Prevent The Spread Of Disease In Irrigation Water

American Floral EndowmentPhytophthora and Pythium are water molds that are difficult to control, especially under warm, wet conditions. Thick-walled oospores survive between crops on plant containers, benches, floors, and in potting media or soil.

Spores include lemon-shaped sporangia, thick-walled chlamydospores, and swimming zoospores. The lemon-shaped spores called sporangia form on the surface of roots, crowns, and other plant tissues. Sporangia may be dislodged from infected plants by irrigation water, drainage water, or windblown rain. In water, sporangia release many swimming spores called zoospores, which spread the disease.

Pythium And Phytophthora: Water Mold Cousins

Pythium nibbles the feeding roots of plants, resulting in stunted growth and death. It can be introduced to the greenhouse via plant plugs or other prefinished plant material, or it can hibernate on dirty plant containers, benches, and walkways.

Although Pythium can be a problem on many annuals and perennials, it seems to favor geraniums and poinsettias. Sanitary conditions that favor good plant growth and minimize stress make the plant less vulnerable to attack by a root rot.

Two types of Phytophthora (Phytophthora nicotianae and P. drechsleri) are usually found in floriculture crops and can cause root, crown, and foliar blights. Symptoms include brown-black cankers at the soil line and diseased roots. P. nicotianae can infect snapdragon, fuchsia, verbena, bacopa, vinca, African violet, and dusty miller, while. P. drechsleri may infect poinsettias.

Recirculating Irrigation Water Can Spread Pythium and Phytophthora

Phytophthora spread occurs from zoospores that move through water. Disease occurrence within nurseries and greenhouses often follows drainage patterns, but windblown rain may allow Phytophthora to spread across a nursery. The cycle of plant infection and zoospore production occurs many times within a single growing season. Thus, low levels of infection early in the season may result in a rapid epidemic, if the disease is not immediately controlled.

Many physical and chemical treatment options have been proposed to disinfect contaminated irrigation, including treatment with substances (chlorine, ozone, surfactants, antimicrobial compounds, biological control agents, ultraviolet light, and sedimentation), and physical removal (filtration).

Treatment Methods For Contaminated Irrigation Water

Recycling irrigation water and recirculating nutrient solutions are beneficial, but can also increase the spread of waterborne pathogens. There are several methods currently available for disinfesting contaminated irrigation water, including the use of antimicrobial compounds such as copper and hydrogen peroxide.

Commercial algaecides contain copper sulfate, chelated copper, or sodium carbonate peroxyhydrate as their active ingredients. Previous studies show that increasing copper ion concentrations in nutrient solutions reduces disease caused by some Phytophthora spp.

Without adequate treatment options for irrigation water, water mold pathogens can continue to cause significant crop losses and reduce floriculture crop quality. One effective strategy to prevent crop losses is to limit pathogen numbers in critical transmission routes or points within a production system, such as in irrigation water. Sand filtration has been proposed as an inexpensive treatment to remove the water molds, including Pythium and Phytophthora, from contaminated water, but variable results have been observed. Spores of water molds are negatively charged, and interactions between spores and the sand filter surface are influenced by the physical and chemical properties of the water and sand.

Some greenhouse irrigation systems already have a filtration unit that uses a screen or paper filters to remove large-sized soil particles and plant debris to keep the micro-emitters of irrigation lines clear. These installed filtration units are not likely to be effective to remove water mold spores, which are much smaller in size.

Filtration Research At Michigan State University

A preliminary greenhouse filtration experiment tested sand filtration media containing positively charged, nano-sized iron-oxide particles embedded on the surface. Results showed that Phytophthora zoospores were readily attached to the synthesized, nano-sized, iron-oxide surface coating of filter sand. The removal of motile zoospores was significantly less than that of the encysted zoospores. The results suggest that through controlling parameters of zoospores (e.g., encystment), solution chemistry (e.g., ion type), or filter media type, zoospore removal can be optimized.

Novel filter media are being tested in small-scale filter units in a greenhouse environment with spores of Pythium aphanidermatum. A trial tested poinsettias that were (A) untreated uninoculated or (B) untreated inoculated, and compared them with inoculated plants irrigated with systems containing (C) a sand filter or (D) an activated carbon filter, and inoculated plants irrigated with (E) an unfiltered system with the labeled rate of Terrazole 35WP added to the water or (F) an unfiltered system that had diseased plants.

Zoospores were added to the pre-filter tanks and were passed through the filters and irrigated onto the ebb-and-flow bench tops to initiate the experiment. Plants were irrigated twice daily for 15 minutes to increase disease pressure. Water was sampled from the holding tanks during the course of the study to determine the concentration of zoospores in solution (Table 1, see slideshow).




The trial concluded after two and a half months. The inoculated control displayed severe root rot and stunting (Figure 1, see slideshow). The sand filter, Terrazole treatment, carbon filter, and diseased plant treatment all had significantly higher foliar fresh weight and plant height than the inoculated control treatment. These results suggest filtration may be useful in a greenhouse setting.

Topics: ,

Leave a Reply

One comment on “Prevent The Spread Of Disease In Irrigation Water

More From Crop Inputs...
Triathlon BA container shot

May 24, 2016

OHP’s Triathlon Biofungicide Now Listed By The Organic Materials Review Institute

Triathlon BA is a broad-spectrum preventative biofungicide that provides control of many foliar and soilborne diseases in ornamentals and herbs.

Read More
Pythium On Chrysanthemum

May 20, 2016

How To Prevent Pythium In Fall Garden Mums

Avoid profit loss in fall garden mums due to pythium root rot with good drainage and integrated pest management practices that reduce risk factors.

Read More

May 19, 2016

Agro-K Expands Distribution In New England Through Partnership With Northeast Agricultural Sales

Agro-K, which manufactures conventional and organic foliar plant nutrients, will distribute its full line of foliar fertilizers and soil biological products through NEAG.

Read More
Latest Stories
Triathlon BA container shot

May 24, 2016

OHP’s Triathlon Biofungicide Now Listed By The Organic …

Triathlon BA is a broad-spectrum preventative biofungicide that provides control of many foliar and soilborne diseases in ornamentals and herbs.

Read More
Two-spotted spider mites, adults and eggs

May 11, 2016

SePRO Launches Summer Insecticide Management Program Fo…

The program is designed to help growers use SePRO’s insect management tools to prevent plant damage from a variety of pests.

Read More
Small Aphid Colony on Calibrachoa

May 2, 2016

How To Stop Aphids In The Greenhouse

When untreated, aphids damage ornamental crops and act as vectors for disease. Integrated Pest Management combined with vigilant scouting can help you stay ahead of the problem.

Read More
Cicada (Greg Hoover, Penn State)

April 26, 2016

Cicadas Set To Emerge In Several Eastern States This Sp…

While there’s no immediate cause for alarm, experts say the cicada’s egg-laying process can damage woody ornamentals and make them vulnerable to diseases.

Read More
Parisitic Wasp Aphidius colemani

April 25, 2016

Plant Growth Regulator Use Can Affect Biological Pest C…

The use of plant growth regulators may negatively influence the outcome of biological control programs, according to researchers at North Carolina State University.

Read More
Beneficial Insectary Orius insidiosus

April 22, 2016

Beneficial Insectary Increasing Production Of Three Bio…

The company is now producing Orius insidiosus, Dalotia coriaria, and Dicyphus hesperus at its California facility, reducing the transit time of perishable biocontrols between producer and grower.

Read More

April 21, 2016

Michigan State University Offers Tips On Greenhouse Soi…

Improper pH and higher than adequate nutrient levels are among the many reasons for regular soil testing.

Read More
Parasitized aphid mummies, ladybird beetle larvae

April 18, 2016

4 Things You Need To Know About Implementing Biological…

Biocontrols are useful alternatives to traditional pesticides that provide effective pest control in the greenhouse. Here are four ways to get started successfully.

Read More
John Wendorf Bayer Ornamentals

April 14, 2016

Bayer’s New Ornamentals Business Manager Aims To Help G…

John Wendorf, who previously managed BFG Supply’s grower division, says when Bayer launches into the ornamentals market this November, growers will have access to a wealth of resources, including a dedicated team focused on ornamentals growers.

Read More
Emerald Ash Borer

March 22, 2016

Canada Implements New Voluntary Biosecurity Standard Fo…

The voluntary standard is designed to protect the greenhouse, nursery, and floriculture industries from invasive plant pests.

Read More

March 22, 2016

EPA Approves Syngenta’s Mainspring GNL Insecticide For …

Featuring the active ingredient cyantraniliprole, Mainspring GNL provides broad-spectrum control of key pests, such as thrips, whiteflies, aphids, caterpillars, leafminers, and leaf-feeding beetles.

Read More
Black Root Rot on Vinca

March 15, 2016

How To Identify Different Root Rots In The Greenhouse

Root rots can cause similar symptoms on hosts. Here are some tips for scouting in your greenhouse.

Read More
One symptom of Botrytis blight is gray, fuzzy sporulation on foliage and flowers, similar to that shown on the flower of this hibiscus

March 11, 2016

Manage Botrytis With These Cultural And Fungicide Contr…

High relative humidity and low temperatures in the greenhouse open the way for Botrytis to develop on plants. A mix of cultural and fungicide control options will help you manage this common disease effectively.

Read More
Biocontrols and beneficials absolutely can be used in outdoor production, with the use of banker plant systems

March 8, 2016

France-Based InVivo Acquiring Bioline, Syngenta’s Bioco…

Bioline, a subsidiary of Syngenta, specializes in the production and marketing of biological control agents, and in particular macroorganisms active against insect pests in fruits, vegetables, and flowers.

Read More

March 5, 2016

Prevent The Spread Of Disease In Irrigation Water

Water-mold pathogens cause significant crop losses and reduce floriculture crop quality. Take measures in your greenhouse to prevent the spread of diseases like Phytophthora and Pythium.

Read More
Bayer Greenhouse Ribbon Cutting

March 1, 2016

Bayer Opens New Greenhouse Research Facility In West Sa…

The $12 million facility will feature two new high-tech greenhouses that will be used in the development of new solutions in vegetable seeds and biologicals.

Read More

February 20, 2016

Hydrogel Technology Means Growers And Their Customers C…

Water and nutrient management are critical elements for quality plant production in the greenhouse. Maintaining the right amounts of available moisture and fertilizer at all times can be pretty labor intensive, but there are tools available to help you keep these inputs at optimum levels as efficiently as possible. Recently, we visited Evonik Industries’ North Carolina production plant for to see how one of these products — Stockosorb — is made, how it works, and learn the benefits of incorporating these tools in your own operation. Learn more about Evonik Industries’ Stockosorb hydrogel product on the Stockosorb website.  

Read More

February 17, 2016

Why It’s Important To Stay One Step Ahead Of Thri…

Keep thrips populations in check and avoid pesticide resistance by using spray and drench products known for their effectiveness.

Read More
[gravityform id="35" title="false" description="false"]