Tag: Vegetable

Tomato and Blossom End Rot

Emily Zobel on

By Jerry Brust, IPM Vegetable Specialist, University of Maryland

This is just a reminder with the usual summer weather we have had lately with stretches of very high temperatures and the occasional very heavy down pour we have had over the last few weeks blossom end rot can become a real problem in tomatoes. Sunny days will suck water through a plant quickly and the downpours will disrupt calcium movement through the plant. The key is to try and maintain consistent soil moisture while the fruit is developing. Easier said than done I know, but soil moisture levels need to be monitored as best as they can. When you see something like figure 1, with all the tomatoes on a cluster with blossom end rot you know the soil moisture fluctuated greatly over a fairly long period of time. Applying some foliar calcium sprays may help, but the applications can’t overcome poor soil moisture management.

Cluster of green tomatoes with blossom end rot ( browning at the base).
Fig. 1 All the tomatoes on this one cluster have blossom end rot—indicating poor soil moisture management. Photo By J. Brust. 

Blossom End Rot Common so Far this Season.

Emily Zobel on

Blossom End Rot Common so Far this Season.

By Jerry Brust, UME

This summer has been unusual as it has been about normal for temperatures if not a little cooler, but we have had greatly varying amounts of rainfall over the last month. Some areas have remained dry with storms just missing farms while others have been hit with some heavy rains. This can make watering vegetables challenging to avoid problems such as blossom end rot, which is caused by a calcium deficit in the developing fruit.

Figure 1. Fig 1. Several different vegetables with blossom end rot.

Calcium (Ca) moves to the plant via mass flow, i.e., where dissolved minerals like calcium move to the root in soil water that is flowing towards the roots. As it passes through the plant Ca is deposited in tiny amounts into the fruit. If anything slows or interrupts this stream the tiny amount of Ca needed at that moment is not deposited and the area furthest from the top of the fruit suffers—resulting in blossom end rot (BER). I have seen more BER this year on a large number of different vegetables than I have in the past several years (fig 1).

Figure two shows how precise and constant the Ca flow in a plant has to be to supply just the right amount of Ca at the right time. The large fruit on this particular plant developed before there was a Ca interruption, but the fruit a little younger suffered a Ca interruption, with the smallest (youngest) fruit suffering the greatest Ca interruption. At the time it was taken tissue analysis from this same plant showed that calcium was in the moderate range when the blossom end rot took place, demonstrating the importance of irrigation and water supply to reduce blossom end rot. Not much you can do about no rains or heavy rains, except try to maintain as even a water supply to your vegetables as is possible and remove any fruit from the plant you find that has blossom end rot.

Fig. 2 Older larger fruit received enough Ca, but younger (smaller) fruit did not so they are showing signs of blossom end rot.

 

 

 

 

 

Are your peppers wilting? Are your melons squishy? Check for Phytophthora blight

Emily Zobel on

Written by Neith Little, Urban Agriculture Extension Agent
Reviewed by Dr. Gerald Brust, IPM Vegetable Specialist and Andrew Kness, Agriculture Extension Agent

Phytophthora blight plagues peppers and melons

The hot wet weather this summer has been the perfect conditions for Phytophthora blight of vegetables. I know of at least one urban farm where this vegetable disease has been confirmed by the University of Maryland Plant Diagnostic Lab.

Vegetables in the squash family and the tomato/pepper/eggplant family are particularly prone to infection with Phytophthora blight. This disease is particularly destructive and difficult to manage. 

What symptoms to watch for: Watch for suddenly wilting plants in wet fields or beds, with brown plant stems at the soil surface and soft, rotting fruit. 

Image above: Phytophthora symptoms on pepper plant. Note wilted leaves and brown stem near base of plant. Photo by Don Ferrin, Louisiana State University Agricultural Center, Bugwood.org
Image above: Phytophthora symptoms on pepper plant. Note wilted leaves and brown stem near base of plant. Photo by Don Ferrin, Louisiana State University Agricultural Center, Bugwood.org
Phytophthora symptoms on watermelon. Note soft “water-soaked” circular lesions on fruit, with white fungal-like growth. Photo by Jason Brock, University of Georgia, Bugwood.org
Image above: Phytophthora symptoms on watermelon. Note soft “water-soaked” circular lesions on fruit, with white fungal-like growth. Photo by Jason Brock, University of Georgia, Bugwood.org

How to manage the disease

  1. Confirm your diagnosis: If you suspect you have Phytophthora blight, seek help confirming the diagnosis. 
  2. Protect your healthy beds. Avoid tracking soil from an infected bed into a clean area. Clean harvesting and weeding tools well. 
  3. Promote good drainage. Avoid overwatering, use raised beds where possible. 
  4. Plant disease-resistant varieties. Here is a list of phytophthora-resistant pepper varieties: https://go.umd.edu/peppervarieties 
  5. Remove infected plants. Put them in the trash or bury them far from your growing area. Do not put in compost that will go back onto the farm. 
  6. Rotate crops. In a bed where you have had Phytophthora, avoid cucurbit crops and solanaceous crops for the next three years. 
  7. Chemical management can be used in conjunction with the above practices. Several fungicides are labeled for Phytophthora blight on vegetable crops. Consult the Mid-Atlantic Commercial Vegetable Recommendation Guide for a list of products and application methods. Always read and follow the label prior to any pesticide applications.

Citations and additional reading:

Food Safety Updates for Maryland Farmers – 11/17/2020

Emily Zobel on

Farm Food Safety Plan
If you have not written a food safety plan for your farm, now is a good time to do so. This Friday, November 20th, the Maryland Food Safety Network is presenting a webinar going into the details of writing a plan. Register with Eventbrite here.

All past webinars are recorded and available to watch on the Maryland Food Safety Network Platforms including Plant Science Food Safety Group, UMD Agriculture Law Education Initiative Food Safety page, and UMD Extension Food Safety Webpage.

 

Virtual Basic GAP training classes!

Virtual Basic GAP training will take place over two half day sessions:

  • (pt. I) Thursday December 3rd | (pt. II) Friday December 4th 8:15 am – 12:00 pm
  • (pt. I) Monday February 15th | (pt. II) Tuesday February 16th 8:15 am – 12:00 pm

More information and to Register for the event here.

 

Need FSMA Produce Safety Rule training?
Register for a virtual session of FSMA Produce Safety Rule training to be held on January 19th & 20th, 11:30 am – 5:00 pm. More information and to Register for the event here.

Advanced GAP Classes Coming Up!
The Plant Science Food Safety Group is planning on offering a series of one hour long, advanced GAP topics in February and March 2021. We need to hear from you as to which time of day would be the best. Click on cocktail, lunch, or morning to record your preference.
a. Cocktail hour, 5 – 6 or 6 – 7pm Cocktail
b. I’m sharpest at lunch time, 11 – noon or noon – 1 pm Lunch
c. With my morning oatmeal, 6:30 – 7:30 or 7 – 8 am Morning

We will take your feedback, then set up times, and invite engaging speakers to discuss food safety topics! Stay tuned! Got feedback questions or comments? Contact Carol Allen, 240-994-5043, callen12@umd.edu.