plant science

Interveinal Chlorosis

One of the most common plant-problems we see in the lab is interveinal chlorosis. This issue can affect house plants and garden vegetables, to landscape trees and shrubs. We often get inquires about the plant-tissue analysis we offer in the soil testing lab as a means to identify various problems. While this is an extremely useful tool for diagnosing nutrient deficiencies, when we see a plant showing interveinal chlorosis, we usually check the soil test results first.

What is interveinal chlorosis? A good place to start is defining what chlorophyll is. Greek for green leaf, chlorophyll is the pigment in plants that gives them their green color, and traps the light necessary for photosynthesis. Photosynthesis is the process in which plants produce sugar from light energy. The chlorophyll molecule is held together by a central Magnesium ion. Interveinal Chlorosis is a yellowing of the tissue between the veins of a leaf due to the decline of chlorophyll production and activity. A give-away tell of interveinal chlorosis is that the veins generally retain their green color, hence the name, interveinal. When a plant cannot produce chlorophyll it loses its green color and could face stunted growth, fail to produce fruit and flowers, and eventually die.

What causes interveinal chlorosis? The quick version is nutrient deficiency. We already know that Magnesium is a central part in chlorophyll, but there are other essential elements like Iron, Manganese, and Molybdenum that are necessary in many enzyme activities, and a deficiency in one of these nutrients can lead to interveinal chlorosis. In our lab we most commonly see interveinal chlorosis caused by a lack of Iron or Magnesium. When thinking about a nutrient deficiency, it’s important to remember that there are other factors to take into account than just whether the nutrient is present in your growing media. Interveinal Chlorosis brought on by a nutrient deficiency can be caused by a pH imbalance, injured roots or poor root growth, and excessive amounts of other available nutrients in your growing media.

How can you get rid of interveinal chlorosis? We are available in the lab, and in the Home & Garden education center to help you figure out what’s causing your interveinal chlorosis. Once you determine what the cause is, fixing the problem shouldn’t be too difficult. Most of the time it’s a pH issue. If your soil is too alkaline, generally having a pH value of over 6.7, iron becomes more insoluble and less available for absorption. Soil pH can be corrected using a few different approaches, the most common method for acidifying soil is adding Sulfur. Generally, 1 lb Sulfur/100 sq ft will lower pH ~ 1 unit. Nutrient deficiencies can also be remedied using foliar and trunk applications, as well as soil treatments amendments.

More information on diagnosing and remedying interveinal chlorosis can be found through the UConn Home & Garden Education Center and the UConn Soil Nutrient Analysis Lab. Information on foliar fertilization can be found here: http://www.soiltest.uconn.edu/factsheets/FoliarFertilization.pdf. Happy Gardening!

Tomato plant leaf with magnesium deficiency.

 -J.Croze

Originally published by the UConn Home & Garden Education Center

Spring Bedding Plant Meetings

Extension word markLeanne Pundt of UConn Extension hosted two Spring Bedding Plant meetings in February for Connecticut growers. One was held in Vernon and the other in Torrington so that all growers were offered a convenient location.
The Meetings began with a discussion on the greenhouse issues of 2012, including downy mildew on garden impatiens.  Leanne offered tips on how to manage pests on ornamentals, vegetables and herb bedding plants.

Extension Educator Jude Boucher presented a virtual tour of how some Connecticut growers are growing vegetables in the greenhouses, a tour of some of the All America Sweepstakes (AAS) winners and losers at the UConn Department of Plant Science Research Farm plus give us updates on late blight on tomatoes

UConn Plant Science Department Head Rich McAvoy covered updates on plant growth regulators, reviewed the best management practices for Plant Growth Regulators (PGR’S) and gave tips on how to hold plants if sales are delayed.   He also gave some tips on nutritional monitoring using the pour thru method and how to calibrate your injector.
Wade Elmer, Plant Pathologist at the Connecticut Agricultural Experiment Station covered emerging diseases such as downy mildews, powdery mildews, botrytis,  leaf spots, root rots and others plus highlighted what diseases to expect on some of the shade tolerant species growing in 2013. 
Overall, both meetings were well attended and very successful. It should be a very successful year for bedding plants.