West Nile virus and to-do list

By John Fulton

[June 01, 2013]  West Nile virus has, unfortunately, become a household phrase. With the extremely wet weather we have had this year, being outside is not very pleasant around dusk. The mosquito numbers are very large, and West Nile virus is of particular concern this year. The virus was first isolated in Uganda, Africa. It can harm humans, birds and other animals. It is transmitted by infected mosquitoes, primarily the northern house mosquito. The mosquito becomes infected after biting wild birds that are the primary host of the virus. The mosquito is actually able to transmit the virus after 10-14 days after biting the infected bird.

The mosquito life cycle has four life stages: egg, larvae, pupa and adult. The female mosquito lays eggs on water or moist soil. Most of the larvae hatch after 48 hours, and the larvae and pupae live in the water. The females need a blood meal before they can lay eggs, so only the females bite. They bite every few days during their adult lives, which may last several weeks.

Preventing mosquitoes is a first step. Homeowners can best accomplish this by eliminating standing water. Tires and old containers are obvious places to start. Drill holes in the bottom of recycling containers, clean clogged gutters, don't allow stagnant water in anything such as birdbaths, change landscape slopes to eliminate standing water, and use larvacides in standing water that can't be eliminated. Bt Israeli is the strain that is effective against mosquito larvae -- not the Bt kurstaki variety commonly used on trees and gardens to kill larvae of moths and butterflies. The mosquitoes have already begun hatching, so treatment time is at hand.

Also protect yourself from bites. Mosquitoes can travel up to three miles from their breeding sites. Make sure that screens and doors are tight, use proper outside lighting such as fluorescent lights, stay indoors at dawn and dusk when mosquitoes are most active, wear long-sleeved shirt and long pants when you must go outside, and use insect repellents properly applied.

The Centers for Disease Control is currently recommending DEET, picaridin and oil of lemon eucalyptus (similar to very low DEET concentrations in repelling mosquitoes). Permethrin for clothing treatment is also available at stores selling outdoor sports and camping supplies. Read and follow all label directions. The DEET percentage affects the length of time mosquitoes will be repelled. For example, a 4.75 percent DEET lasts about 1½ hours, and 20 percent lasts about four hours.

To-do list

• Believe it or not, we're at the proper timing for fall garden plantings. That means potatoes, kale and some others. Some of the planting dates overlap this time of year. That basically means plant it, but you can expect harvest to be closer to fall.

• Keep pruning flowering shrubs after they complete their blooming. That will allow for more flower buds next year. The pruning time for evergreens will be coming up the end of June.

• Bagworm spray time will be coming up mid-June. We'll try to fine-tune the date as we get closer. The cool spring has delayed things to this point, but warm weather could catch us back up to the book timing of June 15. The key is to have the eggs all hatched out, but not have the bagworms grow too large.

• Many borers are susceptible to control at this time throughout the state. Roundheaded appletree borer, flatheaded appletree borer, peachtree borer and viburnum borers are all susceptible to control. Products containing imidicloprid (such as Bayer Advanced Tree and Shrub Insect Control) are systemic (move throughout the plant), last for about a year and are generally good on borers from beetles. The caterpillar-type beetles are better controlled with a more traditional insecticide such as permethrin or bifenthrin.

[By JOHN FULTON, University of Illinois Extension]