Rutgers University | New Jersey Agricultural Experiment Station | Pesticide User Responsibility

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.

June 5, 2019

IPM Update 6/05/19

Sweet Corn

 European corn borer (ECB) moths catches have declined somewhat over the past week.  Overall this flight was very low, and appears to be on the way out.  The majority of moth activity at this time is along the Delaware Bay Shore (see map at left).  Feeding percentages should increase for the next 2 weeks, as eggs that have been deposited hatch.  As of this week, feeding percentages as high as 8-10% were found in whorl corn in Burlington County.  It is likely that feeding has exceeded the 12% threshold in many southern NJ plantings.

ECB Tassel

Sweet corn emerging tassel with ECB droppings.
Photo: Kris Holmstrom

Growers should scout whorl and pre-tassel stage plantings weekly.  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 6/05/19 are as follows:

Allentown   1 Crosswicks   1 Jones Island   1 Pennington   1
Califon   1 Folsom   1 Medford   1 South Branch   1
Centerton   1 Georgetown   1 New Egypt   1 Woodstown   1

[Read more…]

Filed Under: Organic Production, Vegetable Crops
May 31, 2019

Phytophthora blight control in wet weather

Most of New Jersey has been plagued by heavy rains and pop-up thunderstorms these past few days making conditions ideal for pathogens such as Phytophthora blight (P. capsici) on pepper, eggplant, tomato, and cucurbit crops. Now that the temperatures are starting to rise the threat of infection will only begin to increase. Unfortunately, Phytophthora blight can be found on most farms in the southern part of the state. Poor crop rotations with susceptible hosts only make matters worse. The pathogen also has an increasing host range that also includes snap and lima beans, and all other crops, other than a few resistant bell pepper cultivars, lack any resistance to the pathogen.

Control of Phytophthora blight is extremely difficult (even with the use of fungicides) in the extremely wet weather conditions that parts of New Jersey. In the past few years a number of new fungicides, with new active ingredients, have become commercially-available for controlling phytophthora on multiple crops. Mefenoxam or metalaxyl, both once widely-used to effectively control Phytophthora blight has been hit by resistance issues around much of Southern New Jersey the past decade. Growers with a known history of mefenoxam-insensitivity on their farm should use Presidio, Previcur Flex, or Ranman plus a Phosphite fungicide in rotation in their drip application programs. Importantly, if mefenoxam has not been used in particular fields on any crop for a number of years (more than 5+) the fungus may revert back to being mefenoxam-sensitive and control with these products may return. Orondis Gold, mefenoxam, metalaxyl, and the phosphites are the most systemic of the group and should readily be taken up the by plant via application through the drip. Presidio has locally systemic and has translaminar activity and offers protection of the root system via drip. Ranman has protectant-like activity and thus will offer root system protection.

For more information on these fungicides and specific crop uses, please see the 2020/2021 Mid-Atlantic Commercial Fungicide Recommendations Guide.

 

Filed Under: Organic Production, Vegetable Crops Tagged With:
May 31, 2019

Early-season Phytophthora blight control in pepper

Phytophthora blight typically develops in low-lying areas after a heavy rain and can spread quickly throughout the entire field. Fortunately, this spring in New Jersey has been really dry – too dry thus far, but that does not need you don’t need to prepare for potential phytophthora issues down the road. This is particularly important if are in fields with a known history of Phytophthora blight. Although the extended period of dry weather works against Phytophthora development, it can lead to Rhizoctonia root rot issues in newly transplanted plugs.

Cultural Recommendations

In general, planting on a ridge or raised, dome-shaped bed will help provide better soil drainage. In fields with known low-lying or wet areas, avoid transplanting in those areas all together. In fields with a known history of Phytophthora blight, plant ONLY resistant cultivars to help reduce plant losses. If mefenoxam-insensitivity is known to exist in a field/farm, plant only tolerant cultivars. Do not apply mefenoxam or metalaxyl in fields where insensitivity is known to exist.
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Filed Under: Organic Production, Vegetable Crops Tagged With: ,
May 29, 2019

IPM Update 5/29/19

Sweet Corn

 IPM Personnel are still capturing low numbers of European corn borer (ECB) moths, although even these captures are fairly sporadic, and extremely low in the northern counties (see map at left).  Despite this, single digit feeding percentages were found on Middlesex county whorl stage corn on Wednesday of this week.  It is likely that ECB injury has occurred on early plantings in most areas, although it is probably very light.  Early plantings grown under plastic will be at risk first, followed by the first bare ground plantings.   Growers should begin scouting whorl corn for injury.

 

ECB Tassel

Sweet corn emerging tassel with ECB droppings.
Photo: Kris Holmstrom

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 5/29/19 are as follows:

Downer   2 Centerton   1 Hillsborough   1
Medford   2 Elm   1 Jones Island   1
Califon   1 Folsom   1 Oldwick   1

[Read more…]

Filed Under: Organic Production, Vegetable Crops
May 23, 2019

Controlling Septoria Leaf Spot and Bacterial Leaf Blight in Parsley

Septoria leaf spot (SLS) in Parsley can cause significant losses in fields where it has become established. Like other Septoria’s, the leaf spots produced on parsley look much like the leaf spots produced on tomatoes and other crops. Septoria leaf spot overwinters from year to year on infected debris so long crop rotations of 2 or more years are important to help reduce disease pressure. During the season, SLS will spread rapidly with each subsequent rainfall and/or overhead irrigation event. Therefore, early detection and preventative fungicide applications are key to successfully controlling SLS. Unfortunately, very few fungicides are currently labeled making control difficult.

Parsley SLS

Septoria leaf spot of Parsley

Bacterial leaf blight on Parsley

Bacterial leaf blight on Parsley

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Filed Under: Organic Production, Vegetable Crops Tagged With: ,
May 22, 2019

IPM Update 5/22/19

Sweet Corn

Low numbers of European corn borer (ECB) moths continue to be captured in a few traps (see map at left).  Several cold nights may have suppressed the first flight of the season, although declining ECB populations due to transgenic corn may play a part in the low catches.  Early plantings grown under plastic will be at risk first, followed by the first bare ground plantings.   Through the central counties, a few early corn plantings have reached the whorl stage.  Growers should begin scouting whorl corn for injury.  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.

The highest nightly trap catches of ECB for the week ending 5/21/19 are as follows:

Green Creek   2 Crosswicks   1 Pedricktown   1
Beckett   1 Downer   1 Princeton   1
Blairstown   1 New Egypt   1 Woodstown   1

Several corn earworm (CEW) individuals have been captured in blacklight traps this week.  Catches occurred at Port Colden in Warren County, Matawan in Monmouth County and Woodstown in Salem County.  These individuals likely represent a limited overwintered population to our south, and arrived on the southerly breezes that occurred over the weekend and early this week.  There is little threat from these CEW at this time.

[Read more…]

Filed Under: Organic Production, Vegetable Crops