Houseplant Pests and Diseases

 

  How to Identify and Treat Insects and Diseases of Houseplants

Many of us will be picking up a houseplant for someone on our gift list. And many of us will add to the houseplant collection we already have.  Even though the plants look healthy at the garden center, here are a few things to lookout for before bringing that plant home.
 
1) Healthy looking roots – most nursery and garden centers will allow you to gently slide the root ball from the container.  The roots should extend to the edges and be mostly white and pliable.  If the roots are black, or brittle, put it back.  If the root ball is smelly or very wet, put it back.  The continued dryness can be the cause of the brittle roots, whereas the soggy, smelly soil around slimy roots is an indication that the plant has been over-watered many times.

High Salt Content Turn Roots Brown

High mineral content in the water, most specifically salts, can cause root damage as seen here.  The roots are brown, put this plant down.

2) Spotted leaves – If the leaves have a brown tip, this plant has probably been watered with chlorinated tap water, or fluoridated tap water. Don’t buy this one!

Fluoride Damage

Spot on leaves are very common in houseplants.  Scalds on leaves can be caused by water drops on leaves and the light is magnified to literally burn the leaf at that spot.  The bleaching of the chlorophyll kills the leaf tissue.

Take a good look at potential houseplants before leaving the garden center. Clean, healthy plants will bring a lovely addition to your home.

.3) Spots in Patterns on Leaves

Once home, the houseplants can get infected with diseases and insects. These pattern spots are a sign of disease in the houseplant.  Some are tan, while other spots seem to have a ring or halo.  There is no remedy for bacterial diseases in houseplants. Remove infected portions of the plant.  If the bacteria is in all portions of the plant, discard it.

Virus infections are indicated by spots, mosaic stunting, and crinkled leaves.  Virus infections cannot be cured, but rarely harm the plant.  Isolate the infected plant from others and don’t cross use tools that have been in contact with the sick plant to healthy ones. Wipe with a bleach solution and mild soap.

Powdery Mildew on Ivy

Botrytis Blight, or Grey mold  is fuzzy and feeds on dying plant tissue, usually in a cool, dark area.  It feeds on broken or dying plant material.  Frequent inspection can catch this mold early.  Treatment with a fungicide is required to control gray mold. Plants that are prone to grey mold are English Ivy, Dracaena, African Violet, Lipstick vine, Peperomia, and grape ivy. Since most homes are too dry, rather than too wet, grey mold is more prevalent in the nursery setting.  Inspect all plants before purchasing them.

Molds and mildews may appear on your plant if the temperatures are too cool, and allowing the soil to remain too moist. Insect pests seem to be the most cause of houseplant concerns but actually, watering issues cause much of the demise in houseplants. Use a Neem oil specifically for indoor use to keep molds, mildews and root rot from too much water in check.

Here are a few insects that you may see, and some simple remedies that are safe and effective.

Once home, inspect the plant for insects and give the whole plant a good wash.  Using a hard spray will knock off insects like aphids. A dish washing liquid in solution will also work to wash off your new plant. The dish washing liquid makes the water wetter and will remove dust and dirt as well. 

Aphids

Aphids are probably the most common pest on houseplants.  These soft bodied, pear shaped creatures really suck!  No seriously, they suck the plant juices from the underside of new growth causing deformed, or curled leaves.

Spider Mite Web

Spider Mite Damage

Spider Mites seem to be the second most common pest on houseplants.  I showed a pothos of mine in a previous post that had webbing in the branches and leaves.  Too small for the human eye to see at 1/50 inch, these spider mites feed on leaves and infected leaves look grayish or yellow speckled.
Spider mites are not insects, but are related to spiders!  (amazing!)  Too dry of environment, and dusty conditions will allow these mite to thrive. Here again, that water blast will drive the spider mites off.  Misting the plant frequently, 2 – 3 times a week, will help from re-infestation.  Mites do not like water.

Remove Mealy Bugs with Alcohol Swab

Infestation of Mealy Bugs

Mealy Bugs look like a cotton.  These soft creatures are a major pest concern for houseplants.  They like new growth at the stems connection, and like aphids, they suck plant juices which causes leaves to wilt.

Spray solution of Safer(R) Soap

The swabbing with alcohol is an easy remedy for mealy bugs.  But a spray of Insecticidal soap will also work.

My arsonal 

White Flies

White flies are another pest we see frequently in houseplants.  The shriveled leaves are again, from sucking mouth parts of the white fly. Being smaller than fleas, a female can lay up to 150-300 eggs making the problem even more apparent. Remove molted leaves that look like they have a pattern or pathways on the underside. Spray with an Insecticidal soap weekly until the plant is showing no more signs of white fly. Sticky traps are safe to use in the home, and they also will catch thrips. 

Thrips Damage

Sticky traps

Thrips are not as common on houseplants, but if you take the plants outside during warm weather, thrips can hitchhike indoors on your plants. Adults and larvae will suck plant juices from plant cells and the damaged leaves of  the plant will have a white or silver-flecked section on the leaf and is easily seen with light passing through.

Thrips

Thrips and Their Damage

Thrips can fly and jump when disturbed. Control of thrips is similar to aphids – insecticidal soap, and a soupy water spray will control this pest.

Scale looks like brown spots on stems of plants, but these spots move!  Initially scale is nearly invisible, but as they age they turn darker, and the outer shell is more visible.

Scale

Scale Damage

This sucker (no pun intended) will secrete a sticky substance called honeydew.  The honeydew allows sooty mold to develop.  This is also true of the scale, mealy bugs, and aphids. 

Sooty Mold from Honeydew

Sooty Mold - from Thecitrisguy.blogspot.com

One other pest for the houseplant is the fungus gnat.  Bt Bacillus thuringiensis will attach the larvae in the soil.  This natural bacteria is very effective and can be purchases at the hardware store or garden center. Insecticidal soup will work if the soil is saturated.

Fungus gnat

The amount of light for a specific plant,  it’s watering needs, and ideal temperature are cultural requirements for a healthy houseplant. Humidity, and type of soil also specific for a plant.  A care sheet for a houseplant is usually available at the garden center.  On line sites like Guide to Houseplants  can give a great amount of information. Don't let these pests stop you from enjoying houseplants.  They really require minimal care for a great reward.

What houseplants do you grow?  What problems have you had?  If I can’t answer you questions, I’m sure many of our gardening community will be able to help.  Leave your comments, I love comments. 

Native Coneflowers-Challenges and Remedies

Native Coneflower Stands up to Challenges

Echinacea, Purple Coneflowers, are a heat resistant, drought tolerant native plant that is a staple in my garden. I have divided them around the garden for so many years, that I’m not sure of the cultivars anymore. 

Being a native, this group of plants has overcome threat from insects and diseases.  However, that does not mean that coneflowers don’t have some challenges. 
Insect pests that can affect coneflowers include caterpillars, Japanese beetles, grasshoppers, aphids,  mealy bugs, spittle bugs, and thrips.

Aphids are sucking insects that can weaken the stems.  Usually a firm spray of water from the hose will dislodge them. 

Japanese beetles can chew a blossom to shreds in a very short time.  Hand pick them (I use gloves!) and pinch or drop them into a soapy solution.
Mealy bugs and spittle bugs are easy to spot.
 
The mealy bugs are soft-bodied wingless insects look like fuzzy cotton. They feed by inserting long sucking mouthparts, called stylets, into plants and drawing sap out of the tissue. Damage is minimal when only a few pest are present. However, at higher numbers they can cause leaf yellowing and curling as the plant weakens. Mealy bugs feeding is usually accompanied by honeydew, which makes the plant sticky and encourages the growth of sooty molds.
A strong water spray will dislodge mealy bugs, and is usually all that is needed.  If further control become necessary, spray with a soap/oil mixture if the water alone doesn't do the job. Mix 1 tsp. insecticidal soap, 1/2 tsp. horticultural oil, and 1 quart water in a spray bottle.
 

Spittle bugs suck!  Even though they look icky, the really do not do any harm to the plant. They hide in the bubbly secretions seen on plants.  Control of mealy bugs is using the water spray as well. Spray the underside of leaves where the spittle bugs hide. 
Other pests that attack coneflowers are rabbits and deer.  The young plants are often targets.
 
Some pests are not quite as obvious as the deer or rabbit.  The microscopic Eriophyid mites are such pests.  As these mites feed, the plant produces  tufts of growth on the flowers. 
The mite will over winter in debris or the plant crown, and will infect subsequent years growth.  No controls are called for, but a plant can be removed to prevent spread of the mite. 

Other than insects, Echinacea can get a couple of diseases.  One is stem-rot.  This usually occurs when over-watering occurs, or the planting site does not drain well.  Compost added to the soil will allow water to drain, and will keep the roots of the coneflower from staying too wet. 

The Aster yellows is a disease the is transmitted by insects, particularly leaf hoppers, or poor growing methods.  Aster yellows is a viral-like disease and is caused by a phytoplasma (previously called mycoplasma-like organism) and is spread by aster leafhoppers.The densities of aster leafhoppers, and incidence of the disease, can be strongly influenced by the occurrence of certain host weed species. These weed species include quackgrass, plaintain, chickory, knotweed, pineapple weed, stinkweed, wild asters, lambs quarters, sow thistle, ragweed, Kentucky bluegrass and wild carrot.

  
Plants with Aster yellows have distorted, green flowers, and stunted growth. This one is in my garden, and I’m planning to dig it up and throw it.  Aster yellows is not treatable and spreads quickly. 
Black spot, a fungal disease is seen on coneflowers occasionally.  Black spot usually set up during, cool, moist periods. Powdery mildew can also infect coneflowers.
  For the most part, diseases can be prevented by utilizing proper cultural practices such as variety selections, plant and soil nutrition, irrigation and humidity management,  pruning, and row spacing. Air movement is key to reducing these fungal diseases.  Water only when needed, and avoid wetting the leaves.  Remove debris since the spores from these diseases can linger in the soil. 
Once black spot or mildew are observed, the steps to control them are less effective.  Pre-treat susceptible plants before the fungus are seen.  Mix 1 teaspoon vegetable oil, 1 teaspoon baby shampoo, and 1/3 teaspoon baking soda in 2 cups of water. This solution comes right from the kitchen!
Compost tea as a spray is a good option too.  In a five gallon pail, soak a scoop of compost for up to 24 hours.  Strain and spray. 
Echinacea is a long-lived perennial, and thrives in a sunny location.  Soil can be average to poor.  Plants have a  long taproot, to find moisture deep in the soil.  Hardy to Zone 3-8, coneflowers bloom for long periods during the summer. Many cultivars are being developed to extend the sizes and colors.
    Fancy Frills
Doopleganger

  Razamatazz
Hot Lava
Meringue
Echinacea is a native that has many attributes for the landscape.  Prairies or sunny borders, this plant holds it’s own. I feel the coneflower is definitely a keeper in my garden.
 
Thanks for stopping by today.