Rain brings bug, plant problems

June 21, 2008|By BOB KESSLER

Many parts of our area have had much higher than normal rainfalls this year.

The rain creates challenges for plants and for anyone trying to fend off mosquitoes.

For plants, too much rain saturates the soil and reduces the pore space that oxygen can be in. Without proper oxygen, plant roots will start to die.

This can show as a plant suddenly loses branches or the entire plant suddenly turns brown. Don't look for a disease without first looking around the plant. Is it an area that water might collect and stand for a while during these heavy rains? If so you could have a plant that has lost some or most of its root system. Too much mulch (more than 2 to 3 inches) also can lead to soils staying too wet too long, which can lead to a plant's death.

When a plant dies suddenly and you can't see signs of insect problems or a disease, look at what might be happening to the roots.


When it comes to mosquito production, the very wet spring and the sudden hot and humid temperatures have provided the conditions for an increased mosquito population. Some vicious species of mosquitoes have emerged in great numbers. According to Raymond Eckhart, Franklin County West Nile Program Coordinator, what are "causing the current misery are two particularly nasty human biters known by their Latin names Aedes trivittatus and Aedes sticticus."

These mosquitoes are aggressive biters often attacking in a swarm-like manner. The bite is painful and irritating. They even bite in bright sun. Both are floodwater species, whose eggs hatch when floodwaters rise to the level in the soil where the eggs were laid. Eggs remain viable for many years. Their general larval habitat is intermittent woodland pools and they prefer mammals as hosts. As such, they are less apt to transmit, or amplify the West Nile Virus in the bird population, especially this early in the season.

"In addition to these two species that we notice, we also are seeing a large increase over last year of Culex restuans, the bird-biter species primarily responsible for amplification of the West Nile Virus in the bird population," Eckhart said. "Since their preferred hosts are birds, we don't notice them like we do the ones who prefer mammals as hosts."

The Franklin County West Nile Program and Pennsylvania's Department of Environmental Protection (DEP) have conducted three truck ULV sprays so far this year in the county as of this writing. In addition, seven localized adult treatments also have taken place to manage both the Aedes and the Culex populations. The West Nile Virus has not yet been detected in the mosquito or bird population anywhere in the state.

Eckhart recommended that people eliminate as best as possible any and all standing water on their property, and don't neglect to unclog gutters. In hot weather, a mosquito can go from egg to adult in as little as 4 days, and needs no more than a few inches of water to breed. The Franklin County West Nile Program of Penn State Cooperative Extension is available to answer questions, and can be reached at 263-9226.

Bob Kessler specializes in consumer horticulture and energy for Penn State University. He can be reached weekdays at 717-263-9226 or by e-mail at

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