Insect & Disease ID And Diagnosis Guide: Rings, Spots And Dots

Insect & Disease ID And Diagnosis Guide: Rings, Spots And Dots

Seeing rings, spots and dots on your crops? Take a look at these pictures to see common pests and diseases that can lead to rings, spots and dots.

Scouting tip: Consult reference books, Extension literature and notes from grower seminars. Talk with experienced growers, Extension agents and consultants.

Black-rimmed spots on impatiens indicate INSV.

Lupines show leaf spots, drooping of leaves and petiole twisting when infected by an anthracnose fungus.

Irregular brown spots on New Guinea impatiens leaves are caused by the fungus Myrothecium roridum. Look for sporulation on the leaf underside to distinguish from INSV.

White spots with a grainy appearance on poinsettia leaves or bracts indicate powdery mildew.

Round brown spots are a symptom of INSV on cyclamen.

Scattered, 1/8-inch, almost perfectly round spots with a black rim and a paler center are typical for Alternaria leaf spot on impatiens. Yellowing is common.

Scabby spots on sedum leaves indicate powdery mildew. Use a hand lens to confirm.

Whitish haloed spots with a purple rim that buckle out from the leaf, along with lesions along the veins, are signs of poinsettia scab disease.

Tiny, 1/16–to 1/8-inch, round, brown leaf spots and wedge-shaped areas of chlorosis are symptoms of bacterial blight on geraniums caused by Xanthomonas campestris pv. pelargonii.

Pale yellow spots with diffuse margins seen on the top of a poinsettia leaf signal powdery mildew colonies on the leaf undersurface. Use a hand lens to look for fungus strands on the undersurface.

Pale spots on the upper leaf surface of chrysanthemum may signal the presence of chrysanthemum white rust, which is under federal quarantine.

Tiny yellow dotting across part of a geranium leaf is from aphid feeding.

Zonate spots are a symptom of INSV in coleus. Irregular brown markings may also be seen.

Reddish-brown pustules of geranium rust will start as small bumps, and over time will develop concentric sporulation rings.

Round pale spots on the upper surface of a geranium leaf are signs that brown pustules of geranium rust may be found on the undersurface.

A ringspot pattern may show in TSWV-infected zinnia leaves.

Leave a Reply

One comment on “Insect & Disease ID And Diagnosis Guide: Rings, Spots And Dots

More From Crop Inputs...
Bees And Pesticides

August 23, 2016

Studies Offer Conflicting Views On Neonic Effect On Bee Health

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 For Crop Protection

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
Latest Stories
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
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
[gravityform id="35" title="false" description="false"]