Petunias are reliable annuals that bloom from spring until autumn with only minimal maintenance. While petunias tend to be pest-resistant, the plants are occasionally bothered by various insect pests. Weak or neglected petunias are, however, especially prone to insect invasions. To keep petunias healthy, begin by providing adequate water and plenty of bright sunshine.
Slugs are primary pests of petunias and other garden plants, chewing large holes in the leaves during the night and early morning. During the day, slugs hide under plant debris and in other dark, damp areas. It isn’t difficult to know when slugs have been on your plants, as you can see the slimy residue on the leaves and the silvery trails on the ground. Slugs can be picked off by hand or controlled by application of natural or chemical slug baits.
Colonies of spider mites are difficult to see, but the discolored, distorted leaves and the tiny webs are evidence that the mites are present on your petunias. Eventually, the leaves turn yellow and drop off the plant. Spider mites are especially problematic during warm, dry weather in summer and early autumn. Keeping petunias well watered is the best way to prevent spider mites. Pesticides or insecticidal soaps may be needed if infestations are severe.
Thrips are tiny flying insects that survive by punching holes in the leaves, enabling the pests to suck the juice from the cells. You may not see the thrips, but you can recognize the damage by the discolored and damaged foliage. Biological control and use of the thrips’ natural enemies is an effective form of control. Light infestations are sometimes controlled by removing the infested foliage, or by dislodging the pests with a strong stream of water.
Tobacco Budworm Caterpillar
Tobacco budworm caterpillars chew the foliage of petunia plants, quickly destroying flowers and leaves of young plants and seedlings. Although you may never see the caterpillar, proof that it has feasted on petunias includes not only the chewed leaves, but small, black, seedlike droppings the caterpillar leaves behind. Tobacco budworm is sometimes controlled by use of bacterial insecticides such as Bifenthrin or Bacillus thuringiensis.
Daylilies are one of the most pest-free and care-free plants in the perennial garden. Occasionally, though, they may be afflicted by one of several pests that can pose a threat to their appearance, bloom or overall health.
Daylily pests, according to the American Hemerocallis Society, "include insects, mites, molluscs, millipedes and mammals" that feast on the plants or make homes in them. European earwigs, for example, are an insect about 3/4 inch long with pincers on their rear ends that chew holes in leaves and feed on daylily flowers at night.
Slugs may be pests where daylilies are close to hostas.
Aphids are a common insect pest; both adult and larval forms feed on leaves. Spider mites are tiny arachnids that feed on the undersides of leaves. Slugs feed at night on the undersides of leaves, making holes or shredding them. Hemerocallis gall midge, a European pest that has invaded Eastern Canada and the Northeastern U.S., lays eggs that become larvae that feed on leaves.
According to the British Columbia Department of Agriculture, Food and Fisheries, purple coneflower, also known as Echinacea purpurea, is prized for its medicinal properties and is believed to be helpful in fighting against colds, sore throats, toothaches, burns, poison ivy and snakebites. This wildflower grows well in the moist conditions along the banks of rivers and creeks or in a well-tended backyard garden. Although a fairly hardy plant, purple coneflowers are susceptible to a few pests and diseases.
Brown ambrosia, melon and green peach aphids attack purple coneflowers. These tiny pear-shaped insects feed on sap and fluid from the plant’s stems and leaves and then secrete a sugary substance that attracts sooty mold fungus. Aphids multiply quickly and can do extensive damage. Ladybugs are natural aphid predators, but insecticidal soaps are also effective against aphids.
Garden fleahoppers also suck sap from the stems and foliage of the purple coneflower causing bleached or dark-colored coarse spots measuring up to 1/16 inch in diameter. Leaves become distorted, flowers drop, and the plant may die if heavily infested. Garden fleahoppers can produce up to five generations in a single season. However, a single application of pesticide should be adequate for control.
The greenish-yellow aster leafhopper is long, slender and wedge-shaped, measuring about 1/8 inch long and sporting six black spots on its head. Aster leafhoppers spread the viral-like disease aster yellows to purple coneflowers as they suck the sap from the plant during feeding. Leaves will yellow and flowers will be deformed on plants with aster yellows. The disease is not fatal, but the infected plant will never grow and produce as intended. Verbena, salvia and geranium are companion plants to grow with purple coneflowers to prevent aster leafhoppers from infecting the plants.
Sweet Potato Whitefly
Sweet potato or silverleaf whiteflies may also infest purple coneflowers. These tiny white flies can be found on the underside of the leaves and will fly up when the leaves are disturbed. Whiteflies suck sap and nutrients from the plant, weakening the plant and stunting its growth. Like aphids, whiteflies excrete a sweet sticky substance that attracts sooty mold fungus. Neem oil, insecticidal soaps, horticultural oils and whitefly traps are effective means of controlling whiteflies.
In northern gardens, Japanese beetles will eat the foliage of purple coneflowers and disfigure the plants. These metallic green and coppery brown oval insects have a voracious appetite for foliage. Synthetic or chemical pesticides labeled for use against Japanese beetles provide control of these hungry pests.
Chandigarh, July 22: Chaudhary Charan Singh Haryana Agricultural University, Hisar has conducted a survey to take stock of the incidence of various pests on the cotton crops in Hisar, Fatehabad and Sirsa districts.
As per the survey report, the number of the pests affecting the crops adversely is very small. However, the farmers need to be vigilant.
The team comprising Entomologists R K Saini and K K Dahiya conducted a survey in about two dozen villages of districts of Hisar, Fatehabad and Sirsa and found that the number of leaf hopper and white fly was negligible.
The presence of mealy-bug was registered only in 60 per cent fields and its incidence was noticed only on those plants which were grown along the roads or water courses where it was breeding on parthenium popularly known as congress grass and on yellow herbs.
The report saisd as of now, farmers needed not worry about mealy bug, as presence of anacius parasite had also been noticed with the mealy bug. The anacius parasite was destroying mealy bug.
A healthy African violet is easy to recognize. It has well-formed leaves, a strong root system, and frequent blossoms. It is free of rot; mildew; mold; fungus; holes in foliage or in blossoms; and of water-logged stems or leaves. Insect and pest damage is difficult to successfully treat, so prevention is key. This article presents some simple but effective methods to protect an African violet from becoming damaged by insects and/or pests.
- Moderately Easy
things you’ll need:
- African violet
- Watering can with narrow spout
- Absorbent paper towel
- Six feet of horizontal space away from other African violets or houseplants OR Separate room
- Sterilized African violet potting soil
- Use a watering can with a narrow spout.
Keep dry the leaves of your African violet to prevent powdery mildew and crown rot.
If you water your plant from the top, use a watering can with a narrow spout so that it can reach underneath the leaves to water the soil.
If a drop-or more-of water lands on a leaf, touch the edge of an absorbent paper towel to the drop to draw it off of the leaf. Do not return the African violet to its brightly-lit place by a window until the leaf is totally dry, or the leaf can be permanently marked.
- Do not allow the African violet to sit in water collected in the saucer.
Always return to the African violet no later than 30 minutes after watering it and empty the saucer of any excess water so that root rot or crown rot will not develop.
Do not over water. See "How to Water an African Violet" for more information.
- Always isolate a new plant from the others for a good 6 to 8 weeks to see if any damage develops which would indicate the presence of insects or pests.
It’s best to put the new plant in a separate room during this time. If that’s not possible, space the new plant at least six feet away from any others. Be sure that the new African violet is situated optimally for light, warmth and humidity. See "How to Provide Light for an African Violet."
- Immediately wash your hands after tending a new plant.
Thoroughly wash your hands after you have tended the new, isolated plant, to avoid spreading pests to your healthy African violets. Some also cover their clothing before entering the room of the exiled plant so that any mold spores will not transfer to and be carried out of the room by their clothes.
- 1:15 = bleach: water
Routinely wash all saucers, implements, and empty pots; sterilize with a 15 minute soak in a bleach solution (1 part bleach in 15 parts water); and rinse with clean water. A dedicated watering can and other implements should be kept in the separation room.
- When you re-pot or transplant an African violet, use only sterilized African violet potting soil. Never mix in garden soil!
- Doctor Optimara: Diagnosing an African Violet
Each time you water an African violet, inspect the plant for any signs of insect or pest damage. Optimara.com has an excellent online tool for diagnosis and treatment of various African violet illnesses, and the link is included under Resources.
Tips & Warnings
Avoiding insects and pests is much easier than removing an infestation and treating the condition.
Some insects can be removed with a soapy water bath or spray; or by removing individual pests with a cotton-tipped swab saturated with alcohol.
If an African violet is thoroughly infested, you may be able to salvage a leaf for propagation. After removing the leaf, soak it in the bleach solution for 15 minutes before proceeding. See "How to Rejuvenate an African Violet by Repotting."
Do not ignore signs or symptoms of insect and pest infestation. These problems only become worse when treatment is delayed.