Take control of fire ant infestations
Q: How can I kill fire ants without moving the mound from one area to another?
A: Biodiversity of life is incredibly important to a healthy ecosystem, but can we all agree that fire ants should just go? It feels at times like they are our sidewalk jailers: always watchful and paranoid if one step is taken on the lawn.
Unfortunately, the seasonal reprieve is over. Fire ants are waking from their winter slumber and building more mounds. It is also the perfect time to treat them.
Ants and bees are both in the order Hymenoptera, but ants are in the family Formicidae. Red imported fire ants (Solenopsis invicta) were accidentally imported from South America. They are aggressive and can cause a white pustule after a sting. Also, they sting, not bite. Instead of brushing them away, slap down to kill them to reduce more stings.
Texas A&M AgriLife Extension uses a two-step method for a more infested area (five or more mounds in a quarter-acre yard). First, broadcast a bait insecticide in spring or fall. Secondly, treat individual mounds between bait applications. Individual treatments may consist of a chemical or organic application. Liquid drenches are effective within a few hours. There are also organic mound drenches. Pouring 2 to 3 gallons of boiling water on the mound will usually kill around 60 percent of that population if a chemical-free option is preferred. No treatments eliminate all fire ants. Persistence is needed. Be aware: Treatments that control fire ants also affect native ants.
Mistake No. 1: Treating only the visible mounds and/or using home remedies that only focus on one mound at a time.
If you have ever seen fire ant floats that they horrifyingly create with their own bodies in floods, you know these suckers are social creatures. Not all mounds are visible on the surface and many have multiple queens over a given area. Sprinkling one mound will only treat that mound and the ants closer to the surface. Signals are sent causing the remaining colony to pack up and move on down.
Mistake No. 2: Treating at the wrong time of year or too few times.
Fire ants become less active and live deeper in the soil in extreme heat. The best time of year to treat is spring and fall. Foraging ants leave the nest in the morning to search for food. They do not eat solid food themselves but pick up food for the larvae and worker ants that feed the queen. Ideal application temperature falls between 65-95 degrees. Treating in the fall is even better, as populations can be reduced over the winter.
Mistake No. 3: Not following product labels.
Always read the product label and use according to directions. When it comes to insecticides and other chemicals, more is not always best. Tip: Do not pour bait on top of the mound. Place it 2 to 3 feet away to be found more quickly.
For more guidance on fire ant control, visit fireant.tamu.edu.
Brandi Keller
Q: I planted purple oxalis a few years back and it has taken over a flower bed. It is beautiful but aggressive. I have tried several different products to kill it off and nothing has worked. I have even been digging up clusters to remove it, but this hasn’t helped. I would appreciate any expert advice.
A:
Purple oxalis or purple shamrock (Oxalis triangularis) is a rhizomatous herbaceous ornamental plant ideal for shady areas. The foliage resembles a shamrock, and it spreads by an underground rhizome. It blooms in early spring with light pink flowers that may also set seed and cause it to grow outside its original area. It can be successfully controlled through hand weeding when the plants are young. It is difficult to remove all the rhizomes and stolons on established plants. Hand weeding when the soil is moist will make it easier to remove all the underground vegetative portions (roots and rhizomes) of the plant. If the plant is becoming more aggressive and hand weeding isn’t working, you may have to consider a chemical application of either glyphosate, pelargonic acid or ammoniated
soap of fatty acid. Both systemic and contact herbicides will provide effective control, but thorough coverage is needed for the contact herbicides like pelargonic acid or ammoniated soap of fatty acid. Multiple applications of the herbicide may be required.
Paul Winski
Q: How do you get rid of black mold on crepe myrtle?
A:
There are many varieties of crepe myrtle (Lagerstroemia sp.) on the market and in the land
scape today. The sooty mold is a byproduct from either an aphid or crepe myrtle bark scale (CMBS) population that inhabited the tree last season. Control the pest population and the sooty mold disappears. The aphids are pale yellow, pearshaped and often found on the underside of the leaves. Aphids secrete honeydew on which the sooty mold loves to grow. Sooty mold is usually the first thing people notice, but it is evidence that the infestation is well established. CMBS is a newer pest
that is causing many headaches for gardeners and landscapers. The scale insects are white to gray in color and ooze a pink fluid when crushed. The black sooty mold is a result of the honeydew exuded by the scale. Large populations build up in branch crotches and disperse along the branches appearing crusty white to gray.