Pooja Sinha, Ad hoc Assistant Professor, Dept. of Entomology
Minakshi Meshram, Ad hoc Assistant Professor, Dept. of Agricultural Extension
Gulab Das Barman and Devendra Kumar Sahu,Ad hoc Assistant Professor, Dept. of Vegetable Science
Pt.KLS, CHRS, Rajnandgaon, MGUVV

Daisy-like chrysanthemums, Chrysanthemum spp., aka mums, are herbaceous perennials. Most are suited to cultivation in USDA Hardiness Zones 5 to 9.

They prefer full sun, average two to three feet tall, and come in various colors, including green, lavender, pink, purple, red, rust, white, and yellow.

Common Chrysanthemum Pests - The following undesirable insects may visit the chrysanthemums in your outdoor living space to shelter, mate, and feed their young, causing damage in the process.

1. Aphids
Chrysanthemum aphids, Macrosiphoniella sanborni, are sapsucking pests that feed primarily on terminal flower buds and young foliage. Adults are shiny and dark brown, either winged or wingless. Young nymphs are brick red and wingless. The green peach aphid, Myzus persicae, melon/cotton aphid, Aphis gossypii, and root aphids, Pemphigus species, are additional species that may feed upon plants. Aphid colours vary and include black, green, red, white, yellow. Signs of infestation include insects stacked one upon the other, whitish flakes from shed skins, and sticky waste secretions called “honeydew.” There may also be sooty mold, as it grows readily on honeydew. Aphids may not do enough damage to impair blooming, but large infestations can cause leaf anomalies like curling and yellowing, damaged shoots, and stunted growth. Spray affected plants firmly with a hose to dislodge the pests or treat them with an insecticidal soap for the most negligible impact on beneficial pollinators.

2. Beetles
There are numerous types of beetles with feeding habits that damage stems, shoots, roots, leaves, flowers, and buds. The ones most likely to adversely affect chrysanthemums are:
  • Blister beetles, Epicauta spp.
  • Fuller rose beetles, Pantomorus cervinus
  • Rose chafers, Macrodactylus subspinosis
  • Spotted cucumber beetles, Diabrotica undecimpunctata
Beetles have a hard shell and two sets of wings. The first are firm and stationary, and the second afford flight. Wilting and leaves with holes chewed through them may signify the presence of unwanted beetles. Handpicking and dropping beetles into sudsy water, and using traps and lures, are effective eradication methods when started early.

3. Caterpillars
Some of the same caterpillars that wreak havoc on crops may also feed upon chrysanthemums, including:
  • Cabbage loopers, Trichoplusia ni
  • Corn earworms, Heliothis zea
  • European corn borers, Ostrinia nubilalis
  • Cutworms, Noctuidae family
  • Leaf rollers, Tortricidae family

Cabbage looper moths are mottled brown and the larvae are green with white stripes. They make tiny holes in leaf undersides. Corn earworm moths are gray-brown. In the larval stage, they may be black, greenish-brown, maroon, tan, or pink, with dark stripes along their backs and yellow-spotted heads. They are known for leaving lots of “frass” or dark excrement behind when they feed on plant tissue. European corn borer moths are yellowish-brown. The larvae are cream to gray with tiny brown circles along their bodies. Their feeding disfigures buds, flowers, and stems. Adult cutworm moths are brown or black with black, brown, gray, or white markings. Cutworm larvae vary widely and may be black, brown, gray, pink, or tan, glossy or smooth, and spotted or striped. A unique characteristic is that the larvae curl into a “C” shape when disturbed. They chew down new shoots or chew holes in leaves. Adult leafroller moths are dark brown. The larvae are green or brown with black or brown heads. They roll leaves together, join them with silken threads, live inside the cavity, and feed on the foliage. Handpick and drop the pests into sudsy water. Follow up with an application of horticultural neem oil mentioned above.

4. Foliar Nematodes
Foliar nematodes, Aphelenchoides species, are microscopic, worm-like plant parasites. Those most likely to affect chrysanthemums are Aphelenchoides ritzema-bosi. They are hard to detect and impossible to eradicate. Foliar nematodes cause growth anomalies and distinct patches of brown with straight edges along leaf veins. This affected tissue dies and falls away, leaving apparent holes behind. In advanced infestations, the damage extends beyond the foliage, and flowers fail to bloom. Dig up and discard affected plants in the trash.

5. Fungus Gnats
Fungus gnats, Bradysia species, are more likely to affect an overly wet potted plant than one with proper drainage or those growing in the ground. Their larvae are often present in potting soil at the time of purchase. The adults are grayish-black flies, and the larvae are white or transparent with a black head. Fungus gnat larvae feed on roots and may carry pathogens that cause damping off, a disease that causes the sudden death of seedlings. They are merely a nuisance around mature plants with well-developed root systems because the adult flies hover around affected plants. To treat, remove and replace the top inch or two of potting soil, and sprinkle food-grade diatomaceous earth over the top. This natural pesticide is a desiccant and deterrent derived from the skeletons of aquatic organisms. Placing yellow sticky traps near plants is also an effective way to trap adults and eradicate an infestation.

6. Lace Bugs
Chrysanthemum lace bugs, Corythucha marmorata, are sapsucking insects with flattened, elongated, pale yellow to clear bodies They feed voraciously on the undersides of leaves, impairing photosynthesis and leading to foliar decline. Signs of their presence are visible on the upper sides of the leaves in the form of yellowing, and an accumulation of brown excrement and clear skin fragments. Early insecticidal soap or horticultural neem oil treatment may thwart an all-out infestation.

7. Leaf Miners
Leaf miners, chiefly the chrysanthemum leaf miner, Chromatomyia syngenesiae, as well as the American serpentine leaf miner, Liriomyza trifolii, and pea leaf miner, L. huidobrensis, are likely culprits. The adult chrysanthemum leaf miner is a gray to black fly. Its cream-colored larvae burrow through the foliage, leaving unsightly, whitish, winding trails. But with any type of leaf miner infestation, the trails they leave behind are the telltale sign, rather than spotting the pests themselves. Neem oil is an effective treatment. Products containing spinosad, a naturally derived pesticide from soil bacteria, are effective but potentially deadly to bees and other beneficial insects.

8. Mealybugs
Mexican mealybugs, Phenacoccus gossypii, are sapsuckers that feed on plant juices, causing chrysanthemum foliage to be deformed, stunted, and wilted. Honeydew excretions promote sooty mold proliferation. Adult females are oval, gray to white, and wooly looking. Males are tan and winged. Larvae are yellowish. Regular treatments with insecticidal soap help to manage infestations.

9. Midges
The white larvae of chrysanthemum gall midges, Rhopalomyia chrysanthemi (syn. Diarthronomyia chrysamthemi) and D. hypogaea, burrow into the foliage to feed. Their disruption of plant tissue causes cone-like galls, leaf deformities, and stunting. Adult flies are small, like fungus gnats, with reddish to orange-yellow bodies. Remove affected foliage. Pesticides are ineffective.

10. Mites
If mites are a problem, they are likely cyclamen mites, Steneotarsonemus pallidus, and/or two-spotted spider mites, Tetranychus urticae, sapsuckers that feed on plant juices. Cyclamen mites are pinkish-orange spider-like arachnids not visible to the naked eye. They stunt and wither chrysanthemum flowers and foliage. Two-spotted spider mites are nearly-microscopic spiderlike arachnids that present on the undersides of the leaves. They look like rounded, shiny spiders and may be gray, green, or yellow, with two dark spots. Early-season females may be pink or orange. Two-spotted spider mites cause pale dot stippling that merges and causes foliar discoloration. Leaf undersides may be web-covered.

11. Thrips
Thrips are winged sapsuckers that disfigure foliage by feeding on it, causing it to appear stippled, streaked, or silvery. Black excrement is another telltale sign of infestation. Advanced infestations can cause stunted growth. Most nymphs and adults are black, brown, white, or yellow, and some have spots, depending on the species. Those that may pose the greatest threat are chrysanthemum thrips, Thrips nigropilosus, and greenhouse thrips, Heliothrips haemorrhoidalis. A strong spray with the hose, followed by applications of horticultural oil, may be all you need to combat these pests.

12. Other True Bugs
Heteroptera, aka the “true bugs,” is a suborder of insects with specific characteristics, including sucking mouthparts to consume plant or animal tissue, a hardened head underside called a “gula,” and overlapping forewings. They may jump or fly, and their colors vary widely.

13. Whiteflies
Whiteflies are milky-white sapsucking flies that don’t fly long distances but rather rise into the air en masse when startled, like a puff of powder. They hatch on the undersides of leaves, where they begin to feed and leave honeydew behind, rendering plants vulnerable to sooty mold.