Organic Farm Advisory

The Plant & Pest Advisory serves NJ growers by reporting on important pests and recommending responses that are grounded in reproducible trials.

Articles in this section contain information helpful to the NJ commercial organic grower.

Sharing organic practice trial results between land-grant universities is a cost effective way to create a common knowledge base built on the strengths of individual programs. In the sidebar, find institutions with programs in organic agriculture which augment knowledge developed at the Rutgers New Jersey Ag Experiment Station.

Rutgers Cooperative Extension Field Guides: These concise guides help with decision making from pre-planting to harvest. For each crop listed, learn what pests to proactively look for as the season progresses, how to look for them, and when to take action.

Field Guide List

June 3, 2020

IPM Update 6/03/20

Sweet Corn

Increasing numbers of European corn borer (ECB) moths have been captured over the past week, although overall numbers remain low.  At this time, activity is highest in central Morris County and western Burlington County (see ECB map at left).  The number of traps registering moderate catches is fairly low, and catches are widely dispersed.  Overall, this year’s population is late, and whether numbers increase much or not remains an open question.  Early corn is now in whorl or pre-tassel stage and able to support ECB larvae.  It is time to begin scouting corn in these advanced growth stages.

 

 

 

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 (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 6/03/20 are as follows:

Denville   2 Clinton   1 Milford   1
Asbury   1 Downer   1 Oldwick   1
Bellemeade   1 Eldora   1 South Branch   1
Califon   1 Medford   1 Springdale   1

 

Widely scattered, and low catches of corn earworm (CEW) occurred this past week.   While there was an increase in activity over the previous week, this pest does not pose a threat to sweet corn that has not yet reached the silk stage.

The highest nightly trap catches of CEW in black light traps for the week ending 6/03/20 are as follows:

Chester   1 Eldora   1 Milltown   1 Oldwick   1
Crosswicks   1 Elm   1 Morristown   1

[Read more…]

Filed Under: Organic Production, Vegetable Crops
May 30, 2020

Specialty Crops Injury Caused by Dicamba Herbicide Drift

Figure 1. Non-tolerant soybean foliage when exposed to a sublethal rate of dicamba 2 weeks after treatment. Leaves are cupped with the bottom edges curved towards the top surface of the leaves.

By Maggie Wasacz1 and Thierry Besancon2

1 Rutgers Weed Science Graduate Student; 2 Rutgers Weed Science Extension Specialist for Specialty Crops

Glyphosate-tolerant soybeans were first commercialized in 1996 in the United States. By 2006, almost 9 out of every 10 soybean acres were planted with glyphosate-tolerant cultivars. However, reliance on glyphosate alone for soybean weed control stimulates the selection of weed biotypes naturally resistant to glyphosate. By 2019, there were 43 weed species known to be resistant to glyphosate, including species such as Palmer amaranth or waterhemp that can easily out-compete soybean and reduce yield by more than 50% if left uncontrolled.

What is Dicamba Herbicide?

One way to control glyphosate-resistant weeds is to treat them with herbicides other than glyphosate, such as dicamba. Dicamba is a synthetic auxin herbicide that has been used to control broadleaf weeds for over 50 years. Chemical and seed companies have recently developed new soybean varieties that are tolerant to dicamba and that started to be commercialized in 2016. With the development of genetically modified dicamba-tolerant soybeans, dicamba may be sprayed more frequently during the growing season. Additionally, dicamba is regularly applied in corn, for right-of-way applications, and in the early fall for perennial weeds control.

Dicamba can injure sensitive broadleaf plants through tank incorrectly rinsed after spraying dicamba, particle drift during the dicamba application, and vaporization after dicamba has been applied . Particle drift refers to the herbicide being carried off-target by the wind during the application. Wind speed, particle droplet size, nozzle type, carrier volume, application method, and application speed will affect the extent of particle drift. Vaporization, on the other hand, occurs when the herbicide evaporates from the target plant and these vapors travel off-target.  For more information on herbicide drift, please refer to the following PPA post 10-best-management-practices-to-avoid-herbicide-drift.

If some of the dicamba sprayed onto a soybean field moves off-target and lands on a nearby field planted with a sensitive crop, the results can be very harmful. This injury could potentially cause aesthetic damage as well as reduce yield reduction.  Potential for yield loss is influenced by amount of dicamba as well as when the injury occurs. Small volumes of dicamba products can cause leaf cupping and deformation, plant twisting, and in extreme cases, plant death of sensitive crops.

Screening Vegetables for Dicamba Sensitivity

Greenhouse studies conducted at Rutgers University in 2019-2020 screened economically important vegetable crops from the mid-Atlantic region for sensitivity to sublethal doses of dicamba. These micro-rates of dicamba simulated varying levels of drift conditions in the field. To put the rates into perspective, the highest dose in this study was equivalent to about one drop of product per quart of water. The goals of this study are to develop recommendations that can help growers design their planting strategies around dicamba-treated fields as well as to use this data to help refine recommendations to maximize protection of sensitive crops.

Crop-Specific Reactions to Simulated Dicamba Drift

The most sensitive crops in this study were the leguminous crops, including non-tolerant soybean, lima bean, and snap bean, as well as solanaceous crops, such as tomato, eggplant and pepper. These crops demonstrated severe injury.

Soybean injury is characterized by the underside edges of the leaves curling upward toward the top surface of the leaves (Figure 1). Lima bean and snap bean have similar injury symptoms, both exhibiting injury in several ways. Higher rates caused some leaves to not emerge at all, while lower rates caused leaf cupping injury that caused the top edges of the leaves to curve downward towards the ground. Other symptoms included a bubble-like texture on the top sides of the leaves, as well as leaf crinkling.

Figure 2. Eggplant 2 weeks after treatment. The undersides of affected leaves are curled upward toward the top surfaces of the leaves.

Figure 3. Bell pepper 2 weeks after treatment. The leaves are cupped with a bubble-like texture on the top surface.

 

 

 

 

 

 

Figure 4. Tomato 2 weeks after treatment. Leaflets are curled, reduced in size, and deformed.

For eggplant and bell pepper, injury was expressed as the undersides of the leaves curling upward toward the top surface (Figures 2 and 3). Additionally, leaf crinkling is seen in bell pepper foliage (Figure 3). Finally, tomato plants express dicamba injury with leaf twisting, cupping, stunting, and crinkling. At higher rates, these leaflets will be extremely stunted and deformed (Figure 4). Lower rates will show slight cupping, leaf crinkling and a change in leaf surface texture. Among the most tolerant crops from this study were basil, pumpkin, lettuce, and kale. These plants incurred the lowest amount of damage. The moderately sensitive crops included watermelon, cucumber, and summer squash. Watermelon foliage exhibits injury differently than many of the other crops tested in the study. Rather than leaf cupping, watermelon leaf texture appears shriveled and more deeply lobed with small bubbles on the top leaf surface (Figure 5).

 

 

Figure 5. Watermelon 2 weeks after treatment. Leaves are deeply lobed with a puckering, bubble-like texture.

Figure 6. Summer squash 2 weeks after treatment. Leaf edges are curved downward toward the ground.

Figure 7. Cucumber 2 weeks after treatment. Leaf is cupped and the bottom edges of the leaf are curved upward towards the top leaf surface.

 

Summer squash and cucumber, however, show leaf cupping when injured. In summer squash, the top edges of the leaf curve downward towards the ground (Figure 6).  The foliage of cucumber tends to curve the bottom edges upward toward the top surface of the leaf, although both directions of cupping were observed. (Figure 7).

On-Going Research at Rutgers

This summer, Rutgers researchers will select a few of these crops to take yield in a field-based dicamba drift study that tests different drift rates and application timings. Although this study gives some preliminary information, more detailed studies are necessary to confirm these findings. However, in the meantime, this greenhouse work gives us a brief snapshot of which species to be most concerned with when working near dicamba treated fields and provides help with field identification of these injury symptoms.

If you suspect that dicamba drift may have injured your crops, please contact you local county extension agent or Rutgers weed science specialist (Dr. Thierry Besançon) as soon as possible, and take detailed pictures of the observed damages.

 

 

Filed Under: Blueberry, Commercial Ag Updates, Fruit, Organic Production, Tree Fruit, Vegetable Crops, Wine Grape Tagged With: , , , , , ,
May 27, 2020

IPM Update 5/27/20

Sweet Corn

A few European corn borer (ECB) moths have been captured over the past week, though they are too few in number to generate a map image.  While some early corn is now in whorl stage and able to support ECB larvae, adult numbers do not indicate a significant threat as of this week.  We expect numbers to increase over the next 2-3 weeks, and will post maps and management suggestions as this occurs.

The highest nightly trap catches of ECB for the week ending 5/27/20 are as follows:

Asbury   1 Denville   1 Milltown   1
Bellemeade   1 Eldora   1 Springdale   1
Califon  1 Hillsborough   1 Tabernacle   1
Clinton   1 Milford   1

Two corn earworm (CEW) moths were captured this week (Eldora, Cape May County and Port Colden, Warren County) in blacklight traps.  It is possible that these individuals overwintered locally, but in any case, they pose no threat to sweet corn at this time.

SlugThere have been fields of seedling stage sweet corn exhibiting signs of slug injury this past week (streaks on leaves with tissue eaten away, but leaving one layer of epidermal tissue).  Generally the slugs responsible for this injury are a smaller species than the one in the photo at left.   Additionally, corn stem weevils have been discovered this week causing holes in leaves similar to those bill bugs make, but without the linear pattern across the leaf as with bill bug – see photo at right.  The former (slugs) have been found in northern counties on heavier soil for the most part, while the corn stem weevil injury is occurring in Cape May County.  Slug injury Leafgenerally decreases as weather warms and the soil surface dries.  In rare instances of prolonged cool, wet weather, an application of slug bait may be warranted to limit injury to small plants.  In this case, damage should be found on the majority of plants, with slug-favorable weather in the forecast.  Corn stem weevil can sometimes causing severe damage from feeding on leaves and stems of seedlings. Adults are small, 1/8-3/16 inch, brown or black mottled. They hide during daylight beneath plants  or under debris on the soil surface. In recent years, they have been active only in May and June.  Consider an application of a labeled pyrethroid for beetle control in corn if injury is present on 12% or more seedlings.  For insecticide recommendations, see the Sweet Corn section of the 2020 Commercial Vegetable Production Guide.

[Read more…]

Filed Under: Organic Production, Vegetable Crops
May 27, 2020

Vegetable Disease Update – 5/27/20

  • Sand blasting has been reported on a number of leafy green and other crops these past few weeks. Injury from sand blasting predisposes plants to bacterial infections. Remember, all bacteria need a wound or a natural opening, such as a stomata, to gain entry into the plant. Fields with extensive injury need to be scouted regularly, and most likely will need to be sprayed regularly with a copper fungicide or disinfectant-type product to help mitigate infection and spread.
  • For a review on how to avoid sunscald injury on transplanted crops please click here.
  • Bacterial leaf spot has been reported in sweet basil. BLS of sweet basil is a relatively new disease of basil in the US. The bacterium has a large host range and can survive and overwinter in the soil on infested plant debris. Disease development is favored by hot, humid, rainy weather. Periods of hot, dry weather will help mitigate disease development.
  • Club root has been reported in southern New Jersey.
  • Cucurbit powdery mildew season is quickly approaching as more cucurbit crops are planted. For a review of CPM control strategies please click here.
  • Cucurbit downy mildew has been reported as far north as southern Georgia on cucumber and cantaloupe. To track the progress of CDM please visit the CDM forecasting website.
  • With the on and off again rains we have been getting, along with warmer weather this week, all growers should consider applying at-transplanting fungicides for root rot control. Please click here to see this article.
  • Weather conditions have been ideal for fruit rot infections in strawberries. For more information on controlling fruit rots in strawberry please click here.
  • The following is a nice article by Jeanine Davis from NCSU about mixing Serenade with coppers.
  • The 2020/2021 Commercial Vegetable Production Recommendations Guide is available for free online! With many county offices running reduced hours or being closed this is the easiest way to obtain the newest recommendations.
  • For a quick review on managing fungicide resistance development using tank mixes and fungicide rotations, and information on FRAC group 4, FRAC group 7, and FRAC group 3 and FRAC group 11 fungicides please click on hyperlinks.
Filed Under: Organic Production, Vegetable Crops
May 26, 2020

Last “Ask the Ag Agent” Webinar Tonight at 7:00PM

The last springtime Rutgers Cooperative Extension, “Ask the Ag Agent” weekly 1-hour sessions for farmers will take place tonight 5/27/20 at 7:00PM. We realize the season is well underway and most farmers are out in the fields. With the regular sessions ending for now, please reach out to your local County Agricultural Agent at anytime for assistance. We are open for business, and as times have changed we have changed with them.

This last online webinar/call in event will begin promptly at 7:00PM with an open forum to discuss ag-related questions about production, marketing, regulations and any other topics farmers wish to discuss.

Thank you to all who joined each week over the past two months and thank you to the Ag Agents and Extension Specialists who have participated. Bill Bamka, Stephen Komar, Meredith Melendez and Michelle Infante-Casella created and hosted this forum one week after the State of NJ went into lockdown and it has been quite the journey. Please join us for one last session for spring. All are welcome.

To access via WebEx on a computer go to https://go.rutgers.edu/rc9n3kxt

Join by phone
+1-650-429-3300 USA Toll
Access code: 799 743 872 # and then # again to join

Filed Under: Blueberry, Commercial Ag Updates, Cranberry, Field, Forage & Livestock, Food Safety, Fruit, Landscape, Nursery, & Turf, Organic Production, Strawberry, Tree Fruit, Uncategorized, Vegetable Crops, Wine Grape Tagged With:
May 26, 2020

Reminder for Tonight’s On-Farm Direct Marketing, Farmer Panel Webinar

Tonight at 7:00PM – Last Session for the On-Farm Direct Marketing May Webinar series.

Covid directionsFarmer Panel: Tracy Duffield-Duffield’s Farm Market, Dave Specca- Specca’s Pick-Your-Own Farm and Jess Niederer – Chickadee Creek Farm and CSA will discuss what they have changed on their farms due to COVID-19.

Please join us online at https://go.rutgers.edu/k0d59m8h

or

On the phone 1-650-429-3300 with Access code: 226 795 368 # and then # again.

Filed Under: Blueberry, Commercial Ag Updates, Fruit, Organic Production, Strawberry, Tree Fruit, Uncategorized, Vegetable Crops, Wine Grape Tagged With: ,