This fall, I have been getting a lot of questions about mosquitoes and why they are so prevalent this late in the year. There are a few reasons for this. The cooler temperatures we have experienced allows the adults to live a little longer, causing multiple generations of the insect to be present. Their development is also dependent on the temperature with the cycle taking seven to 14 days from egg to adult. This makes our recent temperatures good for quick development of adults. The ideal weather conditions along with the abundance of stagnant water from recent rains have created the perfect storm for the pests.

The way to approach mosquito management is source reduction, that is, remove all stagnant water from bird baths, old tires, wheelbarrows, or anything that holds water for an extended period of time.

Other ways to get rid of mosquito breeding grounds, according to the K-State Research and Extension publication, Pests That Affect Human Health: Mosquitoes and West Nile Virus:

• Eliminate artificial water-holding containers. If that is not possible, empty buckets, cans, bottles, used tires and other containers at least once a week. 
• Fill or drain tree holes, stumps and puddles. 
• Irrigate gardens and lawns carefully to prevent water standing for more than a few days. 
• Check for water trapped in plastic covers on boats and swimming pools. 
• Make sure rain gutters are clean and do not hold water. 

People can also use a wide variety of repellents to lessen the presence of female mosquitoes during the times they’re most active, according to Raymond Cloyd KSE Entomologist. 

Mosquito management can also occur during the early phases of the insect’s life cycle using a larvicide in the form of mosquito dunks or bits.

“You can put mosquito dunks and bits in water to kill mosquitoes in the larval stage,” Cloyd said. They’re completely harmless to pets and fish; all they kill is mosquito larva. So if you have a pond that’s not agitated or a bird bath you don’t want to change, you can throw in these mosquito dunks or bits. They’ll eat it then they’ll die.”

He added: “Dunks and bits are stomach poisons that contain the active ingredient, Bacillus thuringienesis (subspecies kurstaki, or Btk). Btk is a soil-borne bacterium that only kills mosquito larvae. It will manage mosquito larval populations for one to four weeks after application.”

Alicia Boor is the Agriculture and Natural Resources agent with K-State Research and Extension – Cottonwood District. Contact her by email at aboor@ksu.edu or call 620-793-1910.