resistance to a several associated viruses including Tomato chlorotic spot virus (TCSV) and Impatiens necrotic spot virus (INSV). The presence of the Sw-5 gene in tomato plants confers resistance to TSWV by a hypersensitive defense response that causes local lesions on the leaf, preventing the spread of the virus from the infection site through the plant. In 2022, symptoms of TSWV were observed in North Carolina tomato fields on cultivars that had the gene for TSWV resistance (Sw-5). The cultivars from different farms had symptomatic foliage and fruit. Samples were collected from both farms and subjected to sequencing to identify and confirm the presence of resistance-breaking variants, which they did. I mention this because NC is very close by, many growers get their tomato transplants from NC and because the resistance-breaking occurred in the last year or so. These resistance-breaking variants may start to show up in our fields and I am guessing that when they do, we will see 20-40% viral foliar infection and possibly worse in the fruit of resistant plants. For now, we should keep using the resistant cultivars, but watch closely for any breakdown of the resistance.

Resources: 2023. First Report of Resistance-Breaking Variants of Tomato Spotted Wilt Virus (TSWV) Infecting Tomatoes with the Sw-5 Resistance Gene in North Carolina. K. Lahre, R. Shekasteband, I. Meadows, A. E. Whitfield, and D. Rotenberg. Plant Disease vol. 107.

This article appears in Volume 15, Issue 4 of the Vegetable and Fruit News.

Filed Under: Vegetable Crops Tagged With: tomato, tomato spotted wilt virus, TSWV

June 20, 2024 Dave Schmitt and Kaitlin Quinn

Tree Fruit IPM Report June 20, 2024

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. Peaches are at or past pit hardening and fruit now has some resistance to bacterial spot. Infections 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 Treatments for the first generation have past.

OFM 2^nd Generation Timing
		Insecticide Type
County/Region	Degree Days by 6/20 base 45	Conventional 1150-1200 1450-1500	Intrepid/Rimon 1050-1150 1300-1400	Diamides/Virus 1075-1150 1375-1450
Gloucester – Southern	1432	1^st –past 2^nd – June 20-22	1^st –past 2^nd – past	1^st –past 2^nd – past
Middlesex – Northern	1278	1^st – past 2^nd – June 25-28	1^st – past 2^nd – June 21-24	1^st – June 13-16 2^nd – June 23-25

Tarnished Plant Bugs; and Other Catfacing Insects: Catfacing insects are active, and activity has increased with the current weather pattern. Very little recent fruit feeding has been observed.

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. 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. Thrips activity was observed in ripening nectarines this past week in southern counties.

Apples and Pears:

Diseases: Now that primary scab is nearing the end, or 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, Inspire Super, and Aprovia may be effective, and longtime reliable broad spectrum fungicides such as omega, 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 5/20, and in northern counties the week of 5/13. 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 generation codling moth timings have ended. Trap captures Continue and increased in some southern county orchards this week. A biofix was set for CM on April 17^th in both northern and southern counties. Second generation timings are updated below. Rimon is not recommended for this and later generations. The model is predicting applications earlier than normal. In southern counties it appears to be ahead of observed pest development in the field. Trap captures have bottomed out and larvae have only started to emerge from infested fruit. Growers should still follow model predictions but be aware additional treatments may be required should the next flight start later and last longer than predicted.

	Codling Moth Degree Day Timing – Second Generation
		Application and Insecticide Type
County Area	Biofix	Rimon: 75-100DD + 14-17 days later		Intrepid 1150 + 1450 DD Diamides – Altacor, Voliam mixes: (150-200 DD)		Madex 1250 DD + every 7-9 days during brood hatch (later if first spray is an IGR)	Standard Insecticides – Delegate, Avaunt, OP’s, carbamates, pyrethroids 1250 DD + 1550 DD
DD				1150	1450	1250	1250	1550
Southern	April 22	N/A	N/A	6/25	7/5	6/28	6/28	7/8
Northern	May 1	N/A	N/A	6/28	7/10	7/2	7/2	7/14

Wooly Apple Aphid (WAA); Green Apple (Spirea) Aphids (GAA): GAA colonies are still present in some apple blocks. GAA is generally a pest that can be tolerated since they do little direct damage. Treatment thresholds for GAA are if 50% of the shoots are infested with no beneficial insects present. WAA aerial colonies are also beginning to form in southern counties. This is about a month earlier than usually observed. In most years these are controlled by beneficials however in some years like 2022, serious outbreaks can occur. The best control for WAA is Movento applied before or when the first colonies appear. Diazinon is also effective at knocking down infestations. Movento will also control GAA and should control san jose scale when applied in mid-May, and suppress scale when applied in late May or early June. Do not combine diazinon, oil, or oil based penetrants with Captan.

Pear Third generation pear psylla began hatching about June 8. 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, and movento. Pear Psylla are still actively laying eggs and nymphs continue to hatch, although activity appears to be waning.

Grape: Early blooming native grapes were at trace bloom on 5/24, therefore we have set the the Grape Berry Moth biofix at 5/24 for southern counties. 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. Applications have been historically made around the end of June in southern counties. As for diseases we are seeing low levels of phomopsis on older leaves in some vineyards. In untreated vineyards downy mildew symptoms are starting to appear. If you are not seeing downy mildew you have done a good job so far.

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

Pest Event or Growth Stage	Approximate Date	2024 Observed Date
Bud Swell (Redhaven/PF-17)	March 23 +/- 15 Days	March 13
1/4″ Green Tip Red Delicious	March 31 +/- 13 Days	March 18
Pink Peach (Redhaven/PF-17)	April 4 +/- 15 Days	March 18
Tight Cluster Red Delicious	April 9 +/- 13 Days	March 30
Full Bloom Peach (Redhaven/PF-17)	April 9 +/- 14 Days	April 5
Pink Apple (Red Delicious)	April 14 +/- 12 Days	April 9
Full Bloom Apple (Red Delicious)	April 22 +/- 11 Days	April 20
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 22
Pit Hardening	June 15 +/- 9 Days	June 10

Tree Fruit Trap Captures – Southern Counties

	STLM	TABM-A	CM	BMSB	OFM-A	DWB		OFM-P	TABM-P	LPTB	PTB
3/23/2024	70							0
3/30/2024	29				0			0
4/6/2024	421				0			0
4/13/2024	415				7			1
4/20/2024	900				7			0
4/27/2024	312		2		22			1
5/4/2024	137	2	8		27		1	5
5/11/2024	6	2	15		2		1	10	42
5/18/2024	5	6	11		2	6	0	12	41
5/25/2014	33	29	7		4	25	0	44	37
6/1/2024	719	12	12		1	1	0	44	57
6/8/2024	163	7	6			0	27	0	35	52	3
6/15/24	20	10	2	0	0	31	0	10	34	1	20

Tree Fruit Trap Captures – Northern Counties

	STLM	TABM-A	CM	BMSB	OFM-A	DWB	OFM-P	TABM-P	LPTB	PTB	AMBROSIA BEETLE
3/23/2024
3/30/2024
4/6/2024							0				0
4/13/2024							3.25				37.6
4/20/2024							11.75				93
4/27/2024			0				19				50
5/4/2024			1		16		19				124
5/11/2024			3		4		18				112
5/18/2024		4	2		1	2	2		2		83
5/25/2024		7	5		0	16	8		23		55
6/1/2024		16	7		0	28	7		21		37
6/8/2024		17	4		0	23	3		16	2	12
6/15/24		21	2			21	21		27	1	12

Filed Under: Tree Fruit, Wine Grape

June 19, 2024 Kris Holmstrom

Vegetable IPM Update 6/19/24

Sweet Corn

European corn borer (ECB) moths continue to be captured in blacklight traps in the northern and central counties, although catches are occurring at fewer sites. The highest feeding levels are in Somerset and southern Hunterdon Counties. ECB injury is declining as infested plantings pass into the tassel stage and receive the first insecticide application. Plantings now in whorl stage are showing little feeding. While ECB has become something of a local phenomenon in NJ, growers should not assume that feeding is below economic levels in their area. ECB infestations will be present for another 1-2 weeks.

Look for the characteristic “shot-hole” type of feeding (photo below at right) and consider treating when infested plants exceed 12% in a 50 plant sample. As plantings proceed to the pre-tassel stage, ECB larvae may be found in emerging tassels (see photo at left). It is a good idea to treat individual plantings as they move into the full tassel/first silk stage one time. This eliminates any ECB larvae that have emerged with the tassels as they begin to move down the stalk to re-enter near developing ears.

Useful insecticides for this particular application include synthetic pyrethroids (IRAC Grp 3), spinosyns (including OMRI approved Entrust) IRAC Grp 5), and diamides such as Coragen or Vantacor (IRAC Grp 28) or materials such as Besiege which include the active ingredient in Coragen. Synthetic pyrethroids alone should NOT be used for corn earworm (CEW) protection on silking corn. Control with these materials is very inconsistent.

The highest nightly trap catches of ECB for the week ending 6/19/24 are as follows:

South Branch 3	Farmingdale 1	Pennington 1
Califon 1	Hillsborough 1	Princeton 1
Clinton 1	Old Bridge 1

[Read more…]

Filed Under: Organic Production, Vegetable Crops

June 19, 2024 Andy Wyenandt

Cucurbit Downy Mildew Alert – Cucumber – 6/19/24

Cucurbit downy mildew has been confirmed on cucumber in Salem 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 in central North Carolina on 6/4/24. 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 sporulating on the underside of an infected cucumber leaf.

Filed Under: Vegetable Crops Tagged With: cucurbit downy mildew

June 18, 2024 Cesar Rodriguez-Saona

Sparganothis Fruitworm Degree-Day Update: as of June 18, 2024

Based on our degree-day model, Sparganothis fruitworm has accumulated 867 degree-days (DD) as of June 18, using April 15 as the biofix date. This indicates that flight activity has reached the 25% mark. We anticipate that peak flight will likely occur by the end of this week. This model uses averages across several beds, so there may be slight differences depending on the variety. We will continue to provide updates as the season progresses.

Filed Under: Cranberry, Fruit