Verticillium wilt has been reported in eggplant this summer. It is a common soil-borne fungal pathogen that once it has infested soil can remain for a very long time. Verticillium wilt is caused by either Verticillium albo-atrium or Verticillium dahlia and has a wide host range (over 200 plant species). Both pathogens can survive (overwinter) as microsclerotia in the soil. Verticillium wilt prefers cooler weather and drier soils and can be more severe in neutral to alkaline soils. Solanaceous weeds such as Nightshade may harbor the pathogen. [Read more…]
May 25, 2024 Andy Wyenandt
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 2024/2025 Mid-Atlantic Commercial Vegetable Production Recommendations Guide.
May 24, 2024 Andy Wyenandt
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…]
July 27, 2023 Andy Wyenandt
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…]
July 27, 2023 Andy Wyenandt
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.
July 3, 2023 Andy Wyenandt
Diagnosing Verticillium Wilt in Eggplant
Verticillium wilt has been reported in eggplant this summer. It is a common soil-borne fungal pathogen that once it has infested soil can remain for a very long time. Verticillium wilt is caused by either Verticillium albo-atrium or Verticillium dahlia and has a wide host range (over 200 plant species). Both pathogens can survive (overwinter) as microsclerotia in the soil. Verticillium wilt prefers cooler weather and drier soils and can be more severe in neutral to alkaline soils. Solanaceous weeds such as Nightshade may harbor the pathogen. [Read more…]
