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...
steve-larson-bayer

September 23, 2016

Bayer Continues Its Shift Into The Ornamentals Market

The company has announced its 12 distributor partners, and also recently named Steve Larson — formerly with Color Spot Nurseries — as its ornamental specialist.

Read More

September 21, 2016

Floriculture Industry Working To Solve The Whitefly Problem

This summer, the floriculture industry has been faced with a dangerous new development — the detection of the Q-Biotype whitefly (Bemisia tabaci) in outdoor landscapes. It’s the first time that the Q-Biotype has been found in the U.S., outside of a greenhouse or wholesale nursery, since the pest was first detected on an ornamental plant in an Arizona greenhouse in December 2004. This year in Florida, there have been 47 detections of the Q since April, in retail nurseries and residential landscapes in 10 counties in Florida, from Miami-Dade to Duval County, primarily on hibiscus. Other hosts involved are crossandra, eggplant transplants, lantana, ficus, and porter weed. The detections have been in 17 retail nurseries, eight wholesale nurseries, 10 residential landscapes, and two agricultural fields. Other states have reported Q-Biotype detections this year, as well. The discovery of Q-Biotype whitefly in the landscape is troubling for the entire ornamentals industry, […]

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

September 19, 2016

Learn About Biological Controls In The Greenhouse In A New Online Course

Michigan State University Extension (MSU) and Kansas State University Research and Extension are collaborating on a pre-recorded online course on “Biological Control for Greenhouse Growers.”

Read More
Latest Stories
steve-larson-bayer

September 23, 2016

Bayer Continues Its Shift Into The Ornamentals Market

The company has announced its 12 distributor partners, and also recently named Steve Larson — formerly with Color Spot Nurseries — as its ornamental specialist.

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

September 19, 2016

Learn About Biological Controls In The Greenhouse In A …

Michigan State University Extension (MSU) and Kansas State University Research and Extension are collaborating on a pre-recorded online course on “Biological Control for Greenhouse Growers.”

Read More
Bees And Pesticides

August 23, 2016

Studies Offer Conflicting Views On Neonic Effect On Bee…

How much exposure to neonicotinoids do bees need before their health becomes affected? That’s the question two research teams look to answer.

Read More
Chrysanthemum Aphid

August 22, 2016

How To ID And Manage Black Aphids In Chrysanthemums

Growers in Michigan have recently been reporting a higher presence of this pest. Here are some tips on how to control it.

Read More
Cannabis Crop Protection

August 22, 2016

Cannabis Group Stays Focused On Consistent Standards Fo…

The Foundation of Cannabis Unified Standards (FOCUS), is an independent, third-party, not-for-profit organization, is in the process of developing cannabis-specific standards for everything from cultivation and extraction to packaging and retail.

Read More
Leaf Septoria In Cannabis

August 21, 2016

Three Diseases To Watch For In Cannabis Production

The development of root rot, powdery mildew, and leaf septoria can damage cannabis to the point of complete crop loss.

Read More
Greenhouse Whitefly

August 18, 2016

Vestaron Planning For More Research And Development Of …

On the heels of launching Spear-T, its first bioinsecticide, Vestaron has received additional financing that will be used to develop new products with new modes of action.

Read More
BioWorks Mycotrol

August 17, 2016

New Organic Mycoinsecticide From BioWorks Now Registere…

BioWorks’ Mycotrol can be used to manage whitefly, thrips, aphids, and other insects in greenhouses and nurseries.

Read More
Downy mildew lesions on light coleus cultivars feature

August 12, 2016

How You Can Control Downy Mildew In Coleus, Roses, And …

Downy mildew diseases are potentially devastating to ornamental crops and at the very least can cause unsightly damage. Check out the latest research and recommendations for preventing it.

Read More
Jen Browning BASF

August 4, 2016

Horticulturist And Entomologist Jen Browning To Speak A…

Browning will discuss the use of nematodes in managing pests in greenhouses and nurseries.

Read More
Poinsettia, Heavy Whitefly Infestation -Lower Leaves, Insect - Feature

August 3, 2016

Tips For Successful Late-Season Whitefly Control

Managing late-season whiteflies successfully on poinsettia requires preventative measures put in to action early in the production cycle.

Read More
Cannabis Crop Protection

July 28, 2016

Solving The Cannabis Crop Protection Problem

A largely unregulated sector of the industry, state departments of agriculture, biocontrols companies, and other industry pros are dedicated to helping growers make the right pesticide decisions for their operations.

Read More
Aphids On Older Leaves

July 25, 2016

How You Can Stop Aphids By Understanding Their Interact…

Knowing which aphids target which crops and how aphids colonize and move on plants goes a long way toward setting up an effective management plan.

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