Insect & Disease ID And Diagnosis Guide: Discoloration

Insect & Disease ID And Diagnosis Guide: Discoloration

Seeing discoloration on your crops? Take a look at these pictures to see common diseases that can lead to discoloration.

Scouting tip: Consider the history of the crop and your operation’s cultural practices. Have any materials been used on this crop for the first time, or have you recently used a familiar material at a higher rate than usual?

Broad mite feeding causes bronzing on the underside of begonia leaves.

An overdose of a systemic insecticide caused this phytotoxic response in poinsettia leaf tissue.

Brown blotches and leaf drop can signal downy mildew on coleus.

Fringed, purplish-brown to black, 1⁄4-inch spots appear in an established Cercospora leaf spot infestation on pansy. Examine older leaves to find the most characteristic symptoms.

Yellow lines perpendicular to veins may show in hosta leaves infected with HVX.

Blackened veins in this impatiens are not the result of virus infection, but are the response to root uptake of a dilute chlorine bleach solution.

Major element deficiencies of nitrogen and phosphorus may result in reddening or yellowing of portions of geranium leaves.

Tiny, rust-colored flecks and yellowing on geranium leaves beginning at leaf margins are symptomatic of iron or manganese toxicity, resulting from growing at a pH of 5.8 or below on sensitive cultivars.

Faint yellow stippling similar to mite injury signals downy mildew on impatiens — turn leaves over to see white sporulation.

Powdery mildew can cause discolored patches on petals of gerbera.

Lower foliage yellowing on pothos signals the likelihood of Pythium root rot.

Ficus leaves infested with eriophyid mites may discolor and drop from the plant.

Scorched dead areas along the outer edges of poinsettia leaves may indicate excessive levels of sodium or boron at the margin or, in some cases, zinc deficiency.

Pronounced scorching of leaf edges on this mum resulted from an accidental overdose of a slow-release fertilizer.

Yellow mottling is typical of INSV on begonia leaves.

Whitened bracts or stem tissue on poinsettia may result from large Bemisia tabaci–B Biotype whitefly populations feeding on the plants.

Light-colored, serpentine mines through gerbera leaves signal leaf miner feeding. Look for miner frass, pupae, or larvae in the tunnels.

Browning at the base of these New Guinea impatiens leaves is caused by Rhizoctonia attacking tissue in contact with the rooting mix surface.

Feeding by four-lined plant bug can resemble a fungal or bacterial leafspot.

Angular, brown leaf spots on rudbeckia are caused by the fungus Septoria sp.

Leave a Reply

2 comments on “Insect & Disease ID And Diagnosis Guide: Discoloration

More From Crop Inputs...
BASF Orkestra Intrinsic

June 21, 2016

New Mode Of Action From BASF Offers Deeper Disease Control

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 Greenhouses

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 Management Problems

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
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"]