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

Vegetable IPM Update 8/09/23

Sweet Corn

 Fall armyworm (FAW) infestations in whorl stage plantings are increasingly reaching threshold levels, and although they are not found in every field, FAW damage is in all corn growing areas at this time.  In scouted fields, some infestations in whorl corn are in excess of 20%, and are likely much higher in the southern coastal areas.   Growers are advised to check whorl and seedling stage corn plantings weekly for signs of FAW.  Consider treating if infestation rates exceed 10%.  This pest is capable of significant injury to sweet corn plants, resulting in severe stunting and failure to produce viable ears.  Note that growers of Attribute II type genetically engineered corn are unlikely to see damage from FAW.

Infested plantNewly hatched FAW larvae cause holes and scratches on leaves that are similar to European corn borer (ECB) feeding, except that they tend to be more concentrated and always lead down into the whorl  (see photos at left).  As the larvae grow, the feeding becomes more destructive, with large ragged holes and obvious droppings deposited in the whorl (see photo at right)Infested plant

We will provide updates on new FAW appearances and severity as reports come in.  FAW are resistant to synthetic pyrethroids.  Effective sprays should include IRAC grp. 5 (spinosyns) or IRAC grp. 28 (diamides).  The carbamate (IRAC grp. 1A) Lannate is also still effective.  Sufficient water should be used in the applications to allow the solution to penetrate the layer of droppings that may have formed above the caterpillar.

 

European corn borer (ECB) moth activity remains extremely low in areas where blacklight traps are operating in the northern and central counties.  Many plantings exhibiting no ECB injury at all.  We will report on ECB activity should numbers rebound to potentially damaging levels during the second flight.  In recent years, this later flight has not required targeted control in sweet corn.

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Vegetable IPM Update 8/02/23

Sweet Corn

Occurrences of Fall armyworm (FAW) injury are becoming more common, with infestations discovered as far north as Warren County this week.  Some infestations in whorl corn are in excess of 20%.  It is likely that economic infestations are present in much of southern New Jersey now, and could occur anywhere.  Growers are advised to check whorl and seedling stage corn plantings weekly for signs of FAW.  Consider treating if infestation rates exceed 10%.  This pest is capable of significant injury to sweet corn plants, resulting in severe stunting and failure to produce viable ears.

Newly hatched FAW larvae cause holes and scratches on leaves that are similar to European corn borer (ECB) feeding, except that they tend to be more concentrated and always lead down into the whorl  (see photos at left).  As the larvae grow, the feeding becomes more destructive, with large ragged holes and obvious droppings deposited in the whorl (see photo at right)

We will provide updates on new FAW appearances and severity as reports come in.  FAW are resistant to synthetic pyrethroids.  Effective sprays should include IRAC grp. 5 (spinosyns) or IRAC grp. 28 (diamides).  The carbamate (IRAC grp. 1A) Lannate is also still effective.  Sufficient water should be used in the applications to allow the solution to penetrate the layer of droppings that may have formed above the caterpillar.

 

European corn borer (ECB) moth activity remains extremely low in areas where blacklight traps are operating in the northern and central counties.  Many plantings exhibiting no ECB injury at all.  We will report on ECB activity should numbers rebound to potentially damaging levels during the second flight.  In recent years, this later flight has not required targeted control in sweet corn.

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Vegetable IPM Update 7/26/23

Sweet Corn

Fall armyworm (FAW) is increasing in coastal areas, and has been detected at several interior sites as far north as Ocean County. Some infestations in whorl corn are in excess of 20%.  It is very possible that economic infestations are present in much of southern New Jersey now.  Growers are advised to check whorl and seedling stage corn plantings weekly for signs of FAW.  Consider treating if infestation rates exceed 10%.  This pest is capable of significant injury to sweet corn plants, resulting in severe stunting and failure to produce viable ears.

Infected plantInfected plantNewly hatched FAW larvae cause holes and scratches on leaves that are similar to European corn borer (ECB) feeding, except that they tend to be more concentrated and always lead down into the whorl  (see photos at left).  As the larvae grow, the feeding becomes more destructive, with large ragged holes and obvious droppings deposited in the whorl (see photo at right)Infected plant

We will provide updates on new FAW appearances and severity as reports come in.  FAW are resistant to synthetic pyrethroids.  Effective sprays should include IRAC grp. 5 (spinosyns) or IRAC grp. 28 (diamides).  The carbamate (IRAC grp. 1A) Lannate is also still effective.  Sufficient water should be used in the applications to allow the solution to penetrate the layer of droppings that may have formed above the caterpillar.

 

European corn borer (ECB) moth activity remains extremely low in areas where blacklight traps are operating in the northern and central counties.  Many plantings exhibiting no ECB injury at all.  We will report on ECB activity should numbers rebound to potentially damaging levels during the second flight.  In recent years, this later flight has not required targeted control in sweet corn.

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Vegetable IPM Update 7/19/23

Sweet Corn

Fall armyworm (FAW) has begun to appear in coastal areas.  We have low level infestations of this pest in whorl stage sweet corn in Monmouth County, and reports of early populations in Cape May, where FAW was a significant problem last season.  This pest is capable of significant injury to sweet corn plants, resulting in severe stunting and failure to produce viable ears.  Importantly, FAW favors whorl, and even seedling stage sweet corn for egg laying so it is critical that growers check even recently emerged plantings for signs of FAW injury.

Infected plantInfected plantNewly hatched FAW larvae cause holes and scratches on leaves that are similar to European corn borer (ECB) feeding, except that they tend to be more concentrated and always lead down into the whorl  (see photos at left).  As the larvae grow, the feeding becomes more destructive, with large ragged holes and obvious droppings deposited in the whorl (see photo at right)Infected plant

We will provide updates on new FAW appearances and severity as reports come in.  FAW are resistant to synthetic pyrethroids.  Effective sprays should include IRAC grp. 5 (spinosyns) or IRAC grp. 28 (diamides).  The carbamate (IRAC grp. 1A) Lannate is also still effective.  Sufficient water should be used in the applications to allow the solution to penetrate the layer of droppings that may have formed above the caterpillar.

 

European corn borer (ECB) moth activity remains extremely low in areas where blacklight traps are operating in the northern and central counties.  Many plantings exhibiting no ECB injury at all.  We will report on ECB activity should numbers rebound to potentially damaging levels during the second flight.  In recent years, this later flight has not required targeted control in sweet corn.

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What Can Summer Cover Crops Do for Soil Health and Future Crops?

Plants floweringNow that some of our spring planted crops have finished, rather than leaving fields fallow or replanting fields that may have had some issues with plant diseases or insect pests, consider replanting with a summer cover crop. It is not too late to take advantage of summer cover crop benefits. What do summer cover crops do for soil health or future crop improvements? See below:

1. Increase Soil Organic Matter– One of the best attributes of having organic matter in the soil is improvement in soil structure. Adding organic matter improves tilth, water infiltration, water holding capacity, nutrient holding capacity and reduction of soil crusting. Also, as important is the increase in beneficial soil microbes and earthworms. Beneficial microbes can compete with pathogens and help release nutrients. Earthworms can cycle nutrients and improve pore spaces in the soil.
2. Reduce Soil Erosion – Just like with winter cover crops, summer cover crops can also reduce wind and water erosion in fields, especially those with slopes. During summer rainfall events, that can be significant if resulting from tropical storms, runoff may not just include soil loss, but also fertilizer and chemical movement. Therefore, keeping cover on a field during non-production times in any season is an excellent practice.
3. Nitrogen Cycling in the Soil – Nitrogen is often the most limiting nutrient for crop production, since it is so readily lost through nitrification and leaching. Storing nitrogen through plant cycling is an excellent way to improve fertility management. Whether it is a grass or non-leguminous cover crops N is still kept in the mix by the cover crop taking up residual N that wouldPerson holding plant to show root system otherwise be lost. The cover crop plant takes up the nitrogen and after the crop is incorporated it decomposes, thus releasing the N for subsequent crops to use. If legume cover crops are planted, they have the ability to “fix” nitrogen from the atmosphere and through the same decomposition process will provide N for subsequent crops. Be sure to inoculate legume seed just prior to planting with Rhizobium bacteria in order to gain the maximum N fixation benefits.
4. Reduce Weeds – When fields are left fallow after crops are harvested, weed growth can occur. If left to produce seeds, these weeds will multiply in subsequent crops. Therefore, managing the field by planting cover crops between cash crops is a great weed management option. As the cover crop grows, it will suppress the germination and growth of weeds through competition and shading. Some cover crop species can also suppress weeds biochemically, either while they are growing or while they are decomposing, which may prevent the germination or growth of other plants (allelopathy). Research has shown some cover crops like wheat, barley, oats, rye, sorghum, and sudangrass may suppress weeds. In some cases, it has also been reported that residues and leachates from crimson clover, hairy vetch, and other legumes have shown weed suppression.
5. Impacts on Plant Diseases – Cover crop residues could possibly be beneficial when it comes to plant pathogens, or can in some cases increase plant disease organisms. Some cover crop species are in the same plant families as cash crops and may be susceptible to the same disease organisms. Therefore, carrying the pathogen to the next crop. This is why paying attention to crop rotations is so important. In other cases, the cover crop residue can improve soil health in order to produce a better environment for beneficial microbes. By improving soil health, water infiltration, air pore space and other positive attributes, some soil pathogens may not survive as well, as in the case of water molds and water fungi. Some cover crops, like sorghum-sudangrass and sunnhemp, have been reported to reduce nematodes in soils. There are multiple positive factors from cover crops that can combat plant diseases.
6. Impacts on Insects – Like with plant diseases, cover crops can be susceptible to the same insect pests as cash crops. However, they may also attract beneficial insects into an area. Insect pests should be monitored in cover crops, just like in cash crops in order to not let populations get out of control and then move into nearby fields after the cover crop is killed.

For more resources on the us e of cover crops check out these resources: Cover Crops for Sustainable Crop Rotations – SARE

Vegetable IPM Update 7/12/23

Sweet Corn

European corn borer (ECB) moth activity remains extremely low in areas where blacklight traps are operating in the northern and central counties.  Feeding in whorl and pre-tassel stage corn has decreased over the past week.  Many plantings exhibiting no ECB injury at all.    While ECB has become something of a local phenomenon in NJ, growers should not assume that feeding is below economic levels in their area.

emerging tasselsLook 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 small holes in a leafpyrethroids (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 7/12/23 are as follows:

Bellemeade   1 Pennington   1
Hillsborough   1 South Branch   1
Morristown   1

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