Removing The Mask Of Phytophthora

Jeff RichPhytophthora is a pathogen that does not discriminate from crop to crop and because of this, it is the number-one disease of nursery crops nationwide. Phytophthora causes millions of dollars in crop loss each year, partly due to being misdiagnosed or unrecognized, though a majority of crop loss is due to the lack of proper management and sanitation practices. For this reason, Phytophthora is known as the “the plant destroyer.”

Phytophthora is a water mold, therefore it thrives in a wet environment and allows the spores to travel and spread more easily. On top of that, the pathogen is good at reproducing. The spores move into the plant and root tissue under water logged conditions, and it is here that the pathogen is released into the plant and starts to reproduce.

Phytophthora is also great at hiding and its spores can lie dormant for long periods of time, making it difficult to know when an outbreak will occur. Phytophthora can survive in water, soil or any media within a growing environment.

There are more than 100 different varieties of Phytophthora and it is sometimes thought of as a fungus because it acts similarly, but the pathogen affects all plants differently. Typical signs of a Phytophthora infestation are yellow-vein chlorosis, suspicious spots or blotches on leaves, wilting brown-yellowing leaves, dropping of leaves, severe root loss, the presence of canker on root, stems and/or leaves and in severe cases, sudden plant mortality in patches. Some of these symptoms are identical to symptoms caused by natural conditions and other diseases, so it is easy to see the complexity of correctly identifying this disease.

One chemical or practice will not keep Phytophthora away, so how can growers take control of this pest? A program that focuses on the plant, the pathogen and the environment needs to be in place. To ensure all factors are covered, I have come up with an easy to follow program.

1. Sanitation

This first part is essential and often gets overlooked. It is critical to sanitize tools, equipment, structures and even people. Sanitation is important, but it should be noted that cleaning beforehand can significantly help decrease outbreaks. Chemicals shown to be effective for this are Peroxycompounds (hydrogen peroxide and peroxyacetic acid), percarbonates, copper and chlorine, though it is important to note some chemistries don’t kill spores and are harmful for the worker and the environment. It is also important for your sanitation chemicals to have minimal or zero REI to ensure no delays in production.

2. Contaminant-Free Growing Media

Growing media is frequently disregarded in nurseries and greenhouses, but since water and soil are the two major vectors in carrying Phytophthora, growing media needs to be addressed. Separation of growing media and cover is highly recommended and if possible, should be sterilized. There are many economical and effective sterilization chemicals that can be beneficial; one such is peroxycompounds. This chemistry has been deemed a viable alternative when compared to the bromide restrictions and limitations.

3. Water Treatment

It is known that water sources are huge breeding grounds for many pathogens including Phytophthora. Irrigation from ponds suffers from more pathogens than wells, but wells should also be treated. The biofilm within irrigation lines can be full of zoospores, which harbor disease. Treatment of the water as a curative to eliminate biofilm is highly effective, and it reduces spore counts. This is recommended at least once a quarter. Treating water with a maintenance program can also decrease the likelihood of infestation. Quarterly water tests are also recommended.

4. Chemical Rotation

Proper chemical rotation and implementation can significantly reduce the risk of disease. It is important to treat in rotation and treat proactively. Leaning on the same chemical can prove to be less effective and increases the chance of mutation and spread. It is also essential to use a contact, as well as a systemic chemistry, to ensure full environmental coverage. Tank mixing systemic chemistries with broad spectrum contact fungicides also increases the spectrum of activity, minimizing disease risk.

Documented data on spraying potassium phosphate in conjunction with peroxycompounds has been shown to be an effective spray program. Peroxycompounds and fluopicolide with potassium phosphate have also been proven to have results in control and prevention of Phytophthora and other greenhouse and nursery pests.

5. Insect Control

Insects and nematodes can be carriers of Phytophthora zoospores. A proper pesticide program includes instituting a tank mix or rotational program with an insect growth regulator. Azadirachtin-based insecticides can be used to suppress larval and nymph stages of insects, but it is important to look for products that have some anti-feedant capabilities to help suppress insects that have some contact with the plants. Not all azadirachtin products are the same. It is not recommended to use products with a glycogen base because over time, that can act as a food source for unwanted pests.

6. Plant Nutrition

Proper plant nutrition is important for a good defense against Phytophthora. It is essential to make sure to get the proper analysis of your fertilizer program and avoid salt-rich nutrient programs. An effective fertilizer program is balanced and ensures each specific crop is getting the correct amount of nutrients. A healthy immune system can help plants fight this battle. It may be time to reevaluate the current nutrition program or least double check that it matches the current crop’s specific needs and soil conditions.

7. Education

Education is essential to a proper program for Phytophthora control. and implementing a concise program is the best place to start. Growers should check and see how many steps they follow and how many they can add. Checking off all is a daunting task, but starting is pertinent to effective pest control.

Topics: ,

Leave a Reply

More From Crop Inputs...
Roots with plant media background XL-W

July 2, 2016

University Of Florida Offering Online Nutrient Management Course In July

Topics include common nutrient problems, essential nutrients, fertilizer types, how to interpret a fertilizer label, managing total nutrient level, pH, and EC, onsite testing, and growing media.

Read More
Eretmocerus eremicus adult, Parasitic Wasp

July 2, 2016

Beneficial Predators Can Help Control Whiteflies On Poinsettia

Whitefly infestations are a reccuring problem that often plagues poinsettia growers. Successfully keep them in check by letting beneficial predators take the work out of pest control.

Read More
University of Georgia Trial Gardens

June 30, 2016

First-Ever Academy Of Crop Production Offers Snapshot Of The Greenhouse Industry’s Future

Hosted by the Georgia Green Industry Association and the University of Georgia Department of Horticulture, the three-day conference covered everything from unmanned aerial vehicles to remote-sensing greenhouse control systems.

Read More
Latest Stories
BASF Orkestra Intrinsic

June 21, 2016

New Mode Of Action From BASF Offers Deeper Disease Cont…

When it comes to disease control, you need all the help you can get. BASF recently hosted growers, Extension personnel, and trade media to present its newest fungicide with two active ingredients, offering dual modes of action.

Read More
Nematodes-feature

June 4, 2016

New Biocontrols Provide Effective Pest Control In Green…

Biological chemistry manufacturers have introduced several new products recently that offer a range of insect and disease management options. Here’s a look at some of them.

Read More
Whitefly

June 2, 2016

Breaking News: Florida Growers Reporting Major Whitefly…

Reports have come from the Florida Keys to Palm Beach County that whitefly populations in landscapes are reaching unprecedented levels and are not responding to pesticide applications. Biotype-Q has been found in four different communities. University of Florida/Institute of Food and Agricultural Science researchers are working with USDA-APHIS, USDA-ARS, the Florida Department of Agriculture, and growers and landscape professionals to manage the developing problem.

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