March of the Armyworms
The fall armyworm, Spodoptera frugiperda, eats foliage of many different kinds of plants, such as turfgrass, shrubs, and agricultural crops. Armyworms have been seen in large populations as they march in and feed both day and night, causing circular or irregular deadened patches of turfgrass. Armyworms do not usually kill lawns, especially bermudagrass lawns, but will scalp them; however, St. Augustine lawns are more susceptible, and can be completely lost after armyworms feed.

Armyworms have four life stages: egg, larva, pupa and adult. The eggs are very small, and are laid on leaves at night. The larvae hatch from the eggs and feed mostly at night. They tend to hide in thatch and debris in the daytime. The young larva is white with a black head but develops a prominent white line forming an inverted “Y,” with stripes along the body as it matures. The larva will become 2 inches in length before entering the soil to pupate. Then the adult moth emerges, mates and lay eggs. The adult moth has a wingspan of 1½ inches, with silver-white hindwings and dark gray front wings with light and dark splotches.

The locations of large populations of armyworms vary each year throughout the state. However warm, humid climates, along with large amounts of thatch, provide favorable conditions for fall armyworms to multiply. Armyworms should be controlled when they occur in large numbers, or when plant damage becomes excessive. 

Non-Chemical Control Options
Eliminate thatch to reduce sites for armyworms. If damage is seen but the armyworms are not seen, monitor for infestation in the turfgrass by flushing the area with soapy water. This will cause caterpillars to move around within minutes so they can be spotted.

Chemical Control Options
Armyworms can be controlled using insecticides containing the active ingredients permethrin, cyfluthrin, bifenthrin or esfenvalerate. Spot treatments or whole lawn treatments can be effective, depending on the size of the population.

Argentine Ants Are Not Rasberry Crazy Ants

Argentine ant worker. Photo by Elizabeth “Wizzie” Brown, program specialist, Integrated Pest Management, Texas AgriLife Extension.

Argentine ants seem to be causing alarm for some homeowners. Many people are confusing them with the Rasberry crazy ant (recently in the news), since they form dense foraging trails and often invade homes and other structures. Argentine worker ants are all the same size, about 1/8 inch in length, and are dull brown in color. These ants have multiple queen colonies, allowing workers to move freely between colonies. Populations sometimes appear to be a giant super colony. Argentine ants do not bite or sting, but their colony size can be in the hundreds of thousands.

These ants usually nest in cavities in soil, under rocks, in flowerbeds and in branches or cavities of trees. They eat sweets, fresh fruit, and buds of some plants and tend honeydew-producing insects, such as scales and aphids. These ants travel in distinctive trails along sidewalks, up the sides of buildings, along branches of trees and shrubs, along baseboards, and under edges of carpets.

Non-Chemical Control Options
• Trim tree branches and other plants so they do not touch structures, since Argentine ants can use these branches to get into structures.
• Caulk and seal any cracks or little openings around the structure.
• Do not stack firewood and building materials next to structures, since these ants can build nests in these materials.
• Reduce moisture sources such as leaky plumbing and free-standing water in and around structures.
• Clean window sills to remove dead insects, since these ants will feed on dead insects.
• Check potted plants for ants before bringing the plants indoors by watering to check for ants moving within the soil.

Chemical Control Options
Spot treatments at points of entry into structures such as around windowsills and door thresholds may be effective. The insecticide used for these treatments should be a wettable powder or microencapsulated formulation labeled for this type of application. If colonies cannot be located, bait insecticides can be used. Argentine ants are attracted mostly to sweet baits. Baits containing boric acid, hydramethylnon and sulfluramid are suggested for control.

Large Rainfall Equals High Number of Fire Ant Mounds

Fire ant mound in lawn. Photo by Dr. Bart Drees, professor and Extension entomologist, Texas A&M University.

Due to all of the rain in October, fire ants have been expressing their presence by mounding in many grassy areas. The fire ant colonies were always in these areas, but it took all of the rain to make them move above the soil surface. Since the fire ant is a medically important insect pest, steps should be taken for control. Treating this fall will result in fewer fire ants within the area next spring. 

Both fire ant baits and contact insecticides can be broadcast using a hand-held spreader for small areas or a Herd Seeder mounted onto a truck or ATV for larger areas. 
 
For more information, please visit the fire ant webpage at http://fireant.tamu.edu.

About the author: Kimberly Schofield is a program specialist in the field of urban integrated pest management at the Texas A&M Research Center in Dallas.

Mention of commercial products is for educational purposes only and does not represent endorsement by Texas AgriLife Extension or The Texas A&M University System. Insecticide label registrations are subject to change, and changes may have occurred since this article was written. The pesticide user is always responsible for applying products in accordance with label directions. Always read and carefully follow the instructions on the container label.