7 Flower Garden Pests Never to Ignore
These Insect Pests Damage Plants in Multiple Ways
By Jamie McIntosh
No one likes to find their flower gardening efforts thwarted by hungry insects intent on making a meal of our prize specimens. However, some insect pests do more than just snack on our plants; they can introduce fungi and other diseases than can sound the death knell for our favorite flowers.
Gardeners everywhere curse the presence of tiny aphids on rose, honeysuckle, and other flowering foliage growth tips in the springtime. The sucking action of these insect pests causes stunted growth and deformed leaves and flowers. However, aphids bring more havoc to the flower garden in the form of plant viruses and black sooty mold fungus.
Start your aphid battle the natural way: Plant sweet alyssum in the flower garden to draw beneficial wasps, include cosmos to attract hungry lacewings, and add penstemon or yarrow to attract ladybugs. Insect soap and a strong blast of water will take care of heavy infestations.
Borers are an insidious pest, destroying your flowering plants from the inside out. The worst borer in the flower garden is the iris borer, which will tunnel through an entire iris rhizome, leaving bacterial rot in its wake. You should be suspicious if you notice sawdust material around the base of your irises or ragged leaf margins.
Discourage borers by removing iris leaves in the fall, which provide a host for borer moth eggs. In the spring, you can apply the systemic pesticide Merit or the nontoxic spray Garden Shield.
Only about an eighth of an inch long, leafhopper insects look innocuous enough. The green insects don’t congregate in large numbers on plants, and hop away when you approach. However, what you won’t notice is the toxin these hungry pests inject every time they insert their mouthparts into the underside of your flower’s foliage. This allows the damage to travel beyond the chewed part of the leaf, showing up as distorted leaf tips and edges. The insects also spread the aster yellows virus.
Blast leafhopper nymphs from plants with a strong jet of water. Spray adults with insect soap, pyrethrin, or Sevin. Keep dandelion and thistle weeds away from the flower garden, as they provide cover for leafhoppers.
Mealybugs don’t draw much attention, as the pests are only 3/16 of an inch long and move very slowly. The honeydew they excrete supports sooty mold growth. When enough sooty mold accumulates on foliage, it can reduce photosynthesis, weakening the plant and making it even more susceptible to garden pests.
If you notice white fuzzy growths on your plants, you may have mealybugs. Dip a cotton swab in rubbing alcohol and touch it to the pests to desiccate and kill them instantly. You can also spray the pests away with water, or apply Malathion or Orthene pesticide sprays.
Like leafhoppers, plant bugs inject a toxin into your plants’ leaves, buds, and shoots as they feed. The result is a plant mottled with brown or black spots and deformed growth. Dahlias, azaleas, daisies, liatris, and asters are just a few of the flowering plants these bugs feast upon. Gardeners should be on the lookout for tarnished plant bugs and four-lined plant bugs, growing up to ¼ inch long.
Plant bugs are fast moving pests, but you can pluck them off and drop them into a bucket of soapy water if you’re an early riser, as the bugs are sluggish in the morning. Otherwise, spray your plants with neem, Sevin, or diazinon.
At first glance, scale insects may not even seem alive. The waxy covering that serves as a protective shield on the bugs makes them resemble lichen or other natural growths on their host plants. The scale insect under this waxy covering is very alive indeed, feeding on garden plants throughout the entire growing season and houseplants throughout the year. Damage appears as stunted growth, leaf drop, yellow spots on leaves, and sooty mold growth that thrives on the scale’s honeydew.
Parasitic wasps love to use scale insects as hosts, and you may see evidence of this as tiny holes piercing the scale’s armor. This same armor makes scale resistant to many pesticides, but dormant oil can suffocate the insects during the winter season.
Upon disturbance, whiteflies flutter about their host plants like an ephemeral cloud, but their damage is formidable. This is another honeydew-secreting pest, encouraging sooty mold while simultaneously leaving plants yellow and stunted after sucking on plant juices. Some whiteflies also carry plant viruses. Whiteflies are the bane of greenhouse growers, who detect their presence with yellow sticky traps.
Take advantage of the small size and weakness of these insects by using a vacuum to remove them from plants. You can also spray them with insect soap, pythrethrins, and malathion
taken from https://www.thespruce.com/flower-garden-pests-
till next time, this is Becky Litterer, Becky's Greenhouse, Dougherty Iowa