Mosquitoes Don't Have to Suck

They’re back! That buzzing sound you hear isn’t just in your mind; we have officially reentered mosquito season. As folks who work with and around water, we get a lot of questions about these insects and their control. Here are some facts and tips on how best to control these bloodsuckers!

“Fun” Facts:

  • Mosquito eggs are laid on or around water and both the larva and pupa stage are aquatic. 

  • Mosquitoes can breed in as little as one teaspoon of water.  

  • It can take as little as four days for mosquitoes to complete their life cycle from eggs to adults.

  • Both male and female mosquitoes feed on nectar and pollen as their main food supplies, however female adult mosquitoes will take blood meals in order to get the extra protein needed to lay eggs.  With one blood meal, a female mosquito can lay up to 300 eggs.

Taking a Bite out of Getting Bitten:

  • Mosquitoes cannot bite through clothing so you can reduce the chance of getting bit by wearing long pants and long sleeves.  

  • Clothing treated with the insecticide permethrin will deter mosquitoes (and ticks) from landing and feeding on you.  Make sure to read the directions on how to apply it to your clothing.

  • Protect open skin by wearing insect repellents. When selecting a repellent look for one with DEET, picaridin, Icaridin or oil of lemon eucalyptus. These are registered with the Environmental Protection Agency and the Food and Drug Administration and are effective.

  • Always follow the directions on how to apply a repellent. Put on sunscreen first, then repellent, and never apply repellent under clothing or to pets.

  • Citronella candles, mosquito lamps, and butane-powered repellers have limited effectiveness. The repellent is found in their smoke or vapor so areas where the smoke or vapor does not reach are not protected.  They are best used in small areas over short-term periods, such as camping trips.

Bringing the Fight Home: Effective Ways to Control Mosquitoes in Your Yard.

Because they fly, large scale control of mosquitoes is difficult to achieve. Like many other best practices, control starts in your own backyard:

  • Mosquitoes breed in standing water, so removing standing water around your home will help reduce the number of new mosquitoes there.  

    • Clean gutters and make sure they drain well.

    • Corrugated drain pipe attached to downspouts hold water and are a prime place for mosquitoes to breed. Use a smooth drain pipe or cover the open end of a corrugated drain pipe with a piece of pantyhose secured with a rubber band.

    • Twice a week, check and remove water that may be standing in trash and recycling cans, flower pot saucers, children’s and pet toys, wading pools, tires, tarps or plastic sheeting.

    • Ensure that your rain barrels are properly maintained, and their screens are free of debris and there is no access to the interior of the barrel from the outside.

    • Use goldfish, mosquito fish (Gambusia sp.) or mosquito dunks containing Bacillus thuringiensis israelensis (Bti) in ponds and rain barrels.  

    • Clean and add fresh water every three days to bird baths, pet dishes and pollinator water dishes.

  • Be kind to wildlife. Fish, spiders, beneficial insects, bats, and birds all feed on mosquitoes and provide some natural control.

  • Repair or replace window and door screens that have tears or gaps to prevent insects from coming inside your home.

  • Use fans to keep the air circulating when sitting outside on a porch, deck, or patio.

  • Do NOT use bug “zappers,” mosquito traps, or plants marketed as having mosquito repelling properties. Bug zappers kill beneficial insects and very few mosquitoes since they are on at night when most mosquitoes are not active. Mosquito traps attract more mosquitoes to an area. There are no plants that have been found scientifically to keep mosquitoes away.

Pesticides at Home and In Communities:

As we know, pesticides can be pests for our local waterways. As Stewards, it is always best to be up to date and educated on proper use and methodologies so that we can educate our greater communities.

Recently, Rusty Gowland (Class 4) had the opportunity to do just that. Per Rusty:

“I responded to a group that was seeking a group discount on mosquito spraying services for the summer by linking the poisoning of mosquitoes to the poisoning of the birds and frogs that eat mosquitoes and the fox and snakes that eat the birds and the frogs that eat mosquitoes, etc, etc.  I pointed out that we all have pesticides and herbicides that have accumulated through the food chain and in every single one of our own bodies; and that many of them were deemed safe at the time they were applied (e.g. glyphosate a.k.a. Roundup). 

For the sake of our backyard wildlife and for the uncertain links to nervous system and cancer related human impacts, we should be very careful to offer an “organic diet” in our yards.  It was picked up by many and I didn’t really have to remain in the conversation.  I watched as more and more people suggested that we cut back or eliminate chemicals in our community.”

This is a great approach when dealing with pesticides. Here are some more facts:

  • In Maryland, insecticides registered for use to control adult mosquitoes may include the following active chemical ingredients: naledpiperonyl butoxide, tau-fluvalinate, bifenthrin, and permethrin. (Source: Maryland Department of Agriculture) The latter three of these are in a class of chemicals called pyrethroids. They are broad-spectrum pesticides, meaning they do not target just one type of insect, and may kill or negatively affect bees and other beneficial insects. They are also toxic to fish and other aquatic organisms and should not be applied near a water way.   

  • Area-wide sprays or foggers are only effective temporarily, lasting 1-3 weeks depending on the chemical and the weather conditions. They do not prevent, or protect you from, new adult mosquitoes flying in from surrounding areas after sprays are applied. Repeated spraying of the same chemical can lead to insect resistance to the insecticide.

  • If someone you know is considering having a private company apply an insecticide to control mosquitoes, urge them to ask the company which chemical they are going to use and for a copy of the chemical label. Before spraying they may ask him/her to move children’s toys and pet bowls. They might also require the homeowner to avoid the area until the chemical has dried.  

  • If someone you know is applying insecticide to control mosquitoes around a home, remind him/her of the following guidelines: always follow the directions, wear the correct safety equipment, and follow the re-entry time instructions.  Apply first thing in the morning before bees and other insects become active.

  • There are situations in which local officials will conduct mosquito spraying in communities where there are concerns about the spread of mosquito-borne diseases (e.g. Zika Virus and West Nile Virus).

  • Most of these sprays are done late at night or in the early morning hours in order to reduce the chance of killing non-target insects. However, since these sprays are done from the street they might not reach places where mosquitoes are located, such as behind buildings or under porches.

  • The Maryland Department of Agriculture’s Mosquito Control Program maintains a spraying schedule and a list of products used in their mosquito control products. If you would like your home to be excluded from being sprayed, you must fill out a “Request for Exemption Form” and mail it in to MDA. The form can be found on their website here.

  • Mosquito chemical control can be in the form of spraying insecticides that target the adults, larva, or both. Spraying insecticides should only be considered after non-chemical methods have been tried and proven inadequate.

Article originally compiled by Christa Carignan, Debra Ricigliano, and Mary Kay Malinoski. Reviewed by Emily Zobel and Jon Traunfeld, University of Maryland Extension 4/2018. Adapted for the WSA blog by Josh Clark. Original article and additional resources can be found here:

Latin for Gardeners: May 2019

May’s Native Maryland Plant

Asclepias incarnata

(uh-SKLEE-pee-us in-kar-NAY-tuh)

Common Name: Swamp Milkweed


It’s May and so much is blooming – it’s a great time to be outside! Like some of you, I’m remembering the rains from last May and wondering what this May could hold in terms of weather. My plan is to plant more natives that can tolerate wet areas - this beautiful pink milkweed is one of them. If you have a moist sunny spot, I’d suggest you try swamp milkweed, Asclepias incarnata. I planted mine directly outside my sunporch window allowing me to see the ‘magic’ as it happens.


As Master Gardeners and Watershed Stewards, we know that by planting any Asclepias sp. we’re supporting the lifecycle of the amazing Danaus plexippus, better known as the Monarch butterfly. The monarch caterpillar relies exclusively on milkweed species to develop, without it the life cycle of the butterfly is broken – no more Monarchs. Rosalie Barrow Edge helped save our iconic Bald Eagle from extinction, each of us can help save the iconic Monarch – just by planting milkweed.

To fully appreciate milkweed’s beauty be sure to take a careful look at its complex flower structure.


Visit the to learn more about saving the Monarchs.

Alison Milligan

Mstr. Gardener/Mstr. Naturalist/Mstr. Watershed Steward

Chesapeake Bay Landscape Professional (CBLP)

Stormwater Solutions: April 2019

Watershed Steward Recommendations for Residential Stormwater Runoff Problems

Watershed Steward assessment requests are increasingly listing ‘flooding’, ‘saturated lawns’ or general ‘water issues’ as the problem homeowners would like help solving.  Some of the problems can be daunting and out of our realm of expertise – that’s when our Consortium Members¹ are called in. However, while we’re on site, it’s important that Stewards be prepared with basic information to provide some level of guidance and general best-practice advice to these homeowners.  Many residents are simply interested in just getting the stormwater off their property – we know that’s not the solution, but not everyone may know this. With some education we can help them to slow down, spread out, capture and filter runoff before sending it to our waterways.

The health of the Chesapeake Bay report² was released in January 2019; the Bay was downgraded from a C- to a D+.  Stormwater pollution (containing increased amounts of sediment, nitrogen and phosphorous) was listed as the main contributing factor. This is significant because the health of the Bay had been improving, albeit ever so slightly. Runoff continues to be the one contributor to the degradation of our waterways that is not slowing down – it is increasing.  Plants, specifically native plants, are included in all stormwater best-management practices (bmps) that are recommended by the Watershed Stewards Academy and other stormwater management organizations.

Some basic advice to give homeowners:

Disconnect Downspouts: direct them away from the home onto a vegetated area or rain garden. Use a splash block or fist-sized rocks to spread out the water and to dissipate energy. Do not direct them to impervious areas such as driveways, sidewalk or the street where they go directly into a storm drain without any treatment (cooling, slowing down, filtering).


Capture the Water: Install a rain barrel or cistern to capture the rain.  A 55-gallon rain barrel will capture the first flush of rain which is the most polluted. Drain the barrel to your tall fescue lawn, rain garden, or native plant area; plants prefer rain water that is softer and free of chlorine and other chemicals.  Do not water your vegetable garden with roof runoff.

Install a Rain Garden: Rain gardens can be powerful and attractive solutions. Siting is the most important rain garden consideration. Don’t site: Within 10 feet of a building, over a septic drain field, near the edge of a steep slope, into low spots that don’t drain well.  Seek professional advice for best siting and size.

Plant Groundcovers: On thinly vegetated areas, slopes or under trees, groundcovers can be very effective at preventing erosion and slowing down runoff.


Conservation Landscaping: Reduce your lawn and impervious surfaces; add native plants that are adapted to our local climate. Native plants are low-maintenance, they have deeper roots than lawn and will help prevent erosion, soak up and filter runoff while adding value to your property. Mature trees intercept rainwater which slows it down; much of it stays on the leaves to be transpired.  They also sequester carbon, clean the air, cool the planet and provide much-needed habitat for birds.

Steep Slope: Consider terracing.  Keep each terraced area flat and plant densely. This solution often requires professional advice or an engineered design.

Swale: A swale is a shallow, broad depression in a landscape that follows the contour of the land and can be very effective at capturing and filtering water.   A swale can be created if a natural one doesn’t exist.


Install a Bioretention Basin: Sited underground with the ability to capture large amounts of water these basins are best designed by professionals who will size them and insure they function as designed.

Regulatory Jurisdictions: Be aware of local covenants, right-of-way/easements, critical areas, and grading permit requirements before taking on a serious stormwater runoff or drainage project. Visit the Watershed Stewards Academy site for a list of landscaping professionals familiar with these problems.




Native Plants for Wet Areas

Trees: River Birch (Betula nigra), Atlantic White Cedar, (Chamaecyparis thyoides),

Bald Cypress (Taxodium distichum), Willow Oak (Quercus phellos)

Shrubs: Button Bush (Cephalanthus occidentalis), Winterberry (Ilex verticillata),

Highbush Blueberry (Vaccinium corymbosum), Sweet Pepperbush (Clethra alnifolia)

Herbaceous Plants: Rose Mallow (Hibiscus moscheutos), Turtlehead (Chelone glabra),

Blueflag (Iris versicolor), Marsh Marigold (Caltha palustis), Monkeyflower (Mimulus ringens)


~ Alison Milligan – MG/MN 2013
Master Watershed Steward Class 7