Even though much of New Jersey has had wet weather recently, which is more favorable to Pythium and Phytophthora development, Rhizoctonia root rot has been reported over the past few weeks in a number of crops. Rhizoctonia root rot, caused by Rhizoctonia solani, is an important soil-borne fungal pathogen with a very large host range. The pathogen can survive saprophytically on living or dead plant material (organic matter) or as sclerotia in the soil (for more than 3 years). Disease development is favored by warm temperatures, dry (or very well drained) soils and stressed plants. Symptoms of Rhizoctonia root rot may begin as stunted plant growth (with poor root systems) with the appearance of brown lesions at the base of the stem causing wilting with lesions eventually girdling the stem and killing the infected plant. Rhizoctonia root rot infections only extend about an inch above the soil surface (Figure 1), unlike Phytophthora blight infection which can extend much farther up the stem. [Read more…]
Vegetable Crops Edition
Seasonal updates and alerts on insects, diseases, and weeds impacting vegetable crops. New Jersey Commercial Vegetable Production Recommendations updates between annual publication issues are included.
Subscriptions are available via EMAIL and RSS.
Quick Links:
NJ Commercial Vegetable Production Recommendations
Rutgers Weather Forecasting - Meteorological Information important to commercial agriculture.
Controlling Phytophthora blight in eggplant
Phytophthora blight, caused by Phytophthora capsici, can cause crown and fruit rot in eggplant. Unfortunately, most of New Jersey has been plagued by heavy rains and pop-up thunderstorms these past few weeks making conditions ideal for pathogens such as Phytophthora blight on pepper, eggplant, tomato, and cucurbit crops.
Control of Phytophthora blight is extremely difficult (even with the use of fungicides) in the very hot, wet weather conditions that most of New Jersey has been through during the month of July. In the past few years a number of new fungicides, with new active ingredients, have become commercially-available for use on multiple crops. Mefenoxam and metalaxyl, both once widely-used to effectively control Phytophthora blight have been hit by resistance issues around much of Southern New Jersey. Growers with a known history of mefenoxam-insensitivity on their farm should use Presidio or Ranman plus a Phosphite fungicide in rotation in their drip application programs for the control of the crown rot phase of Phytophthora blight. 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. Mefenoxam, metalaxyl, and the phosphite fungicides are the most systemic of the group and should readily be taken up the by plant via application through the drip. Orondis Gold (OXTP + mefenoxam) is also systemic. Presidio is locally systemic, and Ranman has protectant activity and can also be applied via drip.
[Read more…]
Phomopsis fruit rot in eggplant
Phomopsis blight is caused by the fungal pathogen, Phomopsis vexans. It survives between seasons in the soil on infested plant debris. Although the pathogen can infect stems and older leaves, fruit infections are most prominent. Cankers that develop on stems and branches can cause the entire plant to collapse and die. Circular, grayish spots may develop on infected leaves. On fruit, the pathogen causes brownish-black spots that can quickly enlarge causing flat spots that can produce black pycnidia (e.g., fruiting bodies) that produce masses of conidia (spores) which are rain dispersed onto healthy plants and fruit. Phomopsis blight is favored by hot, wet weather (85 – 90 F). Spores germinate in free water on leaves and fruit causing infections. The pathogen can survive on solanaceous weeds such as nightshade, so good weed control is necessary. Crop rotations of 3 to 4 years are recommended. If possible, infected fruit should be harvested and removed from the field to help reduce to inoculum and the spread of the disease. Fields should be scouted on a regular basis, especially fields with a history of Phomopsis blight. Fungicide applications include Quadris Top (difenoconazole + azoxystrobin, 7 +11) or Priaxor (fluxapyroxad + pyraclostrobin, 7 +11) rotated with chlorothalonil every 7 to 10 days. For more information please see the 2022/2023 Mid-Atlantic Commercial Vegetable Production Recommendations Guide.
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.
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.
Agri-Technology and Vegetable Research Twilight Meeting
Where: Rutgers Agricultural Research and Extension Center (RAREC), 121 Northville Rd., Bridgeton, NJ 08302
When: Wednesday August 16, 2023, 5 PM until dark, refreshments and ice cream will be served
This year’s twilight meeting at RAREC will showcase new agricultural technologies for stakeholders in the state. We will showcase the newly installed agrivoltaics system established at RAREC and discuss new technologies for autonomous seeding and weeding as well as drone technologies for improving crop production and decision making.
Agrivoltaics Research at Rutgers – Dan Ward, Director of Rutgers Agricultural Research and Extension Center (RAREC) and the New Jersey Wine Center for Wine Research and Education; and Dave Specca, Rutgers Agrivoltaics Program lead. The demand for clean energy and the development of new technologies for solar electricity generated on producing agricultural land (Agrivoltaics) has driven Rutgers/NJAES to investigate this hybrid technology. We are investigating the effects of putting elevated photovoltaic panels above numerous cropping systems to see what effects the panels have on the crops; and what effects the crops have on the panel’s electrical productivity. Our results will be used in economic models and other recommendations to assist farmers, landowners, and solar developers in deciding whether these combined technologies are a good choice for them.
Presentation and demonstration of Naio OZ autonomous seeding and weeding platforms – Thierry Besançon, Extension Weed Science Specialist for Specialty Crops, Rutgers. The use of small-size electrical autonomous weeders such as the Naio Oz multitask and multi crop robot may help growers to lessen their reliance on fossil fuels for weeding vegetable productions. Using an autonomous weeder can also help alleviating some of the issues with labor availability, especially for burdensome activities such as manual weeding. The GPS guided Naio Oz platform is 100% electric (8 hours autonomy) and versatile through the use a variety of tools (drill, brushes, harrows, hoes blades…) that allow it to weed within and between the crop rows, make furrows, sow, and carry loads to the field. We will present and demonstrate the use of the Naio Oz for autonomous seeding and weeding, and discuss trials currently conducted at RAREC to evaluate weed control efficacy with this system as compared to conventional herbicides.
In-crop cereal cover crop and living mulch trials for vegetables at RAREC – Thierry Besançon, Extension Weed Science Specialist for Specialty Crops, Rutgers. Row-middle weed control in plasticulture vegetable production is becoming increasingly difficult due to a lack of effective herbicides, a need for multiple cultivations, or hand labor. Alternative solutions that integrate multiple weed control tactics are needed to address these issues. One solution is to use cover crops to aid in weed suppression along with an effective herbicide program. A field study is being conducted at RAREC in 2023 to assess the effects of integrating spring-seeded grass cover crops with herbicide treatments for weed control in watermelon. Results from 2023 and from previous studies conducted in 2021 and 2022 show that spring seeded grass cover crops can successfully be integrated with effective herbicide programs for improved weed control between plastic beds.
The potential applications of using drones in agricultural production in New Jersey – Peter Oudemans, Professor and Director P.E. Marucci Center for Blueberry and Cranberry Research and Extension, Rutgers. Drones or UAVs can be used to detect anomalies in agricultural fields to directly determine the impacts of disease, pests, weeds, and soil conditions on crop production. This information can be used to determine economic crop losses, pest management strategies, and provide a wealth of other information that can be used to improve crop production and management decisions by the grower. The potential benefits and drawbacks of using drones in agricultural production will be discussed along with a flight demonstration.
Assessing the production potential of fiber hemp in New Jersey – Raul Cabrera, Extension Specialist in Nursery Production and Management, Rutgers. The recent re-introduction of agricultural/industrial hemp (Cannabis sativa) to New Jersey (2020 season) was initially focused on production of cannabinoid-rich (CBD, CBG) flowers. Saturation of the floral hemp market has abruptly and significantly dropped its economic viability and interest, and focus has shifted to hemp for grain and fiber production. The New Jersey Department of Agriculture funded a pilot program with Rutgers to evaluate the potential of hemp for fiber production, including the viability of agronomic production and potential industrial end uses (bioplastics, textiles, etc.). To this end, three experimental fiber hemp plots are being planted and evaluated at different locations in the state (north, central and south).
Syngenta Product Update – Erin Hitchner, Senior Research and Development Scientist, Syngenta. An update will be given on upcoming product registration and overall pipeline development for new Syngenta active ingredients. An overall description of the pesticide registration process and timelines will also be presented.
Understanding copper resistance development and controlling bacterial leaf spot of bell pepper with resistant varieties – Andy Wyenandt, Extension Specialist in Vegetable Pathology, Rutgers. Over the past three years the pepper and tomato fields throughout New Jersey have been surveyed to determine what species of bacterial leaf spot caused by Xanthomonas spp. are present in the state and if copper resistance is present. Copper based fungicides have been used for decades for the control of bacterial diseases across many different vegetable crops, especially in tomato and pepper. Thus, it is not surprising that ~60% of the bacterial isolates collected throughout the state are resistant to copper fungicides. We will discuss how to control bacterial leaf spot and the benefits of adopting the use of X10R bell pepper varieties to help mitigate losses due to the pathogen.
Controlling Phytophthora blight in cucurbit and other vegetable crops – Andy Wyenandt, Extension Specialist in Vegetable Pathology, Rutgers. Phytophthora blight, caused by Phytophthora capsici, is the most economically damaging vegetable disease in the state. It can cause significant losses in cucurbit, pepper, and tomato crops in any given year. We will discuss the most up-to-date information on how to control P. capsici in cucurbit and other crops using genetic resistance, cultural practice and fungicide chemistry.
Note: Following pesticide credits have been requested: CORE, PP2, 1A and 10
Recognizing Angular Leaf Spot in Cucurbits
Angular leaf spot, caused by the bacterium (Pseudomonas syringae pv. lachrymans), is common in New Jersey and the region. Although it often shows up during cooler, wet weather; it can show up almost anytime during the production season with favorable weather conditions for its development.
Symptoms of angular leaf spot in cucurbit.
Angular leaf spot of pumpkin. Note leaf ‘shot holes’.
Angular leaf spot will first appear in ‘hot spots’ as, small water-soaked lesions which will expand until they reach a larger leaf vein resulting in the angular looking symptoms on leaves. Under heavy disease pressure, the bacteria will infect fruit causing small, water-soaked circular spots. In many cases once weather conditions become dry again, infected tissue in leaves will die and fall out leaving the characteristic ‘shot hole’ symptoms. Control of angular leaf spot begins scouting your fields, particularly in areas that may get shaded and remain wet after heavy rainfalls. Application of labeled rates of fixed copper plus mancozeb to help suppress the spread of the disease until hot, dry weather returns.
