Andy Wyenandt

This is an archive of Dr. Wyenandt's posts on the Plant and Pest Advisory.

July 2, 2020

Preparing for Pepper Anthracnose in 2020

Pepper Anthracnose

Pepper Anthracnose

In recent years, pepper anthracnose caused by Colletotrichum spp. has become a significant problem on some farms in southern New Jersey.

Unlike in tomato, where symptoms are only present in mature (red) fruit, pepper anthracnose can infect pepper fruit at any growth stage. Currently, there are no commercially-available bell or non-bell peppers with known resistance to anthracnose. [Read more…]

Filed Under: Vegetable Crops Tagged With: ,
July 2, 2020

Diagnosing Verticillium Wilt in Eggplant

Verticillium wilt 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.

Diagnostic symptoms of Verticillium wilt in eggplant.

Diagnostic symptoms of Verticillium wilt in eggplant
Photo by Kris Holmstrom

[Read more…]

Filed Under: Vegetable Crops Tagged With: ,
June 30, 2020

Basil downy mildew confirmed in southern New Jersey – ALERT 6/30/20

Basil downy mildew has been confirmed in field-grown basil and sweet basil being sold in ‘box store’ retail establishments in southern New Jersey. All basil growers are encouraged to scout their fields on a daily basis and begin preventative fungicide programs in BDM-susceptible and DMR varieties.

For more information on controlling BDM in the field-grown basil please click here.

For more information on controlling BDM in the greenhouse please click here.

To track the progress of BDM in the US please click here.

Basil Downy Mildew

Basil downy mildew sporulating on the underside of an infected leaf.

Filed Under: Organic Production, Vegetable Crops Tagged With:
June 26, 2020

Vegetable Disease Update – 6/26/20

  • Cucurbit powdery mildew season is here. For a review of CPM control strategies please click here.
  • Cucurbit downy mildew has been reported on cucumber in western MI and as far north as North Carolina on cucumber. For a review of CDM control please click here. To track the progress of CDM on your phone or PC please visit the CDM forecasting website.
  • No reports of Late blight in region. To track the progress of Late blight in the US please click here.
  • Basil downy mildew (BDM) has been reported in southern New Jersey on BDM susceptible sweet basil. All growers are encouraged to initiate preventative fungicide programs on DMR and non-DMR basil. For control options and to follow the progress of BDM in the US on your phone or PC please click here.
  • Bacterial canker has been reported in fresh-market tomato. For a review of bacterial canker in tomato please see report by Dr. Sally Miller at The Ohio State University by clicking here.
  • Diplodia leaf streak, a fungal disease, was identified in sweet corn this past week. Symptoms include the development of numerous pycnidia which produce conidia within the lesions on infected corn leaves. For nice reviews, please see report by Dr. Kiersten Wise and colleagues from the University of Kentucky and report by Dr. Steve Johnson at the University of Maine.
  • White mold, caused by Stromatina cepivorum, has been reported in garlic. For more information, please see report by Crystal Stewart and Frank Hay from Cornell University.
  • Angular leaf spot has been reported in summer squash. Look for angular lesions delimited by leaf veins and ‘shotholes’ in infected leaves that develop after periods of hot, dry weather.
  • Phytophthora blight has been reported in pepper and cucurbit crops.
  • Rhizoctonia and Pythium root rot have been reported in pepper. For a review of identifying and controlling root rots please click here.
  • Septoria leaf spot and bacterial blight have been reported in parsley.
  • Timber rot, or white mold, has been reported in tomato.
  • White rust and Cercospora have been reported in spinach.
  • 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.
  • 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.
  • With the on and off again heavy rains we have been getting, along with warmer weather, all growers should consider applying at-transplanting fungicides for root rot control. Please click here to see these articles.
  • 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
June 12, 2020

Vegetable Disease Update – 6/12/20

  • Cucurbit powdery mildew season is here. 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 and in South Carolina on cucumber. For a review of CDM control please click here. To track the progress of CDM please visit the CDM forecasting website.
  • No reports of Late blight in region. To track the progress of Late blight in the US please click here.
  • Basil downy mildew has been reported central TN from basil started in the greenhouse and in the field in southern FL to date. None has been reported in the region. To follow the progress of BDM in the US please click here.
  • Angular leaf spot has been reported in summer squash. Look for angular lesions delimited by leaf veins and ‘shotholes’ in infected leaves that develop after periods of hot, dry weather.
  • Phytopthora blight has been reported in squash.
  • Rhizoctonia and Pythium root rot have been reported in pepper. For a review of identifying and controlling root rots please click here.
  • Septoria leaf spot and bacterial blight have been reported in parsley.
  • Bacterial canker and speck have been reported in fresh-market tomato.
  • Timber rot, or white mold, has been reported in tomato.
  • White rust and Cercospora have been reported in spinach.
  • 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.
  • 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.
  • With the on and off again heavy rains we have been getting, along with warmer weather, all growers should consider applying at-transplanting fungicides for root rot control. Please click here to see these articles.
  • 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 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