Column
Rust on Hollyhocks, Mosquitoes, and West Nile and Zika Viruses
By John Fulton

[May 20, 2016]  Rust on Hollyhocks - Hollyhocks are one of the traditional, old-fashioned flowers often grown in our area. This year, they are definitely interesting. Even before the flowers open. Most area hollyhocks are infected with rust. Rust is usually a spring and fall disease problem, when it does occur.

leaves, and the top side of the leaves has some rather striking bright yellow to orange spots develop. Rust can attack all plant parts including leaves, stems, and leaf petioles. The rust disease spends the winter in old plant parts on the ground. Removal of the plant material will help reduce infection possibilities. Increasing air flow and reducing humidity will also help. Control is best accomplished by removing infected leaves at the first sign of the rust (on the bottom of the leaves). Chemical control may needed, and sprays containing sulfur are effective.

Mosquitoes, West Nile Virus, and Zika Virus

West Nile Virus (WNV) has, unfortunately, become a household phrase. Add in a newer virus called Zika, and mosquito control is more important than ever. WNV harms humans, birds, and other animals. It is transmitted by infected mosquitoes, primarily the northern house mosquito for WNR, and most often is from mosquitoes feeding on infected birds. The Zika virus is transmitted from infected people, and the Aedes mosquito is one vector. The Zika virus is deemed to be in light to moderate availability in our area of the country in the July to September period by the Center for Disease Control.

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. B.t. Israeli is the strain that is effective against mosquito larvae – not the B.t. variety commonly used on trees and gardens! Larval stages may be found in standing water, 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. Exposed skin should be sparingly treated with a repellent containing up to 30% DEET (up to 10% for children), and make sure to treat thin clothing as well (since mosquitoes can bite through the thin clothing).

[By JOHN FULTON, COUNTY EXTENSION DIRECTOR SERVING LOGAN, MENARD, AND SANGAMON COUNTIES]